AN ABSTRACT OF THE DISSERTATION OF

Robert G. Lee for the degree of Doctor of Philosophy in Geology presented on

September 29, 2008 .

Title: GENESIS OF THE EL SALVADOR PORPHYRY COPPER DEPOSIT, CHILE

AND DISTRIBUTION OF EPITHERMAL ALTERATION AT LASSEN PEAK,

CALIFORNIA.

Abstract approved:

______

John H. Dilles

The El Salvador porphyry copper deposit in the Indio Muerto district of northern

Chile has been geologically investigated for more than 60 years and provides one of the best bases for understanding similar environments of ore formation elsewhere in the world. Fourteen new zircon U/Pb isotopic ages obtained via in situ SHRIMP-RG analysis are here coupled with previous geological studies to allow refinement of the timing of Eocene porphyry magma emplacement responsible for copper and molybdenum mineralization that occurs in several ore bodies within the district. The earliest intrusions are rhyolites that crop out throughout the district, but are more abundant in the north. In contrast, the later granodiorite porphyries were emplaced only in the central and southern parts of the district. Two age periods of mineralization have been documented using zircon U/Pb geochronology. The low grade and small copper deposit at Old Camp in the northern district is associated with a quartz porphyry intrusion that yielded an age of 43.6 ± 0.5 Ma, whereas the main copper molybdenum deposit at Turquoise Gulch is associated with emplacement of the granodioritic L porphyry plug that yielded an age of

42.0 ± 0.5 Ma. The final intrusion is a series of latite porphyry dikes, which post-date ores and yielded a U/Pb zircon age of 41.6 ± 0.5 Ma. Inherited Eocene zircons with ages from ~45 Ma to ~47 Ma are found within younger porphyry intrusions and likely formed via magmatic recycling of older intrusions. Therefore, the zircon U/Pb ages suggest magmatism spanned approximately 5 million years from 47 to 42 Ma, with hydrothermal copper-molybdenum ores dominantly forming during the final stages of porphyry emplacement.

Geochemical analyses by XRF, ICP-MS, electron microprobe and laser-ablation

ICP-MS define a wide range of major, minor and trace element contents for the Eocene porphyry intrusions within the district. The early rhyolite and quartz porphyry intrusions have rare earth contents with strong negative europium anomalies and relatively low Sr/Y and Sm/Yb ratios consistent formation via fractional crystallization of plagioclase-rich mineral assemblages from more mafic parental melts. The granodiorite porphyries have no europium anomalies and a wide range of Sr/Y and Sm/Yb ratios that support an origin via fractional crystallization of garnet, hornblende ± titanite, and minor plagioclase from an andesitic parental melt. The granodiorite intrusions at M Gulch – Copper Hill are ~1 m.y. older and have less evolved trace element ratios than the younger granodiorite intrusions associated with the main mineralization event. The evolving Eocene intrusions are the result of lower to mid crust melts ascending to mix with silica-rich differentiated melts derived from fractional crystallization of older andesitic magmas. Progressive decrease of Eu/Eu* ratios in the zircons with decreasing age gives direct evidence in support of the hypothesis that the main ore mineralization is directly related to the evolution of the upper crustal magma reservoir to progressively more oxidized conditions.

A second goal of this study was to document the mineralogy and zonation of altered wall rock at Lassen National Volcanic Park in northern California, in order to understand the pressure, temperature, fluid composition, and epithermal processes along the southern flank of Lassen Peak. Extensive epithermal wall rock alteration occurs along the southern flank of the Cascadia volcano and includes both active and fossil geothermal systems. Geologic mapping coupled with mineral identification using a portable infrared spectrometer and X-ray diffraction outline several hydrothermal systems within the park. Currently active, steam-heated acid sulfate alteration is characterized by kaolinite, alunite, opal, and cristobalite with accessory iron sulfates.

The active hydrothermal zones are proximal to thermal pools and fumaroles at Sulphur

Works, Pilot Pinnacle, Little Hot Springs Valley, and Bumpass Hell. Three fossil systems occur within andesite lavas and flow breccias of the eroded Pleistocene Brokeoff

Volcano. Intermediate argillic alteration occurs at higher elevations on the flanks of the eroded volcano and is characterized by mixed layer illite-smectite, quartz, pyrite, and albite. Propylitic alteration occurs within the eroded lower elevations of Little Hot

Springs Valley and is characterized by chlorite, calcite, quartz, pyrite, illite, and rare epidote. Also present at a lesser extent is an advance argillic alteration defined by pyrophyllite, dickite, alunite, kaolinite, and quartz formed at Pilot Pinnacle.

©Copyright by Robert G. Lee

September 29, 2008

All Rights Reserved

Genesis of the El Salvador Porphyry Copper Deposit, Chile and Distribution of Epithermal Alteration at Lassen Peak, California

by Robert G. Lee

A DISSERTATION

Submitted to

Oregon State University

in partial fulfillment of the requirements for the degree of

Doctor of Philosophy

Presented September 29, 2008 Commencement June 2009

Doctor of Philosophy dissertation of Robert G. Lee presented September 29, 2008 .

APPROVED:

Major Professor, representing Geology

Chair of the Department of Geosciences

Dean of the Graduate School

I understand that my dissertation will become part of the permanent collection of Oregon State University libraries. My signature below authorizes release of my dissertation to any reader upon request.

Robert G. Lee, Author

ACKNOWLDEGEMENTS

I would like to thank my advisor John H. Dilles for his guidance throughout my tenure at Oregon State University. My committee members Adam J.R. Kent, Frank J.

Tepley III, Anita L. Grunder, and my graduate representative Mary Flahive have been valuable assets during the progression of my research. I am indebted to my co-authors

Richard M. Tosdal, Joe L. Wooden, Frank K. Mazdab, David A. John, and Tanya L.

Abela. Exploraciones Mineras of the Corporacion Nacional del Cobre de Chile provided funding for the zircon geochronology. Analytical and miscellaneous costs were covered by a 2007 Society of Economic Geology (SEG) student research grant and a generous donation by Bill Williams of Freeport McMoRan Copper & Gold, Inc. I would also like to thank Lew Gustafson and Enrique Tidy for providing samples for this study and initiating this project. Walter Orquera of the Exploraciones Mineras at the El Salvador mine provided invaluable assistance in the collection and processing of samples while I was working in Chile along with Ricard Santelices, Christian Rojas, and Eduardo

Gonzalez. The Mineral Resource External Research Program (MRERP) of the US

Geological Survey provided funding for the Lassen Peak project. Patrick Muffler,

George Breit, and Jim Crowley of the USGS all provided valuable assistance during my fieldwork at Lassen Volcanic National Park. My fellow colleagues at Oregon State

University have been a great help during the course of my studies and include Michael

Rowe, Allison Weinsteiger, Mark T. Ford, Barry A. Walker, Denise Giles, Isabelle

Chamberfort, Tony Longo, and Abigail Stephens. Finally I would like to thank my wonderful wife Katie and my two children Robert and Audrey for sticking with me through this long process and their loving support. CONTRIBTUTION OF AUTHORS

Dr. John Dilles assisted with the study design, interpretations of fieldwork, analytical data and provided oversight for all manuscripts presented herein. Dr. Richard M. Tosdal contributed samples and assisted with analytical collection, along with the writing of

Chapter Two. Dr. Joe L. Wooden and Dr. Frank K. Mazdab of the U.S. Geological

Survey provided analytical training and assisted with the analytical work at the Stanford

USGS Micro Analysis Center for zircon trace element analysis. Dr. Frank J. Tepley III provided training and assistance with electron microprobe analysis. Dr. Adam J.R. Kent assisted with collection of trace element data by laser-ablation ICP-MS of mineral separates. Dr. David A. John (USGS-Department of minerals) and Tanya L. Abela provided assistance with fieldwork at Lassen Park, CA and with the writing of Chapter

Four.

TABLE OF CONTENTS

Page

CHAPTER ONE

General introduction to porphyry and epithermal deposits …………. 1

Scope of this study …………………………………………………… 5

The El Salvador porphyry copper deposit, Chile …………………… 6

Zircon geochronology and trace element composition …………….. 11

Previous geochronlogic work at El Salvador ………………………. 12

Geochemical analysis at El Salvador ………………………………. 13

Lassen Volcanic National Park, California ……………….………… 14

CHAPTER TWO

TRACE ELEMENTS AND U/PB AGES OF ZIRCON FROM GRANODIORITE PORPHYRY: TEMPORAL, THERMAL, AND GEOCHEMICAL EVOLUTION OF PORPHYRY COPPER MAGMAS AT EL SALVADOR, CHILE ……………………………………………… 16

Abstract …………………………………………………………….. 17

Introduction ………………………………………………………… 18

Tectonic setting of the Andean precordillera, northern Chile ……… 22

Porphyry intrusions of the Indio Muerto district …………………… 24

Methods ……………………………………………………………. 30

El Salvador porphyry samples ……………………………... 30

Zircon separation procedure ……………………………….. 32

SHRIMP-RG analyses ……………………………………... 34

TABLE OF CONTENTS (Continued) Page

Results ……………………………………………………………… 41

Zircon U/Pb data …………………………………………… 41

Zircon U/Pb age calculations….……………………………. 42

Trace element geochemistry of zircons ……………………. 49

Thermal history of granodiorite porphyries and latite dikes ………. 57

Zircon saturation …………………………………………… 57

Titanium in zircon …………………………………………. 60

Discussion …………………………………………………………. 65

Geologic evolution of the El Salvador magmatic system … 65

Cerro Pelado – Old Camp …………………………………. 68

M Gulch – Copper Hill ……………………………………. 69

Turquoise Gulch porphyry Cu mineralization …………….. 72

Magma recycling and porphyry formation ………………………... 72

Model for the Cu-Mo ore formation of the El Salvador deposit .….. 75

Conclusions ………………………………………………………... 79

Acknowledgements ………………………………………………... 81

References ………………………………………………………….. 81

CHAPTER THREE

THE GEOCHEMISTRY OF PORPHYRY INTRUSIONS FROM THE INDIO MUERTO DISTRICT, EL SALVADOR, CHILE: INSIGHTS INTO MAGMATIC PROCESSES THAT PRODUCE PORPHYRY COPPER DEPOSITS………………………………………..……………… 87

Abstract …………………………………………………………….. 88

TABLE OF CONTENTS (Continued) Page

Introduction ………………………………………………………… 90

Geologic setting ……………………………………………………. 93

Porphyry intrusions ………………………………………………… 96

Quartz rhyolite porphyry …………………………………… 96

Quartz porphyry and late quartz porphyry …………………. 96

X porphyry …………………………………………………. 97

K porphyry …………………………………………………. 98

L porphyry and associated A & R porphyries ……………... 98

Latite porphyry dike ………………………………………... 100

Methods ………………………………………………………….…. 100

Sample preparation …………………………………..……... 100

Whole rock chemical analysis ……………………..……...… 101

Electron microprobe ………………………………………... 102

Quadrupole LA-ICP-MS ………………..………………..… 103

Whole rock geochemistry ……………………..…………………….. 104

Major elements …………………….………………………… 104

Trace elements ………………………………………………. 105

Mineral composition ………………………………………………… 112

Amphibole …………………………………………………… 112

Apatite ……………………………………………………….. 121

Biotite ………………………………………………………... 125

TABLE OF CONTENTS (Continued) Page

Plagioclase …………………………..……………………… 132

Titanite …………………………..………………………….. 138

Discussion ………………………………..……………………….… 142

Amphibole geothermobarometry ...…………………………. 142

Trace element mass balance ..………………………………. 150

Geochemical modeling ……………………………………... 152

Plagioclase-melt equilibrium ……………………………….. 159

Formation of porphyries and copper mineralization ……………….. 163

Acknowledgements …………………………………………..…….. 169

References ……………………………………………………..….... 170

CHAPTER FOUR

THE HYDROTHERMAL ALTERATION ASSEMBLAGES AROUND ACTIVE GEOTHERMAL SYSTEMS IN LASSEN VOLCANIC NATIONAL PARK, NORTHERN CALIFORNIA ……………………….. 178

Abstract …………………………………………………………….. 179

Introduction …………………………………………………………. 181

Geological and volcanological setting ……………………………… 184

Geology of Brokeoff Volcano ………………………………. 186

Methods and analytical techniques ……………………………….... 189

Hydrothermal alteration mineralogy ……………………………….. 194

Bumpass Hell …………………………………………….… 195

Little Hot Springs Valley …………………………………... 201

TABLE OF CONTENTS (Continued) Page

Pilot Pinnacle ……………………………………………..… 205

Sulphur Works …………………………………………..….. 206

Structural Features ………………. ………………………………… 207

Landslides ……………………………………………………….….. 207

Geochemistry ……………………………………………………..… 208

Hydrogen isotopes ……………………………………….…. 210

Discussion …………………………………………………….….…. 210

Conclusions ……………………………………………………….… 216

Acknowledgements ……………………………………………….… 218

References ……………………………………………………….….. 218

CHAPTER FIVE

Conclusions ……………………………………………………….… 221

Bibliography ………………………………………………………………... 226

Appendices ………………………………………………………………..… 241

Appendix A: El Salvador samples ..……………………………….… 241

Appendix B: SHRIMP-RG analytical procedures and results …….… 252

Appendix C: Electron microprobe analytical procedures and results .. 269

Appendix D: LA-ICP-MS analytical procedures and results ………... 285

Appendix E: Lassen Peak ……………………………………………. 308 LIST OF FIGURES

Figure Page

1.1 General distribution of porphyry Cu and epithermal Au-Ag deposits that occur throughout North and South America …………………… 3

1.2 Regional geologic map of the Indio Muerto district ………………... 8

1.3 Geologic map of the Indio Muerto district and El Salvador porphyry Cu(Mo) deposit, northern Chile ……………………………………. 10

1.4 Location map outlining major volcanic centers in the Cascade Mountains …………………………………………………………… 15

2.1 Tectonic map of northern Chile outlining major fault zones, Cordilleras and porphyry copper deposits ………………………….. 23

2.2 Geologic map of the 2600 m level of the Indio Muerto district, northern Chile ……………………………………………………..... 25

2.3 Photomicrographs of main porphyry types analyzed ………………. 27

2.4 Cathodoluminescence images of selected zircon grains ………….... 33

2.5 Terra-Wasserburg Concordia diagrams showing U/Pb geochronologic data with interpreted weighted mean age for selected samples …….. 47

2.6 Rare earth element (REE) plots for selected samples analyzed by SHRIMP-RG ………………………………………………………... 53

2.7 Trace element plots from individual zircon grains …………………. 57

2.8 Zircon Hf variation diagrams ………………………………………. 59

2.9 Whole rock SiO 2 wt. % variation diagram ………………………….. 62

2.10 Cathodoluminescence images of El Salvador zircon grains with corrected temperatures based on Ti content (± 2ºC) ……………….. 64

2.11 Trace element content vs. Ti temperature of zircon illustrating core, rim, and sector zones from the K porphyry, A porphyry, and latite dike 66

2.12 Probability density plot of all U/Pb zircon spot ages analyzed from the fourteen samples but excluding spots with inherited (Mesozoic), discordance, and probable Pb loss …………………………………. 67 LIST OF FIGURES (Continued) Figure Page

2.13 Summary of El Salvador chronology comparing relative ages vs. robust U/Pb zircon ages from this study …………………………… 71

2.14 Enlarged Th/U vs. Yb/Gd ratio plot for El Salvador zircons ………. 76

2.15 Enlarged Hf ppm vs. Eu/Eu* plot for Eocene-age zircons …………. 77

2.16 Conceptual north-south cross-sectional model for the formation of the El Salvador porphyry-Cu district ……………………………….. 80

3.1 Geologic map and ore distribution of the El Salvador porphyry copper deposit, northern Chile ……………………………………… 94

3.2 Major element oxide versus SiO 2 concentrations normalized to volatile free for El Salvador porphyry intrusions ………………….... 109

3.3 Trace element variation diagrams for El Salvador porphyry intrusions …………………………………………………………..… 110

3.4 Amphibole Al 2O3 vs. TiO 2 (in wt. %) diagram from L porphyry and latite dike samples from Turquoise Gulch ….………………..... 115

3.5 Classification diagrams for calcic-amphiboles after Leake et al. (1997) 116

3.6 Photomicrographs of L porphyry amphiboles from Turquoise Gulch 117

3.7 Backscattered electron image (BSE) of L porphyry amphibole analyzed by electron microprobe ……………………………………. 118

3.8 Photomicrographs of amphiboles and sieved plagioclases from the El Salvador latite dike samples …………………………………….. 119

3.9 REE diagram for amphiboles from latite dike sample ES-12792 normalized to chondrite ……………………………………………. 120

3.10 Photomicrographs of apatite phenocrysts from El Salvador latite porphyry dike ………………………………………………………. 122

3.11 Reflected, BSE, and X-ray images of latite dike apatite grain ES-12792ap-7 ……………………………………………………… 123

3.12 Chondrite normalized REE diagram for apatite from the El Salvador district …………………………………………………………….… 126 LIST OF FIGURES (Continued)

Figure Page

3.13 Plane-polarized photomicrograph of biotite from the K porphyry of Turquoise Gulch ……………………………………………………. 127

3.14 Cross-polarized photomicrograph of L porphyry from Turquoise Gulch ……………………………………………………………….. 128

3.15 Variation diagrams for biotites from selected El Salvador porphyries. 130

3.16 Photomicrograph of plagioclase phenocryst from sample ES-12800 L porphyry from M Gulch ………………………………………….. 135

3.17 Photomicrograph of sieved plagioclase from sample ES-12792 latite dike from Turquoise Gulch …………………………………………. 136

3.18 Ba (ppm) vs. Sr (ppm) plot of plagioclase grains from the El Salvador district ……………………………………………………………….. 137

3.19 Reflected light images of titanites from sample ES-12792 latite dike from Turquoise Gulch ……………………………………………….. 139

3.20 Variations of cations plotted as a function of molar Ti content for titanites from the K porphyry (ES-12785a), L porphyry (ES-12787), and latite dike (ES-12792)……………………………………….…. 141

3.21 Titanite REE diagrams ……………………………………………... 143

3.22 Temperature vs. pressure diagram outlining amphibole crystallization fields………………………………………………………………….. 147

3.23 Mass balance REE diagram for whole rock and mineral phenocrysts from the Turquoise Gulch porphyries ……………………………….. 151

3.24 Y (ppm) vs. Sr/Y for whole rock and mineral phases from the El Salvador porphyry suite …………………………………………. 155

3.25 Sm/Yb vs. La/Sm plots for El Salvador whole rock and mineral Analyses ……………………………………………………………. 158

3.26 Calculated melt equilibrium concentrations in equilibrium with measured plagioclase Ba and Sr compositions.……………………... 162

3.27 Geologic evolution of the El Salvador porphyry copper deposit …… 168 LIST OF FIGURES (Continued)

Figure Page

4.1 Geologic and tectonic setting of Lassen volcanic region …………... 183

4.2 Geologic map of the Brokeoff Volcano region showing rock sequences, structure, active fumaroles and intrusive dikes and plugs 188

4.3 Infrared spectra analysis of dickite and kaolinite …………………… 191

4.4 Representative infrared spectra “stack plots” from Bumpass Hell, Pilot Pinnacle, and samples from northern and southern Little Hot Springs Valley………………………………………………………. 192

4.5 Sample maps denoting major mineral locations defined by PIMA for the Brokeoff volcano area …………………………………………... 196

4.6 Representative XRD spectra for selected Brokeoff Volcano samples 197

4.7 Scanning electron microscope images of hydrothermal alteration textures and minerals at Brokeoff Volcano ………………………… 198

4.8 Photographs outlining alteration and hydrothermal features within Lassen Volcanic National Park……………………………………… 203

4.9 Geochemical plots of major and trace elements vs. titanium (Wt. %). 209

4.10 Distribution of hydrogen isotopic values and oxygen isotope contours along the south flank of Lassen Peak………………………………. 212

4.11 Simplified sketch from southwest to the northeast outlining the geothermal systems on the south flank of Lassen Peak……………. 215

4.12 Map of the hydrothermal alteration assemblages in the Brokeoff Volcano region …………………………………………………...… 217

LIST OF TABLES Table Page

2.1 U/Pb geochronologic data for zircos from the El Salvador Porphyries …………………………………………………………… 36

2.2 Summary of interpreted zircon 206 Pb/ 238 U ages for El Salvador porphyry samples …………………………………………………... 43

2.3 Composition of zircon grains from the El Salvador district ……..… 50

2.4 Zircon saturation temperatures defined from whole rock major element concentrations …………………………………………….. 61

2.5 Trace element composition for Latitie, K porphyry, and A porphyry zircons analyzed by SHRIMP-RG for entire trace element suite ….. 63

3.1 Whole-rock geochemical results for selected El Salvador intrusions . 106

3.2 Composition of selected amphiboles by electron microprobe analysis 114

3.3 Composition of selected apatites by electron microprobe analysis …. 124

3.4 Average composition of biotites from electron microprobe analysis 129

3.5 Composition of selected plagioclase by electron microprobe analysis 134

3.6 Composition of selected titanites by electron microprobe analysis … 140

3.7 Calculated temperatures and pressures for amphiboles from ES-12792 Latite dike ……………………………………………….. 148

3.8 Calculated melt compositions derived from inherited Mesozoic age zircons for La, Sm, and Yb …………………………………………. 160

4.1 Hydrothermal alteration assemblages at Brokeoff Volcano, California 200

4.2 Hydrogen isotopic composition of whole rock and <15 mm size fractions from Brokeoff Volcano, California ………………….…… 211

LIST OF APPENDIX TABLES

Table Page

A1 El Salvador whole rock X-ray fluorescence analyses ……………… 246

A2 El Salvador whole rock ICP-MS analyses ………………………..... 250

B1 SHRIMP-RG analytical data from El Salvador zircon separates …... 255

C1 Quantification settings for mineral analyses by electron microprobe 270

C2 El Salvador amphibole composition by electron microprobe analysis 273

C3 El Salvador apatite composition by electron microprobe analysis …. 275

C4 El Salvador biotite composition by electron microprobe analysis ….. 278

C5 El Salvador plagioclase composition by electron microprobe analysis 280

C6 El Salvador titanite composition by electron microprobe analysis … 282

D1 El Salvador mineral compositions by Quadrapole LA-ICP-MS analysis 286

E1 PIMA and XRD Mineral Identifications from Lassen Peak samples 310

E2 Whole Rock Geochemical Analyses for Lassen samples ………….. 314

LIST OF CD APPENDICES

CD Appendices

CD Appendix I: Zircon images

CD Appendix II: Mineral calculations

CD Appendix III: PIMA files

CD Appendix IV: Lassen GIS files

This Dissertation is dedicated to the memory of my mother and father; Sheila A. Box-Lee and Robert P. Lee. GENESIS OF THE EL SALVADOR PORPHYRY COPPER DEPOSIT, CHILE AND DISTRIBUTION OF EPITHERMAL ALTERATION AT LASSEN PEAK, CALIFORNIA

CHAPTER ONE

General introduction to porphyry and epithermal deposits

Magmatic-hydrothermal systems include economic porphyry deposits and associated epithermal deposits and are important contributors of gold, silver, copper, molybdenum, tungsten, manganese, tin, lead, and zinc that annually contribute billions of dollars to the industrial world. These deposits result when hydrothermal fluids are released from shallow granitoid magma chambers of intermediate to silicic composition and react with overlying rock to form hydrothermal ore minerals, veins, and wall-rock alteration (Gustafson and Hunt, 1975; Arribas, 1995; Sillitoe, 1997; Lang and Titley,

1998; Seedorff et al., 2005). Magma chambers that form these deposits typically reside at depths of 3 to 10 km and sequentially intruded upward in small volumes to produce porphyry dikes and porphyry type (Cu-Mo-Au) deposits mainly at depths of one to four km but sometimes as much as six to eight km. Magma-derived aqueous fluids accompany the porphyry dikes and stocks and commonly un-mix at low pressure (<1.4 kb) to form a vapor and a brine. The volumetrically dominantly vapor may rise to the surface where it interacts with meteoric waters to form high-sulfidation epithermal gold-silver deposits characterized by advanced argillic alteration and pyrite-enargite-luzonite-covellite mineralization. While there is geologic evidence that high-sulfidation epithermal deposits and porphyry deposits are related (Hedenquist et al., 2000; Gustafson et al.,

2004), the details of the timing and evolution of these porphyry-epithermal systems remains unclear. 2

Ore-related magmatic-hydrothermal systems typically display long periods of ore- forming magmatism, generally 3-10 m.y. with multiple intrusive centers occurring within the same region, e.g. Butte, Montana (~4 m.y.); Chuquicamata, Chile (~4 m.y.); El

Salvador, Chile (~5 m.y.); and Yanacocha, Peru (~6 m.y) (cf., Longo, 2005). These deposits may consist of multiple intrusive events (Rohrlach and Loucks, 2005; Seedorff et al., 2005) with ore deposition occurring late during the lifespan of the magmatic systems (cf., Gustafson and Hunt, 1975). However, this is not always the case and the nature between barren and economic intrusions and the associated hydrothermal fluids remains unknown. The source of components in the upper crustal magma chambers from which ore-bearing fluids are derived is still under debate. Hypotheses include those that propose derivation via fractionation of a hydrous mantle-derived basaltic melt in the lower or middle crust (Kay and Mpodozis, 2001; Rohrlach and Loucks, 2005) and those that propose derivation by assimilation, fractional crystallization, mafic recharge with open-system volatile loss within a upper crustal magma chamber (cf., Field et al., 2005;

Chambefort and Dilles, 2006). Recent studies on fluid inclusions (Ulrich et al., 1999;

Rusk et al., 2004; Rusk, 2007) indicate a dominantly magmatic source for the formation of the hydrothermal fluids, while magmatic vapor supplies the metal ligands for ore- transport and eventual deposition.

Porphyry copper and epithermal gold-silver deposits occur within Cenozoic-

Mesozoic arc terrains along the western edges of the Americas and within Paleozoic rocks of the Appalachians in northeastern United States (Figure 1.1). These types of economic deposits are commonly associated with magmatic arc segments where subduction-related magmas intrude crustally shortened terrains. Porphyry magmas 3

Figure 1.1. General distribution of porphyry Cu and epithermal Au-Ag deposits that occur throughout North and South America. Figure is modified from compilations by John H. Dilles. 4 are characterized by phenocrysts of plagioclase, quartz, orthoclase, biotite, and hornblende within a fine grained aplitic ground mass (Seedorff et al., 2005). Accessory minerals may vary within each deposit and consist of apatite, titanite, zircon, magnetite, and Fe-Ti oxides. Veins and sulfide deposition are associated with hydrothermal potassium silicate and sericitic alteration that are dominated by magmatic water

(Sheppard et al., 1969; Sheppard and Gustafson, 1976; Bowman et al., 1995; Hedenquist et al., 2000). Hydro-fractures form in host-rocks as fluids are released from magmas allowing porphyry magmas to rise and be emplaced concurrently with hydrothermal fluid ascent. This rapid upward emplacement produces the porphyry aplitic texture due to aqueous fluid loss and “pressure-quenching” of the intruding magmas (Burnham, 1979).

Fluids that ascend to the surface mix with meteoric water producing low-pH advanced argillic alteration directly above ascending fluids and near-neutral pH intermediate argillic alteration along the periphery of surface deposits (Arribas, 1995).

Determining when the magmatic and hydrothermal liquids that scavenge and deposit ore metals form in these systems as well as the source of the magma(s) that host and form these deposits is essential to forming a model of magmatic-hydrothermal system formation and ore deposition. The timing of magma/ore emplacement, the possibility of multiple magma recharge and magma generation events, as well as the oxidation state of the magma are key points to a comprehensive model of formation.

Such models can be developed by studying the age and compositions of accessory minerals that form in magmatic-hydrothermal ore deposits.

5

Scope of this Study

This dissertation comprises three manuscripts that present detailed geochronologic and geochemical analyses from the El Salvador porphyry copper deposit,

Chile (Chapters two and three), and the distribution and petrography of hydrothermal altered rocks at Lassen Volcanic National Park, California (Chapter four). This study expands the current geochronology of the El Salvador district and is the first to detail the geochemical compositions from pheonocrysts and accessory minerals from the deposit.

Detailed geochemical investigation provides a model for the formation of the porphyry intrusions that host ore-mineralization in the deposit.

Hydrothermal activity at Lassen Peak has formed multiple alteration events including one of the largest active geothermal systems in the Cascade Arc. Alteration is related to the mixing of meteoric water with magmatic water to produce advanced argillic and intermediate argillic alteration (Ingebritson and Sorey, 1985; 1987), similar to epithermal deposits that are closely associated with porphyry deposits at depth

(Hedenquist et al., 2000; Sillitoe and Hedenquist, 2003). The Cascade Range however lacks the large deposits of Cu-Au-Ag deposits seen in other epithermal deposits around the world. This study provides a detailed alteration map along the southern flank of

Lassen Peak and is part of the U.S. Geological Survey Cascades project in order to understand the epithermal processes that form in the Cascades compared with other epithermal deposits. Analyzing the alteration at Lassen Volcanic National Park provides key interpretations in understanding the formation multiple stages of alteration with time.

6

The El Salvador Porphyry-Copper Deposit, Chile

The El Salvador (Cu + Mo and trace Au) deposit is one of the southernmost late

Eocene porphyry copper centers in northern Chile, and represents a unique deposit for determining the formation of porphyry copper deposits. The El Salvador porphyry copper deposit lies in the Indio Muerto district of the Third Region, northern Chile along the Pre-Cordillera part of the Atacama Desert at ~3000 m elevation immediately west of the Andean crest marking the Chile-Argentina border. The ore body is one of the best- documented porphyry Cu deposits on Earth. Geological mapping, petrology and geochemical analyses of hydrothermal alteration and mineralization, and age-dating have been collected over the last 40 years mainly by geologists from the Anaconda Company, the Chilean geological survey (Sernageomin), and Corporacion Nacional del Cobre de

Chile (Codelco) (Gustafson and Hunt, 1975; Cornejo et al., 1997; Cornejo et al., 1999;

Gustafson et al., 2001). Previous work has established the size and relative age of intrusions, the vein sequence and sulfides in the orebodies, and the zoning patterns of hydrothermal ore minerals, silicate alteration minerals and veins.

The late Paleozoic Sierra Batholith to the east and Mesozoic volcanic and sedimentary rocks of the Sierra Fraga Formation and Mantos Gruesos sequence in the west form the basement rocks of the Indio Muerto district, and are overlain by Upper

Triassic to Cretaceous age sedimentary rocks (Figure 1.2). These include sedimentary rocks and andesites of the Llanta Formation to the west and marine carbonates with interbedded volcanics of the Quebrada del Salitre, Montandón and Asientos Formations, and Quebrada Vicuñita sequence to the east (Cornejo et al., 1997). 7

Magmatism at this latitude (26.3°S) has migrated eastward with time, with

Jurassic ages along the Chilean coast, Cretaceous ages in the Central Valley, Paleogene and Eocene ages in the Pre-Cordillera, and Miocene and Quaternary ages along the

Argentina frontier. The Pre-Cordillera lies along the Domeyko fault system, a north- south network of late Eocene reverse and strike-slip faults that parallel the continental margin (Figure 1.2, inset). Paleocene volcanism within the Indio Muerto district includes large volumes of trachybasalts, trachyandesites, and rhyolite lavas, domes, and tuffs

(Cornejo et al., 1994, 1997). The Los Amarillos-Kilómetro Catorce volcanic sequence lies to the west of El Salvador and ranges in age from 62 to 60 Ma (Cornejo et al., 1997).

The largest volume of volcanic and plutonic rocks during this time comprises diorites, ignimbrites, monzonites, and rhyolitic rocks of the El Salvador Caldera and Indio Muerto

Domes. The El Salvador Caldera is defined by densely welded rhyolite ignimbrites that are cut by normal and “scissor” faults to the south of the El Salvador deposit (Figure 1.2).

Cornejo et al. (1997) suggest that due to the fault structure and volcanic facies the caldera complex is a trap-door caldera. Whole rock and biotite K-Ar ages indicate a period of two million years between 61 and 63 Ma for the time of formation for the caldera

(Cornejo and Mpdozis, 1996; Cornejo et al., 1999).

Shortening occurred during the late Creataceous to the Paleocene with the activation of the Sierra Miranda thrust and the Mantos Gruesos fault as well as other faults which cut and deform Paleocene and older rocks. Syn- to post-tectonic Eocene intrusions include a series of porphyry and granitic intrusions that range from ~44 to ~41

Ma associated with Cu-Mo ores in the Indio Muerto district and principally from ~41 to

8

Figure 1.2. Regional geologic map of the Indio Muerto district. Chile and Argentina map denotes tectonics and major porphyry copper deposits within northern Chile. Black square in geologic map denotes location of Figure 1.3 and roughly outlines the location of the El Salvador porphyry copper deposit.

9

33 Ma associated with Au and Cu ores in the Potrerillos district (Marsh et al., 1997).

Following mineralization, slow uplift accompanied by erosion and a drying climate led to the oxidation of the upper parts of the sulfide orebodies, and development of supergene

Cu sulfide and exotic oxide ores during the period between ~38 and 15 Ma (Mote et al.,

2001; Bissig and Riquelme, 2007). Hypogene and later supergene acidic fluids have altered many of the rocks above 3000 m elevation at the El Salvador deposit (Watanabe and Hedenquist, 2001). Since 15 Ma, hyper-arid conditions have prevailed in the

Atacama Desert.

The El Salvador ore deposit is centered on the largest granodiorite porphyry intrusive complex at Turquoise Gulch where the initial discovery was made (Perry,

1960). Other centers of porphyry intrusions occur in a 5 by 10 km area and are located at

O-nose, Granite Gulch, M Gulch-Copper Hill, Red Hill, and Cerro Pelado. O-nose, M

Gulch-Copper Hill and Old Camp centers have low-grade copper mineralization and have been mined where supergene enriched (Gustafson et al., 2001). Cerro Pelado contains porphyry Mo mineralization associated with quartz rhyolite porphyries that are about one m.y. older than the other porphyry intrusions (Gustafson and Hunt, 1975; Gustafson et al., 2001).

The porphyries include, in order of decreasing relative age established by cross- cutting field relations, rhyolite porphyry, Quartz porphyry, X porphyry, K porphyry, L porphyry, and latite porphyry dikes (Figure 1.3). The Cu-Mo mineralization and hydrothermal alteration apparently began with emplacement of the X porphyry, reached a peak associated with the K porphyry, and declined with emplacement of the L porphyry

(Gustafson and Hunt, 1975). Rhyolite porphyry predates all hypogene sulfide 10

Figure 1.3. Geologic map of the Indio Muerto district and El Salvador porphyry Cu(Mo) deposit, northern Chile. Modified from Gustafson et al. (2001) and compilations by El Salvador mine geologists. Map elevation is at 2600 m level. 11 mineralization at Turquoise Gulch, whereas latite porphyry entirely post-dates mineralization. Many of the porphyries in these areas have been tentatively correlated on the basis of texture, petrology, igneous mineralogy, and associated hydrothermal features to the porphyries in the Turquoise Gulch center (Gustafson et al., 2001). In total, at least eleven textural and temporal varieties of porphyry intrusions have been identified in all centers. Porphyries in these areas are characterized by hydrothermal alteration and some contain subeconomic Cu-Mo mineralization; however, this mineralization is less abundant than what is observed at Turquoise Gulch.

Zircon Geochronology and Trace Element Composition

This project was initiated by Lew Gustafson and Enrique Tidy in order to constrain the timing of newly discovered porphyry intrusions and prior intrusions using new and advanced geochronologic techniques. The second chapter of this thesis details the geochronology and geochemistry from zircons separated from distinct intrusions within the El Salvador deposit.

Zircons crystallize as accessory minerals within non-alkaline intermediate to silicic magmas. Zircon typically forms as ~100-500 µm long grains with complex internal oscillatory zonation, and in some cases have inherited cores. Magmatic zircon saturates at ~1000º and continually crystallizes to ~700º C (Finch and Hanchar, 2003;

Hanchar and Watson, 2003). Zircon commonly provides excellent U/Pb and Th/Pb isotopic ages because it is both chemically robust and concentrates U and Th relative to melt. Analyses by sensitive high resolution ion microprobe with reverse geometry

(SHRIMP-RG) allows for the complete quantification of elements within zircon 12 including titanium, rare earth elements (REE), hafnium, uranium, and thorium among others (Mazdab and Wooden, 2006).

Zircon compositions can be used to examine trace element behavior, crystal fractionation, the assimilation of crustal materials, deep crustal fractionation and mafic recharge. Zircon preferentially incorporates a suite of lithophile elements including middle and heavy REE, hafnium, uranium, and thorium in concentrations dependant upon the pressure, temperature, and composition of the magma or fluid from which they form

(Hanchar and van Westrenen, 2007). Recent advances in the Ti-in-zircon geothermometer (Watson and Harrison, 2005; Watson et al., 2006) allow for the determination of the temperature at which the zircon crystallized within the coexisting melt as long as the activity of Ti is known.

Previous Geochronlogic Work at El Salvador

Existing Ar-Ar, K-Ar, U/Pb zircon, and Re-Os ages indicate a four to five million year life span for the porphyry intrusions in the El Salvador deposit (Gustafson and Hunt,

1975; Cornejo et al., 1997; Watanabe et al., 1999; Watanabe and Hedenquist, 2001).

Silicic quartz rhyolite and quartz porphyries represent the oldest Eocene intrusives in the district at ~45 to ~44 Ma. Granodioritic porphyries and associated vein deposition vary in age ranging from ~43.5 to ~41.5 Ma. The northwest trending latite dikes represent the final intrusive event within the district at ~41 Ma. The relative ages of these porphyries are well-established by cross-cutting relationships (Gustafson and Hunt, 1975), and it is likely that there are at least a dozen stages of porphyry intrusions. Correlations of intrusives from one porphyry center to another is impossible due to lack of contacts, and geochronology studies have not been able to resolve this issue via absolute ages due to 13 errors on ages (except Re-Os) that are typically ±1 m.y. or more (2σ) (cf., Gustafson et al., 2001). Tosdal et al. (2000) and Tosdal (pers. commun., 2006) analyzed zircons via

SHRIMP and found inherited cores in the early X porphyry with ages of 130-165 Ma

(n=5), 210 Ma, and 355 Ma but no inherited cores in the late L porphyry. They argue on the basis of the inherited zircons and the primitive and homogeneous Sr (0.7040) and Pb isotopes that the magmas assimilated relatively primitive (basaltic) crust at a relatively deep level.

Geochemical Analysis at El Salvador

Very little work has been conducted in order to understand the petrogenesis and geochemistry of the El Salvador magmas. At El Salvador, hydrothermal ore fluids are derived from the intermediate composition dikes and plugs that generally have an aplitic groundmass and abundant phenocrysts of plagioclase, quartz, hornblende, biotite, magnetite, with accessory minerals of titanite, apatite and zircon (Gustafson and Hunt,

1975; Field and Gustafson, 1976). This assemblage is similar to other porphyry copper deposits reflecting near-solidus temperatures for the magmas (cf. Naney, 1983; Dilles,

1987). Chapter three details the petrographic and geochemical analysis of whole rock, pheocrysts, and accessory minerals in order to model the formation of the magmas responsible for ore deposition. Electrom microprobe and laser-ablation ICP-MS analyses were conducted on phenocrysts of amphibole, apatite, biotite, plagioclase, and titanite from selected intrusions within the deposit.

14

Lassen Volcanic National Park, California

The fourth chapter of this thesis outlines the work conducted at Lassen Volcanic

National Park, California as part of a joint collaboration between Oregon State University and the USGS Mineral Resource External Research Program (MRERP). Lassen Peak is the southernmost active volcano in the Cascade Arc (Figure 1.3) and currently has the highest volume of active thermal pools and fumaroles within the Cascades. Detailed mapping of hydrothermally altered wall rocks produced by both the fossil and the active geothermal system was conducted in conjunction with the USGS and permission by the

National Park Service in order to synthesize a geologic map of the epithermal system at

Lassen. The distribution and mineralogy of the advanced argillic to intermediate argillic fossil systems and active steam-heated acid sulfate alteration was determined by short- wave infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and geochemical analyses. This study presents a detail geologic map of the hydrothermal alteration along the southern flank of Lassen Peak. All data from this project were compiled and plotted using the mapping software ArcView™ and ArcMap™. A digital map of all sample locations and mineral analyses is available in ArcMap™ format in the attached CD appendix.

All analytical methods and complete tables of data utilized in this study are outlined in the appendices.

15

Figure 1.4. Location map outlining major volcanic centers in the Cascade Mountains. Lassen Volcanic Center represents the southern most extension of active volcanism within the Cascades. Modified from Guffanti and Weaver (1988). 16 CHAPTER TWO

TRACE ELEMENTS AND U/PB AGES OF ZIRCON FROM GRANODIORITE PORPHYRY: TEMPORAL, THERMAL, AND GEOCHEMICAL EVOLUTION OF PORPHYRY COPPER MAGMAS AT EL SALVADOR, CHILE

Robert G. Lee John H. Dilles Richard M. Tosdal Joe L. Wooden Frank K. Mazdab

This manuscript is in preparation for submission to Economic Geology

17 Abstract

Uranium-lead zircon ages and zircon trace element geochemistry document the temporal, chemical, and thermal evolution of granodioritic magmas associated with porphyry Cu (Mo-Au) ores in the El Salvador district, Chile. Zircons from fourteen diorite, granodiorite, and granite porphyry intrusions have been analyzed in situ by ion microprobe (SHRIMP-RG) for isotopic and trace element contents. The new 207 Pb – corrected 206 Pb/ 238 U ages suggest a magmatic lifespan of more than five million years from ~46 to 41 Ma. The bulk of zircon ages range from ~44 to ~43 Ma and correspond to peak magmatic fluxes during the intrusion of the Quartz and X porphyries, whereas waning stage magmatism is recorded by the K and L porphyries from 42.5 to ~42 Ma followed by final intrusion of post-mineralization latite dikes at 41.6 ± 0.5 Ma. Porphyry copper mineralization progressed temporally from north to south, with weak mineralization at Old Camp (~43.5 Ma) and M Gulch (~43 Ma) that evolved to the main mineralization stage at Turquoise Gulch (~42 to 42.5 Ma). Mesozoic as well as

Paleocene and Eocene age inherited zircons older than the host intrusions indicate that younger porphyry magmas recycled both basement rocks and previous porphyry intrusions.

Trace element concentrations of zircon vary widely within individual porphyry samples and between samples, record magmatic processes such as cooling and crystallization versus heating attending mafic magma input, melting, and magma mixing.

The Ti-in-zircon geothermometer provides estimates of 750º to 620º C for zircon crystallization in the granodiorite porphyries, but a much larger range of 850º to 630º C for a late latite dike. The latite dike records mixing between high temperature deeply derived (>10 km) andesitic or basaltic melt and the granodioritic upper crustal magma

18 chamber. The span of ages and variation in the zircon trace element concentrations suggest that the porphyry intrusions represent the tapping of one (or more) evolving granodiorititc magma chamber that was periodically heated, locally remelted, and mixed with mafic magma during recharge events.

Hafnium content of zircon increases with progressive crystallization and magma cooling. Europium anomalies (Eu/Eu* < 1) in zircons become more pronounced with increased Hf content but display two distinct evolutionary paths: All zircons from intrusions evolve from 8000 to 14000 ppm Hf, but Eu/Eu* of early Quartz porphyry evolves from 0.8 to 0.3, whereas late K and L porphyry evolve from 0.8 to 0.65. The

Eu/Eu* ratio of zircon reflects the Eu 3+ /Eu 2+ ratio of the melt, and therefore that the K and L porphyries at Turquoise Gulch were the most strongly oxidized of the El Salvador magmas. The strongly oxidized trend of the K and L porphyry magmas is apparently directly linked to extraction of large amounts of copper, sulfur, and chlorine-enriched magmatic-hydrothermal aqueous fluids from these magmas to produce the main porphyry copper mineralization.

Introduction

Hydrous intermediate to silicic calc-alkaline magmas crystallize in the upper crust to form granitoid plutons that are globally associated with large sulfur- and metal-rich magmatic-hydrothermal mineral deposits. Magmatic-hydrothermal systems include economic porphyry deposits and associated epithermal deposits and are important contributors of gold, silver, copper, molybdenum, lead, and zinc that annually produce billions of dollars for the industrial world. Porphyry deposits result when hydrothermal fluids are released from shallow magma chambers of intermediate to silicic composition

19 and react with overlying rock to form hydrothermal ore minerals, veins, and wall-rock alteration (Gustafson and Hunt, 1975). These magma chambers typically reside at depths of 3 to 10 km and are sampled by small volumes of magma that sequentially intrude upward to produce porphyry dikes and porphyry type (Cu-Mo-Au) deposits at depths of 2 to 5 km (Seedorff et al., 2005).

Ore-related magmatic-hydrothermal systems typically display long periods of magmatism (~3 to 10 m.y.) documented by multiple intrusions, e.g . Butte, Montana (~4 m.y.; Dilles et al., 2003); Tampakan, Philippines (~8 m.y.; Rohrlach and Loucks, 2005) and Yanacocha, Peru (~6 m.y.; Longo, 2005). Hydrothermal ore deposition predominately occurs late in the lifespan of the magmatic systems associated with porphyry-type intrusions (c.f., Sillitoe, 1988; Seedorff et al., 2005). The Chuquicamata and El Abra complexes in northern Chile have been dated via several methods including

K-Ar, Ar-Ar, and U/Pb, (Dilles et al., 1997; Reynolds et al., 1998; Ballard et al., 2001;

Campbell et al., 2006) and the age of ore-bearing porphyries spans approximately two million years. Recent work by Campbell et al. (2006), indicate barren intrusions were emplaced over a five million year period prior to the ore bearing intrusion at the El Abra mine. This suggests that porphyry intrusions can occur over a period of several millions of years with a build up of magmatism prior to economic deposition.

The Eocene (42-41 Ma) El Salvador porphyry copper deposit in the Indio Muerto district of northern Chile is one example where long-lived intrusions occurred prior to and during copper deposition (Gustafson and Hunt, 1975; Cornejo et al., 1997; Gustafson et al., 2001). In aggregate, the El Salvador district represents a moderate sized porphyry

Cu(Mo-Au) district containing approximately 15 M tones of copper resources both in the main Turquoise Gulch center and in smaller centers at Old Camp, M Gulch-Copper Hill,

20 and Cerro Pelado. During the Eocene, magmatism commenced at approximately 45

Ma with intrusion of a series of quartz-feldspar to feldspar porphyries and was sustained for a period ~5 million years (Gustafson and Hunt, 1975). This magmatism culminated with the emplacement of a series of granodioritic stocks, plugs, and dikes and the formation of the main porphyry copper deposit at Turquoise Gulch between 42 and 41

Ma (Gustafson and Hunt, 1975; Cornejo et al., 1997; Gustafson et al., 2001). Previous geochronological studies in the El Salvador porphyry Cu-Mo district were extensive and include more than 30 K-Ar, 40 Ar-39 Ar, and U/Pb zircon determinations, but these ages have relatively large errors (2 σ errors typically are ± 1 million years or more; see detailed summary of Gustafson et al., 2001). The relative chronology of the intrusions is well- known within individual centers based on the seminal early work by mine geologists

(Gustafson and Hunt, 1975), but uncertainty remains in the absolute ages of the intrusions within each individual igneous center and from one center to another.

The source of components from which ore-bearing fluids are derived in the upper crustal magma chambers is still debated. Hypotheses include: 1) derivation via fractionation of a hydrous mantle-derived basaltic melt in the lower or middle crust (Kay and Mpodozis, 2001; Rohrlach and Loucks, 2005) and 2) derivation by assimilation, fractional crystallization, mafic recharge with open-system volatile loss within a upper crustal magma chamber (cf., Field et al., 2005; Chambefort et al., in press). Recent studies on fluid inclusions from magmatic-hydrothermal deposits suggest dominance of magmatic sources for the bulk of the hydrothermal fluids, with magmatic vapor supplying the metal ligands for ore-deposition (Ulrich et al., 1999; Rusk et al., 2004;

Halter et al., 2005; Rusk et al., 2008).

21 To understand magmatic-hydrothermal systems and ore deposition, it is essential to understand the relative timing of the fluids that scavenge and deposit ore metals, as well as the processes that produce both the productive magmas and the derived hydrothermal fluids. Key points of a comprehensive model of magma and ore emplacement include the chemical evolution of magma and recharge events and the oxidation state of the magma source. Such models can be developed by studying the U-

Pb age and composition of zircons that form as accessory minerals in igneous rocks associated with magmatic-hydrothermal ore deposits (e.g. Pettke et al., 2005; Pelleter et al., 2007).

The processes that form mineralizing magmas can be investigated by studying trace elements in zircon. Zircon crystallizes as an accessory mineral in non-alkaline intermediate to silicic magmas. It typically forms ~100-200 µm long grains with complex internal oscillatory zonation, and in some cases has inherited cores. Magmatic zircon saturates at ~950º and continually crystallizes to ~750º C or less (Finch and

Hanchar, 2003; Hanchar and Watson, 2003; Miller et al., 2003). The trace element compositions of magmatic zircons preserve the initial composition of the melts or fluids from which they crystallized. Zircon preferentially incorporates a suite of lithophile elements including middle and heavy rare earth elements, Hf, U, and Th in concentrations dependant upon the pressure, temperature, and composition of the melt or fluid (Hanchar and van Westrenen, 2007). The trace element compositions of magma may be estimated from the zircon compositions and record various magmatic processes such as mafic recharge and heating, assimilation of deep or shallow crustal materials, and cooling and attendant crystallization or crystal fractionation. Thus, the compositions of zircons of

22 known ages can be used to track the temporal and thermal evolution of the magma and silicic melt.

We have analyzed zircons from fourteen hypabyssal porphyry intrusions ranging from nearly equigranular to porphyry texture from the El Salvador district for U/Pb ages and trace element composition. The zircons we have analyzed span intrusion from the earliest silicic porphyry intrusions to the final latite dikes. This data set presented below represents one of the largest sets of zircon age and trace element data ever produced for porphyry systems (cf., Ballard et al., 2002; Campbell et al., 2006), and both documents the absolute ages of various intrusions and consequently the ages of porphyry Cu (Mo-

Au) mineralization events, and provides constraints on how the magmas evolved thermally, compositionally, and chemically. The trace element and age data provide direct evidence for the timing of mafic magma input, recycling of earlier intrusions into younger magmas, and increase of oxidation state of the late magmas from which the bulk of porphyry Cu-(Mo-Au) ores were deposited in the El Salvador district.

Tectonic setting of the Andean precordillera, northern Chile

Transpressional arc parallel fault systems along the Andean margin focused local magma ascent and pluton emplacement (Taylor et al., 1998). These fault systems migrated east with time from Late Triassic to early Cretaceous of the Atacama Fault Zone in the Cordillera La Costa; Late Cretaceous Central Valley Fault Zone; and Late

Cretaceous to Eocene Domeyko Fault Zone in the Cordillera Domeyko (Figure 2.1). The

Domeyko fault system is a north-south network of late Eocene reverse and strike-slip faults that parallel the continental margin and define the Precordillera of the Andean Arc

(Elderry et al., 1996).

23

Figure 2.1. Tectonic map of northern Chile outlining major fault zones, Cordilleras and porphyry copper deposits. Major porphyry Cu-(Mo) deposits denoted by solid black squares with deposit/mineralization ages listed in brackets. Modified from Cornejo et al., 1997; Taylor et al., 1998; and Camus and Dilles, 2001.

24 The Eocene-Oligocene belt within the Cordillera Domeyko hosts a series of porphyry copper deposits are spatially and temporally associated with the magmatic arc

(Camus and Dilles, 2001). These porphyry belts extend from Peru to central Chile and are time transgressive with the eastward migration of the arc. The El Salvador porphyry

Cu(Mo-Au) district lies in the Indio Muerto district of the Third Region, Chile between

26º and 27º S latitude, within the Pre-Cordillera immediately west of the Andean crest along the Chile-Argentina border, and is within the Atacama Desert at an elevation of approximately 3000 m.

Porphyry intrusions of the Indio Muerto district

A series of rhyolite and granodiorite porphyry intrusions that range in age from

~44 to 40 Ma were emplaced in late Paleozoic to Cenozoic volcanic and sedimentary rocks. These include Paleocene (63 to 55 Ma) calderas with associated ignimbrites, rhyolites, and trachytes, and minor amounts of syntectonic Eocene andesite and rhyolite effusive rocks (Cornejo et al., 1994; Cornejo et al., 1997). Several of the porphyry intrusions are temporally associated with porphyry Cu-Mo in the Indio Muerto district

(Gustafson et al., 2001) and porphyry and skarn Cu-Mo and epithermal Au mineralization in the Potrerillos district approximately 3 km to the south (Marsh et al., 1997).

The geology of the El Salvador district has been studied in considerable detail by geologists of the Anaconda Company (Gustafson and Hunt, 1975), Sernageomin

(Cornejo et al., 1997), and the Compania Minera de Cobre de Chile (CODELCO)

(Gustafson et al., 2001). The lithology of the Indio Muerto district is shown in Figure 2.2 with porphyry names from by Gustafson and Hunt (1975) and Gustafson et al. (2001).

Granodiorite porphyry intrusions intrude Paleozoic and upper Cretaceous andesite

25

Figure 2.2. Geologic map of the 2600 m level of the Indio Muerto district, northern Chile. Sample location, type, and interpreted U/Pb ages (±2 σ, 95% confidence) from this study denoted by solid black squares. Modified from Gustafson et al. (2001) and compilations by CODELCO geologists.

26 volcanic and sedimentary rocks as well as Paleocene rhyolite domes and pyroclastic rocks associated with the El Salvador caldera (Cornejo et al., 1997). These intrusions form multiple centers which include from north to south, Cerro Pelado, Old Camp, M

Gulch-Copper Hill, Red Hill, Turquoise Gulch, and Granite Gulch as well as several smaller centers.

Based on field relations the oldest intrusions are rhyolite porphyry and quartz porphyry. The quartz-sanidine rhyolite porphyry and breccia is referred to as rhyolite porphyry after Gustafson and Hunt (1975) and crops out near Cerro Pelado. The quartz- sanidine rhyolite exposed at Cerro Pelado is approximately 43 to 45 Ma based on a U-Pb zircon age 43 ± 1 Ma and a whole rock K-Ar age of 45.3 ± 2.0 Ma (samples IT-3, ES-

7458; Cornejo et al., 1997). Gustafson and Hunt (1975) determined an age of 45.4 ± 1.4

Ma based on a Rb-Sr isochron of six whole-rock specimens. The rhyolite porphyry is not in contact with quartz porphyry, but the latter is inferred to be younger and is interpreted to belong to the same magmatic event that produced the rhyolite porphyry based on composition and field relations (Gustafson et al., 2001). Quartz-plagioclase granite porphyry referred to here as quartz porphyry after Gustafson and Hunt (1975) crops out as a series of dikes and plugs throughout the entire district with the largest outcrop at the

Old Camp open pit. The quartz porphyry is characterized by large quartz (1-5 mm dia.,

Figure 2.3A) and plagioclase (1-3 mm dia.) and altered biotite pheoncrysts in a fine- grained, aplitic quartzofeldspathic groundmass (Gustafson and Hunt, 1975; Cornejo et al.,

1997). Two ages from the intrusion at Old Camp yielded 43.8 ± 0.2 Ma (biotite 40 Ar-

39 Ar; Gustafson et al., 2001) and 42.3 ± 1.3 Ma (zircon U-Pb; Cornejo et al., 1997).

Granodiorite porphyries make up the younger intrusions within the district and are characterized by phenocrysts of plagioclase, hornblende, biotite, and locally minor

27

Figure 2.3. Photomicrographs of main porphyry types analyzed: Qtz – quartz, apl – aplite, Mfe – mafic enclave, Plg – plagioclase, Bi – biotite, Hnbl – hornblende. A. Quartz porphyry from Old Camp with large quartz phenocrysts in a fine grained aplitic groundmass. Small phenocrysts of biotite and plagioclase also occur. Highly altered mafic enclaves are rare but also occur. B. K porphyry from Turquoise Gulch, coarser grained groundmass of quartz and plagioclase with phenocrysts of plagioclase, biotite, and hornblende. C. L porphyry from M Gulch, with coarse plagioclase phenocrysts in a fine-grained groundmass. D. L porphyry from Turquoise Gulch composed of equigranular plagioclase, biotite, and hornblende in coarse groundmass rich in quartz and alkali feldspar. E. A porphyry from M Gulch with phenocrysts of biotite and plagioclase in a fine grained biotite, hornblende, and plagioclase rich groundmass. F. Latite dike with large sieved plagioclase, hornblende, and biotite phenocrysts in a pilotaxitic groundmass.

28 amounts of quartz. Granodiorites vary from nearly equigranular in the center of stock- like intrusions to porphyries with up to 50 volume percent fine-grained (<0.5 mm) quartzofeldspathic aplitic groundmass (cf., L porphyry of Turquoise Gulch, Gustafson and Hunt, 1975). Individual porphyries are distinguishable based on textural differences and cross-cutting relationships (Gustafson and Hunt, 1975). Based on cross-cutting relations in Turquoise Gulch, these porphyries include in order of decreasing relative age the X porphyry (weakly porphyritic to equigranular granodiorite), K porphyry (porphyry with aplitic quartzofeldspathic groundmass, Figure 2.3B), L porphyry (texturally variable heterogeneous intrusions of porphyritic to equigranular granodiorite porphyry with large

0.5 to 6 mm long plagioclase (Figure 2.3C, 2.3D), and the A porphyry (with abundant fine-grained 0.1 to 0.4 mm groundmass and dioritic composition; Figure 2.3E). The A porphyry intrusions are closely associated with the L porphyry and locally occur as the late, outer, and more mafic margin of the L porphyry intrusion in the northwest part of

Turquoise Gulch (Gustafson and Hunt, 1975). The K, L, and A porphyries all yield K-Ar and Ar-Ar ages of about 41 to 42 Ma for samples from Turquoise Gulch (Gustafson and

Hunt, 1975; Cornejo et al., 1997; Gustafson et al., 2001). The youngest intrusion post- dates all Cu (Mo-Au) mineralization and forms narrow west-northwest striking latite dikes. The latite contains about ~64 wt. percent silica and phenocrysts of sieved and spongy plagioclase with abundant melt inclusions, amphibole, and biotite set in a pilotaxitic fine-grained groundmass (Figure 2.3F), and appears to be the product of mixing of mafic and silicic magmas.

The main underground porphyry Cu-Mo mine at El Salvador is centered on the series of porphyry intrusions in the Turquoise Gulch area. Quartz porphyry predates all hypogene sulfide mineralization here. The Cu-Mo mineralization and hydrothermal

29 alteration may have begun with emplacement of the X porphyry, reached a peak following and closely associated with emplacement of the K porphyry, and was largely completed before final emplacement of the L porphyry; nonetheless, a few quartz- molybdenite veins and numerous late polymetallic veins with sericitic selvages cut the margins of the L porphyry (Gustafson and Hunt, 1975). The latite dikes entirely post- date Cu-Mo sulfides, but are associated with late-stage pebble dikes, tourmaline, pyrite, and sericite-clay (Gustafson et al., 2001; Watanabe and Hedenquist, 2001).

Elsewhere in the district, the porphyries have been tentatively correlated on the basis of texture, petrology, and associated hydrothermal features to the porphyries in the

Turquoise Gulch center (Gustafson et al., 2001). At the M Gulch – Copper Hill porphyry

Cu(Mo) center, the Quartz, K, L, and A porphyries are similar in texture, composition, and relative ages to those found elsewhere in the district, but here Cornejo et al. (1997) reported an age range of ~44 to 43 Ma for L porphyry which is older than the ~42 Ma ages reported for the L and A porphyries in Turquoise Gulch. On this basis, Cornejo et al. (1997) interpreted M Gulch – Copper Hill to represent an older porphyry intrusion center slightly older than the Turquoise Gulch center and that intrusions here tapped an evolving silicic magma chamber with mafic input. At M Gulch, copper mineralization is hosted in quartz porphyry and adjacent andesite and cut by L and A porphyry (Gustafson et al., 2001). The A porphyry here is found on the western contact of the L porphyry, and is more weakly mineralized than the L porphyry. The A porphyry appears to represent a quenched, mafic margin of the L porphyry or a related and slightly younger intrusion

(Figure 2.2). In the west part of the pit west of the L and A porphyry exposures, a narrow

5 to 10 m-wide feldspar porphyry dike termed the R porphyry cuts the M Gulch breccia related to the L porphyry (Gustafson et al., 2001). The R porphyry also appears to be

30 closely associated with the L and A porphyries here. Although the contact is not exposed, the lower degree of alteration and finer-grained quenched groundmass of the R porphyry compared to the A porphyry suggest that the former is slightly younger.

To the south at Granite Gulch a sample of A porphyry texturally similar to the L porphyry is associated with weak porphyry copper mineralization. A sample of this L porphyry yielded K-Ar age of 42.1 ± 2.3 Ma (hornblende; Gustafson and Hunt, 1975), and 40 Ar-39 Ar ages of 42 to 43 Ma (biotite, hornblende; Gustafson et al., 2001).

In summary, previous isotopic ages suggest that multiple porphyries intruded over a 3 million year period from ~44 to ~41 Ma, and that L porphyry intrusions associated with porphyry Cu (Mo-Au) mineralization may have been slightly older at M Gulch compared to Granite Gulch and Turquoise Gulch (Cornejo et al., 1997; Gustafson et al.,

2001).

Methods

El Salvador porphyry samples

Fourteen samples were collected from the El Salvador district for zircon analysis via SHRIMP-RG technique. Sample ES-3239, quartz porphyry from the underground mine at Turquoise Gulch was collected by Lew Gustafson. Samples IT-9 (L porphyry) and IT-10 (X porphyry) were originally collected by Corenjo et al. (1997), who obtained

Ar-Ar ages of 41.2 ± 1.1 Ma and 41.6 ± 1.2 Ma for the two samples, respectively, and

U/Pb zircon ages of 41 ± 2 Ma and 41.8 ± 2.3 Ma, respectively. The identical zircon mineral separates from these samples were reanalyzed in this study for comparison. Ten samples were collected from surface exposures, underground mine workings, and from drill core and represent a survey of the several distinct intrusive centers within the district

31 (Figure 2.2). Samples with the least hydrothermal alteration were collected insofar as possible, but this was not always possible due to the extensive alteration within the deposit (Gustafson and Hunt, 1975; Gustafson et al., 2001; Watanabe and Hedenquist,

2001).

Two samples of quartz porphyry were collected at the Old Camp pit. ES-12808 is a quartz porphyry with quartz phenocrysts set within a fine-grained aplitic groundmass with 2-3 volume percent pyrite and chalcopyrite (Figure 2.3A). Sample ES-12791 is a late and brecciated quartz porphyry dike that was affected only by low-temperature or supergene kaolinite alteration and lacks quartz veins and chalcopyrite. The late quartz porphyry dike cuts the quartz veined and pyrite-chalcopyrite-bearing quartz porphyry sampled by ES-12808 and was sampled from a bench on the south-southwest side of the main pit.

Three samples were collected from M Gulch – Copper Hill: L porphyry, A porphyry, and R porphyry. Gustafson and Hunt (1975) reported that the A porphyry represents a dike that is associated with and emplaced at the end stages of the L porphyry intrusions. The L porphyry was collected on the east edge of the M Gulch open pit, and in this locality the A porphyry appears to represent a mafic border phase of the L porphyry intrusion. The R porphyry was collected in the western part of the M Gulch pit and displays a weak propylitic alteration.

Three samples were collected from the Turquoise Gulch underground mine: a K porphyry (ES-12785a) and L porphyry (ES-12787) from the 2440 level of Inca Norte and a latite dike from the 2476 level of Inca Oeste. The latite sample was relatively fresh with minor smectite alteration as compared to surface samples that are completely altered to montmorillonite (Gustafson et al., 2006).

32 South of Turquoise Gulch, two samples were collected from drill core: an X porphyry (ES-12811) and a K porphyry (ES-12807). One sample of the L porphyry (ES-

12789a) was collected from Granite Gulch.

Zircon separation procedure

Zircons were separated by crushing the rock in a steel jaw crusher, and then pulverizing to powder using a steel disk grinder at the El Salvador mine. The powders were then sieved to <500 micron size and the heavy mineral fraction was concentrated using a Wilfley table, and then separated using a magnetic Frantz isodynamic separator at the Oregon State University mineral separation laboratory. Euhedral, well-formed zircons were hand-picked under a binocular microscope. Lab procedures emphasize careful cleaning (with air, water, soap, alcohol), between samples to assure minimal possibilities of cross-sample contamination.

Zircons were mounted in a 2.54 cm diameter epoxy plug together with a zircon age standard R33 (419.9 ± 1.5 Ma; Black et al., 2004) and a rare earth element zircon standard Madagascar Green (Frank Mazdab, personal communication, 2007). The plugs were polished to expose grain centers and photographed in reflected light and using a cathodoluminescence (CL) detection system at the Stanford University with a JEOL JSM

5600 scanning electron microscope operating at 15 kv accelerating potential. The CL images were used to screen the zircons; “Cl-dark” areas of high uranium content were selected for analysis due to the low uranium content in the El Salvador samples (Figure

2.4). U-rich zones contain <20 to >3000 ppm U, but average ~300 ppm U. CL-images of the zircon in each sample display a range of textures including oscillatory growth zones, sector zoning, and rounded cores (Figure 2.4). In the current study, zircon rims

33

Figure 2.4. Cathodoluminescence images of selected zircon grains from three samples that illustrate oscillatory growth zoning (OG), sector zoning (S), and older inherited cores (C). A. IT-10 X porphyry from Turquoise Gulch. B. ES-12782 R porphyry from M Gulch. C. IT-9 L porphyry from Turquoise Gulch. Circles mark the location of individual ion microbe analyses with a spot diameter of 30 µm. Ages (in Ma) are given with 1σ error.

34 displaying regular concentric (oscillatory) growth zones were sampled and interpreted to represent normal magmatic crystallization where zircon is saturated within the melt

(Vavra, 1994; Hoskin, 2000; Hoskin and Schaltegger, 2003). Identifiable truncated or resorbed cores were typically avoided although they were sometimes sampled in cases where the core represented the only “dark” portion of the grain. Inherited cores with ages

>45-41 Ma were sampled but represent <5% of all spots analyzed.

SHRIMP-RG analyses

The U-Th-Pb and trace element concentrations of zircons were analyzed using a sensitive high resolution ion microprobe reverse geometry (SHRIMP-RG) at the Stanford

USGS Micro Analysis Center (SUMAC) housed at Stanford University and jointly owned and operated by the U.S. Geological Survey. Samples were run over three sessions from February 2007 to February 2008. The zircon mount was Au coated and placed in the sample chamber where an 8nA 16 O2-primary ion beam removed surface contamination and the gold coat prior to collection of positive secondary ions (c.f. Miller and Wooden, 2004). The U-Th-Pb ratios were corrected using the standard zircon R33

(Black et al., 2004) which has a 419 ± 1 Ma age and was analyzed approximately every

90 16 204 206 207 fourth analysis during the run. Six mass scans of peaks at Zr 2 O, Pb, Pb, Pb,

208 Pb, 238 U, 232 Th 16 O, and 238 U16 O were collected for each analysis with beam tuning and centering conducted on the 238 U16 O peak (c.f. Miller and Wooden, 2004). Count times of

8s and 24s were used for 206 Pb and 207 Pb respectively with average counts determined over the six scans per run.

Rare earth element (REE) concentrations were simultaneously analyzed as described by Mazdab and Wooden (2006). The trace elements were corrected using an in house zircon standard Madagascar Green which was analyzed five to six times over the

35 course of a twenty-four hour run. Concentrations of elements were derived from mass analyses of: 139 La, 140 Ce, 146 Nd, 147 Sm, 153 Eu, 155 Gd, 163 Dy 16 O, 166 Er 16 O, 172 Yb 16 O,

180 Hf 16 O and were analyzed with 1 to 2 second count times averaged over six counting sequences. Analysis of Pr is considered unreliable due to peak interference from

140 Ce 1H, so Pr concentration is estimated by normalizing to ⅓ La concentration and ⅔ Nd concentration (Wooden et al., 2006; Claiborne et al., 2006).

During the final session (February 2008) three samples (ES-12785a, ES-12783, and ES-12792) were reanalyzed for the entire trace element suite currently available for analysis on the SHRIMP-RG using masses: 7Li, 9Be, 11 B, 19 F, 23 Na, 24 Mg, 27 Al, 30 Si, 31 P,

32 S, 35 Cl, 39 K, 40 Ca, 45 Sc, 48 Ti, 49 Ti, 51 V, 52 Cr, 55 Mn, 56 Fe, 74 Ge, 89 Y, 93 Nb, 93Zr 1H, 96 Zr,

139 La, 140 Ce, 141 Pr, 146 Nd, 147 Sm, 153 Eu, 165 Ho, 157 Gd 16 O, 159 Tb 16 O, 163 Dy 16 O, 166 Er 16 O,

169 Tm 16 O, 172 Yb 16 O, 175 Lu 16 O, 180 Hf 16 O, and 206 Pb. 49 Ti was selected for calculation of titanium concentrations due to the 96 Zr peak interference with 48 Ti (Claiborne et al.,

1996). Each mass peak was normalized to the 30 Si count rate to minimize instrumental drift and sputtering effects. Normalized count rates were calibrated to the Madagascar green standard. Aluminum, calcium, and iron count rates were monitored to determine any contamination by inclusions or altered zones in zircon.

Data reduction was done using the Squid/Isoplot software of Ludwig (2001;

2003), and results are listed in Table 2.1. Uranium content for the samples varied but

30% of the samples analyzed had U values less than 100 ppm. The low U concentration for individual spots yields errors ranging from about ± 1 to 5% (1 σ). The El Salvador samples are relatively young, therefore, the amount of 235 U is low, and the 207 Pb/ 235 U ratio and age has a large error that is typically 3 to 6%. For this reason the 206 Pb/ 238 U ratio with its smaller error (1-2 %, 1σ) is used for the age calculation. The raw 206 Pb/ 238 U

36 Table 2.1. U/Pb geochronologic data for zircons from the El Salvador porphyries. 206 C-Pb 206 238 Rad Pb U Th 206 238 1σ 207 206 1σ Pb / U 1σ S # note 207 206 Pb/ U Pb/ Pb (ppm) (ppm) (ppm) Pb/ Pb err err Age (Ma) err ES-12808; Quartz porphyry; Old Camp; UTM 7,0989,940N 445,110E; Elv 2650 m 1 Pb loss 1.93 351 230 0.83821 0.00640 1.4 0.0601 10.8 40.5 0.6 2 Con 2.07 362 222 0.83835 0.00667 1.3 0.0532 5.3 42.5 0.6 3 Dis 3.11 515 573 0.83851 0.00703 1.1 0.0488 4.5 45.0 0.5 4 Dis 0.61 101 96 0.83837 0.00706 2.5 0.0911 8.0 42.9 1.1 5 Con 3.54 610 572 0.83839 0.00676 0.8 0.0524 6.4 43.1 0.4 6 Dis 1.21 203 114 0.83842 0.00694 1.4 0.0624 5.7 43.7 0.6 7 Con 6.53 1112 994 0.83843 0.00683 0.6 0.0479 3.2 43.8 0.3 8 Con 1.84 317 325 0.83838 0.00675 1.1 0.0537 5.2 43.0 0.5 9 Con 4.17 700 274 0.83847 0.00693 0.7 0.0499 3.5 44.4 0.3 10 Con 1.80 303 290 0.83845 0.00693 1.1 0.0540 7.2 44.1 0.5 11 Con 1.69 295 386 0.83835 0.00667 1.2 0.0521 5.5 42.6 0.5 12 Dis 0.27 45 18 0.83840 0.00705 2.8 0.0829 16.6 43.3 1.4 13 Con 0.88 148 106 0.83844 0.00693 1.5 0.0555 8.2 44.0 0.7 ES-3239; Quartz porphyry; Turquoise Gulch; UTM 7,096,410N 444,610E; Elv 2935 m 1 Con 0.99 170 82 0.83840 0.00677 1.7 0.0504 7.9 43.3 0.8 2 Con 6.70 1124 359 0.83848 0.00694 0.6 0.0479 2.7 44.5 0.3 3 Dis 0.45 76 47 0.83843 0.00695 2.2 0.0613 9.5 43.81.0 4 Con 4.12 718 126 0.83838 0.00668 0.7 0.0456 3.3 43.0 0.3 5 Con 0.85 141 63 0.83852 0.00705 1.7 0.0481 8.3 45.2 0.8 6 Con 3.55 606 358 0.83842 0.00682 0.8 0.0502 3.8 43.6 0.4 7 Con 6.23 1042 420 0.83849 0.00696 0.6 0.0458 2.8 44.8 0.3 8 Pb loss 0.37 68 35 0.83821 0.00635 2.3 0.0556 10.6 40.3 1.0 9 Con 1.19 206 158 0.83838 0.00673 1.3 0.0519 6.1 43.0 0.6 10 Con 0.71 120 42 0.83845 0.00688 1.8 0.0470 9.0 44.2 0.8 11 Pb loss 0.78 141 91 0.83827 0.00643 1.6 0.0463 7.8 41.4 0.7 12 Con 0.65 105 41 0.83858 0.00722 1.8 0.0520 8.6 46.1 0.9 13 Con 0.48 84 24 0.83839 0.00675 2.2 0.0514 10.1 43.1 1.0 14 Con 3.54 612 653 0.83838 0.00672 0.8 0.0494 3.7 43.1 0.4 15 Con 4.95 824 373 0.83850 0.00699 0.7 0.0475 3.2 44.9 0.3 ES-12791; Late quartz porphyry; Old Camp; UTM 7,098,730N 444,950E; Elv 2711 m 1 Con 1.95 334 250 0.83841 0.00678 1.0 0.0478 5.1 43.5 0.5 2 Con 3.69 645 235 0.83836 0.00665 0.8 0.0486 3.7 42.7 0.3 3 Con 6.77 1148 814 0.83845 0.00687 0.8 0.0475 2.8 44.1 0.4 4 Pb loss 1.21 216 114 0.83830 0.00652 1.2 0.0498 5.8 41.7 0.5 5 Pb loss 0.98 174 58 0.83832 0.00659 1.5 0.0517 7.2 42.1 0.7 6 Con 0.88 151 98 0.83839 0.00675 1.6 0.0487 7.8 43.3 0.7 7 Con 5.55 945 483 0.83843 0.00683 0.7 0.0478 3.6 43.9 0.3 8 Pb loss 1.08 193 69 0.83830 0.00649 1.4 0.0459 7.2 41.8 0.6 9 Pb loss 0.48 86 40 0.83828 0.00655 2.0 0.0571 8.8 41.5 0.9 10 Con 1.67 288 109 0.83840 0.00678 1.1 0.0520 6.0 43.3 0.5 11 Con 5.44 931 469 0.83842 0.00680 0.6 0.0485 3.5 43.6 0.3 12 Con 3.56 610 293 0.83843 0.00679 0.8 0.0439 3.8 43.8 0.3 13 Pb loss 0.92 168 95 0.83821 0.00635 1.6 0.0554 7.1 40.4 0.7 14 Con 5.11 863 338 0.83845 0.00689 0.7 0.0489 3.2 44.2 0.3 15 Con 1.57 268 127 0.83843 0.00682 1.2 0.0463 6.2 43.8 0.6 16 Con 1.61 276 200 0.83840 0.00680 1.2 0.0528 6.8 43.4 0.5 17 Con 2.09 357 220 0.83843 0.00682 1.0 0.0470 5.1 43.8 0.5 18 Con 5.30 905 617 0.83842 0.00681 0.7 0.0502 3.4 43.6 0.3 19 Ec 19.42 3093 1220 0.83863 0.00731 0.3 0.0473 1.6 46.9 0.2

37 Table 2.1. cont. 206 C-Pb σ σ 206 238 σ Rad Pb U Th 206 238 1 207 206 1 Pb / U 1 S # note 207 206 Pb/ U Pb/ Pb (ppm) (ppm) (ppm) Pb/ Pb err err Age (Ma) err ES-12811; X porphyry; Turquoise Gulch; UTM 7,095,950N 443,930E; Elv 2574 1 Con 0.97 166 248 0.83844 0.00681 1.6 0.0431 8.5 44.0 0.7 2 Con 0.55 97 144 0.83831 0.00654 2.1 0.0469 10.1 42.0 0.9 3 Pb loss 0.14 24 12 0.83822 0.00649 4.4 0.0712 17.7 40.5 1.9 4 Ec 1.05 175 121 0.83852 0.00701 1.6 0.0434 8.2 45.3 0.8 5 Con 1.37 235 123 0.83841 0.00680 1.5 0.0511 7.1 43.4 0.7 6 Con 1.62 275 430 0.83843 0.00684 1.3 0.0492 6.4 43.8 0.6 7 Ec 0.32 54 20 0.83848 0.00693 2.4 0.0466 11.6 44.6 1.1 8 Con 0.97 164 79 0.83844 0.00689 1.4 0.0518 6.6 44.0 0.6 9 Con 0.51 88 41 0.83837 0.00670 1.9 0.0512 8.9 42.8 0.8 10 Mz 5.58 239 153 0.84689 0.02712 0.7 0.0490 2.8 172.6 1.2 11 Pb loss 0.88 160 67 0.83825 0.00644 1.4 0.0554 6.4 41.0 0.6 12 Mz 2.67 109 51 0.84744 0.02841 1.0 0.0482 4.2 180.9 1.9 13 Ec 1.08 180 98 0.83850 0.00700 1.4 0.0492 6.5 44.9 0.6 14 Age 0.76 132 58 0.83836 0.00671 1.6 0.0536 7.2 42.8 0.7 15 Mz 1.48 86 30 0.84388 0.01997 1.2 0.0495 5.3 127.3 1.6 16 Ec 3.68 595 305 0.83858 0.00720 0.7 0.0490 3.3 46.1 0.3 IT-10; X porphyry; Turquoise Gulch; UTM 7,096,350N 444,250E; Elv 2445 m 1 Con 0.88 152 213 0.83836 0.00679 1.5 0.0642 20.1 42.7 1.0 2 Dis 0.20 33 25 0.83825 0.00713 3.2 0.1319 14.0 41.0 1.7 3 Con 1.95 331 802 0.83841 0.00685 1.0 0.0572 4.5 43.5 0.5 4 Con 1.94 326 265 0.83846 0.00692 1.0 0.0500 5.8 44.3 0.5 5 Dis 0.18 30 19 0.83825 0.00700 3.3 0.1180 34.1 41.1 2.6 6 Con 0.39 64 42 0.83840 0.00705 2.3 0.0816 13.4 43.4 1.2 7 Con 0.30 49 35 0.83849 0.00711 2.5 0.0628 13.5 44.8 1.2 8 Con 0.20 34 15 0.83834 0.00703 3.1 0.0967 11.7 42.4 1.4 9 Mz 3.55 187 42 0.84477 0.02210 0.9 0.0494 3.6 140.8 1.3 10 Mz 3.67 144 60 0.84787 0.02967 0.9 0.0552 3.3 187.2 1.7 11 Dis 0.16 24 16 0.83847 0.00758 3.5 0.1186 17.8 44.4 2.0 12 Mz 1.01 53 10 0.84474 0.02240 1.6 0.0634 6.2 140.3 2.3 13 Dis 0.25 43 30 0.83825 0.00684 2.7 0.1017 9.3 41.0 1.2 14 Con 0.31 53 16 0.83828 0.00682 2.5 0.0914 11.3 41.5 1.2 15 Dis 0.19 31 18 0.83842 0.00727 3.2 0.1014 17.7 43.6 1.7 16 Dis 0.42 68 35 0.83839 0.00712 2.2 0.0917 19.5 43.3 1.4 17 Con 0.28 45 21 0.83839 0.00710 2.7 0.0903 9.3 43.2 1.2 18 Mz 2.94 126 65 0.84680 0.02718 0.9 0.0572 3.6 171.3 1.7 ES-12785a; K porphyry; Turquoise Gulch; UTM 7,096,410N 444,410E; Elv 2440 m 1 Pb loss 1.97 351 290 0.83827 0.00652 0.9 0.0579 5.2 41.3 0.4 2 Pb loss 1.06 188 90 0.83825 0.00657 1.3 0.0701 6.0 41.0 0.6 3 Dis 0.91 153 61 0.83841 0.00690 1.5 0.0626 5.8 43.5 0.7 4 Dis 1.92 325 231 0.83841 0.00687 1.0 0.0584 5.6 43.5 0.5 5 Dis 1.10 187 92 0.83838 0.00688 1.3 0.0671 10.6 43.1 0.7 6 Dis 1.19 195 111 0.83837 0.00710 1.2 0.0948 4.3 42.9 0.6 7 Dis 1.50 256 119 0.83837 0.00683 1.1 0.0652 5.1 42.9 0.5 8 Dis 1.67 289 185 0.83833 0.00674 1.1 0.0673 4.3 42.2 0.5

38 Table 2.1. cont. 206 C-Pb σ σ 206 238 σ Rad Pb U Th 206 238 1 207 206 1 Pb / U 1 S # note 207 206 Pb/ U Pb/ Pb (ppm) (ppm) (ppm) Pb/ Pb err err Age (Ma) err ES-12807; K porphyry; Turquoise Gulch; UTM 7,095,770N 443,780E; Elv 2384 m 1 Pb loss 0.31 59 26 0.83808 0.00618 2.8 0.0750 11.5 38.4 1.2 2 Pb loss 0.42 80 39 0.83814 0.00620 2.4 0.0588 10.8 39.2 1.0 3 Con 1.48 260 264 0.83831 0.00662 1.4 0.0566 6.2 42.0 0.6 4 Pb loss 0.35 64 21 0.83816 0.00632 2.6 0.0665 11.0 39.7 1.1 5 Con 0.31 54 23 0.83830 0.00658 2.8 0.0560 12.5 41.8 1.2 6 Con 0.32 55 23 0.83830 0.00664 2.8 0.0641 11.9 41.8 1.2 7 Pb loss 0.38 69 48 0.83820 0.00639 2.5 0.0626 10.8 40.2 1.1 8 Pb loss 0.27 51 31 0.83814 0.00627 2.9 0.0689 11.8 39.2 1.2 9 Con 1.15 200 137 0.83836 0.00668 1.5 0.0517 6.9 42.7 0.7 10 Pb loss 0.39 70 47 0.83823 0.00642 2.5 0.0576 11.5 40.7 1.1 11 Con 0.67 113 88 0.83846 0.00692 1.9 0.0491 10.0 44.3 0.9 12 Dis 0.47 82 40 0.83829 0.00663 2.3 0.0663 9.4 41.61.0 13 Con 0.35 61 20 0.83835 0.00665 2.6 0.0495 12.0 42.6 1.1 14 Con 0.90 157 99 0.83834 0.00665 1.8 0.0519 8.2 42.4 0.8 15 Pb loss 0.39 71 31 0.83824 0.00647 2.4 0.0617 10.2 40.8 1.0 16 Con 0.63 112 94 0.83829 0.00655 1.9 0.0549 8.8 41.6 0.8 17 Con 0.50 90 66 0.83827 0.00649 2.2 0.0546 9.9 41.3 0.9 18 Con 0.45 82 62 0.83825 0.00645 2.5 0.0550 17.1 41.0 1.1 19 Pb loss 0.28 52 24 0.83804 0.00624 2.9 0.0942 10.1 37.8 1.2 20 Dis 0.34 54 26 0.83840 0.00726 2.6 0.1053 8.4 43.3 1.2 ES-12800; L porphyry; M Gulch-Copper Hill; UTM 7,097,301N 444,806E; Elv 2700 m 1 Ec 0.99 162 67 0.83855 0.00712 1.3 0.0474 6.3 45.70.6 2 Con 0.85 145 80 0.83840 0.00680 1.4 0.0529 6.6 43.3 0.6 3 Con 1.11 194 119 0.83835 0.00664 1.2 0.0498 5.8 42.5 0.5 4 Ec 7.16 1153 484 0.83859 0.00723 0.5 0.0481 2.3 46.4 0.2 5 Mz 2.61 285 79 0.84002 0.01065 0.9 0.0471 4.0 68.30.6 6 Con 1.68 279 156 0.83849 0.00698 1.0 0.0473 5.7 44.8 0.5 7 Con 1.78 303 170 0.83844 0.00684 1.0 0.0467 4.9 44.0 0.5 8 Con 1.20 202 89 0.83847 0.00692 1.2 0.0477 6.0 44.4 0.6 9 Con 2.05 356 324 0.83839 0.00672 0.9 0.0483 4.2 43.1 0.4 10 Con 1.15 196 93 0.83843 0.00683 1.3 0.0500 6.0 43.7 0.6 11.1Ec 0.32 53 21 0.83852 0.00705 2.4 0.0491 11.4 45.2 1.1 11.2 Con 0.87 149 91 0.83843 0.00683 1.4 0.0485 6.8 43.8 0.6 12 Con 1.55 262 124 0.83845 0.00688 1.0 0.0480 5.0 44.1 0.5 ES-12783; A porphyry; M Gulch-Copper Hill; UTM 7,097,125N 444,568E; Elv 2661 m 1 Con 1.03 175 85 0.83843 0.00683 1.6 0.0492 7.6 43.7 0.7 2 Con 0.67 116 43 0.83837 0.00670 2.0 0.0492 9.0 42.9 0.9 3 Con 1.19 199 81 0.83847 0.00692 1.6 0.0458 7.3 44.5 0.7 4 Con 1.14 204 72 0.83828 0.00651 1.4 0.0541 6.5 41.5 0.6 5 Con 1.46 255 185 0.83838 0.00668 1.3 0.0462 7.9 43.0 0.6 6 Con 1.51 262 147 0.83838 0.00674 1.3 0.0519 6.1 43.0 0.6 7 Con 0.63 105 36 0.83847 0.00696 1.9 0.0507 9.3 44.5 0.9 8 Con 1.36 236 125 0.83840 0.00674 1.2 0.0464 6.1 43.3 0.6 9 Ec 1.98 322 187 0.83855 0.00715 1.2 0.0524 5.5 45.6 0.6 10 Con 0.97 174 92 0.83827 0.00649 1.5 0.0531 7.1 41.4 0.7 11 Pb loss 1.75 329 67 0.83817 0.00620 1.0 0.0481 4.8 39.8 0.4 12 Con 0.98 172 77 0.83837 0.00665 1.6 0.0432 8.1 42.9 0.7 13 Con 1.56 273 127 0.83834 0.00665 1.3 0.0528 5.9 42.4 0.6 14 Con 0.86 152 109 0.83835 0.00660 1.8 0.0441 9.0 42.5 0.8 15 Ec 2.81 465 168 0.83852 0.00704 1.0 0.0471 4.8 45.2 0.5 16 Con 0.47 78 37 0.83845 0.00692 2.2 0.0524 10.8 44.2 1.0 17 Con 0.83 149 83 0.83828 0.00652 1.7 0.0540 7.6 41.5 0.7 18 Con 0.51 88 36 0.83837 0.00672 2.0 0.0511 9.5 42.9 0.9

39 Table 2.1. cont. 206 C-Pb σ σ 206 238 σ Rad Pb U Th 206 238 1 207 206 1 Pb / U 1 S # note 207 206 Pb/ U Pb/ Pb (ppm) (ppm) (ppm) Pb/ Pb err err Age (Ma) err ES-12782; R porphyry; M Gulch-Copper Hill; UTM 7,097,266N 444,306E; Elv 2624 m 1 Con 2.06 351 294 0.83838 0.00682 1.3 0.0620 9.2 43.0 0.6 2 Con 1.87 316 119 0.83843 0.00687 1.3 0.0534 5.5 43.8 0.6 3 Mz 6.38 260 144 0.84744 0.02853 0.9 0.0521 3.2 180.8 1.6 4 Dis 0.15 22 14 0.83836 0.00768 3.8 0.1558 18.8 42.82.4 5 Con 5.32 906 372 0.83843 0.00684 0.7 0.0486 4.2 43.8 0.3 6 Pb loss 1.14 202 107 0.83823 0.00656 1.3 0.0749 7.8 40.7 0.6 7 Con 1.45 241 102 0.83846 0.00699 1.3 0.0597 15.1 44.2 0.8 8 Con 2.96 511 152 0.83838 0.00674 0.9 0.0527 4.1 43.0 0.4 9 Con 0.98 169 72 0.83835 0.00671 1.5 0.0556 6.7 42.6 0.7 10 Con 5.25 896 1116 0.83843 0.00682 0.6 0.0484 4.5 43.8 0.3 11 Pb loss 0.39 70 32 0.83818 0.00648 2.3 0.0801 10.4 40.0 1.0 12 Pb loss 1.94 354 117 0.83821 0.00637 1.1 0.0582 4.8 40.4 0.5 13 Dis 0.51 86 46 0.83834 0.00684 2.1 0.0760 8.5 42.4 0.9 14 Con 4.38 766 381 0.83835 0.00665 0.7 0.0494 4.2 42.6 0.3 15 Con 0.96 164 66 0.83835 0.00680 1.6 0.0673 11.2 42.6 0.8 16 Dis 0.44 72 41 0.83841 0.00710 2.2 0.0859 11.2 43.4 1.1 17 Con 0.99 168 56 0.83840 0.00685 1.5 0.0588 8.4 43.3 0.7 ES-12789a; L porphyry; Granite Gulch; UTM 7,094,339N 443,412E; Elv 2850 m 1 Dis 0.27 48 18 0.83828 0.00660 2.7 0.0640 10.4 41.51.2 2 Dis 0.21 34 13 0.83839 0.00739 3.2 0.1195 11.7 43.3 1.6 3 Pb loss 2.15 395 149 0.83822 0.00635 1.0 0.0527 4.6 40.5 0.4 4 Dis 0.22 34 21 0.83835 0.00757 3.1 0.1491 18.1 42.62.1 5 Con 1.26 216 89 0.83841 0.00679 1.3 0.0482 6.1 43.5 0.6 6 Con 9.16 1543 1510 0.83846 0.00691 0.5 0.0493 2.4 44.3 0.2 7 Dis 0.27 42 19 0.83855 0.00741 2.8 0.0799 20.9 45.71.6 8 Dis 0.30 49 36 0.83839 0.00701 2.7 0.0811 9.9 43.21.2 9 Dis 0.24 39 21 0.83831 0.00706 3.0 0.1095 13.0 41.91.5 10 Dis 0.37 62 57 0.83835 0.00691 2.4 0.0810 11.5 42.5 1.1 11 Dis 0.33 55 34 0.83838 0.00701 2.5 0.0841 14.7 43.0 1.3 12 Pb loss 0.39 70 58 0.83818 0.00646 2.3 0.0769 9.2 40.0 1.0 13 Dis 0.21 32 14 0.83843 0.00782 3.2 0.1522 8.3 43.8 1.6 14 Dis 0.25 40 25 0.83835 0.00708 3.0 0.0999 17.4 42.6 1.6 15 Dis 0.20 30 13 0.83846 0.00772 3.3 0.1359 17.0 44.2 2.0 IT-9; L porphyry; Turquoise Gulch; UTM 7,096,410N 444,240E; Elv 2445 1 Con 0.99 177 84 0.83826 0.00653 1.5 0.0631 6.2 41.1 0.6 2 Con 1.08 191 89 0.83830 0.00658 1.4 0.0566 6.9 41.8 0.6 3 Con 0.86 152 65 0.83830 0.00659 1.5 0.0575 6.7 41.8 0.7 4 Con 0.92 164 67 0.83829 0.00656 1.5 0.0583 6.5 41.6 0.6 5 Dis 0.29 49 31 0.83844 0.00700 2.6 0.0665 10.9 43.91.2 6 Dis 0.38 64 14 0.83838 0.00702 2.3 0.0850 8.8 43.01.1 7 Con 1.01 178 78 0.83828 0.00658 1.4 0.0632 6.1 41.4 0.6 8 Con 0.89 155 74 0.83833 0.00670 1.5 0.0626 10.9 42.2 0.7 9 Con 1.43 255 116 0.83827 0.00654 1.2 0.0599 10.9 41.4 0.6 10 Con 0.86 151 62 0.83834 0.00661 1.5 0.0475 12.6 42.4 0.7 11 Con 1.13 199 93 0.83833 0.00663 1.3 0.0542 7.0 42.2 0.6 12 Con 5.92 1031 1018 0.83837 0.00668 0.6 0.0483 2.8 42.8 0.3 13 Dis 0.75 125 49 0.83846 0.00699 1.8 0.0596 12.0 44.2 0.9 14 Dis 1.15 192 103 0.83844 0.00695 1.4 0.0592 9.3 44.0 0.7

40

Table 2.1. cont. 206 C-Pb σ σ 206 238 σ Rad Pb U Th 206 238 1 207 206 1 Pb / U 1 S # note 207 206 Pb/ U Pb/ Pb (ppm) (ppm) (ppm) Pb/ Pb err err Age (Ma) err ES-12787; L porphyry; Turquoise Gulch; UTM 7,096,420N 444,390E; Elv 2440 m 1 Con 0.78 143 98 0.83823 0.00637 1.8 0.0527 8.1 40.7 0.8 2 Con 0.18 34 15 0.83820 0.00635 3.7 0.0586 14.6 40.2 1.6 3 Con 0.72 130 64 0.83825 0.00639 2.0 0.0491 8.7 41.0 0.8 4 Con 0.39 72 29 0.83822 0.00634 2.5 0.0489 13.9 40.6 1.1 5 Con 0.86 161 104 0.83817 0.00625 1.8 0.0563 7.3 39.7 0.7 6 Con 1.24 214 155 0.83838 0.00675 1.5 0.0545 6.2 43.0 0.7 7 Con 0.54 103 39 0.83812 0.00612 2.2 0.0547 9.3 38.9 0.9 8 Con 0.79 141 66 0.83828 0.00648 1.9 0.0506 8.1 41.5 0.8 9 Con 0.56 104 54 0.83816 0.00629 2.2 0.0623 8.6 39.7 0.9 10 Con 0.47 82 56 0.83834 0.00662 2.4 0.0509 12.5 42.3 1.1 11 Con 1.52 266 208 0.83835 0.00663 1.3 0.0486 5.8 42.5 0.6 12 Con 1.46 258 194 0.83832 0.00658 1.3 0.0519 5.6 42.0 0.6 13 Con 1.17 217 186 0.83820 0.00626 1.6 0.0477 7.0 40.2 0.6 14 Con 0.79 139 69 0.83834 0.00664 1.8 0.0509 7.6 42.5 0.8 15 Con 0.67 125 61 0.83817 0.00625 2.0 0.0539 8.3 39.8 0.8 16 Con 0.71 125 66 0.83836 0.00665 1.9 0.0472 8.6 42.7 0.9 17 Con 0.58 103 64 0.83831 0.00660 2.2 0.0543 9.3 42.0 1.0 18 Con 0.60 109 61 0.83824 0.00641 2.2 0.0527 15.8 40.9 1.0 ES-12792; Latite dike; Turquoise Gulch; UTM 7,096,245N 443,800E; Elv 2476 m 1 Pb loss 1.73 325 188 0.83815 0.00622 1.4 0.0564 5.2 39.5 0.6 2 Pb loss 3.60 678 619 0.83814 0.00618 0.7 0.0559 3.2 39.3 0.3 3 Dis 2.19 378 261 0.83834 0.00675 0.9 0.0659 3.7 42.3 0.4 4 Dis 1.81 319 656 0.83827 0.00659 1.0 0.0670 4.0 41.3 0.4 5 Dis 3.08 558 363 0.83825 0.00642 0.8 0.0536 3.6 40.9 0.3 6 Con 3.43 606 470 0.83831 0.00658 0.7 0.0533 3.4 42.0 0.3 7 Dis 1.18 202 115 0.83836 0.00679 1.2 0.0638 11.2 42.7 0.6 8 Dis 0.33 56 24 0.83817 0.00685 2.3 0.1252 8.3 39.81.1 9 Dis 1.95 353 273 0.83823 0.00644 0.9 0.0603 4.4 40.7 0.4 10 Con 3.32 581 1348 0.83834 0.00665 0.7 0.0525 4.4 42.4 0.3 11 Dis 1.61 287 401 0.83825 0.00652 1.1 0.0645 4.8 41.0 0.5 12 Con 3.21 574 337 0.83829 0.00651 0.7 0.0515 3.4 41.6 0.3

Zircon grains (S #) from El Salvador porphyry samples measured by SHRIMP-RG. Uranium and Th concentrations and measured 206 Pb/ 238 U and 207 Pb/ 206 Pb ratios 206 determined by comparison with zircon standard R33 (Black et al., 2004). Pb/ 238 U model ages are corrected for common lead by the given observed C-Pb 207 Pb/ 206 Pb ratios. Note signifies grains that are concordant (Con), discordant (Dis), display probable lead- loss (Pb loss), Mesozoic inherited grain (Mz), and interpreted Eocene inherited grain (Ec). Raw data reduction was done using SQUID 1.02 (Ludwig, 2001).

41 age was corrected for common Pb contributions using the measured common

207 Pb/ 206 Pb ratio (Schmitt et al., 2003; Miller and Wooden, 2004). Because 204 Pb is low in abundance and therefore yields poor counting statistics, it does not yield precise estimates of common Pb contributions to 206 Pb. Instead, the common 206 Pb is estimated based on the measured 207 Pb/ 206 Pb ratio and the assumption of concordancy (Ludwig,

2001, 2003). The ages herein are therefore the 207 Pb – corrected 206 Pb/ 238 U ages and are given at 95% (2 σ) confidence level.

Results

Zircon U/Pb data

Six to eighteen spots were analyzed from the fourteen samples collected from El

Salvador. A total of 165 spot ages were used for age determinations (Table 2.1) after

10% of spots were culled based on Pb-loss, discordance, and individual spot errors greater than 3 σ. Most of the samples analyzed in this study yield complicated spectra of

206 Pb/ 238 U ages, of which >90% fall in the range of 40 to 46 Ma, and a small percentage

(5%) yield Mesozoic ages interpreted as inherited grains. Most of the individual spot analyses within a single sample overlap within 2 σ error. However, a few spot analyses do not overlap within the main population and give older ages with low error (1%). The presence of two or more analytically distinct Eocene zircon ages in a single sample suggests two or more age populations within a single sample. In addition, a few zircons

(<5%) yield ages that are too young based on being younger than the age of the post- mineral latite intrusion, and are likely the result of post-crystallization Pb-loss due to weathering and groundwater leaching. In order to identify the age of zircons we have employed “probability analysis” using one of the Isoplot functions. The populations

42 were selected based on the lowest mean sum of the weighted deviates (MSWD) after

Wendt and Carl (1991) and cumulative probability plots given by a distinct subset.

MSWD are statistical measures of the ratio between observed and expected scatter of the data. Where MSWD are near or equal to one the assigned errors are the only cause of scatter and one age population may be assumed, whereas deviations greater or less than one indicate underestimation or overestimation of analytical errors (Ludwig, 2000;

Ludwig, 2003).

Representative sample populations were plotted on Terra-Wasserburg Concordia diagrams (Figure 2.5). Ages of grains that were discordant and younger than the main population were omitted from the age analysis as probable Pb-loss. The remaining concordant ages are reported as weighted mean averages of the 206 Pb/ 238 U age with two sigma error (95% interval of confidence) (Figures 2.5A, B, C, D, H, I, L, M, N). In some cases many discordant grains were older and appear to show common Pb-inheritance. In these cases regression lines were used to calculate the intercept with Concordia modified to account for initial U-Th disequilibrium using the observed common Pb ( 207Pb/ 206 Pb =

0.8383 ± 0.0001) (e.g. Schmitt et al., 2003; Miller and Wooden, 2004). These intercept ages are used as the interpreted ages and yield similar ages to the weighted mean average and have viable MSWD values (Figures 2.5E, F, G, J, K).

Zircon U/Pb age calculations

Fourteen new U/Pb zircon ages are presented for porphyries from the El Salvador deposit (Table 2.2). The oldest samples analyzed are from the quartz porphyries collected from Old Camp and Turquoise gulch. Thirteen grains were analyzed from sample ES-12808 (quartz porphyry from the base of the Old Camp pit). Three grains were discarded to probable lead loss and discordance at the 2 σ error level (Figure 2.5A).

43 Table 2.2. Summary of interpreted zircon 206 Pb/ 238 U ages for El Salvador porphyry samples.

Coordinates 206 /238 Sample # Rock Type Location Elv. (m) Pb U Age NE ES-12782 R porphyry M Gulch - Copper Hill 7,097,266 444,306 2624 43.3 ± 0.4 (13) ES-12783 A porphyry M Gulch - Copper Hill 7,097,125 444,568 2661 42.8 ± 0.5 (14) ES-12785a K porphyry Turquoise Gulch 7,096,410 444,410 2440 42.9 ± 0.4 (6) ES-12787 L porphyry Turquoise Gulch 7,096,420 444,390 2440 41.8 ± 0.5 (11) ES-12789a L porphyry Granite Gulch 7,094,339 443,412 2850 43.9 ± 0.4 (13) ES-12791 Late quartz porphyry Old Camp 7,098,730 444,950 2711 43.6 ± 0.3 (13) ES-12792 Latite dike Turquoise Gulch 7,096,245 443,800 2476 41.6 ± 0.5 (9) ES-12800 L porphry M Gulch - Copper Hill 7,097,301 444,806 2700 43.8 ± 0.6 (9) ES-12807 K porphyry Turquoise Gulch DD-1367 269-286m 7,095,770 443,780 2384 42.3 ± 0.5 (12) ES-12808 Quartz porphyry Old Camp 7,098,940 445,110 2650 43.6 ± 0.6 (10) ES-12811 X porphyry Turquoise Gulch DD-8480 168.1m 7,095,950 443,930 2574 43.8 ± 0.7 (10) ES-3239 Quartz porphyry Turquoise Gulch 7,096,745 444,610 2935 44.0 ± 0.6 (13) IT-9 L porphyry Turquoise Gulch 7,096,410 444,240 2445 42.2 ± 0.5 (10) IT-10 X porphyry Turquoise Gulch 7,096,350 444,250 2445 43.4 ± 0.5 (14) 206 Pb/ 238 U ages in Ma corrected using common 207 Pb correction with number of grains per age given in parenthesis. All samples collected by lead author except ES-3239 collected by Lew Gustafson and IT-9 & IT-10 collected by Cornejo et al. (1997) and used with permission.

44 The remaining spots (n=10) yield a weighted mean 206 Pb/ 238 U interpreted age of 43.6 ±

0.6 Ma with a MSWD of 2.4. The late quartz porphyry and associated breccia (ES-

12791) that cuts the quartz porphyry at Old Camp contains a group that yields a robust weighted mean age of 43.6 ± 0.3 Ma (n=13) with a MSWD of 1.2 (Figure 2.5B). The sample also contains one grain that is 46.9 ± 0.2 Ma, which is concordant and may represent an inherited zircon derived from an older intrusion. Five grains were discarded on the basis of probable Pb-loss because they yield younger ages, and greater errors relative to the older zircon grains. The 43.6 ± 0.3 Ma is analytically indistinguishable from the interpreted age of the 43.6 ± 0.6 Ma age of the Old Camp quartz porphyry.

The quartz porphyry from Turquoise Gulch (ES-3239) yielded an interpreted age of 44.0 ± 0.6 Ma (n=13) with an MSWD of 5.0 after removal of two younger points with younger ages interpreted to be the result of Pb-loss (Figure 2.5C). The large dispersion of the data points indicated by the high MSWD suggests the possibility of two age populations which yield 43.2 ± 0.3 Ma (n=7) with an MSWD of 0.41 and 44.7 ± 0.3 Ma

(n=5) with an MSWD of 0.44. The older set of zircons yields an age that is analytically distinct from the 43.6 ± 0.6 Ma age we interpret for the quartz porphyry from Old Camp.

However the low MSWD (<1) for each age subpopulation suggests an overestimation of the ages and we prefer the 44.0 ± 0.6 Ma age as this is consistent with previously reported ages for the quartz porphyry (Gustafson and Hunt, 1975; Cornejo et al., 1997).

All of the X and K porphyries are difficult to interpret due to the wide spread and high error of individual zircon ages. The two X porphyries contain zircons that yield ages similar to both the interpreted quartz porphyry ages (~43.6 Ma) and contain older

45-46 Ma age zircons recognized in the quartz porphyry from Old Camp. In addition, the

X porphyries contain several inherited zircon grains (n = 7) that yield Mesozoic ages

45 consistent with previous Mesozoic zircon ages from the X porphyry reported by

Cornejo et al. (1997) and Tosdal et al. (2000). Sample ES-12811 of the X porphyry from south of Turquoise Gulch yielded an interpreted age of 43.8 ± 0.7 Ma (n=10) with a

MSWD of 1.7 (Figure 2.5D). One grain gave a slightly older age of 46.1 ± 0.7 (2 σ) Ma that we interpret as an inherited Eocene age grain. Two grains show apparent Pb-loss.

This sample also contained two grains of Jurassic age (180.9 ± 1.9 Ma, 172.6 ± 1.2 Ma) and one grain of late Cretaceous age (127.3 ± 1.6 Ma). Sample IT-10 of X porphyry from the 2445 level of the Turquoise Gulch underground mine was previously analyzed by Cornejo et al. (1997) and yielded a 41.6 ± 1.2 Ma K-Ar biotite age and 41.8 ± 2.3 Ma

U/Pb zircon age. Our results show discordance towards common lead and give an intercept age of 43.4 ± 0.5 Ma (n=14) with a MSWD of 1.17 (Figure 2.5E). Our new age is within error of both the previous U/Pb age reported by Cornejo et al. (1997) and with our other X porphyry sample, but is older the the K-Ar age (41.6 Ma). The latter age apparently represents thermal resetting. This sample also contained two grains of

Jurassic age (187.2 ± 1.7 Ma, 171.3 ± 1.7 Ma) and two grains of early Cretaceous age

(140.8 ± 1.3 Ma, 140.2 ± 2.3 Ma).

The two K porphyry samples we analyzed yielded slightly different apparent ages.

Sample ES-12807 collected from drill core between Turquoise Gulch and Granite Gulch

(Figure 2.2) yields an age of 42.2 ± 0.5 Ma (n=12) with a MSWD of 0.97 after removal of eight young discordant ages due to probable Pb-loss (Figure 2.5F). Sample ES-12785a was collected underground in the 2440 level and yielded an common lead intercept age of

42.9 ± 0.4 Ma (n=6) with a MSWD of 0.95 after discarding the youngest two ages

(Figure 2.5G).

46 Five samples were analyzed to test geographic and local age span of L porphyries and the related A and R porphyries: L, A, and R porphyry from M Gulch –

Copper Hill, L porphyry from Turquoise Gulch, and L porphyry from Granite Gulch.

The main population of zircons from L porphyry sample at M Gulch – Copper Hill (ES-

12800) yielded an age of 43.8 ± 0.6 Ma (n=9) MSWD of 1.9 that is similar to the interpreted age of the quartz porphyries. Three zircon grains from this sample have

Eocene ages between 45 and 46 Ma that are concordant (Figure 2.5H). This sample also contained a single zircon with a late Cretaceous age of 68.3 ± 1.2 Ma (2 σ). The A porphyry from M Gulch (ES-12783) yielded one population with an interpreted age of

42.8 ± 0.5 Ma (n=14) with an MSWD of 1.9 (Figure 2.5I). The A porphyry also contained two grains with older 45 Ma ages. One grain was concordant but gave an age of 39.7 ± 0.8 Ma which is younger than any age given for this deposit and was omitted from the weighted mean age. The R porphyry from M Gulch (ES-12782) yielded a main population with an intercept common lead age of 43.3 ± 0.4 Ma (n=13) with an MSWD of 1.3. Three grains are discordant and younger and were discarded from the interpreted weighted mean age (Figure 2.5J). The R porphyry also contained one inherited grain with a Mesozoic age of 180.8 ± 1.6 Ma. The zircon ages from M Gulch – Copper Hill are similar to the Ar-Ar and U/Pb ages reported by Cornejo et al. (1997) and Gustafson et al. (2001) from M Gulch intrusions.

The L porphyry from Granite Gulch (ES-12789a) contains multiple discordant zircon grains and an emplacement age for this sample is difficult to interpret. Following the removal of two younger ages, presumably due to Pb-loss, an intercept age of 43.9 ±

0.4 Ma (13) with a MSWD of 1.16 was determined (Figure 2.5K). Note that this age is

47

48

Figure 2.5. Terra-Wasserburg concordia diagrams showing U/Pb geochronologic data with interpreted weighted mean age for selected samples. Open circles represent data not used in age calculations. Filled circles are the interpreted intrusion age and shaded circles represent possible older Eocene age zircon grains. Dashed regression line assumes intercept with common Pb ( 207 Pb/ 206 Pb = 0.8383 ± 0.0001) with interpreted 206 Pb/ 238 U intercept age given (c.f. Schmitt et al. 2003). Error on ages and error ellipses all at 2 σ level. A. ES-12808 quartz porphyry from Old Camp. B. ES-12791 late quartz porphyry from Old Camp. C. ES-3239 quartz porphyry from Turquoise Gulch. D. ES-12811 X porphyry from Turquoise Gulch. E. IT-10 X porphyry from Turquoise Gulch. F. ES- 12807 K porphyry from Turquoise Gulch. G. ES-12785a K porphyry from Turquoise Gulch. H. ES-12800 L porphyry from M Gulch. I. ES-12783 A porphyry from M Gulch. J. ES-12782 R porphyry from M Gulch. K. ES-12789a L porphyry from Granite Gulch. L. IT-9 L porphyry from Turquoise Gulch. M. ES-12787 L porphyry from Turquoise Gulch. N. ES-12792 Latite dike from Turquoise Gulch.

49 indistinct from and nearly identical to the age of the L porphyry from M Gulch –

Copper Hill.

Sample IT-9 from Turquoise Gulch at the 2445 level of the Turquoise Gulch underground mine and contains both concordant and discordant grains (Figure 2.5L) that together yield an interpreted age of 42.4 ± 0.5 (n = 14) with a MSWD of 2.1. Removing the discordant grains with older ages gives an interpreted age of 42.2 ± 0.5 Ma (n=10) with a MSWD of 1.6. ES-12787 was collected from the same L porphyry at the 2440 level and when six younger and one older grains are discarded yields an age of 41.8 ± 0.5 Ma (n=12) with a MSWD of 0.95 which is within error of the L porphyry sample IT-9 collected southwest of this locality.

The sample of a Latite Dike (ES-12792) from Turquoise Gulch in the Inca Oeste area of the underground mine yielded an age for all twelve zircon (mostly discordant) of

41.2 ± 0.7 Ma (n = 12) with an unacceptable MSWD of 8.1. Three grains each gave ages of 39 Ma that are interpreted to result from Pb-loss. Removing the younger ages yields an interpreted age of 41.6 ± 0.5 Ma (n = 9) with a MSWD of 3.0 (Figure 2.5N). The latite dike postdates all intrusive and hydrothermal alteration in the El Salvador district and the younger 41.6 Ma zircon age reported is consistent with field relations and the ages of older intrusions and hydrothermal events reported here and in previous studies.

Trace element geochemistry of zircons

The trace element content of zircons from the El Salvador district vary with distinct differences between older and younger units (Table 2.3). Grains were culled based on apatite inclusions (determined by enriched LREE contents: Hinton and Upton,

1991; Sano et al., 2002) and age values with low confidence (i.e. Pb-loss, discordance, and error greater than 3 σ). While trace element content may be robust in those zircons

50 Table 2.3. Composition of zircon grains from the El Salvador district. Age Hf La Ce Nd Sm Eu Gd Dy Er Yb Analyzed Spot Rock Type Eu/Eu* Ce/Ce* (Ma ± 1 σ) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) IT-10-10 X ppy 187.2± 1.7 15485 0.01 11.63 0.18 0.51 0.25 4.7 20.2 43 106 0.48 177 ES-12811-12 X ppy 180.9± 1.9 10764 0.01 14.47 0.51 1.31 0.72 12.5 48.8 100 227 0.54 170 ES 12782-3 R ppy 180.8± 1.6 10768 0.01 33.73 0.71 2.16 0.92 26.0 116.0 232 485 0.37 378 ES-12811-10 X ppy 172.6± 1.2 11375 0.05 29.58 0.58 1.69 0.81 18.9 81.1 171 373 0.44 131 IT-10-18 X ppy 171.3± 1.7 10077 0.05 13.44 0.42 1.22 0.70 13.8 60.3 129 272 0.52 62 IT-10-9 X ppy 140.8 ± 1.3 15896 0.01 7.90 0.06 0.31 0.17 4.5 32.6 100 298 0.44 193 IT-10-12 X ppy 140.2 ± 2.3 12877 0.01 5.29 0.06 0.29 0.16 3.8 23.6 66 188 0.47 131 ES-12811-15 X ppy 127.3 ± 1.6 11704 0.01 16.99 0.20 0.82 0.46 10.1 54.6 137 347 0.48 302 ES-12800-5 L ppy 68.3 ± 0.6 12538 0.01 19.49 0.26 0.96 0.45 8.8 42.3 94 227 0.47 353

ES 12808-2 Qtz ppy 42.5 ± 0.6 11117 0.33 52.30 1.22 4.03 1.81 47.5 233.2 418 731 0.40 49 ES 12808-3 Qtz ppy 45.0 ± 0.5 10952 0.02 91.45 1.32 4.38 2.42 43.6 173.4 296 536 0.53 638 ES 12808-5 Qtz ppy 43.1 ± 0.4 11095 0.03 117.39 2.32 7.94 3.64 88.8 378.5 630 1053 0.42 413 ES 12808-6 Qtz ppy 43.7 ± 0.6 10808 0.16 32.04 0.53 1.67 0.99 18.4 81.4 155 307 0.54 65 ES 12808-7 Qtz ppy 43.8 ± 0.3 12621 0.02 104.74 1.30 5.26 2.17 53.0 233.5 394 687 0.39 640 ES 12808-8 Qtz ppy 43.0 ± 0.5 7854 0.22 64.94 12.01 17.71 10.84 107.5 310.0 512 936 0.75 37 ES 12808-9 Qtz ppy 44.4 ± 0.3 12841 0.02 89.36 0.99 4.39 2.00 57.6 314.7 624 1171 0.38 679 ES 12808-10 Qtz ppy 44.1 ± 0.5 10375 0.02 35.34 0.60 1.99 1.19 20.1 79.2 146 290 0.57 273 ES 12808-11 Qtz ppy 42.6 ± 0.5 8750 0.04 59.49 2.82 6.53 3.81 53.9 182.0 297 515 0.62 182 ES 12808-13 Qtz ppy 44.0 ± 0.7 9785 0.02 31.73 0.71 2.14 1.35 23.4 104.8 195 379 0.58 237

ES-3239-1 Qtz ppy 43.3 ± 0.8 10596 0.03 30.40 0.67 2.14 1.37 23.7 108.0 215 433 0.58 174 ES-3239-2 Qtz ppy 44.5 ± 0.3 12982 0.01 80.63 0.73 3.34 1.03 42.2 228.3 442 839 0.26 757 ES-3239-3 Qtz ppy 43.8 ± 1.0 7669 0.02 15.08 0.66 1.94 1.55 19.1 75.1 145 293 0.77 111 ES-3239-4 Qtz ppy 43.0 ± 0.3 13831 0.02 17.49 0.39 2.44 0.81 35.4 276.6 563 1209 0.26 150 ES-3239-5 Qtz ppy 45.2 ± 0.8 9107 0.06 19.59 0.49 1.39 0.92 14.2 65.8 132 279 0.63 78 ES-3239-6 Qtz ppy 43.6 ± 0.4 10546 0.04 94.16 0.99 3.71 1.82 39.0 174.8 320 594 0.46 415 ES-3239-7 Qtz ppy 44.8 ± 0.3 11186 0.03 79.32 0.77 3.41 1.14 40.8 209.7 392 718 0.29 400 ES-3239-8 Qtz ppy 40.3 ± 1.0 9129 0.02 11.69 0.30 0.94 0.56 8.4 42.6 87 182 0.60 109 ES-3239-9 Qtz ppy 42.9 ± 0.6 10309 0.02 43.55 0.86 3.48 1.92 40.2 181.9 322 561 0.49 260 ES-3239-10 Qtz ppy 44.2 ± 0.8 10045 0.01 16.25 0.31 1.10 0.72 10.9 55.1 116 255 0.63 193 ES-3239-12 Qtz ppy 46.1 ± 0.9 8895 0.01 11.83 0.37 1.22 0.72 10.9 51.5 108 244 0.60 166 ES-3239-13 Qtz ppy 43.1 ± 1.0 10646 0.01 11.21 0.22 0.70 0.40 7.1 34.8 75 178 0.54 159 ES-3239-14 Qtz ppy 43.1 ± 0.4 9641 0.04 232.05 3.48 10.54 6.72 104.9 363.2 546 879 0.61 652 ES-3239-15 Qtz ppy 44.9 ± 0.3 10969 0.02 128.07 1.04 4.43 2.01 61.8 336.8 652 1166 0.37 892

ES-12791-1 Lt Qtz Ppy 43.5 ± 0.5 11076 0.04 40.48 0.46 1.49 0.82 16.4 68.9 127 248 0.50 218 ES-12791-3 Lt Qtz Ppy 44.1 ± 0.4 13908 0.05 85.09 1.41 5.06 1.86 53.7 267.4 514 983 0.34 255 ES-12791-6 Lt Qtz Ppy 43.3 ± 0.7 11211 0.03 22.94 0.38 1.14 0.54 9.8 39.2 75 159 0.49 160 ES-12791-7 Lt Qtz Ppy 43.8 ± 0.3 13617 0.05 62.72 0.98 5.55 2.11 73.9 451.3 900 1583 0.32 239 ES-12791-10 Lt Qtz Ppy 43.3 ± 0.5 10603 0.08 20.35 0.25 0.82 0.43 8.9 46.3 104 237 0.49 85 ES-12791-11 Lt Qtz Ppy 43.6 ± 0.3 12823 0.03 75.42 0.76 3.66 1.40 43.9 234.6 458 870 0.34 442 ES-12791-12 Lt Qtz Ppy 43.8 ± 0.4 11070 0.02 53.35 0.54 2.14 1.00 25.4 129.5 237 430 0.41 402 ES-12791-14 Lt Qtz Ppy 44.2 ± 0.3 13889 0.02 83.69 1.45 6.27 1.77 67.8 355.5 662 1193 0.26 525 ES-12791-15 Lt Qtz Ppy 43.8 ± 0.6 11730 0.03 34.95 0.39 1.28 0.55 13.0 58.8 118 254 0.41 263 ES-12791-16 Lt Qtz Ppy 43.4 ± 0.5 11353 0.02 33.08 0.41 1.31 0.68 12.4 52.8 103 231 0.51 259 ES-12791-17 Lt Qtz Ppy 43.8 ± 0.5 11328 0.04 47.05 0.76 3.40 1.68 37.3 184.8 345 620 0.45 228 ES-12791-18 Lt Qtz Ppy 43.6 ± 0.3 11521 0.03 155.73 1.44 6.81 2.87 82.1 409.5 746 1279 0.37 757 ES-12791-19 Lt Qtz Ppy 46.9 ± 0.2 14171 0.02 80.54 1.59 8.63 2.35 106.7 680.4 1318 2409 0.24 404

IT-10-1 X ppy 42.7 ± 1.0 8426 0.15 49.35 7.96 16.76 10.40 116.0 297.7 412 696 0.72 42 IT-10-2 X ppy 40.9 ± 1.7 8550 0.03 11.02 2.26 3.61 2.06 22.5 62.1 95 174 0.69 47 IT-10-3 X ppy 43.5 ± 0.5 7099 0.57 139.48 34.15 51.40 30.40 273.8 619.9 747 1102 0.78 30 IT-10-4 X ppy 44.3 ± 0.5 9304 0.03 39.25 1.78 4.63 2.77 40.4 142.5 238 415 0.62 178 IT-10-5 X ppy 40.9 ± 2.6 9726 0.01 11.10 1.04 1.81 1.21 12.8 44.3 75 142 0.77 88 IT-10-6 X ppy 43.3 ± 1.2 10595 0.02 12.04 1.07 1.90 1.23 14.2 49.6 92 195 0.72 79 IT-10-7 X ppy 44.7 ± 1.2 8540 0.03 11.10 1.38 2.42 1.47 16.5 55.1 96 190 0.71 47 IT-10-8 X ppy 42.3 ± 1.4 8440 0.01 8.50 0.64 1.34 0.86 9.8 41.1 84 186 0.72 114 IT-10-11 X ppy 44.3 ± 2.0 9305 0.02 8.09 1.48 2.73 1.51 17.1 46.3 72 139 0.67 56 IT-10-13 X ppy 40.9 ± 1.2 9278 0.02 10.70 1.44 2.48 1.53 17.3 53.2 89 176 0.71 70 IT-10-14 X ppy 41.4 ± 1.2 12130 0.01 9.12 0.15 0.37 0.23 3.0 13.1 27 65 0.66 165 IT-10-15 X ppy 43.5 ± 1.8 8980 0.02 9.05 1.11 1.90 1.20 12.2 34.7 60 127 0.76 67 IT-10-16 X ppy 43.2 ± 1.4 8589 0.02 15.20 0.85 1.79 1.14 15.3 70.3 152 320 0.66 126 IT-10-17 X ppy 43.1 ± 1.2 11273 0.01 8.10 0.20 0.53 0.32 5.2 22.2 46 108 0.59 179

51 Table 2.3. cont. Age Hf La Ce Nd Sm Eu Gd Dy Er Yb Analyzed Spot Rock Type Eu/Eu* Ce/Ce* (Ma ± 1 σ) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) ES-12811-1 X ppy 44.0± 0.7 8701 0.13 57.99 9.33 18.61 10.82 112.8 261.1 368 632 0.72 51 ES-12811-2 X ppy 42.0± 0.9 7574 0.06 77.82 10.68 28.22 18.36 172.3 418.6 537 828 0.80 116 ES-12811-4 X ppy 45.3± 0.8 10688 0.02 24.08 0.38 1.12 0.65 10.9 45.4 84 179 0.57 256 ES-12811-5 X ppy 43.4± 0.7 12915 0.02 36.66 0.46 1.42 0.71 15.7 67.2 132 279 0.45 379 ES-12811-6 X ppy 43.8± 0.6 7809 0.05 220.85 14.75 37.24 26.80 305.9 838.2 1072 1479 0.76 317 ES-12811-7 X ppy 44.6 ± 1.1 9166 0.02 8.22 0.41 1.08 0.72 8.2 33.1 68 157 0.74 83 ES-12811-9 X ppy 42.8 ± 0.9 10996 0.01 12.84 0.22 0.70 0.38 6.4 25.8 55 128 0.54 243 ES-12811-13 X ppy 44.9 ± 0.6 12271 0.01 25.66 0.37 1.22 0.61 11.8 51.6 100 212 0.49 334 ES-12811-14 X ppy 42.8 ± 0.7 12222 0.01 20.38 0.22 0.84 0.41 8.1 37.6 75 167 0.48 299 ES-12811-16 X ppy 46.1 ± 0.3 12991 0.02 56.62 0.58 2.20 0.96 28.2 141.5 266 493 0.37 532

ES-12785a-3 K ppy 43.5 ± 0.7 12505 0.02 24.46 0.57 1.43 0.92 14.0 54.2 107 240 0.63 193 ES-12785a-4 K ppy 43.5 ± 0.5 11984 0.01 38.99 0.53 1.57 1.05 14.9 52.1 90 182 0.66 506 ES-12785a-5 K ppy 43.1 ± 0.7 11003 0.06 34.70 0.59 1.48 1.02 14.3 54.7 104 217 0.67 132 ES-12785a-6 K ppy 42.8 ± 0.6 11306 0.22 30.43 0.61 1.32 0.78 11.4 37.2 65 135 0.61 47 ES-12785a-7 K ppy 42.8 ± 0.5 11550 0.02 49.46 0.77 2.23 1.40 20.5 85.4 167 355 0.63 347

ES-12807-3 K ppy 42.0 ± 0.6 9698 0.02 54.75 1.23 3.08 2.15 29.9 104.5 171 313 0.68 335 ES-12807-5 K ppy 41.8 ± 1.2 10625 0.01 11.67 0.30 0.80 0.50 6.4 23.8 42 95 0.68 156 ES-12807-6 K ppy 41.7 ± 1.2 8958 0.01 10.94 0.39 1.12 0.69 8.2 27.9 52 115 0.69 120 ES-12807-9 K ppy 42.7 ± 0.7 9160 0.02 43.22 1.12 2.84 1.93 28.0 101.8 177 325 0.66 274 ES-12807-10 K ppy 40.7 ± 1.1 9314 0.03 14.56 2.07 3.76 2.14 22.3 57.8 83 150 0.71 62 ES-12807-12 K ppy 41.6 ± 1.0 9122 0.02 16.56 0.56 1.26 0.86 11.4 41.4 74 151 0.69 146 ES-12807-13 K ppy 42.6 ± 1.1 10944 0.02 12.41 0.13 0.33 0.21 3.1 13.9 26 62 0.62 152 ES-12807-14 K ppy 42.4 ± 0.8 8851 0.02 29.60 1.06 2.69 1.90 25.8 88.2 153 291 0.69 188 ES-12807-15 K ppy 40.8 ± 1.0 12096 0.02 15.23 0.20 0.60 0.46 6.0 26.8 53 130 0.73 187 ES-12807-16 K ppy 41.6 ± 0.8 8685 0.07 24.47 3.99 6.50 3.95 40.5 100.3 138 240 0.74 45 ES-12807-17 K ppy 41.3 ± 0.9 9495 0.06 18.55 2.30 4.14 2.37 24.0 63.1 90 163 0.72 45 ES-12807-18 K ppy 41.0 ± 1.1 9572 0.04 17.76 2.50 4.27 2.53 26.2 66.6 95 168 0.73 54

ES-12800-2 L ppy 43.3 ± 0.6 11299 0.01 25.93 0.52 1.60 0.83 15.3 65.0 138 318 0.51 282 ES-12800-4 L ppy 46.3 ± 0.2 13168 0.00 103.89 0.92 4.32 1.46 52.2 264.2 506 948 0.29 3391 ES-12800-6 L ppy 44.8 ± 0.5 11132 0.01 43.62 0.57 1.92 1.01 19.2 82.7 166 344 0.50 518 ES-12800-8 L ppy 44.4 ± 0.6 11866 0.01 33.72 0.43 1.27 0.65 12.7 59.6 127 284 0.49 377 ES-12800-9 L ppy 43.1 ± 0.4 10967 0.02 42.30 0.67 2.09 1.05 17.6 70.6 135 289 0.53 358 ES-12800-10 L ppy 43.7 ± 0.6 11059 0.03 39.04 0.53 1.60 0.78 16.1 76.7 165 375 0.46 219 ES-12800-11.2 L ppy 43.8 ± 0.6 10680 0.00 22.38 0.46 1.21 0.60 10.7 45.5 92 212 0.51 485 ES-12800-12 L ppy 44.1 ± 0.5 11718 0.01 42.78 0.54 1.75 0.87 18.9 85.4 171 360 0.46 688

ES-12783-1 A ppy 43.7 ± 0.7 10751 0.02 26.24 0.40 1.16 0.59 11.4 52.2 112 256 0.49 238 ES-12783-2 A ppy 42.9 ± 0.9 10289 0.04 15.36 0.35 1.11 0.58 10.2 49.8 105 243 0.53 98 ES-12783-3 A ppy 44.5 ± 0.7 12064 0.03 33.51 0.45 1.45 0.69 15.6 74.8 166 376 0.44 218 ES-12783-5 A ppy 43.0 ± 0.6 10903 0.04 33.27 0.50 1.59 0.89 15.4 58.8 111 226 0.54 162 ES-12783-6 A ppy 43.0 ± 0.6 10220 0.04 41.15 0.73 2.04 1.19 20.9 88.0 188 421 0.55 180 ES-12783-7 A ppy 44.5 ± 0.9 10318 0.02 16.94 0.37 1.28 0.76 11.1 56.0 121 272 0.61 166 ES-12783-8 A ppy 43.3 ± 0.6 10485 0.02 32.47 0.48 1.67 0.87 16.2 76.9 158 325 0.51 267 ES-12783-10 A ppy 41.4 ± 0.7 11075 0.02 30.54 1.14 3.63 1.70 29.8 110.7 193 364 0.50 177 ES-12783-12 A ppy 43.0 ± 0.7 10919 0.02 32.70 0.53 1.78 1.06 17.9 85.9 177 381 0.57 238 ES-12783-13 A ppy 42.4 ± 0.6 11077 0.02 46.81 0.62 2.05 0.99 21.3 100.1 212 458 0.45 417 ES-12783-14 A ppy 42.5 ± 0.8 10222 0.02 15.33 0.37 1.23 0.75 10.3 38.0 70 149 0.64 132 ES-12783-15 A ppy 45.2 ± 0.5 11850 0.03 56.76 0.52 1.57 0.82 17.9 96.5 240 610 0.47 366 ES-12783-16 A ppy 44.2 ± 1.0 8560 0.03 11.64 0.46 1.22 0.84 11.4 51.4 104 220 0.69 81 ES-12783-17 A ppy 41.5 ± 0.7 11067 0.04 26.74 0.41 1.24 0.70 13.0 59.7 127 285 0.53 146 ES-12783-18 A ppy 42.9 ± 0.9 9727 0.02 14.84 0.41 1.19 0.88 12.9 62.1 130 285 0.68 129

ES 12782-1 R ppy 43.0 ± 0.6 9659 0.02 57.49 2.29 6.62 4.26 59.6 218.8 367 682 0.65 260 ES 12782-2 R ppy 43.8 ± 0.6 11361 0.02 27.96 0.58 1.77 0.81 18.3 85.7 179 384 0.43 253 ES 12782-5 R ppy 43.8 ± 0.3 13101 0.06 67.19 0.84 3.00 1.39 38.2 198.5 387 745 0.39 221 ES 12782-7 R ppy 44.2 ± 0.8 12793 0.02 37.67 0.65 1.76 0.97 19.0 90.2 201 448 0.51 293 ES 12782-8 R ppy 43.0 ± 0.4 12650 0.02 42.59 0.35 0.91 0.53 10.4 68.8 224 672 0.52 430 ES 12782-9 R ppy 42.6 ± 0.7 11235 0.03 25.68 0.43 1.36 0.78 14.8 66.7 145 318 0.53 161 ES 12782-10 R ppy 43.7 ± 0.3 12158 0.04 109.43 2.34 9.24 3.92 103.7 481.8 815 1315 0.38 339 ES 12782-13 R ppy 42.3 ± 0.9 10550 0.01 14.96 0.37 1.28 0.83 12.8 53.9 103 225 0.62 222 ES 12782-15 R ppy 42.6 ± 0.8 12275 0.01 26.33 0.36 1.29 0.77 12.8 60.8 132 294 0.57 344 ES 12782-16 R ppy 43.4 ± 1.1 9820 0.03 12.21 0.78 1.60 1.01 13.6 52.5 102 221 0.66 72 ES 12782-17 R ppy 43.3± 0.7 11612 0.03 22.77 0.35 1.01 0.58 11.4 56.1 125 295 0.51 161

52 Table 2.3. cont. Age Hf La Ce Nd Sm Eu Gd Dy Er Yb Analyzed Spot Rock Type Eu/Eu* Ce/Ce* (Ma ± 1 σ) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) ES 12789a-1 L ppy 41.5± 1.2 12374 0.01 10.70 0.22 0.47 0.37 4.7 21.2 44 110 0.75 179 ES 12789a-2 L ppy 43.1± 1.6 11074 0.01 6.77 0.19 0.46 0.33 4.6 19.0 38 86 0.69 106 ES 12789a-4 L ppy 42.4± 2.1 9146 0.03 10.34 1.50 2.55 1.47 16.3 48.8 82 164 0.69 49 ES 12789a-5 L ppy 43.5± 0.6 12112 0.07 31.70 0.43 1.32 0.63 13.7 63.2 138 308 0.45 122 ES 12789a-6 L ppy 44.3± 0.2 14580 0.02 139.82 1.82 8.08 3.23 91.7 429.7 761 1357 0.36 737 ES 12789a-7 L ppy 45.6 ± 1.6 9669 0.01 9.80 0.34 1.01 0.60 7.8 29.6 57 129 0.64 114 ES 12789a-8 L ppy 43.1 ± 1.2 8974 0.03 12.41 2.36 3.58 2.14 23.2 60.8 97 185 0.71 42 ES 12789a-9 L ppy 41.8 ± 1.5 8573 0.01 8.91 0.53 1.36 0.80 9.4 37.3 73 153 0.68 110 ES 12789a-10 L ppy 42.5 ± 1.1 9067 0.02 17.42 0.67 1.64 1.23 16.6 62.3 114 227 0.71 140 ES 12789a-11 L ppy 42.9 ± 1.3 11616 0.01 14.52 0.70 1.84 1.10 15.8 49.9 83 165 0.62 135 ES 12789a-13 L ppy 43.5 ± 1.6 10614 0.02 7.78 0.33 0.72 0.51 6.4 23.0 42 94 0.73 70 ES 12789a-14 L ppy 42.5 ± 1.6 11286 0.02 10.44 0.77 1.80 1.08 13.1 40.4 65 132 0.68 75 ES 12789a-15 L ppy 44.0 ± 2.0 11039 0.01 7.94 0.28 0.72 0.49 5.9 22.2 42 95 0.72 119

IT-9-1 L ppy 41.1 ± 0.6 11032 0.01 32.37 0.56 1.63 0.97 15.7 57.5 106 221 0.58 492 IT-9-2 L ppy 41.8 ± 0.6 11542 0.01 34.82 0.67 1.71 0.96 15.8 60.3 113 240 0.56 338 IT-9-3 L ppy 41.8 ± 0.7 11181 0.01 27.55 0.53 1.45 0.95 13.1 51.4 95 202 0.67 362 IT-9-4 L ppy 41.6 ± 0.6 11807 0.03 27.98 0.35 1.25 0.75 12.1 49.5 97 211 0.59 216 IT-9-5 L ppy 43.9 ± 1.2 9598 0.02 11.48 2.04 3.48 1.89 19.1 49.6 72 132 0.70 62 IT-9-6 L ppy 42.9 ± 1.1 13088 0.01 7.27 0.06 0.27 0.13 3.1 14.9 38 97 0.43 165 IT-9-7 L ppy 41.4 ± 0.6 11939 0.01 30.64 0.47 1.33 0.86 13.2 51.3 101 226 0.62 519 IT-9-8 L ppy 42.2 ± 0.7 11282 0.01 29.92 0.56 1.70 1.03 15.0 56.1 101 211 0.62 340 IT-9-9 L ppy 41.3 ± 0.6 11377 0.01 43.03 0.75 2.01 1.23 19.4 74.2 142 300 0.60 401 IT-9-10 L ppy 42.4 ± 0.7 11855 0.01 27.41 0.42 1.22 0.77 12.5 49.0 95 209 0.60 392 IT-9-12 L ppy 42.8 ± 0.3 11239 0.03 32.03 0.55 2.01 1.13 22.5 75.2 127 244 0.51 196 IT-9-13 L ppy 44.2 ± 0.9 11679 0.01 23.10 0.44 1.26 0.83 11.5 45.6 90 198 0.66 272 IT-9-14 L ppy 44.0 ± 0.7 10405 0.01 36.05 0.79 1.95 1.38 18.9 80.8 148 296 0.69 314

12787-1 L ppy 40.7 0.8 10570 0.06 33.92 0.97 2.55 1.67 21.3 69.0 105 197 0.69 113 12787-2 L ppy 40.2 1.6 9163 0.01 10.39 0.43 1.08 0.64 7.5 23.8 40 81 0.68 117 12787-3 L ppy 41.0 0.8 11900 0.02 32.35 0.69 1.89 1.10 16.4 60.2 107 220 0.60 221 12787-4 L ppy 40.6 1.1 9204 0.01 13.94 0.19 0.51 0.34 4.8 16.1 28 58 0.66 199 12787-5 L ppy 39.7 0.7 10969 0.02 55.87 0.74 2.01 1.17 19.5 72.3 124 242 0.57 375 12787-8 L ppy 41.5 0.8 11207 0.02 34.26 0.60 1.91 1.07 15.9 60.8 111 227 0.59 295 12787-9 L ppy 39.7 0.9 10945 0.27 29.04 0.72 1.43 0.89 14.1 50.2 89 182 0.60 37 12787-10 L ppy 42.3 1.1 11241 0.02 21.13 1.81 3.91 2.05 25.7 67.5 93 171 0.62 111 12787-11 L ppy 42.5 0.6 11890 0.01 43.18 0.61 1.76 1.06 15.0 51.2 84 168 0.62 412 12787-12 L ppy 42.0 0.6 11720 0.02 47.03 0.81 2.17 1.25 17.9 59.4 100 204 0.61 372 12787-13 L ppy 40.2 0.6 10225 0.04 56.13 2.72 6.05 3.75 45.6 130.7 189 322 0.69 182 12787-14 L ppy 42.5 0.8 10999 0.02 32.86 0.69 1.76 1.03 16.2 59.7 106 215 0.59 238 12787-15 L ppy 39.8 0.8 12654 0.01 27.23 0.53 1.32 0.80 12.0 42.1 74 151 0.61 269 12787-16 L ppy 42.7 0.9 11666 0.02 22.35 0.39 0.92 0.52 8.1 28.1 47 97 0.58 230 12787-17 L ppy 42.0 1.0 11914 0.01 26.16 0.39 1.25 0.73 10.6 36.6 62 128 0.61 356 12787-18 L ppy 40.9 1.0 11905 0.04 28.16 0.55 1.49 0.85 14.0 46.7 83 173 0.57 146

ES-12792-3 Latite 42.3 ± 0.4 12547 0.01 53.49 0.80 2.39 1.46 21.5 67.0 103 185 0.62 533 ES-12792-4 Latite 41.3 ± 0.4 9286 0.13 184.00 11.17 24.41 13.75 192.4 436.6 467 612 0.61 158 ES-12792-5 Latite 40.9 ± 0.3 10650 0.02 151.33 3.24 10.25 6.59 95.6 283.7 380 562 0.64 667 ES-12792-6 Latite 42.0 ± 0.3 13387 0.01 46.85 0.73 1.87 1.09 14.7 44.6 76 151 0.63 422 ES-12792-7 Latite 42.7 ± 0.7 12387 0.03 47.42 2.33 5.17 3.06 35.0 91.6 114 176 0.69 198 ES-12792-9 Latite 40.7 ± 0.4 11911 0.02 71.60 1.04 3.28 2.18 31.1 96.3 143 246 0.65 493 ES-12792-10 Latite 42.4 ± 0.3 7077 0.39 373.07 41.92 81.79 48.05 535.4 1063.3 1036 1206 0.70 97 ES-12792-11 Latite 41.0 ± 0.5 8681 0.58 146.26 33.27 47.51 29.07 225.9 431.3 444 615 0.85 32 ES-12792-12 Latite 41.6 ± 0.3 14401 0.03 24.17 0.37 0.87 0.60 8.2 23.3 43 107 0.68 180

53

54

Figure 2.6 (Previous page). Rare earth element (REE) plots for selected samples analyzed by SHRIMP-RG. A. Mesozoic age zircons. B. Quartz porphyry sample shows a REE pattern with a relatively high negative Eu-anomaly with one enriched pattern with a small Eu anomaly. C. Late quartz porphyry sample shows large negative Eu-anomaly similar to the quartz porphyry sample ES-12808. D. X porphyry sample from Turquoise Gulch contains two distinct patterns similar to the quartz porphyry. E. L porphyry from M Gulch. F. & G. The K porphyry and L porphyry show similar patterns with smaller Eu anomalies than the older quartz and X porphyries. The two outlying patterns in the L porphyry represent zircon core analyses that yield older Eocene ages of 42.9±1.1 and 43.9±1.2 Ma. H. Latite dike sample shows the highest variation between individual grains. The K porphyry and latite dike samples were analyzed with the full REE suite whereas the other samples represent data analyzed during the U/Pb process as outlined in Mazdab and Wooden (2006), samples normalized to chondrite values of Anders and Grevesse (1989) multiplied by 1.3596 as after Korotev (1996).

55 with poor age calculations (Hanchar and Westrenen, 2007) the focus of this paper is to relate zircons from earlier porphyry intrusions to potentially similar grains that have been recycled into younger intrusions.

REE concentrations were normalized to chondrite values of Anders and Grevesse

(1989) multiplied by 1.3596 as proposed by Korotev (1996). This procedure results in a

Sm value of 0.200 µg/g and REE concentrations similar to early chondrite composites.

REE diagrams (Figure 2.6) plot typical zircon patterns (i.e. Hanchar et al. 2001; Hoskin and Schaltegger, 2003; Hanchar and Westrenen, 2007) with enriched HREE, depleted

LREE, positive Ce anomalies and negative Eu anomalies. The HREE and MREE content as well as the extent of Eu anomalies vary between older and younger El Salvador units and are discussed below (Figure 2.7).

A total of nine inherited Mesozoic zircon grains were analyzed from both core and rim samples within the X porphyries and L and R porphyries from M Gulch (e.g.

Figure 2.4). These zircons most likely are derived from basement terrain beneath El

Salvador that was partially melted by the ascending porphyry magmas. Five middle

Jurassic (187 – 171 Ma) zircons have similar REE patterns with moderate negative-Eu anomalies (Figure 2.6A). Two grains from sample IT-10 are early Cretaceous (140 Ma) and differ in REE pattern from the other inherited grains. They are depleted in light REE

(LREE) and middle REE (MREE) and are enriched in heavy REE (HREE) compared to the other Mesozoic grains. Two other Cretaceous (127 and 68 Ma) grains were also analyzed and yield REE patterns similar to the mid Jurassic grains.

The quartz porphyries, X porphyries, K porphyries, and the latite dike tend to show a large variation in REE patterns and abundances. In some cases the abundance

56 varies by more than 20x. The L porphyries, however, do not show a large variation in

REE content or pattern within the younger age population for each sample.

Three distinct REE patterns are evident within the Eocene age grains. Grains associated with the quartz porphyry samples and older inherited Eocene grains in the relatively younger samples show a REE pattern with a higher negative-Eu anomaly and convex upward MREE to HREE pattern (Figure 2.6B,C). The L porphyry from M

Gulch-Copper Hill contains an older 46Ma grain that gives a similar REE pattern to the quartz porphyry samples (shaded line Figure 2.6D). A second pattern is illustrated by grains that show an enriched REE pattern with little to no Eu-anomaly as seen in the X porphyry 9ES-12811) where two REE patterns are evident (Figure 2.6E). Grains with this patter show high Th/U and low Yb/Gd ratios (Figure 2.7A) and high concentrations of Th, U, Eu, and Yb (Figure 2.7B,C,D). This pattern is observed in the quartz porphyry,

X porphyry, R porphyry, and the latite sample. The final pattern is characterized by lower REE content, a small Eu anomaly, and a straight HREE to MREE pattern (Figure

2.6F,G.). This pattern is more prominent in the younger age populations. The latite dike sample shows the highest variation (Figure 2.6H) up to 20x difference between sample grain analyses.

The Hf content ranges from 7,000 to 14,500 ppm for all the samples (Table 2.3), and as in other magmatic systems apparently increases with magma evolution and crystallization. There is a systematic variation when comparing Hf to REE concentrations and ratios (Figure 2.8). Th/U values decrease with increasing Hf content

(Figure 2.8A), whereas Yb/Gd and both Ce and Eu anomalies increase as Hf content increases (Figure 2.8B,C,D). Each unit typically shows wide scatter in these plots

57 whereas the latite sample shows distinct trends (eg. Figures 2.7E, 2.8D). The implications for these trends are discussed further below.

Thermal history of granodiorite porphyries and latite dikes

Zircon saturation

Zircon saturation temperatures (Watson and Harrison, 1983; Hanchar and

Watson, 2003) were calculated for selected samples based on whole rock major element chemistry (Table 2.4). Whole rock concentrations were determined by XRF analyses conducted at Washington State University geoanalytical laboratory (c.f., Johnson et al.,

1999). Titanium content generally decrease with increasing silica content (Figure 2.9A) and Zr/Hf ratios vary between 30-40 (Figure 2.9B) similar to cumulate rocks that have undergone repeated fractionation and thermal fluctuations (i.e. Clairborne et al., 2006).

Whole rock values were used as assumed melt compositions to calculate the silica and peraluminous “M” factor after (Harrison and Watson, 1983). Hanchar and Watson

(2003) suggest this is a good first order approximation for zircon saturation although other factors including oxygen fugacity, halogen content, and Fe and Mg concentration may affect zircon solubility (e.g., Keppler, 1993; Baker et al., 2002). Indeed the M value for the latite dike sample fell outside of the stability range for the model and yielded a temperature higher (820º C) than would be expected based on the experimental calibrations. As the latite sample most likely represents a mixed magma due to the presence of sieved feldspars (e.g. Coombs et al., 2000; Figure 2.3F) and the large variability within the zircon samples (Figures 2.8, 2.9), any saturation temperature calculated would be suspect.

58

Figure 2.7. Trace element plots from individual zircon grains. A. Th/U vs. Yb/Gd. B. U ppm vs. Th ppm. C. Eu ppm vs. Eu/Eu*. D. Yb ppm vs. Eu/Eu*. E. Ce/Sm vs. Yb/Gd. F. Sm/Yb vs. La/Sm. MG-CH – M Gulch – Copper Hill, GG – Granite Gulch, TG – Turquoise Gulch.

59

Figure 2.8. Zircon Hf variation diagrams. Hf content of zircon increase with magmatic evolution and crystallization of zircon. Explanation same as in Figure 7. A. Hf (ppm) vs. Th/U; B. Hf (ppm) vs. U (ppm). C. Hf (ppm) vs Th (ppm). D. Hf (ppm) vs. Yb/Gd. E. Hf (ppm) vs. Eu/Eu*. F. Hf (ppm) vs. Ce/Ce*. Symbols same as in Figure 2.7.

60 Saturation temperatures for the granodiorite samples varied from 780 to 730 ºC, with an average temperature of 748 ºC. All the samples that contained significant amount of zircon and were all zircon saturated.

Titanium in zircon

Titanium and full trace element concentrations of zircons were determined for samples ES-12785a, ES-12783, and ES-12792 (Table 2.5). We used the Ti-in-zircon thermometer of Watson and Harrison (2005) corrected to an activity of TiO 2 ≈ 0.7 to reflect titanite and titanomagnetite saturation after Claiborne et al. (2006) to estimate zircon crystallization temperature. Uncertainty in the activity of TiO 2 can introduce high error in calculated temperatures, but melts saturated in a Ti phase will have constant TiO 2 activities and differences within calculated zircon temperatures will be real (Claiborne et al., 2006). The calculated temperatures varied for the three samples ranged from 850 to

630 ºC.

Sample ES-12785a (K porphyry Turquiose Gulch) yielded temperatures from 750 to 671 ºC. Core temperatures were distinctly hotter (750 to 711 ºC) than the rims (728 to

671 ºC) suggesting a cooling and fractionating magma chamber. Three grains were analyzed in this sample with three spot analyses per grain in the core, rim and within the sector zone corresponding to the adjacent rim spot (Figure 2.10). Ti and Hf contents were less within the bright CL sector zones yielding temperatures 18-12 ºC cooler than that of the corresponding rim temperatures. REE contents however, were not lower within these zones. Watson and Liang (1995) suggest that sector zoning is dependent on growth rate and lattice diffusivity. If Ti is enriched along a particular growth surface during crystallization, this difference will be preserved due to the slow diffusion rate of

Ti in zircon (Cherniak and Watson, 2007). While the temperatures determined here are

61 Table 2.4. Zircon saturation temperatures defined from whole rock major element concentrations 1. Sample ES-12782 ES-12783 ES-12785a ES-12787 ES-12789a ES-12791 ES-12792 ES-12800 ES-12807 ES-12795 Rock Type R ppy A ppy K ppy L ppy L ppy GG Lt qtz ppy Latite dike L ppy MG K ppy X ppy Major Elements (Weight %):

SiO 2 65.90 60.31 69.47 66.88 63.41 71.71 63.71 65.35 68.30 60.79

TiO 2 0.57 1.04 0.58 0.67 0.76 0.64 0.93 0.67 0.62 0.89

Al 2O3 17.01 19.78 14.98 16.64 17.47 20.62 17.06 17.78 15.81 19.38 FeO* 4.14 6.70 2.42 3.00 5.67 1.05 4.08 3.85 3.30 2.82 MnO 0.15 0.03 0.01 0.03 0.03 0.00 0.07 0.03 0.01 0.01 MgO 1.44 2.55 1.32 1.31 1.77 0.12 1.72 1.73 1.56 2.00 CaO 0.44 1.69 2.77 3.87 3.54 0.31 5.42 1.86 4.26 5.79

Na 2O 2.65 5.66 4.42 4.97 5.09 4.20 4.59 6.06 4.63 5.96

K2O 7.50 1.92 3.84 2.42 1.96 1.22 2.13 2.49 1.33 2.04

P2O5 0.21 0.34 0.18 0.21 0.28 0.13 0.28 0.19 0.18 0.32 LOI (%) 2.63 3.51 2.58 0.82 1.13 6.38 4.96 2.05 3.99 2.83

SO 3 ≥ 0.35 0.18 1.01 0.20 0.10 0.17 0.09 0.12 1.45 2.09 Sum 99.23 98.63 99.47 99.45 98.99 99.76 99.36 98.93 99.43 99.23 Zr 111 139 104 121 133 119 127 125 113 152 Zr/Hf 33.4 38.0 34.2 32.4 34.6 33.6 34.8 35.3 32.4 39.7 M2 1.27 1.32 1.71 1.96 1.66 1.74 0.64 4 1.52 1.68 2.11 T oC3 764 779 729 727 752 739 820 757 737 722 1. Whole rock major element concentrations determined by XRF, oxides normalized to volatile free. 2. M value equals the cation ratio (Na+K+2Ca)/(Al*Si) after the Watson and Harrison (1983) model. 3. Zircon saturation temperature assuming Zr concentration and M value of whole rock as melt. 4. Latite M value falls outside accepted range for calculation by model.

62

Figure 2.9. Whole rock SiO 2 wt. % variation diagram A. TiO 2 wt. % and B. Zr/Hf ratios for El Salvador porphyry samples. Major oxides normalized to volatile free.

63

ppm ppm ppm ppm normalizedGd^0.5). Eu/(Sm^0.5 * P-RG for P-RG entire tracesuite. element ppm .24 41.99 9.60 86.74 20.26 12221 0.694 .03 45.98 10.27 96.29 20.65 12316 0.668 ppm 2.94 37.680.61 8.78 54.41 79.08 12.26 113.37 16.703.57 23.72 8809 12011 33.39 0.656 0.725 9.02 98.58 27.06 15721 0.878 2.97 55.67 12.88 116.20 23.39 11822 0.660 8.236.16 52.51 47.49 12.33 117.72 11.11 101.66 24.53 21.87 12103 10027 0.655 4.21 0.686 27.49 6.10 59.66 12.68 10906 0.801 53.94 80.06 17.27 147.84 29.44 12085 0.700 76.37 103.50 21.08 171.32 32.08 11965 0.669 92.56 142.6361.45 30.74 269.55 99.62 51.09 21.90 198.91 11520 39.58 0.639 11709 0.619 80.08 150.1246.49 100.5960.96 34.55 127.0325.57 313.34 24.06 226.17 30.58 49.00 62.18 286.63 48.13 11.43 12254 60.57 110.79 11915 0.456 10689 23.28 0.570 0.563 10426 0.519 1 55.32 80.49 16.44 133.71 24.913 8925 136.792 0.811 237.12 40.11 51.84 67.19 446.79 15.33 87.91 142.60 11470 29.70 0.603 10036 0.771 2 43.18 72.61 16.21 146.94 29.99 9894 0.644 8 78.31 155.50 35.41 319.60 61.92 11389 0.554 4 73.467 141.77 66.09 32.77 143.38 306.37 35.04 63.42 332.52 12049 69.28 0.586 11072 0.590 1 55.930 113.52 45.10 25.939 245.57 91.077 28.09 50.59 20.97 55.05 50.53 197.15 11018 105.00 11.96 42.43 0.599 24.69 107.96 11697 235.92 23.84 0.701 48.80 10334 11976 0.716 0.656 18 218.12 282.35 52.58 398.2237 68.93 61.27 10597 109.67 0.617 24.56 219.30 43.81 9699 0.634 00 41.61 71.03 15.61 144.24 30.66 10865 0.645 03 42.17 66.15 14.89 137.28 29.08 10107 0.676 .92 44.35 90.42 21.59 209.03.73 44.52 33.28 11836 63.76 0.566 .37 15.05 147.55 38.11 32.54 76.88 11573 18.28 0.683 172.47 38.25 11602 0.617 ppm 7.51 86.76 161.46 36.17 332.58 66.60 11385 0.642 2.58 464.63 983.46 220.50 1902.08 331.44 17609 0.223 6 14.76 148.37 206.84 40.97 333.24 60.80 9502 0.641 .92 58.76 572.72 716.62 128.32 935.92 152.22 10610 0.618 7.80 90.49 762.40 785.25 133.00 960.72 151.29 8031 0.626 ppm 09.86 50.45 399.62 420.69 77.08 577.37 97.40 8285 0.839 ppm ssion. Europium anomaly calculated chondrite from ssion. anomaly Europium ppm ppm ppm porphyry, and porphyry, zircons porphyry A SHRIM by analyzed ppm ppm La Ce Pr Nd Sm Eu Ho Gd Tb Dy Er Tm Yb Lu HfEu/Eu* r Watsonr of and Harrison(2006) see text for discu ppm C o Temp 49 Ti ppm 6.1Rim6.2Core7.1Core8.1Rim8.2Core 4.24 10.859.1Rim 13.44 701 789 5.18 811 11.94 718 8.42 799 0.01 0.01 0.02 764 38.6 9.3 448.8 0.03 0.13 0.05 0.07 0.29 17.3 0.02 25.2 0.56 0.44 5.59 0.14 85.5 0.06 1.95 19.92 1.00 0.29 0.08 0.78 1.28 12.47 0.59 194.76 1.01 17.52 1.05 1.87 188 8.79 15.84 0.67 3.27 1.13 11.68 7.40 4.93 24.31 2.09 7.70 2.43 15.85 53.18 2 34.10 2.76 5. 12.0 3 4.1Core5.1Rim 19.20 8.47 850 7649.2Core 0.22 342.0 0.03 4.30 135.2 1.04 20.78 0.12 702 48.23 2.57 26.68 220.73 8.60 0.04 34 5.19 17.8 78.10 0.05 75.89 0.43 23. 1.28 0.96 14.24 11.15 3.6 1.1Rim3.2Core 2.93 670 8.04 0.00 759 30.5 0.06 0.01 0.40 24.3 1.17 0.07 0.71 0.78 9.89 2.10 8.20 1.61 19.10 2.68 17.40 25 5.4 1.2Core2.1Mid Rim3.1Rim 10.79 7.41 788 751 4.29 702 0.02 0.00 66.6 20.1 0.01 0.13 0.05 73.1 1.53 0.63 0.08 4.53 1.52 0.89 3.16 0.92 3.19 48.93 15.88 49.5 2.01 12.56 25.66 4.0 26.25 7.81 2.1Mid Rim4.1Rim5.1Rim 5.777.1Rim 728 4.37 3.51 703 3.50 0.01 685 685 51.0 0.01 0.01 0.04 52.8 0.01 27.9 0.65 0.08 21.6 0.04 2.02 0.61 0.03 0.38 1.34 2.14 0.26 33.61 1.02 1.26 0.81 19.89 0.655.1Rim 23.84 0.502.1Core 12.26 17.826.1Rim 9.60 8.66 5.78 4.17 6.48 3.04 4.19 3 2.39 699 7.27 700 25 749 0.00 0.05 49.0 0.02 12.0 0.06 24.6 0.04 0.58 0.05 0.28 1.75 0.55 0.74 0.85 1.54 0.49 31.73 0.89 18.95 18.45 25.48 9.12 6.70 14.90 3.68 5.30 1.1Rim 5.777.2Core7.3Sector 728 5.54 3.03 0.02 724 74.3 673 0.12 0.07 0.02 1.06 27.3 21.8 3.63 0.04 0.07 2.14 0.66 33.28 0.33 28.66 1.68 1.22 9.16 0.96 0.68 32.13 18.12 16.67 10.83 6.1 3 8.1Rim8.2Core 2.94 7.28 671 750 0.01 0.01 21.1 9.5 0.06 0.06 0.25 0.33 0.81 0.96 0.51 0.62 11.17 10.25 6.92 7.88 2.65 2.26 2 2 11.1Core12.1Rim 17.86 1.75 842 631 0.52 144.3 0.01 1.60 14.7 31.08 0.10 46.04 0.17 27.13 117.54 0.34 2 0.30 6.15 3.29 1.14 1 13.2Rim 6.95 745 0.01 11.2 0.04 0.22 0.83 0.39 10.19 6.47 2.33 16.1Rim11.2Core 5.41 722 3.43 683 0.01 41.1 0.01 0.03 17.6 0.54 0.05 1.83 0.62 1.11 3.50 29.82 18.06 1.05 205.28 6.4 58.01 3 11.1Rim 5.65 726 0.03 19.0 0.09 0.45 1.32 0.82 27.44 13.51 5.4 10.1Rim11.3Core 4.05 69712.3Sector15.1Core 4.79 0.01 711 3.18 36.0 5.06 677 0.07 0.00 716 0.53 13.3 0.01 1.52 0.04 0.05 17.4 0.94 0.36 10.5 0.02 24.12 0.83 0.09 0.32 14.96 0.60 0.94 0.95 4.8 11.43 2.02 0.61 7.73 15.86 1.14 2.5 15.47 9.53 14.35 3 4. 10.2Core11.1Rim11.2Sector12.1Rim 6.9912.2Core 3.79 3.05 746 691 673 3.93 5.67 0.01 694 0.02 727 0.01 13.6 25.0 14.9 0.08 0.00 0.05 0.01 0.06 0.84 32.2 0.36 0.24 1.88 9.4 0.05 1.05 0.81 1.11 0.02 0.47 0.79 14.72 0.56 0.19 1.32 18.14 13.26 13.90 0.50 11.28 0.90 4. 7.56 0.36 21.76 3.9 2 13.30 5.79 4.8 3.81 1.30 1 Table2.5. elementcompositions Trace Latite,for K Sample Location ES-12792 ES-12785a Temperature calculated Ti-in-zirconby geothermomte ES-12783

64

Figure 2.10. Cathodoluminescence images of El Salvador zircon grains with corrected temperatures based on Ti content (± 2ºC). Numbers correspond to zircon grain sample number. A. Zircons from sample ES-12785a show sector zoning and rounded cores. Core temperatures vary from 750 to 711 ºC, whereas rim temperatures vary from 728 to 671 ºC. Sector zones are 12-18 ºC cooler than corresponding rim temperatures indicating Ti concentration is higher within the non-sector zones. Hf and Th concentration are also lower within these sector zones, however, no other trace element is depleted in these zones. B. Sample ES-12792 shows a temperature range from 850 to 631 ºC, with a higher temperature range of 850 to 750 ºC occurring within the cores of the grains.

65 estimates for crystallization temperatures, our results suggest the choice of spot must be taken into consideration when analyzing zircon samples.

Sample ES-12792 (latite dike from Turquiose Gulch) shows the largest temperature variation from 850 to 631 ºC with temperatures calculated from the zircon cores higher than rim temperatures at 850 to 750 ºC. The latite sample shows the highest variation with trace element concentration (Figure 2.6H) compared with granodiorite porphyries. A plot of T vs. Hf content and trace element ratios (Figure 2.11) shows a correlation between decreasing temperature and increasing Hf comparable to zircon fractional crystallization as described by Wooden et al. (2006). The greater than 200 ºC range in Ti-in-zircon temperatures in the latite sample and the trace element variation cannot be explained by only fractional crystallization. The higher temperatures of zircon cores most likely represent crystallization from a high T melt, injected into the magma chamber, whereas the lower T represents overgrowths of zircon from the bulk magma chamber.

Discussion

Geologic evolution of the El Salvador magmatic system

The new age data from the El Salvador porphyry Cu-Mo deposit suggests that the magmatic system is long-lived with episodic intrusions spanning 5 million years from

~46 Ma to ~41 Ma (Table 2.1). Figure 2.12 outlines the total age distribution for 165 spots analyzed in this study. The plot forms a distinct Gaussian curve with magmatism initiating at approximately 46-47 Ma and peak magmatic zircon crystallization between

43 and 43.5 Ma. The number of zircon ages progressively decrease until the final emplacement age at

66

Figure 2.11. Trace element content vs. Ti temperature of zircon illustrating core, rim, and sector zones from the K porphyry, A porphyry, and latite dike. The latite sample shows the largest variation between individual spot analyses consistent with the trace element plots listed earlier. A. Hf ppm vs. T. B. Th/U vs. T. C. Yb/Gd vs. T.

67

Figure 2.12. Probability density plot of all U/Pb zircon spot ages analyzed from the fourteen samples but excluding spots with inherited (Mesozoic), discordance, and probable Pb loss. The oldest Eocene interpreted ages occur at ~45-46 Ma and potentially represent older intrusions related to the Cerro Pelado rhyolite porphyries. Increase in magmatism begins at ~44 Ma and peaks at ~43 Ma coinciding with quartz porphyry and X porphyry intrusions. Minor ore mineralization associated with the Old Camp and M Gulch-Copper Hill centers potentially occur at the same time. Ore mineralization at Turquoise Gulch coincides with the K and La porphyry intrusions at ~42 Ma. Final magmatism occurs at ~41.5 Ma with the intrusion of latite dikes.

68 ~41.5 Ma. There are subtle but distinct peaks in this diagram roughly corresponding to the emplacement of quartz porphyry at ~43.5 to 44 Ma, the X porphyries at ~43 Ma, and the K and L porphyries at Turquoise gulch at ~41.5 to 42 Ma. Whereas the Gaussian curve may suggest an age of 43 Ma with an error distribution from 47 to 40 Ma, based on the 2σ errors for our interpreted ages we suggest that these peaks represent robust ages

(Figure 2.13). The corresponding peaks on the diagram appear to roughly map the temporal variation of the flux of magma into the upper crust in the El Salvador district.

One possibility is that deep-sourced mafic magma intruded into a shallow chamber periodically and initiated partial melting, local mixing of magmas and subsequent cooling to saturate and crystallize new zircon.

Cerro Pelado – Old Camp

There are few surface ages representing the 45-46 Ma time span interpreted as the beginning of porphyry magmatism in this deposit. Potentially, this ~45 Ma age could represent the age of zircons crystallized from the quartz rhyolites and quartz rhyolite porphyries exposed at Cerro Pelado surrounding the main mineralization deposits as dated by Gustafson and Hunt (1975) at 45.3 ± 2.0 Ma. Alternatively, these ages may represent a magma source not represented at the surface but the initial melting and formation of an unknown magma chamber at some depth below the deposit.

The similar or identical ages (43.6 Ma and 44.0 Ma) from the two widely separated localities suggest that the quartz porphyry underlying the entire Indio Muerto district and the quartz porphyry at Old Camp were emplaced at approximately the same time. These intrusions represent dikes and sills emplaced over a 4 km distance from north to south.

69 The 43.6 ± 0.3 Ma population in the late quartz porphyry is analytically indistinguishable from the interpreted age of the 43.6 ± 0.6 Ma age of the Old Camp quartz porphyry. The quartz porphyry contains quartz veins and pyrite-chalcopyrite mineralization, but the cross-cutting late quartz porphyry and breccia truncates the quartz veins and contains only weak supergene clay alteration. These two U/Pb ages establish the age of pyrite-chalcopyrite mineralization at Old Camp at ~ 43.6 Ma.

M Gulch – Copper Hill

The geochronologic data from the three samples collected at M Gulch are similar to the previous ages reported by Cornejo et al., (1997), where both older 44 to 43 Ma seen in the L porphyry sample (ES-12800: 43.8 ± 0.6 Ma) ages and younger 43 to 42 Ma as seen in the A porphyry (ES-12783: 42.8 ± 0.5 Ma). The L porphyry at M Gulch is texturally similar to the L porphyry along the outer edges at Turquoise Gulch (Gustafson and Hunt, 1975). The interpreted 43.8 Ma age for the L porphyry is similar to the interpreted age of the texturally similar L porphyry at Granite Gulch (43.9 ± 0.4). This age however is problematic as the L porphyry clearly cuts irregular quartz porphyry dikes in the M Gulch pit (Gustafson and Hunt, 1975; Gustafson et al., 2001). Indeed the L porphyry at both locals is relatively younger than the quartz porphyry but yield older weighted mean ages of 43.8 Ma compared to the quartz porphyry ages of 43.6 and 44.0

Ma. Based on the geology the interpreted age appears to be an overestimation of the age and the lower error limit for the L porphyry sample which is within analytical error of the quartz porphyry ages is the most likely age for this sample. The zircon trace element data for the L porphyries differs from the quartz porphyry samples suggesting a slightly different formation history between these two samples (e.g. Figures 2.6, 2.7).

70 Cornejo et al. (1997) interpreted the porphyry intrusions at M Gulch to represent granodiorite intrusions emplaced contemporaneously with the quartz porphyry intrusions and were derived from different parent magmas or as part of an evolving magma chamber. Trace element data from this study suggest that the source of the magmas may differ but both are the result of an evolving mixed and fractionated parental source.

Several interpretations of the new data are possible: 1) the zircon grains analyzed from the L porphyries were all inherited from older magmas and intrusions and the L porphyry was sufficiently cool that it neither melted these older zircons nor crystallized many new zircons, or 2) the L porphyry at M Gulch-Copper Hill represents an older intrusion compared to the intrusion at Turquoise Gulch. Based on our observations and the previous analytical work of Cornejo et al. (1997), we suggest the latter interpretation where the L porphyry at M Gulch-Copper Hill is an older intrusion of similar texture to the L porphyry intrusion at Turquoise Gulch. The L porphyry from Granite Gulch is more difficult to interpret as it is chemically and petrologically similar to the L porphyry from Turquoise Gulch (Figures 2.7, 2.9). The presence of multiple discordant grains in the sample (Figure 2.5K) suggests the age may be an overestimation of the actual age.

Alternatively, this sample may represent an early intrusion of a porphyry chemically similar to the L porphyry at Turquoise Gulch.

Low intensity pyrite-chalcopyrite-bornite mineralization occurs in the quartz porphyry intrusion at M Gulch and is spatially related to the feldspar porphyries which contain low sulfide contents (Gustafson et al., 2001). The age of the L porphyry presented here suggests that mineralization at M Gulch occurred contemporaneous with the pyrite-chalcopyrite-bornite mineralization at Old Camp.

71

Figure 2.13. Summary of El Salvador chronology comparing relative ages vs. robust U/Pb zircon ages from this study. Relative ages based on field mapping by CODELCO geologists (Gustafson and Hunt, 1975; Gustafson et al., 2001); OC – Old Camp, TG – Turquoise Gulch, MG – M Gulch, GG – Granite Gulch. Shaded bars indicate mineralization between 43-44 Ma for the Old Camp and M Gulch-Copper Hill centers and 41.5-42.5 for the Turquoise gulch center. *Re-Os ages from molybdenite in a B-vein (42.2 ± 0.2 Ma) and 5 point isochron from a pyrite-tennantite D-vein (42.4 ± 0.5 Ma) (Watanabe et al., 1999; Watanabe and Hedenquist, 2001). Solid squares represent interpreted intrusion age from this study. Shaded diamond original age interpretation for samples IT-10 and IT-9 from Cornejo et al., 1997. Error bars are all 2 σ.

72 Turquoise Gulch porphyry Cu mineralization

The L porphyry at Turquoise Gulch is interpreted by Gustafson and Hunt (1975) to have been emplaced after most quartz-molybdenite B veins, but before polymetallic D veins with sericitic selvages. These two mineralization events have been dated previously using the Re-Os method and yield ages of 42.2 ± 0.19 Ma and 42.0 ± 0.20 Ma for molybdenite in B veins and 42.37 ± 0.45 Ma for a five-point sulfide isochron for D veins (Watanabe et al., 1999). The mineralization ages and the interpreted L porphyry zircon age of 42.2 Ma are within analytical error (Figure 2.13). Based on these dates mineralization and associated hydrothermal alteration occurred at ~ 42.2 ± 0.5 Ma and was synchronous with the L porphyry intrusion at Turquoise Gulch.

Magma recycling and porphyry formation

Most of the samples in the Indio Muerto District contain a bimodal or multi- modal population of Eocene zircon ages. Old zircon grains within a relatively younger sample are clearly defined by both Gaussian distribution and trace-element compositions of high HREE and low Eu/Eu* similar to the quartz porphyry and earlier intrusions (e.g.

Figures 2.7C,D, 2.8E). We suggest that these grains have been reincorporated from an older melt into the younger intrusion either by assimilation of early intrusive rocks or that the magma chamber continuously evolved over a period of several million years.

The Hf content in zircon is an effective proxy for the crystallization of zircon in a melt through its cooling history (Pupin, 2000; Claiborne et al., 2006; Watson et al., 2006,

Wooden et al., 2006). As zircon crystallizes in a melt, the hafnon (HfSiO 4) content will increase as the concentration of Zr in the melt decreases (Watson and Harrison, 1983;

Miller et al., 2003). Zircon preferentially incorporates Zr over Hf during crystallization,

73 thus Hf content of the residual melt increases with crystallization and decreasing temperature of melt (Claiborne et al., 2006). Recent zircon studies using the Ti-in-zircon thermometer (Watson and Harrison, 2005), corroborate the hypothesis (Watson et al.,

2006; Claiborne et al., 2006; Wooden et al., 2006) and the El Salvador zircons record a decrease in T of crystallization with increased Hf content (Figure 2.11A).

Uranium and thorium concentrations vary directly within each population (Figure

2.7A,B). The concentration ranges of Th and U are much greater in the older El Salvador units (quartz porphyries: U 3100-70 ppm, and Th (1200-20 ppm); X porphyries: U 660-

20 ppm, and Th 740-10 ppm) than the younger intrusions associated with mineralization

(K porphyries: U 330-50 ppm, and Th 240-20 ppm; L porphyries: U 960-28ppm, and Th

940-10 ppm). Two L porphyry zircon grains ES-12800-4 (U - 1260 ppm, Th - 530 pppm,

206 Pb/ 238 U - 46.3 ± 0.2 Ma) and ES-12789a-6 (U - 1440 ppm, Th - 1390 ppm, 206 Pb/ 238 U -

44.3 ± 0.2 Ma) (Table 2.1) have U and Th values similar to the quartz porphyry values.

Their U/Pb age however, suggests that these grains are inherited from the rocks associated with or earlier than the quartz porphyry intrusions. Th/U ratios for the samples vary from 2.4 to 0.2, however, a majority of the data yields a ratio of 0.5 roughly

2:1 U to Th. This is clearly evident in the K and L porphyry intrusions (Figure 2.7B), whereas the older quartz and X porphyries and the late latite intrusion deviate from this pattern.

High concentrations of U and Th in zircon most likely occur in highly fractionated melts with relatively high U and Th contents (Miller and Wooden, 2004).

The high U and Th concentrations with increasing Hf content (Figure 2.8B,C) in the quartz porphyries may occur either by increased crystallization rate as the system approaches eutectic-like conditions or changes in partition coefficients for U and Th as T

74 drops and the melt structure changes with increased water content (Clairborne et al.,

2006). The relatively high U and Th concentrations and large negative Eu anomalies with increasing Hf content (Figure 2.8E) would suggest that the quartz porphyries formed from a melt that has undergone feldspar fractionation.

The concentrations of U and Th in zircon from the K and L porphyries decrease slightly but remain relatively constant at a Th/U ratio of 0.5 as Hf increases (Figure 2.14).

Low U and Th content in the K and L porphyries (Figure 2.8B,C) may be explained by the entrainment and mixing of these grains within a fractionated magma chamber with low U and Th, and the potential for apatite and titanite coming onto the solidus as the temperature drops. The drop in MREE may also indicate fractionation of amphibole ± titanite in the magma chamber.

Several grains of X porphyry and latite have enriched MREE and HREE with no

Eu-anomaly (Figures 2.6D, F). They also have low Hf content and high Th/U ratios

(Figures 2.8A, 2.14) suggesting that these grains formed in a hot, relatively unfractionated melt. These grains may record a reheating or recharge event into the magma chamber prior to the subsequent entrainment, fractionation, and continued crystallization within a segregating melt as shown in the other grains by the high Ce/Ce*, low MREE and HREE, and high Hf content. The quartz porphyry and M Gulch – Copper

Hill zircons define linear array between the low Yb/Gd and high Th/U ratios of the X and latite grains and a higher Yb/Gd and lower Th/U ratio (Figure 2.14). The Turquoise

Gulch zircons form a curved array along the same points potentially due to fractionation following the recharge event, whereas the quartz porphyry and M Gulch – Copper Hill zircons reflect mixing between a possible crustal melt and a andesitic or basaltic melt.

75 Figures 2.7C and 2.7D outline Eu-anomaly vs HREE and Eu content respectively. The quartz porphyries define a trend of crystallization as HREE partitions into zircon and increasing negative Eu/Eu*. The Hf vs. Eu anomaly shows a clear distinction between quartz porphyry samples and zircon grains older than 43.5 Ma compared to younger zircons (Figure 2.15). All the older Eocene zircon grains define a trend of increased negative Eu anomaly (0.7 to 0.2) with increased Hf which is most likely the result of plagioclase fractionation during crystallization. Grains younger than

44 Ma define trends with increasing Hf having both low Eu/Eu* although there is overlap between the two trends. The K and L porphyries from Turquoise Gulch have less negative Eu anomalies (0.7 to 0.55) than the L, A, and R porphyries from M Gulch (0.7 to 0.35). Assuming increasing Hf content as a proxy for zircon crystallization (Figures

2.8, 2.11), El Salvador porphyries trend toward less negative Eu anomalies with time. Eu becomes incompatible in plagioclase as the oxidation state increases in the magma thus decreasing Eu/Eu* during differentiation (Wilke and Behrens, 1999: Ballard et al., 2002).

Figure 2.15 outlines this trend between early quartz porphyry zircons, zircons from A

Gulch, and zircons from K and L porphyries from Turquoise Gulch.

Model for the formation of the El Salvador deposit

Based on the zircon geochemistry and the associated U/Pb ages outlined above, we propose that the porphyry intrusions in the El Salvador deposit represent the progressive tapping over a four million year period of a complexly evolving magma chamber or possibly multiple chambers at some as of yet unknown depth (Figure 2.16).

The earliest ages (~46 – 43.5?) represent the emplacement of early pulses of plagioclase

76

Figure 2.14. Enlarged Th/U vs. Yb/Gd ratio plot for El Salvador zircons. Black box outlines X porphyry and latite dike zircons with high Th/U ratios and low Yb/Gd ratios that reflect less fractionated and hotter conditions during crystallization. Solid line outlines quartz porphyry and M Gulch – Copper Hill mixing trend between the hotter less fractionated melt and a potential crustal melt. Dashed line outlines fractionation trend of Turquoise Gulch porphyries.

77

Figure 2.15. Enlarged Hf ppm vs. Eu/Eu* plot for Eocene-age zircons. The oldest zircon grains (>43.5 Ma) show evolution to high Hf at low Eu/Eu* consistent with plagioclase crystallization and include all quartz porphyry samples and inherited grains from later porphyries. Younger zircon grains (<43.5 Ma) illustrate evolution to a wide variety of Eu/Eu* values. Ruled region denotes field for all M Gulch porphyries. Shaded region denotes ~42 Ma aged K and L porphyry zircons from Turquoise Gulch. Arrows denote potential crystallization paths as Hf content increases in zircon during magma crystallization, lower arrow signifies Eu/Eu* decreases as Eu 2+ is incorporated into plagioclase, while upper arrow denotes crystallization path in a more oxidized melt.

78 fractionated magma. The pronounced peak of zircon ages at 43.5 – 43 Ma likely represent the formation of a granodioritic melt by the emplacement of a mafic magma into a mid- to upper-crustal chamber (c.f. Miller and Wooden, 2004). Preferential depression of MREE content with respect to LREE and HREE with increasing Hf content

(Figure 2.6, 2.8d) suggests the fractionation of amphibole ± apatite ± titanite during and following this period (c.f. Ballard, 2001). The presence of Mesozoic zircons in the X porphyries at this time period suggests the assimilation of basement terrain wall rocks during formation. Tosdal et al. (2000) suggest that the presence of the inherited zircons and primitive Sr and Pb isotopic compositions represent the assimilation of primitive basaltic crust at a relatively deep level.

The presence of early Eocene zircons in these late granodiorites suggests the solidification and remelting of the source magma chamber and subsequent entrainment and mixing of the zircons during mafic recharge. Multiple stages of cooling and crystallization would increase the water content leading to water saturation and most likely forming a vapor-rich cap at the top of the magma chamber. At higher oxygen fugacities copper would remain in the melt as magmatic sulfur would occur as sulfate

2- (SO 4 ) which is more soluble in silicate melts (Field et al., 2005). Copper and other chalcophile elements would partition into the vapor/fluid phase during fluid saturation

(Ulrich et al., 1999) and form Cu-mineralization as the fluids migrate to the surface.

Increasing oxidation state post 45 Ma formed small porphyry-Cu centers at Old

Camp and M Gulch at ~43.5 Ma. Oxidation state increased towards the later porphyry intrusions at Turquoise Gulch culminating in the large chalcopyrite-bornite mineralization event at ~42 Ma. The final magmatic event occurred at 41.5 Ma with the mixing of a mafic melt with the granodiorite magmas forming the latite dikes. These

79 dikes were most likely emplaced following a change in tectonics allowing these narrow dikes to penetrate the solidified chamber.

Conclusions

Zircons from the El Salvador porphyry-Cu district provide important new information about the formation of the magmatic history of the deposit.

1) Fourteen new SHRIMP-RG 206 Pb/ 238 U ages have been determined for the El

Salvador district with the oldest surface age ~44 Ma to the youngest at ~41.1 Ma. Early inherited Eocene ages of 46 Ma suggest the magmatic complex responsible for the economic deposit formed over a span of 5 million years. These new ages corroborate previous geochrologic studies in the region. Successively younger porphyry intrusions contain inherited Eocene age zircons suggesting reincorporation of earlier intrusions into later melt.

2) The oldest Eocene aged zircons have high U and Th concentrations, low Eu- anomalies, and relatively enriched REE contents. The magmas from which these zircons crystallized most likely were produced from a less oxidized melt undergoing plagioclase fractionation. Younger zircons show less varied U and Th concentrations with constant

Th/U ratios, moderate Eu-anomalies, and varied REE content. This suggests crystallization in an increasingly oxidized granodioritic magma chamber likely following mafic input into the chamber.

3) Crystallization of the magma chamber over this extended 4 to 5 million year period occurred under increasing oxidizing conditions. Copper accumulated in the melt during crystallization and partitioned into the final magmatic-hydrothermal fluid as the magma

80

Figure 2.16. Conceptual north-south cross-sectional model for the formation of the El Salvador porphyry-Cu district with age progression from left to right. Initial intrusive events occurred from ~46 to 44 Ma with rhyolite and quartz porphyry melts that had undergone significant feldspar fractionation and the probable initiation of a magma chamber formation at depth. During the magma chamber formation Mesozoic basement rock was assimilated early and was incorporated into the X porphyries. Mafic recharge events sustained the magma chamber as it evolved into a granodiorite magma and initiated porphyry pulses. Mineralization formed around the final L porphyry intrusion at Turquoise Gulch at ~42 Ma. The final Latite intrusion represents a mixing of a high- temperature mafic? magma and the granodiorite melt and was emplaced after a shift in the tectonic regime allowing the penetration through the crystallized chamber. Explanation on diagram CP – Cerro Pelado; OC – Old Camp; MG – M Gulch, TG – Turquoise Gulch, GG – Granite Gulch. See text for further discussion of model.

81 became fluid saturated during the L porphyry formation. Age correlations suggest that

Cu mineralization occurred at ~42 Ma with the L porphyry at Turquoise Gulch intruding syn- to immediately after this event. The final latite dike intrusions most likely represent the last pulse of mafic recharge that mixed with an upper magma chamber and was emplaced after the main mineralization event.

Acknowledgments

This project was funded in part by Exploraciones Mineras (EMSA) of the

Corporacion Nacional del Cobre de Chile (CODELCO) and by a 2007 Society of

Economic Geology (SEG) student research grant and a generous donation from Freeport

McMoran Copper & Gold, Inc. The authors would like to thank Lew Gustafson and

Enrique Tidy for initiating this study and for providing samples for analyses. We thank

NSF, USGS, and Stanford for use of the SHRIMP-RG. Barry A. Walker and Mark Ford assisted with data acquisition on the SHRIMP-RG. Walter Orquera, Ricard Santelices,

Christian Rojas, and Eduardo Gonzalez of Exploraciones Mineras at the El Salvador mine assisted in the collection and initial processing of the samples in Chile.

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87

CHAPTER THREE

THE GEOCHEMISTRY OF PORPHYRY INTRUSIONS FROM THE INDIO MUERTO DISTRICT, EL SALVADOR, CHILE: INSIGHTS INTO MAGMATIC PROCESSES THAT PRODUCE PORPHYRY COPPER DEPOSITS

Robert G. Lee John H. Dilles Frank J. Tepley III Adam J.R. Kent

Pending editing and submission 2009 88

Abstract

The El Salvador porphyry copper deposit comprises several ore-mineralization centers in the Indio Muerto District of Northern Chile, with Turquoise Gulch the largest of these centers. Ores are contemporaneous with a series of at least eight lithogically distinct and Eocene age porphyry intrusions characterized by phenocrysts set in a fine aplitic to granitic groundmass and range in composition from granodiorite to granite.

Both major and trace element geochemical compositions distinguish between the earliest intrusions associated with volumetrically minor amounts of Cu (Mo) ore from later intrusions associated with the major Cu (Mo) ore deposit centered under Turquoise

Gulch. The earliest intrusions are granitic in composition with phenocrysts of quartz, plagioclase, and biotite and include the quartz rhyolite porphyry associated with molybdenum-pyrite ores and the quartz porphyry associated with minor pyrite- chalcopyrite-bornite ore. Both intrusions are characterized by rare earth contents with a strong negative europium anomaly and relatively low Sr/Y and Sm/Yb ratios consistent with plagioclase fractional crystallization from a mafic parental melt. Most of the younger intrusions have a granodioritic composition and contain phenocrysts of plagioclase, hornblende, biotite, quartz, apatite, titanite, ilmenite, magnetite, and zircon.

The content of rare earth and other trace elements and the wide range of Sr/Y and Sm/Yb ratios support the origin of the granodiorite X, K, and L porphyries via crystal fractionation of garnet and hornblende ± titanite from a parental andesite magma. The final intrusion was a post-mineral latite porphyry dike that contains two hornblende compositional types as well as plagioclase phenocrysts with sieved or wormy textured zones containing melt inclusions. 89

Electron microprobe and laser ablation – ICP-MS analyses were employed to characterize the major and trace element concentrations of amphibole, apatite, biotite, plagioclase, and titanite crystals from several porphyries. Amphiboles from the granodiorite porphyries have been affected by variable amounts of hydrothermal alteration and have compositions ranging from magnesio-hornblende to actinolite, whereas the post-mineral latite dike contains both edenite and titanian pargasite amphiboles. Amphibole geothermobarometry define pressures of ~6 kb and temperatures greater than 900 ºC at which the titanian pargasites were formed, whereas the edenites formed at lower temperatures ~815 ºC within the upper crust suggesting mixing between mid and upper crust melts in the formation of the latite. Apatite (and titanite) trace element compositions from granodiorite to latite porphyry evolve similarly from a high to low Y concentration and from low to high Sm/Yb ratio. Plagioclase compositions in the granodiorite porphyries vary from An 40 to An 15 whereas compositions in the latite porphyry range from An 52 to An 42 and contain relatively higher Sr and lower Ba concentrations. The inversion of the Sr and Ba concentrations of plagioclase to estimated melt concentrations by use of published crystal-melt partition coeffiecents yields distinctive melt compositions. The elevated values of Sr and Ba for the latite magma are likely the product of mafic magma injecting into and melting a plagioclase-rich host rock.

The granodiorite porphyries illustrate a linear increase of both Sr and Ba with differentiation that likely reflects magmatic evolution via crystal fractionation of a plagioclase-poor assemblage.

The main copper mineralization event at Turquoise Gulch formed as a result of repeated injections of the mafic magma that ascended from ~20 km into an upper crustal 90 magma chamber. The lack of a Eu-anomaly in the younger granodiorite porphyries compared with the older quartz and rhyolite porphyries suggests they were relatively more oxidized. Input of volatiles, and potentially copper from the mafic injections into this highly oxidized late granodiorite magma chamber may have allowed for the efficient partitioning of copper into the hydrothermal fluid phase and the eventual deposition of ore. In comparison the older quartz and rhyolite porphyry intrusions are associated with minor ore deposits possibly due to the less efficient transport of copper under less oxidizing conditions.

Introduction

Porphyry copper deposits are important contributors of copper, gold, molybdenum, and silver and represent over 60% of the world’s source of copper (Singer,

1995; Seedorff et al., 2005). The large hydrothermal deposits are produced by magmatic hydrothermal fluids related to granitoid porphyry intrusives. There has been great interest in the formation of magmas that produce porphyry copper (Mo-Au) deposits

(Gustafson and Hunt, 1975; Sillitoe and Gappe, 1984; Dilles, 1987; Lang and Titley,

1998; Kay and Mpodozis, 2001; Proffett, 2003; Rohrlach and Loucks, 2005; Lickfold et al., 2007). Magmas that produce porphyry intrusions associated with economic deposits represent the source of most metals (c.f., Hedenquist and Lowenstern, 1994). Recently, some investigations have proposed that ore-producing magmas may form in low- to mid- crustal magma chambers by hydrous melting of magma and fractionation of hornblende or garnet (Kay and Mpodozis, 2001; Rohrlach and Loucks, 2005). The ore-producing magmas in many cases form large batholithic upper crustal magma chambers from which 91 porphyries directly related to ore fluids are derived (cf., Dilles, 1987). The magmas evolve via assimilation of wall rock, fractional crystallization and mafic recharge under highly oxidizing conditions to produce ore-related porphyries that may contribute to metal, sulfur, and water that constitute ore fluids for porphyry and high sulfidation Cu-Au ore deposits (Ulrich et al., 1999; Harris et al., 2003; Field et al., 2005). Distinguishing the source, characteristics, and processes of formation of these magmas is essential to understanding how these important mineral deposits form.

The El Salvador porphyry copper deposit in northern Chile is a large Cu(Mo-Au) deposit related to a series of rhyolite to granodiorite porphyries that were emplaced over a period of ~5 Ma (Chapter 2). Multiple intrusive centers occur in the deposit with small mineralization events occurring at ~43.5-44 Ma followed by the main mineralization event at Turquoise Gulch at ~42 Ma (Gustafson and Hunt; 1975; Cornejo et al., 1997;

Gustafson et al., 2001; Lee et al., 2007). Previous work has established the size and geometry of the deposit, the conditions of mineralization and the nature of the mineralized zones (Gustafson and Hunt, 1975), however, only a little work has addressed the petrological evolution of the porphyry intrusions and the relationships between the hydrothermal mineralization and the magmatic history of the porphyries (Cornejo et al.,

1999; Matthews et al., 2000). Previous trace element geochemical data on Chilean porphyry intrusions has been used to propose that crystal fractionation of pyroxene occurred in early magmas prior to ore-formation, whereas crystal fractionation of hornblende, titanite, apatite, and zircon occurred in later porphyry magmas temporally related to ores (Kay et al., 1991; Ballard, 2001; Kay and Mpodozis, 2001). The roles and importance of these mineral phases in ore formation is not clearly understood. Pyroxene 92 was not observed in the porphyry intrusions at El Salvador, however, the latter phases are found in increasing volume percent in the younger intrusions of the deposit (Gustafson and Hunt, 1975; Gustafson et al., 2001). The El Salvador magmas have been proposed to be highly oxidized as well as contain a S- and Cl-rich co-magmatic fluid phase allowing for the efficient transport and deposition of ore bearing minerals (Gustafson, 1979;

Matthews et al., 2000).

This study examines the geochemical composition of whole rock and phenocrysts from the various porphyry intrusions that represent the span and temporal evolution of the El Salvador deposit in order to estimate the depth and temperature for the origin of the magmas, the petrologic processes that the magmas underwent during ascent. The behavior of ore-forming Cu, Mo, S, and Cl and their proxies in the magmas are also examined so as to resolve how these components are concentrated in ore-forming hydrothermal fluids.

Mineral phenocrysts including plagioclase, hornblende, biotite, and accessory phases of titanite, apatite, and zircon represent 50 to 70 vol. % of the porphyries sampled.

These phases were analyzed by electron microprobe and laser ablation inductively coupled mass-spectrometry (LA-ICP-MS). Herein, the concentration of major and trace elements in the phenocrysts in these porphyries is used together with crystal/melt partition coefficients to calculate melt compositions. The estimated melt compositions in turn are used to constrain the source of the magmas, and in particular discriminate between the roles of mafic magma input, deep and mid-crust partial melting, and upper crustal assimilation. Volatiles as well as copper and other ore forming elements are in turn transported from the mafic source into the upper crust where they are either retained 93 in the magma or transported into hydrothermal fluids under high oxidizing conditions

(Mathews et al., 1994; Ulrich el al., 1999).

Geologic Setting

The El Salvador porphyry Cu-Mo deposit of the Indio Muerto District is the southernmost late Eocene porphyry deposit of northern Chile (Figure 3.1), and is hosted in both porphyries and their wall-rocks that include late Cretaceous to Paleocene volcanic rocks of the Indio Muerto region. The Paleocene rocks include andesite lavas, volcaniclastic sedimentary rocks, and the Indio Muerto rhyolite dome complex. The rhyolites range in age from 60 to 58 Ma and are related to the El Salvador caldera

(Cornejo et al., 1997). Geologic mapping, petrology, analyses of hydrothermal alteration and mineralization, and age-dating by K-Ar, 40 Ar-39 Ar, U/Pb zircon, and Re-Os techniques have been conducted over the last 40+ years (e.g. Gustafson and Hunt, 1975;

Cornejo et al., 1997; Cornejo et al., 1999; Gustafson et al., 2001; Watanabe et al., 1999;

Watanabe and Hedenquist, 2001).

At least four porphyry Cu-Mo centers have been discovered in the Indio Muerto

District near El Salvador and are associated with a variety of porphyry intrusions in a 5 by 10 km area. The main ore deposit at Turquoise Gulch occurs as a chalcopyrite-bornite halo around the plug-like L porphyry intrusive complex, which is the largest intrusion in the district and ranges from diorite to granodiorite (57 to 68 wt.% silica). The other porphyry ore centers at Granite Gulch, M Gulch-Copper Hill and Old Camp have low- grade copper mineralization that has been mined where supergene enriched (Gustafson et al., 2001). Cerro Pelado at the north end of the district (Figure 3.1) represents an 94

Figure 3.1. Geologic map and ore distribution of the El Salvador porphyry copper deposit, northern Chile. Figure modified from Gustafson et al. (2001) and new U/Pb zircon age interpretations from Chapter Two.

95 additional center of sub-economic porphyry Mo ore associated with 45 to 44 Ma quartz rhyolite porphyries that are about 1 m.y. older than the other porphyry intrusions in the district (Gustafson et al., 2001). Hydrothermal ore fluids are derived from the intermediate and silicic composition porphyries that in most cases have an aplitic groundmass and abundant phenocrysts of plagioclase, ± hornblende, ± biotite, ± quartz with accessory magnetite, ilmenite, titanite, apatite and zircon (Gustafson and Hunt,

1975; Field and Gustafson, 1976).

U/Pb zircon, Ar-Ar, K-Ar and Re-Os ages (Cornejo et al., 1999; Lee et al., 2007;

Gustafson et al. 2001; Watanabe et al., 1999) indicate an approximately 5 million year span from ~47 to 42 Ma for near surface intrusions beginning with more silicic quartz rhyolite and quartz porphyries, culminating in intermediate composition ore porphyries

(X, K, L porphyries and associated A & R porphyries), and ending with late latite dikes.

The relative ages of these porphyries are well-established by cross-cutting relationships, and it seems likely that there are at least eight stages of porphyry intrusions (Gustafson et al., 2001).

Hydrothermal breccias including tourmaline breccias and “igneous” breccias occur throughout the district and appear to be associated with the emplacement of porphyry intrusions (Gustafson and Hunt, 1975; Watanabe and Hedenquist, 2001). At

Turquoise Gulch the breccias form radial swarms away from the central L porphyry granodiorite stock and are associated with late subsurface veining and the emplacement of the L porphyry. Latite dikes and associated pebble dikes cut all rock types, alteration, and mineralization in the district (Watanabe and Hedenquist, 2001). 96

Supergene clay alteration affects all surface deposits and locally extends down to depths greater than 100 meters (Gustafson and Hunt, 1975; Mote et al., 2001). The associated copper sulfide enrichment zones formed at ~20-13 Ma based on Ar-Ar dating of supergene alunite and copper-bearing manganese oxyhydrates (Mote et al., 2001;

Bissig and Riquelme, 2007). These formed, among others, the Damiana exotic copper ore body to the southwest of Turquoise Gulch and supergene chalcocite-covellite blanket at Turquoise Gulch.

Porphyry Intrusions

Quartz rhyolite porphyry

The quartz rhyolite porphyry is a series of porphyry intrusions that occur in the

Cerro Pelado center approximately 3 km northeast of Turquoise Gulch. The quartz rhyolite was not sampled in this study, but is described in detail by Gustafson (1979) and

Gustafson et al. (2001). The rock type contains phenocrysts of sanidine, plagioclase, quartz and biotite in a microcrystalline quartz and alkali feldspar groundmass with trace amounts of mica and rutile.

Quartz porphyry and late quartz porphyry

Quartz porphyry (72-75 wt. % SiO 2, Gustafson, 1979) represents one of the earliest and most silicic intrusion types. Texturally, the Quartz porphyry is distinguished by abundant coarse quartz (5-10 mm), plagioclase, and biotite phenocrysts in a microcrystalline groundmass of quartz and in most cases sericite (Gustafson and Hunt,

1975; Gustafson et al., 2001). The groundmass constitutes 50-60 volume percent, and grains range from 0.05 to 0.1 mm in diameter. The quartz porphyry contains rare 97 phenocrysts of K-feldspar but lacks amphibole and contains trace amount of zircon. Old

Camp, located 2 km northeast of Turquoise Gulch, is centered on a series of quartz porphyry intrusions that are believed to form partial ring dikes associated with rhyolite porphyries at Cerro Pelado (Gustafson et al., 2001). Dikes of the quartz porphyry extend south-southwest to Turquoise Gulch. Recent U/Pb ages from zircon of both the Old

Camp and Turquoise Gulch quartz porphyries yield ages of 43.6 ± 0.6 Ma and 44.0 ± 0.6

Ma respectively, and support the hypothesis that these are part of the same or contemporaneous intrusive event (Lee et al., 2007; Chapter 2).

On the southwest side of the Old Camp pit, the main quartz porphyry body containing veins, pyrite and chalcopyrite is cut by a late unmineralized quartz porphyry of similar composition (71 wt. % SiO 2 Table 3.1). This late quartz porphyry is similar to the typical quartz porphyry lithology and contains phenocrysts of plagioclase and quartz with minor amounts of biotite and hornblende. Extensive supergene clay alteration has destroyed most textural features; however, the late quartz porphyry distinctly cuts the early quartz porphyry and lacks pyrite-chalcopyrite mineralization present in the earlier quartz porphyry.

X porphyry

The X porphyry is a strongly hydrothermally altered fine-grained equigranular granodiorite. Most of the X porphyry contains moderately strong potassic alteration

(Gustafson and Hunt, 1975; Gustafson, 1979). The X porphyry contains abundant plagioclase along with quartz, K-feldspar, biotite, with accessory zircon, apatite and trace oxides. Primary hornblende is typically replaced by hydrothermal biotite and sulfides, and plagioclase is locally replaced by K-feldspar. The X porphyry is one of the more 98

mafic porphyries in the district (60.79 wt.% SiO 2 Table 3.1) and has an age of ~43.5 Ma

(Cornejo et al., 1997; Lee et al., 2007).

K porphyry

The K porphyry is a feldspar porphyry consisting mainly of euhedral plagioclase, biotite, and local quartz “eye” phenocrysts set in a fine-grained groundmass. Amphibole is also present but in most cases has been replaced by biotite and sulfides during potassium silicate alteration typical of rock exposures (Gustafson and Hunt, 1975).

Accessory minerals include zircon, magnetite, with trace amounts of titanite and apatite.

Plagioclase ranges from 1-5 mm in length, and constitutes 40-70 volume percent of K porphyry samples. The K porphyry occurs in the south and southeastern areas of

Turquoise Gulch where it cuts both Paleocene andesite and the Eocene X porphyry and is cut in turn by the main feldspar L porphyry mass (Figure 3.1).

L porphyry and associated A & R porphyries

The L porphyry body has textures ranging from true porphyry with an aplitic groundmass to phenocryst-rich zones to a nearly equigranular intrusion with 10 vol. % groundmass and unzoned plagioclase; the spatial distribution of these three textures has been mapped in detail and is complex and irregular but broadly concentric around several coarse centers (Figure 9 of Gustafson and Hunt, 1975, p. 874). Porphyry contains plagioclase, amphibole, biotite, and trace amounts of quartz. Accessory minerals include zircon, titanite, magnetite, ilmenite, and apatite. Mafic enclaves were observed commonly in the L porphyry from Granite Gulch but only rarely in the L porphyry from

Turquoise Gulch. The L porphyry at Turquoise Gulch has punched through both X and

K porphyries and the central part of this intrusion is relatively unmineralized (although 99 minor potassic and sericitic alteration is still present) with the main ore body forming as a halo within the X and K porphyries that surround the L porphyry.

At M Gulch-Copper Hill, a texturally similar porphyry occurs that has been termed L porphyry by Gustafson et al. (1975), however, U/Pb and Ar-Ar determinations yield ages 1-2 million years older than the L porphyry at Turquoise Gulch (Cornejo et al.,

1997; Lee et al., 2007; Chapter 2). Texturally, the L porphyry at M Gulch-Copper Hill has a higher percentage groundmass (50-60 vol. %) similar to the periphery of the L porphyry at Turquoise and Granite Gulches.

A and R porphyries are also present at M Gulch-Copper Hill and represent more mafic composition intrusions that cut the L porphyry. The A porphyry at M Gulch -

Copper Hill appears to be a gradational mafic phase formed on the edge of the L porphyry intrusion, however, it is also possible that it is a separate intrusion within the host rock. It contains a fine-grained dark groundmass up to 70 volume percent that is rich in biotite and hornblende. Phenocrysts include plagioclase, biotite, hornblende, with trace oxides and zircon. Rare K-feldspar has been reported in this rock type (Gustafson and Hunt, 1975), but was not observed in this study. The L and A porphyries in the M

Gulch pit cut irregular quartz porphyry dikes that are considered to be contemporaneous with the Old Camp quartz porphyries (Gustafson and Hunt, 1975; Gustafson et al., 2001).

The largest bodies of A porphyry occur in Turquoise Gulch where they intrude along the central southwester edge of the L porphyry (Gustafson and Hunt, 1975).

In the center of the M Gulch pit a distinct feldspar porphyry with plagioclase and hornblende phenocrysts in an aplitic groundmass cuts andesite breccias west of the L porphyry intrusion and has been named R porphyry (Gustafson et al., 2001). The R 100 porphyry post-dates the main copper mineralization event at M Gulch-Copper Hill and contains only trace pyrite. The R porphyry contains chlorite replacements of biotite as well as 2-3 vol. % small <1 mm rounded quartz phenocrysts. The field relations and the

U/Pb zircon age of this porphyry suggest it is younger than the L porphyry in M Gulch to the east (Lee et al., 2007).

Latite porphyry dike

North- to northwest- striking and steeply dipping narrow latite dikes post-date all other intrusive and mineralization events in the district. They consist of a fine- to medium-grained pilotaxitic groundmass with sieved plagioclase phenocrysts rich in melt inclusions as well as hornblende and quartz. Biotite was observed as rare <1mm grains.

Apatite is present up to 1 volume percent and other accessory phases include trace amounts of zircon, titanite, magnetite, and ilmenite. Latite samples represent the least altered samples in El Salvador with the exception of supergene clay alteration at the surface. As a result these contain the best minerals for the study of magmatic origin and are heavily analyzed in this study.

Sample locations and descriptions for all rock types analyzed are given in

Appendix A.

Methods

Sample Preparation

Mineral analyses were performed on multiple rock types collected in cooperation with Corporacion Nacional del Cobre de Chile (CODELCO) geologists from the El

Salvador district. Samples were collected from open pit benches, from the underground 101 mine, and drill core. Thin sections from these samples were prepared in the rock processing laboratory at the El Salvador mine. Rock samples were initially crushed at the

El Salvador mine steel standard jaw crusher and disk mills prior to mineral separation and whole rock chemistry.

Mineral grains were separated from the powders at Oregon State University using a combination of wilfley table, magnetic separation, and hand-picking techniques.

Apatites, titanite, and amphibole were hand picked under a binocular microscope and mounted on a one inch round plug using SpeciFix™ resin and curing agent. The plug was polished using diamond paste in oil and heated in a vacuum oven prior to analyses by electron microprobe.

Apatites from sample ES-12792 (Latite porphyry dike) were mounted on double- sided tape both parallel and perpendicular to the c-axis. This was done to determine the reliability of fluorine analyses, because F may diffuse during electron microprobe analysis (Stormer et al., 1993). Electron microprobe X-ray maps were also used to determine variations in sulfur content as is reported to occur in apatite from porphyry deposits (Streck and Dilles, 1998).

Whole rock chemical analysis

Major and trace element concentrations for twenty-six rock types representing the various porphyries and dikes at the El Salvador deposit were measured by XRF and ICP-

MS at the Washington State University Geoanalytical laboratory following techniques outlined in Johnson et al. (1999). Approximately twenty grams of sample were crushed to powder using an automated agate mortar and pestle crusher. The powders were mixed with dilithium tetraborate (2:1 ratio for XRF and 1:1 ratio for ICP-MS) and fused at 102

~1000 ºC in a muffle furnace. The resulting fused beads are cooled and reground to powder with the XRF powders refused a second time in the oven and the cooled glass beads are then loaded into the XRF spectrometer. The ICP-MS powders after being reground are dissolved into solution and run in the mass spectrometer.

Alteration is prevalent within the district (Gustafson and Hunt, 1975; Watanabe and Hedenquist, 2001), and although care was taken to select samples with little alteration several analyses yielded low totals (<90%). All major whole rock values reported herein are normalized volatile free to 100% (total minus LOI and SO 3), and represent those samples with un-normalized analytical totals greater than 95 weight %.

Locations and descriptions for all samples are given in Appendix A.

Electron microprobe

Major element contents of minerals were analyzed at Oregon State University using a Cameca SX-100 electron microprobe. Data reduction was conducted online using a stoichiometric PAP matrix correction program (Pouchou and Pichoir, 1984).

Back-scattered electron (BSE) images were acquired using the Peak Site software.

Amphibole, plagioclase, mica, and titanite grains were analyzed using a focused 1 µm beam with 15 kV accelerating voltage and 30 nA beam current. Apatites were analyzed using a beam diameter of 2 µm with 15 kV acceleration voltage and 20 nA beam current.

Elements analyzed included the following:

Amphibole: Na, Mg, Si, K, Ca, Ti, Mn, Cr, Fe, F, Cl, Al.

Apatite: P, Fe, Ca, F, Mn, Cl, S, Ce, Na, Mg, Si.

Bioitite: Na, Si, Al, Mg, K, Ca, Ti, Mn, Fe, F, K, Ca, Ti, Cl.

Plagioclase: Na, Fe, Ca, K, Ti, Si, Al, Mg, Sr. 103

Titanite: Si, Al, Ca, Mn, Fe, Na, Mg, F, K, Ti.

X-ray composition maps were conducted on two apatite grains using the same beam operating conditions. Elements analyzed during the procedure included:

F K α on spectrometer 1 using the PC0 crystal.

Si K α on spectrometer 2 using the LTAP crystal.

S K α on spectrometer 3 using the LPET crystal.

Fe K α on spectrometer 4 using the LIF crystal.

Ca K α on spectrometer 5 using the PET crystal.

Full quantification settings and detection limits are given in Appendix C. Mineral formulas were calculated assuming ideal stoichiometry and are described in detail in the text. Worked calculations are presented in the CD Appendix II.

Quadrupole LA-ICP-MS

Trace element concentrations for phenocyrst phases amphibole, plagioclase, biotite, apatite, and titanite were conducted in the W.M. Keck Collaboratory for Plasma

Mass Spectrometry at Oregon State University using a NewWave DUV 193nm ArF

Excimer Laser with aperture-focused optics. Analytical conditions for Quadrupole LA-

ICP-MS analyses are similar to those given in Kent et al. (2004) and Kent and Ungerer

(2006). Samples were mounted in a sample chamber as either thin sections or one inch diameter round epoxy plugs. During the ablation process He was used as the carrier gas for the ablated particulate, and this was mixed with Ar gas immediately prior to the entry into plasma torch. Background mass counts were measured for 40 seconds prior to each analysis and subtracted from the mass counts collected during ablation of the samples for

45 seconds. Signal conditions for the plasma torch was optimized prior to analysis using 104 standard protocols for the instrument where signal strengths of 43 Ca and 232 Th were maximized while maintaining ThO/Th ratios below 2.5% during ablation of NIST 610 glass. Analyses were performed using 50 and 70 mm ablation spot sizes with pulse frequencies of 3 Hz and 5 Hz for thin sections and plug mounts respectively. A mass table consisting of 29 Si, 31P, 43 Ca, 47 Ti, 65 Cu, 85 Rb, 86 Sr, 88 Sr, 89 Y, 90 Zr, 93 Nb, 137 Ba, 138 Ba,

139 La, 140 Ce, 141 Pr, 146 Nd, 147 Sm, 153 Eu, 157 Gd, 159 Tb, 163 Dy, 165 Ho, 166 Er, 169 Tm, 172 Yb,

175 Lu, 208 Pb, 232 Th, and 238 U with dwell time of 10 ms per mass peak. Trace element abundances were calculated relative to the NIST 610 glass standard, which was analyzed both prior to and after unknown analysis. Values used in this calibration are given in

Kent et al. (2004). 29Si and 43 Ca were used as internal normalizing isotopes in conjunction with SiO 2 and CaO contents measured by electron microprobe. USGS glass

BCR-2G was also analyzed to monitor accuracy and precision. All analytical data are presented in Appendix D.

Whole rock geochemistry

Major elements

There have been few geochemical studies on the rocks at El Salvador prior to this research (Gustafson and Hunt, 1975; Gustafson, 1979; Cornejo et al., 1999; Matthews et al., 2000). Gustafson (1979) proposed two groups based on chemical analyses reported by him and Gustafson and Hunt (1975): 1) early silicic volcanism consisting of Indio

Muerto rhyolites and quartz rhyolites and 2) the quartz diorite to granodiorite porphyry intrusions of the main El Salvador porphyry system. He was unable to classify the quartz 105 porphyry due to small sampling, but suggested that it represents a transition between the early rhyolites and main porphyry series.

Major element compositions from the El Salvador Eocene porphyries analyzed in this study range from 60 to 72 wt. % SiO 2 (Table 3.1). Contents of Al 2O3, FeO*, TiO 2, and P 2O5 decrease with increasing SiO 2, except for the late quartz porphyry which has an

Al 2O3 content of 21 wt. % (Fig. 3.2). MgO, CaO, Na 2O and K 2O show more scatter as a result of slight gains and losses during weak hydrothermal alteration, but MgO and Na 2O generally decrease with increasing silica. The quartz porphyry sample is not plotted but has SiO 2 content of 86 wt. %, which is much higher than previously reported by

Gustafson (1979). It follows the general trend of decreasing Al, Fe, Ti, and P content with increasing silica as seen in the other porphyry samples; however the higher silica content is likely due to intense quartz-sericite alteration of the sample. The early granodiorite (X and K) porphyries have been strongly altered to potassium-silicate assemblages and as a result MgO, CaO, and Na 2O contents have been primarily depleted

(Gustafson, 1979; Watanabe and Hedenquist, 2001). The affects of potassic alteration is consistent with the observed major element contents and LOI in these porphyry intrusions

(Table 3.1, Fig. 3.2).

Trace elements

The El Salvador porphyry intrusions have major- and trace-element compositions consistent with a calc-alkaline rock suite (Figure 3.3). Chondrite-normalized rare earth element (REE) abundances generally show similar patterns to previous analyses

(Gustafson 1979; Cornejo et al., 1999). The porphyries are characterized by relatively high REE content (5 to 100x chondrite) and are generally enriched in light REE (LREE) 106

Table 3.1. Whole-rock geochemical results for selected El Salvador intrusions 1. Sample ES-12808 ES-12791 ES-12795 ES-12785a ES-12807 ES-12800 Rock Type 2 Qtz ppy Late Qtz ppy X ppy K ppy K ppy L ppy MG Major Elements 3 (Weight %):

SiO 2 86.87 71.71 60.79 69.47 68.30 65.35

TiO 2 0.134 0.640 0.894 0.583 0.619 0.672

Al 2O3 5.76 20.62 19.38 14.98 15.81 17.78 FeO* 2.78 1.05 2.82 2.42 3.30 3.85 MnO 0.012 0.001 0.010 0.013 0.012 0.028 MgO 0.24 0.12 2.00 1.32 1.56 1.73 CaO 0.06 0.31 5.79 2.77 4.26 1.86

Na 2O 0.62 4.20 5.96 4.42 4.63 6.06

K 2O 3.49 1.22 2.04 3.84 1.33 2.49

P 2O5 0.028 0.131 0.320 0.177 0.184 0.187 Sum 100.00 100.00 100.00 100.00 100.00 100.00

SO 3 0.63 0.18 2.16 1.04 1.52 0.12 LOI (%) 4.27 6.38 2.83 2.58 3.99 2.05 Trace Elements (ppm): Ni 3 0 6 6 6 7 Cr 5 3 4 6 5 4 Ba 600 147 305 588 521 476 Rb 35 38 68 74 26 90 Sr 43 466 757 453 557 463 Zr 29 119 152 104 113 125 Cu 10510 70 2160 720 410 3710 Zn 39 21 20 24 22 187 Pb 4 5 3 3 3 10 La 5.0 14.3 15.1 12.7 18.2 23.2 Ce 10.5 32.5 31.8 26.7 37.2 44.9 Pr 1.3 4.5 4.1 3.4 4.6 5.4 Nd 5.3 19.3 17.8 13.8 18.3 20.6 Sm 1.2 6.1 3.7 2.8 3.6 4.0 Eu 0.3 2.0 1.2 0.8 1.0 1.3 Gd 1.0 5.6 3.0 2.0 2.7 3.1 Tb 0.1 0.7 0.4 0.3 0.3 0.5 Dy 0.8 2.7 2.1 1.3 1.7 2.8 Ho 0.1 0.4 0.4 0.2 0.3 0.6 Er 0.4 0.8 1.0 0.5 0.7 1.5 Tm 0.1 0.1 0.1 0.1 0.1 0.2 Yb 0.3 0.6 0.8 0.4 0.5 1.5 Lu 0.1 0.1 0.1 0.1 0.1 0.2 Th 1.9 3.0 1.7 2.6 1.9 2.8 Nb 3.3 7.8 5.4 6.1 5.9 6.9 Y 4.0 7.4 10.2 5.8 7.6 13.8 Hf 1.0 2.8 3.6 2.7 2.6 3.4 Ta 0.4 0.7 0.4 0.5 0.4 0.5 U 0.4 2.0 0.4 0.5 0.4 1.5 1 Major element oxides and Ni-Pb analyzed by XRF, La-U analyzed by ICP-MS. 2 Rock types determined by texture and assemblage. MG - M Gulch, TG - Turquoise Gulch, GG - Granite Gulch 3 Major element concentrations normalized to volatile free. *Total Fe reported as FeO. 107

Table 3.1. cont. Sample ES-12783 ES-12781 ES-12782 ES-12786 ES-12787 ES-12790 Rock Type 2 A ppy MG R ppy MG R ppy MG L ppy TG L ppy TG L ppy TG Major Elements 3 (Weight %):

SiO 2 60.31 61.47 65.90 64.81 66.88 62.90

TiO 2 1.037 1.110 0.572 0.760 0.668 0.887

Al 2O3 19.78 17.74 17.01 17.67 16.64 18.64 FeO* 6.70 7.66 4.14 3.48 3.00 3.71 MnO 0.031 0.170 0.146 0.011 0.030 0.023 MgO 2.55 0.81 1.44 1.45 1.31 2.68 CaO 1.69 3.77 0.44 4.26 3.87 2.52

Na 2O 5.66 4.77 2.65 5.51 4.97 5.84

K 2O 1.92 2.15 7.50 1.81 2.42 2.70

P 2O5 0.344 0.349 0.205 0.239 0.205 0.091 Sum 100.00 100.00 100.00 100.00 100.00 100.00

SO 3 0.19 0.22 0.36 0.44 0.20 0.10 LOI (%) 3.51 3.94 2.63 0.89 0.82 1.15 Trace Elements (ppm): Ni 9 24 6 6 7 10 Cr 7 11 5 7 8 13 Ba 352 496 1652 496 549 268 Rb 81 38 150 61 53 138 Sr 488 659 229 739 640 572 Zr 139 145 111 146 121 119 Cu 3703 50 80 320 240 1460 Zn 233 815 234 15 29 171 Pb 6 6 13 2 3 3 La 15.4 20.3 14.6 17.5 20.0 19.7 Ce 33.0 43.7 30.5 38.7 40.9 38.6 Pr 4.3 5.8 3.9 5.1 5.1 4.7 Nd 18.4 24.1 15.5 20.7 20.0 17.2 Sm 5.1 4.9 3.3 4.1 3.8 3.0 Eu 2.0 1.4 1.1 1.2 1.1 1.0 Gd 7.3 3.4 2.7 3.0 2.7 2.2 Tb 1.2 0.4 0.4 0.4 0.3 0.3 Dy 7.0 2.0 2.2 1.7 1.6 1.6 Ho 1.3 0.3 0.4 0.3 0.3 0.3 Er 3.2 0.7 1.0 0.6 0.6 0.8 Tm 0.4 0.1 0.1 0.1 0.1 0.1 Yb 2.4 0.5 0.9 0.5 0.5 0.8 Lu 0.3 0.1 0.1 0.1 0.1 0.1 Th 1.7 1.7 2.8 2.7 3.5 3.2 Nb 6.5 7.5 6.4 7.1 7.0 6.4 Y 32.0 8.3 10.2 7.3 7.0 7.6 Hf 3.6 3.8 2.9 3.7 3.2 3.2 Ta 0.4 0.5 0.6 0.5 0.5 0.5 U 1.7 0.6 1.2 0.7 1.4 0.7 1 Major element oxides and Ni-Pb analyzed by XRF, La-U analyzed by ICP-MS. 2 Rock types determined by texture and assemblage. MG - M Gulch, TG - Turquoise Gulch, GG - Granite Gulch 3 Major element concentrations normalized to volatile free. *Total Fe reported as FeO. 108

Table 3.1. cont. Sample ES-12796 ES-12804 ES-12814 ES-12789a ES-12792 ES-12793 ES-12809 Rock Type 2 L ppy TG L ppy TG L ppy TG L ppy GG Latite dike Latite dike Latite dike Major Elements 3 (Weight %):

SiO 2 65.42 63.58 65.50 63.41 63.71 67.28 63.80

TiO 2 0.759 0.789 0.809 0.762 0.934 0.827 0.887

Al 2O3 17.34 17.47 18.31 17.47 17.06 16.98 17.03 FeO* 3.35 5.92 3.19 5.67 4.08 3.86 6.47 MnO 0.030 0.020 0.013 0.034 0.067 0.027 0.065 MgO 1.56 1.51 1.56 1.77 1.72 1.75 1.23 CaO 3.98 2.69 3.02 3.54 5.42 2.81 3.56

Na 2O 5.02 4.16 5.40 5.09 4.59 3.46 4.46

K 2O 2.30 3.61 1.93 1.96 2.13 2.75 2.23

P 2O5 0.242 0.253 0.253 0.283 0.284 0.249 0.271 Sum 100.00 100.00 100.00 100.00 100.00 100.00 100.00

SO 3 1.06 0.64 0.05 0.11 0.10 0.69 0.28 LOI (%) 2.55 2.80 1.56 1.13 4.96 5.13 3.81 Trace Elements (ppm): Ni 6 11 9 13 13 12 16 Cr 4 7 8 7 10 8 12 Ba 611 706 532 511 524 459 562 Rb 49 126 53 65 34 54 36 Sr 627 551 659 629 675 475 571 Zr 121 131 145 133 127 120 128 Cu 520 2464 340 1240 40 1110 90 Zn 50 161 43 201 75 168 218 Pb 4 4 4 7 3 32 8 La 16.3 40.0 22.1 19.2 19.3 16.5 19.2 Ce 34.8 73.1 45.7 37.9 40.4 34.7 40.1 Pr 4.5 8.1 5.8 4.8 5.2 4.4 5.1 Nd 18.5 29.3 22.9 19.4 21.4 17.7 20.8 Sm 3.7 5.0 4.5 4.0 4.2 3.5 4.0 Eu 1.2 1.5 1.4 1.1 1.2 1.0 1.2 Gd 2.7 3.3 3.4 3.2 3.0 2.6 2.9 Tb 0.3 0.4 0.4 0.4 0.4 0.3 0.3 Dy 1.6 1.7 2.0 2.3 1.8 1.6 1.7 Ho 0.3 0.3 0.3 0.4 0.3 0.3 0.3 Er 0.6 0.6 0.8 1.0 0.6 0.7 0.6 Tm 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Yb 0.5 0.5 0.6 0.8 0.5 0.6 0.5 Lu 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Th 2.3 2.3 2.8 3.2 1.8 1.9 1.8 Nb 6.7 6.4 7.2 6.4 7.0 6.3 7.0 Y 7.0 6.9 8.7 10.9 7.4 7.1 6.7 Hf 3.3 3.5 3.2 3.5 3.5 3.1 3.6 Ta 0.5 0.5 0.5 0.5 0.4 0.4 0.4 U 0.6 2.1 0.8 1.0 0.8 0.8 0.8 1 Major element oxides and Ni-Pb analyzed by XRF, La-U analyzed by ICP-MS. 2 Rock types determined by texture and assemblage. MG - M Gulch, TG - Turquoise Gulch, GG - Granite Gulch 3 Major element concentrations normalized to volatile free. *Total Fe reported as FeO. 109

Figure 3.2. Major element oxide versus SiO 2 concentrations normalized to volatile free for El Salvador porphyry intrusions. MG-CH – M Gulch-Copper Hill, GG – Granite Gulch, TG – Turquoise Gulch. 110

Figure 3.3. Trace element variation diagrams for El Salvador porphyry intrusions. A. REE diagram of Eocene age intrusions from 44-43 Ma. Quartz rhyolite and quartz porphyry sample data are from Gustafson (1979). B. REE diagram of Eocene age intrusions 43-41.5 Ma. C. Spider diagram of Eocene age intrusions from 44-43 Ma. D. Spider diagram of Eocene age intrusions from 43-41.5 Ma. Diagrams normalized to chondrite values of McDonough and Sun (1995). Age values based on U/Pb interpreted ages from Chapter 2.

111 and depleted in heavy REE (HREE) with La/Lu ratios of 50 to 550 (Figure 3.3A,B). The older Eocene age (>~43 Ma) porphyry intrusions from Old Camp, M Gulch-Copper Hill, and Granite Gulch display more variation in REE abundance and pattern compared to the younger (43-41.5 Ma) K and L porphyry and latite dike intrusions from Turquoise Gulch.

The quartz rhyolite and quartz porphyry samples were originally analyzed by Gustafson

(1979) and have strong negative europium anomalies (Eu/Eu* = 0.22 and 0.80, respectively). The other porphyries show no europium anomaly and therefore are consistent with the probable lack of plagioclase crystal fractionation during the magma evolution in contrast to the quartz rhyolite and quartz porphyry which likely evolved by preferential plagioclase crystallization and removal. The late quartz porphyry is preferentially enriched in middle REE (MREE) compared to the other porphyry intrusions. The A porphyry from M Gulch-Copper Hill is also enriched in MREE and

HREE relative to all other porphyry intrusions. The X porphyry and the L porphyries from M Gulch-Copper hill and Granite Gulch have higher HREE (Yb-Lu) concentrations relative to the porphyries from Turquoise Gulch.

All the porphyry intrusions show a wide range of incompatible trace element concentrations (Cs and Rb 6 to 65x chondrite; Th and U 50 to 280x chondrite) most likely due to remobilization by hydrothermal alteration. The porphyries have relatively low Nb (22-32), Ta (27-50), Y (3-20), Yb (2-14) and high Sr (31-103) concentrations compared with the other trace element concentrations (Figure 3.3C, D). The older

Eocene intrusions show a large range of Y and Yb concentrations, whereas samples of the younger K, L, and Latite intrusions show little variation.

112

Mineral composition

Amphibole

Compositions of amphiboles were determined by electron microprobe analysis from the late stage relatively unaltered intrusions of L porphyry and latite dike. Two samples of L porphyry were analyzed on thin sections from the personal collection of

Lew Gustafson, whereas amphiboles from the latite dike (ES-12792) were hand-picked and mounted on an epoxy plug. Amphiboles from older intrusions have undergone potassic alteration to form hydrothermal biotite, and analyses of relict amphibole yielded poor analytical totals and as a result were not used in this study.

We use the amphibole nomenclature of Leake et al. (1997) with revisions by

Hawthorne and Oberti (2006), on basis of both photographic characteristics and chemical composition. The structural formula for amphibole compositions was calculated assuming 23 oxygen atom equivalents using the method in Leake et al. (1997), corrected for F and Cl compositions. Fe 3+ was estimated assuming a total cation sum of 15 and excluding A-site alkalis. This gives a minimum value of Fe 3+ but gives consistent stoichiometric totals for all samples analyzed (Table 3.2). Weight percent H 2O and oxygen equivalents for F and Cl were estimated assuming (F + Cl + OH) = 2, where H 2O is calculated by dividing OH - in the atomic formula by 2 and then dividing by the 23 oxygen normalizing factor and multiplying by the atomic weight of H 2O.

Amphibole shows a positive correlation of Al 2O3 with TiO 2 for the L porphyry samples, whereas the latite dike amphiboles display a bimodal population of high TiO 2

(2.5-3.0 wt. %) and low TiO 2 (0.8-1.0 wt. %) amphiboles (Figure 3.4). It also appears that the low Ti amphiboles contain two populations of Al 2O3 content one at ~8.5 wt. % 113 and one at ~10.0 wt. %. Based on the amphibole classification scheme of Leake et al.

(1997) the L porphyry amphiboles vary from magnesio-hornblende to actinolite, whereas the latite amphiboles are titanian pargasite and edenite (Figure 3.5).

The L porphyry samples contain patchy green hornblende to pale green actinolite with associated hydrothermal biotite along edges of grains (Figures 3.6, 3.7) and are similar to other porphyry-Cu deposits found in Chile (i.e., Ambrus, 1977; Agemar et al.,

1999). Plagioclase and magnetite inclusions also occur within the grains.

Compositionally these hornblendes show a wide range between magnesio-hornblende to actinolite with a positive correlation of Si and Mg number (Figure 3.5b). The hornblendes from the latite sample retain their igneous texture and are slightly replaced by calcite (Figure 3.8).

Trace element concentrations show distinct differences between the titanian pargasites and edenites. The chondrite normalized REE pattern of both the titanian pargasites and the edenite containing 10.75 wt.% Al2O3 have similar concave down shape with the edenites having a slight negative europium anomaly (Figure 3.9). The 8.5 wt.%

Al 2O3 edenites have a distinctly different pattern with enriched LREE (La & Ce) relative to the MREE and HREE. This is also reflected in La/Nd ratios in which the low-Al 2O3 edenites vary from 0.48 to 0.75 whereas the higher Al 2O3 amphiboles have consistent ratios from 0.16 to 0.2. The titanian pargasites contain higher concentrations of Sr (220 to 360 ppm) and Ba (80-115 ppm) compared to the edenites (Sr = 25 to 130 ppm and Ba

= 35 to 64 ppm) (Appendix D). Copper concentrations ranged from 3 ppm to below detection limit in all of the amphiboles analyzed.

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Table 3.2: Composition of selected amphiboles by electron microprobe analysis. Rock type L porphyry L porphyry L porphyry L porphyry L porphyry L porphyry Latite dike Latite dike Latite dike Latite dike Sample # ES-3081- ES-3081- ES-3081- ES3076- ES3076- ES3076- ES12792A ES12792A ES12792A ES12792A 2.1rim 3.2core 4.4core 3.3core 4.5rim 4.7rim m-1 m-6 m-7 m-9 a Amph type Act-Hbl Act Act-Hbl Act-Hbl Mag-Hbl Act Ti-Par Ti-Par Edn Edn Wt.%

SiO 2 51.51 54.89 51.07 51.52 49.17 53.90 42.03 42.02 44.99 45.26 TiO 2 1.14 0.14 1.25 1.04 1.26 0.52 2.80 2.88 0.85 1.00

Al 2O3 4.57 1.99 4.69 4.43 5.87 2.93 12.95 13.27 10.67 8.74 b FeO 9.83 9.57 9.95 9.85 11.15 8.67 10.67 10.97 15.72 17.86 Na 2O 1.24 0.29 1.27 1.24 1.39 0.85 2.57 2.63 1.98 1.55 K2O 0.43 0.10 0.43 0.37 0.48 0.19 0.39 0.38 0.53 0.76 MgO 17.74 18.15 17.62 17.66 16.01 18.89 15.00 14.53 12.47 11.61 CaO 11.11 12.38 11.08 11.33 11.30 11.56 11.33 11.15 10.35 11.28 MnO 0.35 0.35 0.46 0.42 0.45 0.36 0.10 0.13 0.28 0.42

Cr 2O3 0.00 0.00 0.00 0.01 0.00 0.00 0.11 0.07 0.02 0.00 Cl 0.12 0.20 0.11 0.07 0.10 0.05 0.01 0.02 0.03 0.03 c 2.07 2.07 2.07 2.08 2.03 2.11 2.05 2.05 2.02 2.00 H2O Sum 100.11 100.14 100.00 100.01 99.20 100.03 100.01 100.09 99.90 100.50 Ideal cation proportions based on 23 oxygen equivalents and minimum Fe 3+ calculation of Leake et al. (1997) Si 7.347 7.761 7.306 7.360 7.157 7.612 6.121 6.131 6.655 6.722 Al IV 0.653 0.239 0.694 0.640 0.843 0.388 1.879 1.869 1.345 1.278 sum T 8.000 8.000 8.000 8.000 8.000 8.000 8.000 8.000 8.000 8.000 Al VI 0.116 0.093 0.098 0.106 0.163 0.100 0.345 0.414 0.516 0.252 Ti 0.122 0.015 0.134 0.111 0.138 0.056 0.306 0.316 0.095 0.111 Fe 3+ 0.000 0.000 0.000 0.000 0.000 0.000 0.052 0.000 0.000 0.100 Cr 0.000 0.000 0.000 0.001 0.000 0.000 0.013 0.008 0.002 0.000 Mg 3.771 3.827 3.757 3.761 3.474 3.977 3.256 3.162 2.750 2.570 Fe 2+ 0.991 1.065 1.011 1.021 1.224 0.868 1.028 1.100 1.638 1.967 Mn 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 sum C 5.000 5.000 5.000 5.000 5.000 5.000 5.000 5.000 5.000 5.000 Mg 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Fe 2+ 0.182 0.067 0.180 0.155 0.133 0.156 0.220 0.238 0.306 0.152 Mn 0.042 0.042 0.056 0.051 0.055 0.043 0.012 0.016 0.035 0.053 Ca 1.698 1.875 1.699 1.734 1.762 1.750 1.768 1.743 1.640 1.795 Na 0.078 0.015 0.065 0.060 0.050 0.051 0.000 0.003 0.019 0.000 sum B 2.000 2.000 2.000 2.000 2.000 2.000 2.000 2.000 2.000 2.000 Na 0.264 0.065 0.286 0.284 0.341 0.181 0.727 0.741 0.550 0.447 K 0.079 0.018 0.078 0.068 0.090 0.035 0.072 0.072 0.099 0.143 sum A 0.343 0.084 0.365 0.352 0.431 0.216 0.799 0.813 0.649 0.591 Total 15.343 15.084 15.365 15.352 15.431 15.216 15.799 15.813 15.649 15.591 0=Cl 0.028 0.046 0.026 0.017 0.022 0.013 0.002 0.004 0.007 0.006 OH- 1.972 1.954 1.974 1.983 1.978 1.987 1.998 1.996 1.993 1.994

Mg/(Mg+Fe) 0.763 0.772 0.759 0.762 0.719 0.795 0.715 0.703 0.586 0.537

(Na+K) A 0.343 0.084 0.365 0.352 0.431 0.216 0.799 0.813 0.649 0.591 a Amphibole types based on IMA classification Leake et al. (1997). Act = Actinolite, Act-Hbl = Actinolitic-hornblende, Mag-Hbl = Magnesio-hornblende, Ti-Par = Titanian pargasite, Edn = Edenite. b Reported as total FeO for simplicity of table. c Calculated from stoichiometry

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Figure 3.4. Amphibole Al 2O3 vs. TiO 2 (in wt. %) diagram from L porphyry and latite dike samples from Turquoise Gulch. Samples ES-3081 and ES-3076 originally collected and used with permission by Lew Gustafson. Concentrations measured by electron microprobe.

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Figure 3.5. Classification diagrams for calcic-amphiboles after Leake et al. (1997). A. Molar Si vs. Ti. B. Molar Si vs. molar Mg/(Mg + Fe) number for Ca > 1.0 and (Na + K) A <0.5. 117

Figure 3.6. Photomicrographs of L porphyry amphiboles from Turquoise Gulch. A. Cross-polarized image outlining plagioclase, quartz, and hornblende phenocyrsts in a quartz- and plagioclase-rich groundmass. The hornblende shows a dissolution/reaction texture and is partly replaced by plagioclase and oxides. B. Plane-polarized image of patchy actinolites partly replaced by biotite and oxides. Plag – Plagioclase, Qtz – quartz, GM – quartzofeldspathic groundmass, Bio – biotite, Hbl – hornblende, Act – actinolite, Ox – Fe-Ti oxide.

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Figure 3.7. Backscattered electron image (BSE) of L porphyry amphibole analyzed by electron microprobe. Bio – biotite, Act-hbl – actinolitic hornblende, FeOx – iron oxide, Mag-hbl – Magnesio-hornblende, Plag – plagioclase.

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Figure 3.8. Photomicrographs of amphiboles and sieved plagioclases from the El Salvador latite dike samples. Amphiboles are characterized as titanian pargasites and edenites and contain inclusions of plagioclase and Fe-Ti oxides. Minor calcite replacement occurs along the rims of the grains. Plagioclase shows either completely sieved textures or sieved cores with unsieved growth bands or rims. Groundmass is typically pilotaxitic and makes up 60 to 70 vol. % of the rock. Plag – plagioclase, Amph – amphibole, Qtz – quartz, Ox – oxide. 120

Figure 3.9. REE diagram for amphiboles from latite dike sample ES-12792 normalized to chondrite. Chondrite values from McDonough and Sun (1995).

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Apatite

Apatite occurs as an accessory mineral in all the feldspar porphyries and latite dikes of the El Salvador district. The grains from the granodiorite porphyries range in size from <0.1 to 0.75 mm and are colorless to white in thin section. The latite dike apatites are slightly larger ranging from 0.1 to 1.5 mm in size and are colorless with skeletal cores. A few grains within the latite sample locally contain rectangular inclusions and large amorphous melt(?) inclusions (Figure 3.10). X-ray maps show variable Si content within the inclusions and little to no Ca content (Figure 3.11). Iron was not detected in the inclusions and neither was sulfur using the X-ray maps. Electron dispersion scans using the electron microprobe detected variable amounts of Si, Al, K,

Ca, Mg, Fe, Na, P, and Ti within the inclusions. The rectangular inclusions appear to be crystalline minerals that are potentially orthopyroxenes on the basis of low to undetectable Ca and EDS detected Mg when analyzed by the electron microprobe (Figure

3.11C). The rectangular mineral inclusions in some cases themselves contain inclusions of apatite (Figure 3.11).

Microprobe analyses were performed on apatite from R porphyry, K porphyry, L porphyry from Turquoise and Granite Gulch, and from the latite porphyry dike (Table

3.3). The ideal formula was calculated using 25 oxygen element equivalents assuming

2+ 2+ 2+ general apatite formula A 10 [TO 4]6(OH,F,Cl) 2, where the A-site contains Ca , Fe , Mg ,

Mn 2+ , Na +, Ce 3+ , and the T-site is occupied by P 5+ , Si 4+ , and S 6+ and OH - was calculated assuming (F + Cl + OH) = 2. Fluorine contents ranged from 0.97 to 4.02 wt. %, whereas chlorine contents ranged from 0.07 to 1.14 wt. % although one sample did have 1.53 wt.

% Cl (Sample # 1289a-2.2 Table 3.3). This suggests that most of the apatites sampled 122

Figure 3.10. Photomicrographs of apatite phenocrysts from El Salvador latite porphyry dike. A. Large amorphous inclusions are common in the grains and may represent silicate melt inclusions. B. Rectangular minerals are found in the cores of the apatites and are typically brown in thin section. Ap – apatite, MI – Silica melt inclusion?, Inc – rectangular brown orthopyroxene? inclusion, Ox – oxide.

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Figure 3.11. Reflected, BSE, and X-ray images of latite dike apatite grain ES-12792ap-7. A. Reflected light image looking perpendicular to the C-axis. Laser ablation pits outlined with black circles have 50 µm diameters. The dark mass in the center of the grain extends down through the core. B. Backscattered electron image with gray to tan inclusions outlined with black lines. C. Ca K α X-ray map of apatite grain. Note apatite inclusion within the dark rectangular inclusion. The rectangular inclusion is believed to be a pyroxene although no Ca occurs within this inclusion. D. Si K α X-ray map showing distinct variation in the Si content in the apatite inclusions. Amorphous inclusions are believed to represent silica melt inclusions. Bars are all at 200 µm length.

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Table 3.3: Composition of selected apatites by electron microprobe analysis. Rock Type R ppy R ppy K ppy K ppy L ppy GG L ppy TG L ppy TG Latite Latite sample # 12781-1.1 12782-2.3 128785a-1.4 12785a-2.1 12789a-2.2 12787-1.2 12787-3.1 12792-7.1 12792-20.1 Weight % CaO 54.08 54.48 54.39 54.52 54.42 54.01 54.36 55.45 54.67

P2O5 40.79 41.42 41.67 41.06 41.25 41.32 40.70 42.50 41.47 FeO 0.28 0.13 0.12 0.26 0.05 0.11 0.06 0.03 0.10 MnO 0.14 0.15 0.14 0.21 0.18 0.07 0.00 0.09 0.09

SO 3 0.15 0.00 0.22 0.23 0.03 0.30 0.03 0.08 0.17

Ce 2O3 0.09 0.03 0.10 0.19 0.16 0.45 0.27 0.03 0.09

Na 2O 0.06 0.01 0.21 0.19 0.04 0.25 0.01 0.04 0.06 MgO 0.00 0.00 0.01 0.02 0.00 0.01 0.00 0.01 0.03

SiO 2 0.06 0.02 0.00 0.00 0.13 0.16 0.15 0.05 0.05 F 1.34 3.42 2.42 2.56 1.61 2.17 2.70 1.77 1.47 Cl 0.23 0.13 0.32 0.36 1.53 0.89 0.07 0.12 0.13 sum 97.21 99.80 99.60 99.58 99.40 99.72 98.33 100.18 98.33 Ideal cation site occupancy based on 25 oxygen equivalents Ca 9.818 9.607 9.611 9.677 9.709 9.570 9.753 9.723 9.788 Fe 0.040 0.018 0.017 0.037 0.007 0.015 0.008 0.004 0.013 Mn 0.020 0.021 0.019 0.029 0.026 0.010 0.000 0.012 0.013 Ce 0.005 0.002 0.006 0.011 0.010 0.027 0.016 0.002 0.005 Na 0.019 0.004 0.067 0.060 0.013 0.080 0.002 0.012 0.020 Mg 0.000 0.000 0.003 0.005 0.000 0.002 0.000 0.002 0.007 Sum A 9.903 9.652 9.723 9.819 9.765 9.704 9.779 9.756 9.848 P 5.854 5.774 5.820 5.760 5.817 5.787 5.771 5.891 5.868 Si 0.010 0.003 0.000 0.000 0.022 0.026 0.026 0.009 0.009 S 0.019 0.000 0.028 0.028 0.004 0.037 0.003 0.010 0.021 Sum T 5.883 5.777 5.848 5.788 5.842 5.851 5.800 5.909 5.898 Total 15.786 15.429 15.570 15.607 15.607 15.555 15.579 15.665 15.746

0=F 0.565 1.440 1.017 1.077 0.680 0.912 1.138 0.746 0.621 0=Cl 0.053 0.031 0.075 0.083 0.354 0.206 0.016 0.029 0.030 OH- 1.382 0.529 0.908 0.840 0.966 0.882 0.847 1.226 1.349

125 are fluor-apatites with partial solid solution with chlorine and hydroxyl varieties (Deer et al., 1992).

The REE concentrations of apatite for the K, L, and latite porphyries show distinct differences between each sample (Figure 3.12). The K porphyry is enriched in

HREE compared to the L porphyry and latite. The L porphyry has a higher variation in

La and Ce compared to the MREE and HREE. The apatites from the latite show a wide range of REE concentrations up to 500x difference between the MREE and HREE

(Figure 3.12). All the apatites have negative europium anomalies. Other trace element concentrations also vary with strontium content higher in the latite dike (420 to 600 ppm) compared with the K porphyry (~385 ppm) and L porphyry (190 to 260 ppm) (Appendix

D).

Biotite

Biotite was analyzed in thin sections from seven different samples. Both magmatic and hydrothermal biotites were analyzed with preference towards magmatic where present. Igneous biotite phenocrysts are medium-grained from 2 to 4 mm in size, dark brown to light brown in color, and commonly contain inclusions of plagioclase, Fe-

Ti oxides, rutile needles, and zircon (Figure 3.13). The latite dike samples contain rare

(<1 volume percent) igneous biotite grains 0.5 to 1 mm in size. Hydrothermal biotite replace patchy amphiboles in all feldspar porphyries and is light brown to green in thin section compared to dark brown phenocrysts of magmatic biotite (Figure 3.14).

Average biotite electron microprobe analyses are given in Table 3.4. Formula proportions were normalized to 22 oxygen equivalents as outlined in Deer et al. (1992), where OH- is calculated assuming (F + Cl + OH) = 4. Following the formula of the 126

Figure 3.12. Chondrite normalized REE diagram for apatite from the El Salvador district. Chondrite values from McDonough and Sun (1995).

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Figure 3.13. Plane-polarized photomicrograph of biotite from the K porphyry of Turquoise Gulch. The biotite grain is a golden brown in plane light and contains inclusions of plagioclase (Plg), zircon (Zir, outlined in image) and small <5 µm rutile needles not visible in this image. Resorbed edges are evident at the contact with the quartz (Qtz) aplite groundmass as well as hydrothermal biotite (Bio) and sericite (Ser) replacement along the edge of the grain.

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Figure 3.14. Cross-polarized photomicrograph of L porphyry from Turquoise Gulch. Phenocrysts consist of plagioclase (Plg), quartz (Qtz), and biotite (Bio). Quartz and plagioclase make up the groundmass. Plagioclase shows slight to no zoning and contains minor sericite (Ser) alteration. Most Fe-Ti oxides are magnetite with trace amount of ilmenite.

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Table 3.4: Average composition of biotites from electron microprobe analysis. Rock Type 1 L ppy MG-CH A ppy MG-CH R ppy MG L ppy GG K ppy TG L ppy TG Sample # ES-12800 (13) ES-12783 (12) ES-12781 (6) ES-12789a (5) ES-12785a (19) ES-12787 (8) Weight %.

SiO 2 37.76 39.03 37.23 38.61 38.42 38.51

Al 2O3 15.10 15.33 14.23 13.88 13.88 13.53 MgO 14.97 14.60 13.59 16.05 15.83 15.45 FeO 15.10 15.43 17.59 14.42 15.14 15.83

K2O 9.14 9.11 8.39 9.32 9.06 9.28

TiO 2 3.80 2.88 3.63 4.52 3.89 4.08

Na 2O 0.18 0.09 0.49 0.10 0.12 0.10 CaO 0.00 0.03 0.05 0.03 0.03 0.02 MnO 0.08 0.08 0.22 0.13 0.06 0.08 F 0.20 0.23 0.26 0.23 0.77 0.34 Cl 0.19 0.24 0.04 0.36 0.14 0.16 Total 96.50 97.03 95.72 97.64 97.33 97.38 2 Corr Total 96.38 96.88 95.60 97.47 96.97 97.20 Ideal cation site occupancy based on 22 oxygen equivalents Si 5.577 5.716 5.605 5.635 5.653 5.668 Al IV 2.423 2.284 2.395 2.365 2.347 2.332 Sum Z 8.000 8.000 8.000 8.000 8.000 8.000 Al VI 0.207 0.366 0.132 0.023 0.063 0.017 Ti 0.422 0.318 0.411 0.496 0.431 0.452 Fe 1.865 1.891 2.220 1.761 1.865 1.949 Mn 0.010 0.010 0.028 0.017 0.007 0.010 Mg 3.296 3.187 3.046 3.492 3.473 3.390 Sum Y 5.800 5.772 5.836 5.789 5.839 5.818 Ca 0.000 0.004 0.008 0.004 0.004 0.003 Na 0.051 0.026 0.141 0.028 0.035 0.028 K 1.722 1.704 1.612 1.734 1.701 1.742 Sum X 1.773 1.734 1.761 1.766 1.740 1.773 O=F 0.084 0.095 0.111 0.095 0.326 0.145 O=Cl 0.043 0.055 0.010 0.082 0.033 0.037 OH- 3.873 3.850 3.879 3.823 3.641 3.818

H2O 3.928 3.935 3.858 3.923 3.705 3.885 Mg/(Mg+Fe) 0.639 0.628 0.578 0.665 0.651 0.635

1Rock type defined by location where ppy - porphyry, MG-CH - M Gulch - Copper Hill, MG - M Gulch, & TG - Turquoise Gulch 2Corrected total Sum - (O-F,Cl)

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biotite group X 2Y6[Z 8O20 ](OH,F,Cl) 4 all K, Na, and Ca is added to the X-site, Ti, Fe, Mg,

Mn, and Al VI is added to the Y-site, and Al IV and Si is added to the Z-site which totals to

8 by definition.

All the biotites analyzed vary between 0.53 to 0.69 Mg/(Mg+Fe) and 1.9 to 3.1 total molar Al and fall within the main biotite classification field (Figure 3.15A). MgO

(wt. %) and FeO (wt. %) vary in the A, R, and K porphyries whereas the L porphyries all have similar compositions within each sample (Figure 3.15B). Molar K versus molar Si suggests most of these samples have undergone little alteration (Figure 3.15C). Those samples with molar K <1.6 potentially represent biotite that has been affected by minor amounts of low temperature acidic alteration as K is preferentially removed to produce vermiculite or hydro-bioitite (Deer et al., 1992). The L and K porphyries from Turquoise

Gulch and the L porphyry from Granite Gulch follow the ideal Si + Al = 8 line where all

Si and Al fill the tetrahedral site (Figure 3.15D). The other samples are depleted in Si and contain excess Al, which fills both the tetrahedral and the octahedral site. The A porphyry has the greatest variation in total molar Al (2.26-2.94) relative to all the other samples with the L porphyries from M Gulch – Copper Hill and Granite Gulch show the lowest variations (<0.1).

Most trace element analyses for the biotite were at or below detection limit for the

REE. Barium concentrations varied between individual samples with magmatic grains enriched (3400 to 5000 ppm) relative to hydrothermal biotite associated with hornblende

(200 to 1200 ppm) (Appendix D). Copper contents ranged from below detection limit to greater than 1000 ppm for all grains analyzed. No clear correlation was evident between individual samples and copper content although samples from M Gulch – Copper Hill 131

Figure 3.15. Variation diagrams for biotites from selected El Salvador porphyries. Both hydrothermal and igneous biotites presented. A. Mg/(Mg+Fe) vs. molar Al biotite classification diagram with ideal end members phlogopite (K 2Mg 6Si 6Al 2O20 (OH) 4), siderophyllite (K 2Fe 4Al 2Si 4Al 4O20 (OH) 4), and annite (K 2Fe 6Si 6Al 2O20 (OH) 4). B. MgO (wt. %) vs. FeO (wt. %), analysis by electron microprobe. C. Molar K vs. Si, values less than 1.6 for K potentially represent secondary alteration of biotites. D. Molar Al vs. Si, ideal biotite end member plots at Si = 6.0 and Al = 2.0 along the ideal tetrahedral site line where total Si + Al = 8.0.

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both in the A and L porphyry contained higher concentrations (70 to 1200 ppm) relative to the other samples most likely to due copper inclusion from weathering effects (Ilton and Veblen, 1988).

Plagioclase

Plagioclase is the most abundant igneous mineral in the porphyries of the El

Salvador district constituting ~40 to ~70 % of the phenocrysts and equigranular minerals by volume (Gustafson and Hunt, 1975). Plagioclase morphology varies between individual rock units and includes porphyritic, glomeroporphyritic, and pilotaxitic textures. Grains are typically weakly zoned with slight oscillatory and normal zoning

(Figures 3.14, 3.16). Latite samples contain phenocrysts of sieved plagioclase in a pilotaxitic ground mass. Sieve textures vary from sieved cores with unsieved rims to sieved cores with unsieved regrowth mantled by sieved rims (Figure 3.17). Complex and multiply sieved zones suggests multiple periods of heating/melting and cooling/crystal growth due to the mixing between “hot” and “cold” melts (Coombs et al., 2000).

Plagioclase in the latite commonly shows sericite dusting within sieved cores, fractures, and growth zones.

Microprobe analyses were conducted on relatively fresh plagioclases where present in K, L, A, and R porphyries and latite dike samples (Table 3.5). Formulas were calculated following the procedure outlined in Deer et al. (1992) assuming 8 oxygens.

Plagioclase anorthite (An), albite (Ab), and orthoclase (Or) contents were calculated using the following formulas in molar elemental proportions:

An = (Ca + Fe + Mg)/(Ca + Fe + Mg + Na + K) 133

Ab = (Na)/(Ca + Fe + Mg + Na + K)

Or = (K)/(Ca + Fe + Mg + Na + K)

Plagioclase compositions range from An 15 to An 53 within the district (Appendix

B). Variation is low among individual samples with An 15-43 in the K porphyry, An 30-40 in the L porphyries (although rims of pure albite are present in the M Gulch – Copper Hill sample due to secondary hydrothermal alteration), An 36-43 in the A porphyry, An 36-50 in the R porphyry, and An 40-53 in the latite dike. The latite sample has higher An contents

(An 50 -An 52 ) within the sieved cores and rims compared with the unsieved growth zones around the sieved cores which range from An 40-45 (Figure 3.17).

Plagioclase from the L and A porphyries from M Gulch, K and L porphyries from

Turquoise Gulch and the latite dike from Turquoise Gulch was analyzed by LA-ICP-MS.

All the samples contain detectable but trace amounts of LREE, whereas MREE (except

Eu) and HREE were below detection limits. Lead concentrations are similar for all samples and range from 2 ppm to 12 ppm. The barium and strontium concentrations outline two distinct fields, one for the main feldspar porphyries, and one for the latite dike samples (Fig. 3.18). The plagioclase from latite contains a higher concentration of

Sr (~1500 to ~2300 ppm) and a lower concentration of Ba (~100 to ~300 ppm) compared with plagioclase from the K, L, and A porphyry samples (~1000 to ~1500 ppm Sr and

~250 to ~500 ppm Ba, respectively). The partition behavior of Sr and Ba between plagioclase and melt is dependant upon the anorthite content of the plagioclase crystal, temperature, and to a lesser degree the melt composition (Blundy and Wood, 1991;

Bindemen et al., 1998). The variation in composition and the presence of sieved texture

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Table 3.5: Composition of selected plagioclase by electron microprobe analysis. Rock Type L ppy MG L ppy MG A ppy R ppy K ppy L ppy GG Latite Latite 1 sample # 2.5core 2.2rim 1.2rim 1.4core 2.5rim 1.2rim 2.1rim 2.3gz Weight %

SiO 2 60.52 69.07 58.64 55.11 59.32 60.36 54.99 58.05

Al 2O3 25.28 21.06 26.41 28.60 26.41 25.30 28.25 26.62

Na 2O 7.24 10.67 6.73 5.24 6.77 7.12 5.23 6.28 CaO 5.98 0.16 7.39 9.94 6.87 5.87 9.99 7.89 FeO 0.17 0.07 0.17 0.27 0.19 0.17 0.32 0.19

K2O 0.42 0.16 0.19 0.21 0.43 0.50 0.17 0.33

TiO 2 0.00 0.00 0.01 0.03 0.03 0.00 0.01 0.02 MgO 0.01 0.00 0.00 0.01 0.01 0.00 0.02 0.01 SrO 0.09 0.00 0.11 0.25 0.09 0.22 0.21 0.20 sum 99.72 101.20 99.65 99.64 100.11 99.55 99.18 99.60 Ideal cation site occupancy Si 2.695 2.970 2.624 2.490 2.639 2.694 2.496 2.605 Al 1.327 1.068 1.394 1.524 1.386 1.332 1.512 1.409 Sum Z 4.022 4.037 4.018 4.013 4.025 4.025 4.008 4.014 Na 0.625 0.890 0.584 0.459 0.584 0.616 0.460 0.546 Ca 0.285 0.007 0.354 0.481 0.327 0.281 0.486 0.379 Fe 0.006 0.003 0.006 0.010 0.007 0.006 0.012 0.007 K 0.024 0.009 0.011 0.012 0.024 0.029 0.010 0.019 Ti 0.000 0.000 0.000 0.001 0.001 0.000 0.000 0.001 Mg 0.001 0.000 0.000 0.000 0.000 0.000 0.001 0.001 Sr 0.002 0.000 0.003 0.006 0.002 0.006 0.005 0.005 Sum X 0.944 0.909 0.959 0.970 0.947 0.938 0.974 0.958 Total 4.966 4.946 4.977 4.984 4.971 4.963 4.983 4.972 Or 2.56 0.99 1.16 1.25 2.57 3.09 1.01 2.01 Ab 66.36 97.94 61.11 47.71 61.95 66.12 47.49 57.35 An 31.08 1.07 37.73 51.04 35.49 30.80 51.49 40.64 1 gz - growth zone between sieved core and sieved rim (see Figure 3.18)

135

Figure 3.16. Photomicrograph of plagioclase phenocryst from sample ES-12800 L porphyry from M Gulch under crossed polars. Grains show little to no zoning and minor secondary albite (Ab) along the rims of the grains (Ab). Rare biotite (Bio) inclusions were observed within the grains. Laser ablation pits (La-pit) have 70 µm diameters.

136

Figure 3.17. Photomicrograph of sieved plagioclase from sample ES-12792 latite dike from Turquoise Gulch. Sieved cores are common within the latite grains. An contents derived by electron microprobe analysis. The sieved rim along the left side of the image and the zone of regrowth in the grain suggests the possibility of multiple periods of magma mixing. Laser ablation pits (LA-Pit) have 70 µm diameters.

137

Figure 3.18. Ba (ppm) vs. Sr (ppm) plot of plagioclase grains from the El Salvador district. Latite samples show a distinct enrichment in Sr and depletion in Ba compared to the feldspar porphyry samples. Ppy – porphyry, MG-CH – M Gulch – Copper Hill, TG – Turquoise Gulch. K porphyry includes data from both ES-12785a and ES-12807.

138 in plagioclase from the latite may represent mixing or mingling between a mafic and silicic melt, as discussed below (Singer et al., 1995; Coombs et al., 2000).

Titanite

Titanite was observed only in the late intrusive K and L porphyry intrusions and latite dike samples from Turquoise Gulch. Grains were hand picked from magnetic separates and mounted for microprobe and laser ablation analyses. Grains ranged from pale green to brown in the K porphyry to light brown and orange in the L porphyry and latite dike. All grains were less than 2 mm in size. Titanites from the latite dike sample contained inclusions of Fe-Ti oxide (Figure 3.19).

Selected electron microprobe analyses are given in Table 3.6. Formulas were calculated based on 5 oxygens in the ideal titanite formula ABOTO 4 where the A-site is filled by Ca 2+ , Mn 2+ , Na +, K +, and REE 3+ the B-Site is filled by Ti 4+ , Fe 3+ , Al 6+ , and the

4+ 4+ T-site is filled by Si and Al . Fe 2O3 is positively correlated with TiO 2 content as is

3+ Al 2O3 to a lesser degree. This may be cause in part by Fe substituting into the B-site due to an increase in oxygen fugacity (Figure 3.20). The K porphyry contains two populations of titanites with high (0.037-0.050) and low (0.014-0.023) molecular Al content. Molar Fe/Al ratios vary between 0.77-0.89 and 2.54-3.00 for samples of the K porphyry, 1.00-2.65 for the L porphyry, and 0.60-0.96 for the latite dike (Figure 3.21D).

Kowallis (1997) argues that Fe/Al content can be used to discriminate the origin of titanite where Fe/Al ratios in titanites are less than 0.1 in eclogite facies rocks, 0.1 to 0.25 in other metamorphic rocks, 0.1 to 0.5 in hydrothermal veins, 0.5 to 1.0 in quartz-bearing intrusive igneous rocks, near 1.0 in intermediate to silicic volcanic rocks, and greater than

2.0 in silica-undersaturated igneous rocks. There is no evidence that either the K or the L 139

Figure 3.19. Reflected light images of titanites from sample ES-12792 latite dike from Turquoise Gulch. A. ES-12792-Ti-2. B. ES-12792-Ti-3. Ilmenite (ilm) inclusions occur in the cores of the grains. Large holes in grains are laser ablation pits, scale bars are 100 µm.

140

Table 3.6: Composition of selected titanites by electron microprobe analysis. Rock Type K ppy K ppy K ppy L ppy L ppy L ppy Latite Latite Latite sample # 1.1 4.3 7.1 2.1 17.1 19.1 1.1 4.1 9.1 Weight %

SiO 2 30.47 30.47 30.04 30.07 30.36 30.02 29.81 30.51 30.39

TiO 2 39.20 40.14 39.40 39.89 39.65 39.79 40.43 40.25 40.37 CaO 27.02 27.53 26.88 27.10 27.63 26.88 27.33 27.67 27.45

Fe 2O3 1.52 1.64 1.52 1.79 1.73 2.01 1.15 1.35 1.14

Al 2O3 1.21 0.38 1.22 0.68 0.87 0.76 0.89 0.91 1.03 MnO 0.15 0.01 0.09 0.04 0.05 0.09 0.03 0.12 0.07

Na 2O 0.01 0.04 0.01 0.04 0.02 0.04 0.02 0.00 0.02 MgO 0.00 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 F 0.01 0.01 0.00 0.00 0.00 0.01 0.02 0.00 0.02 sum 99.60 100.23 99.17 99.60 100.30 99.60 99.69 100.83 100.49 Ideal sites Si 0.997 0.993 0.987 0.986 0.989 0.985 0.976 0.988 0.986 Al IV 0.003 0.007 0.013 0.014 0.011 0.015 0.024 0.012 0.014 Sum T 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 Al VI 0.043 0.008 0.035 0.012 0.022 0.014 0.011 0.022 0.025 Ti 0.965 0.984 0.974 0.984 0.971 0.982 0.996 0.980 0.985 Fe 3+ 0.037 0.040 0.038 0.044 0.042 0.050 0.028 0.033 0.028 Sum A 1.045 1.032 1.046 1.041 1.036 1.046 1.035 1.035 1.038 Ca 0.947 0.962 0.947 0.952 0.964 0.945 0.959 0.960 0.954 Mn 0.004 0.000 0.003 0.001 0.001 0.003 0.001 0.003 0.002 Na 0.001 0.003 0.001 0.002 0.001 0.002 0.001 0.000 0.001 Sum B 0.952 0.964 0.950 0.955 0.967 0.950 0.962 0.963 0.957 Total 2.997 2.996 2.996 2.996 3.003 2.995 2.997 2.999 2.996 molar Fe/Al 0.801 2.769 0.795 1.673 1.273 1.689 0.826 0.954 0.703

141

Figure 3.20. Variations of cations plotted as a function of molar Ti content for titanites from the K porphyry (ES-12785a), L porphyry (ES-12787), and latite dike (ES-12792). A. Ti vs. Fe 3+ . B. Ti vs. Al. C. Ti vs. Ca. D. Ti vs. Fe/Al. All concentrations are given in atoms per formula unit (a.p.f.u.). Note the two apparent populations in the K porphyry with one similar to the latite titanites.

142 porphyry represent silica undersaturated rocks as they contain quartz. The two populations of titanites in the K porphyry could suggest either mixing of two different source melts or hydrothermal processes in the formation of these minerals. The K porphyry sample has undergone potassic alteration; however, it is unclear if one of the titanite populations formed under hydrothermal processes as texturally the titanite grains appear to be igneous in origin.

All the titanites have enriched REE concentrations 100-10000 times that of chondrite (Figure 3.21). The titanites with low molar Fe/Al ratios from in the K porphyry have higher REE content and a wider range of MREE and HREE content than the titanite with high molar Fe/Al ratios, but show a similar pattern (Figure 3.21A). The L porphyry shows a similar REE pattern, however two samples show positive europium anomalies.

The latite dike shows a consistent pattern with larger variation in MREE and HREE content relative to LREE content similar to the K porphyry. Uranium concentrations of titanite vary considerably between units. The K porphyry titanites with Fe/Al molar ratios < 1 have U values of ~30 ppm whereas those grains with Fe/Al molar ratios >2 have U values of 3 to 10 ppm. No other variation in trace element composition is seen between the high and low Fe/Al titanites.

Discussion

Amphibole Geothermobarometry

Compositions of calcic amphiboles depend largely upon the pressure and temperature conditions under which they crystallize (Allen et al., 1975; Allen and

Boettcher 1978; Spear 1981; Hammarstrom and Zen, 1986; Ernst and Liu 1998). 143

Figure 3.21. Titanite REE diagrams for A. K porphyry B. L porphyry and C. Latite dike. Chondrite normalization values of McDonough and Sun (1995). 144

Potassium, aluminum, sodium, titanium, and molar Mg/(Mg+Fe) typically increase with pressure and temperature in amphibole whereas silica, manganese, and calcium decrease.

Oxygen fugacity also plays an important role, because increases in ƒO 2 will cause a decrease in titanium, tetrahedral Al, and alkalies (Na+K) in the A-site (Helz, 1973, 1979;

Czamanske and Wones, 1973; Anderson and Smith, 1995).

Total molar aluminum (Al T or Al IV + Al VI ) has been calibrated for use as a geobarometer and results in the linear correlation of pressure and aluminum content

(Hammarstrom and Zen, 1986; Hollister et al., 1987; Johnson and Rutherford, 1988;

Rutter et al., 1989; Blundy and Holland, 1990; Schmidt, 1992; Anderson and Smith,

1995). These geobarometers require a temperature estimate that can be fixed by a natural granitic assemblage in which amphibole formed in equilibrium with quartz, plagioclase, biotite, magnetite, and a Ti-phase such as titanite or ilmenite (Hammarstrom and Zen,

1986). The aluminum content as a function of pressure has been experimentally calibrated for granitic liquids over a pressure range ~2-8 kb at temperatures of ~675º to

780ºC (Johnson and Rutherford, 1988; Rutter et al., 1989; Blundy and Holland, 1990;

Schmidt, 1992). A temperature greater than 800ºC leads to an underestimation in pressure (i.e., Figure 1 of Anderson and Smith, 1995).

The titanium content in hornblende is strongly dependant upon and increases with temperature and can be applied as a magmatic geothermometer (Holloway and Burnham,

1972; Helz, 1973; Allen and Boettcher, 1978; Otten, 1984; Ernst and Liu 1998; Féménias et al., 2006). Oxygen fugacity increases from the quartz-fayalite-magnetite (QFM) buffer to the magnetite-hematite (MH) buffer and has been observed to lower the titanium content of hornblende (Helz, 1973). As a result these titanium geothermometers for 145 hornblende often assume oxygen fugacity is close to the QFM buffer, which is often the case with basaltic magmas but is too low for hydrous, oxidized arc magmas with fO2 between +1 and +3 log units above the nickel-nickel oxide buffer curve. The amphiboles must also crystallize from Ti-saturated magmas which may be assumed if Ti-rich minerals (e.g., ilmenite, rutile, titanite) are present (Helz, 1973; Féménias et al., 2006).

The semiquantitative Ca-amphibole thermobarometer of Ernst and Liu (1998) outlines isopleths of Al 2O3 and TiO 2 concentrations in amphibole as a function of pressure and temperature (Figure. 3.22). The titanian pargasites from the latite dike are plotted on the diagram and suggest equilibrium temperatures of 850-930 ºC and pressures of 4-8 kb. The temperature and pressure estimates from the Ernst and Liu (1998) diagram where the latite amphiboles plot are based on the experimental data of Helz

(1973, 1979) which incorporate high temperature and pressure experiments with titanium.

The edenite amphiboles would plot at temperatures of <700 ºC and pressures of ~6 and

~4 kb. The temperatures and pressures estimated for the edenite samples are most likely underestimated using the Ernst and Liu (1998) method as the experimental data for that part of the field used basalt composition and the edenites most likely formed within an upper crustal andesite to dacite magma chamber. The magnesio-hornblende to actinolites of the L porphyry samples would plot along a path of decreasing temperature on this diagram due to the dueteric alteration of these minerals. The Ti-in-amphibole geothermometer of Otten (1984) was derived from the experimental data of Helz (1979) and applied to the latite samples:

T(ºC) = 1,204 * (Ti a.p.f.u.) + 545 for temperature less than 970 ºC, where

Ti is calculated on the basis of 23 oxygen equivalents. 146

Temperatures calculated using this thermometer give values of 862-933 ºC for the titanian pargasites (Table 3.7).

The Blundy and Holland (1990) amphibole-plagioclase geothermometer was applied as a secondary test to determine temperatures assuming the An contents in plagioclase analyzed by electron microprobe are in equilibrium with the edenite:

T = (0.677P – 48.98 + Y)/(-0.0429 – 0.008314LnK)

Where K = [(Si – 4)/(8 – Si)]X Ab and Y = 0 for X Ab >0.5 and

2 -8.06 + 25.5(1- XAb ) for XAb <0.5

Pressure was determined using the calibration of Anderson and Smith (1995):

P(kb) = 4.76Al * 3.01 * [((T-675)/85)*(0.53Al + 0.005294(T-675))] where Al is

total molar Al and T is in ºC.

An iterative approach was taken in order to determine the temperature and pressure at which the amphibole samples formed. Anorthite composition for the latite dike varies from An 40 to An 53 with the lower An contents occurring within the unsieved regrowth zones (Figure 3.17). The high-Al 2O3 edenite has an average molar Si of 6.6 and a total molar Al value of 1.88. Assuming it formed in equilibrium with the plagioclase the temperatures and pressures vary from 785 to 860 ºC and 3.9 to 1.7 kb for An 40 to An 50

(higher An contents outside of Anderson and Smith (1995) calibration range). At plagioclase compositions of An 45 the equilibrium temperature is approximately 815 ºC.

Pressure estimates from Anderson and Smith (1995) is approximately 3.1 kb (Table 3.7).

For the titanium pargasites assuming they are in equilibrium with plagioclase of higher An content due to the liquid line of descent by plagioclase, calculated temperatures range from ~930 to 950 ºC for plagioclase compositions of An 60-80 . The 147

Figure 3.22. Temperature vs. pressure diagram outlining amphibole crystallization fields. Shaded lines and values show experimental Al 2O3 and TiO 2 isopleths as a function of pressure and temperature modified from Ernst and Liu (1998). Open field represents the latite titanian pargasites which plot at pressures of ~6 kb over temperatures of 900 ± 30 ºC and potentially represent a mid-crustal conduit or magma chamber. Closed field represents the latite edenites which plot at pressures of 785 to 860 ºC and 3.9 to 1.7 kb and potentially represent an upper crustal magma chamber. Solid arrow reflects the potential hydrothermal alteration path of the amphiboles from the L porphyry.

148

Table 3.7. Calcluated temperatures and pressures for amphiboles from ES-12792 Latite dike. 1 T a o b Sample # Amphibole type TiO 2 (wt.%) Al 2O3 (wt.%) Al a.p.f.u. Ti a.p.f.u. Otten '84 ( C) A&S '95 (kb) Am-1.1 Ti-pargasite 2.66 13.17 2.26 0.29 897 - Am-1.2 Ti-pargasite 2.80 12.95 2.22 0.31 914 - Am-1.3 Ti-pargasite 2.71 13.29 2.29 0.30 904 - Am-2.1 Ti-pargasite 2.74 13.80 2.40 0.30 911 - Am-4.1 Ti-pargasite 2.86 13.38 2.33 0.32 927 - Am-4.2 Ti-pargasite 2.83 13.53 2.34 0.31 922 - Am-6.1 Ti-pargasite 2.88 13.27 2.28 0.32 925 - Am-6.2 Ti-pargasite 2.89 13.26 2.29 0.32 928 - Am-8.1 Ti-pargasite 2.37 12.10 2.10 0.26 862 - Am-10.1 Ti-pargasite 2.92 13.26 2.26 0.32 927 - Am-11.1 Ti-pargasite 2.94 13.57 2.33 0.32 933 - Am-12.1 Ti-pargasite 2.63 13.07 2.26 0.29 893 - Am-12.2 Ti-pargasite 2.94 13.29 2.28 0.32 933 - Am-7.1 high-Al edenite 0.85 10.67 1.86 0.09 - 3.0 Am-7.2 high-Al edenite 0.93 10.99 1.92 0.10 - 3.2 Am-3.1 low-Al edenite 0.91 8.67 1.51 0.10 - 1.7 Am-9.1 low-Al edenite 1.00 8.74 1.53 0.11 - 1.7 Am-9.2 low-Al edenite 0.95 8.51 1.49 0.11 - 1.5

1Amphibole type determined from Leake et al. (1997) classification. Ti-pargasite - titanian pargasite, TTotal aluminum per formula unit (Al IV +Al VI ). a Calibration from Otten (1984): T ( oC) = 1204*Ti(a.p.f.u)+545 b Calibration from Anderson and Smith (1995): P (kbar) = 4.76*Al T-3.01-((T-675)/85)*((0.53*Al T)+0.005294*(T-675)) where T = 815 oC Dash represents poor or bad results due to temperature and composition calibration of the experiment.

149 pressure estimates can not be applied to the titanian pargasites as the Anderson and Smith

(1995) geobarometer leads to low P estimates in some cases less than 0.1 kb due to the high temperature at which the titanian pargasites formed.

Temperature estimates using the titanium-in-zircon geothermometer of Watson and Harrison (2002) gave a range of temperatures from 630-850 ºC for zircon from latite

(Chapter two; Table 2.5). Analyses from the cores of the zircons yield temperatures from

750-850 ºC, whereas rim analyses yield temperatures of 630-720 ºC. The core estimates are similar for the edenite calculated temperatures, whereas the rim temperatures most likely represent late stage cooling of the melt. The higher core temperatures should be the logical temperature for the edenite samples if they formed within the same melt.

SHRIMP-RG U/Pb age determination on the latite zircons to determine if two age populations are present were inconclusive due to Pb-loss, high error, and small sample population.

The above amphibole thermometers and barometers suggest the titanian pargasites formed at temperatures of ~900 ºC and pressures of ~6 kb equating to ~20 km for the equilibration depth assuming average crustal densities and pressure gradients.

The edenite samples presumably formed at lower temperatures and pressures consistent with an upper crustal magma chamber at depths of 6 to 10 km. The presence of both amphibole types within the latite dikes suggests that the latite melt ascended from the low to mid crust and mixed within the upper magma chamber prior to final emplacement at or near the surface.

150

Trace element mass balance

Partition coefficients are generally high between mineral and melt for large ion lithophile (LIL) and lanthanide elements within hornblende and accessory minerals and partitioning is largely dependant on melt composition, temperature, and pressure

(Ryerson, and Hess, 1978; Blundy and Wood, 1994; Adam and Green, 1994). The accessory mineral phases apatite and titanite host the majority of REE within the whole rock budget (Figure 3.23). Zircon analyzed by SHRIMP-RG (Chapter two) is enriched in

HREE but is a low abundance trace phase (<0.1 vol. %) in the whole rock. Calculated bulk rock values using volume percent of average mineral concentration corresponds well with analytical whole rock values (dashed orange line, Figure 3.23). Both the calculated

K and the L porphyry REE contents are slightly elevated in MREE and HREE relative to the analytical whole rock values (Figure 3.23A-B), however this may be due to mineral phases such as amphibole that were not analyzed due to the alteration of these phases within the feldspar porphyries. As a result zircon, apatite, and titanite values are more heavily weighted causing the 2x overestimation of the mass balance calculation. The calculated bulk rock for the latite porphyry follows the whole rock analytical concentration suggesting that these mineral phases make up the main players within the

REE and trace element budget (Figure 3.23C).

All the trace mineral phases have negative europium anomalies except for the titanian pargasites and a small portion of titanites from the L porphyry (Figures 3.9, 3.12,

3.21, 3.23). This suggests that all the mineral phases except for the pargasites and L 151

Figure 3.23. Mass balance REE diagram for whole rock and mineral phenocrysts from the Turquoise Gulch porphyries. Mass balance calculations assume feldspar phenocryst and groundmass at 60-65 vol. %, apatite and titanite at 0.5 vol. %, zircon at 0.1-0.2 vol. % and amphibole in the latite at 10 vol. %. A. K porphyry B. L porphyry C. Latite porphyry dike. 152 porphyry titanites crystallized from melts where plagioclase was concurrently crystallizing as an important (>50% of crystals) crystallizing phase. Two titanites with the lowest REE abundances from the L porphyry also have anomalous and positive europium anomalies suggesting they formed shortly after melting of a plagioclase-rich rock, for example following mafic magma injection into the shallow L porphyry mamga chamber that may have elevated temperature and melted plagioclase.

The trace element compositions of the low-Al edenites are distinctly different from the high-Al edenites and titanian-pargasites. The latter amphiboles show similar compositions to amphiboles analyzed from the andesites and dacites related to the giant epithermal-Au deposit at Yanacocha, Peru (Chamberfort et al., 2007; Isabelle

Chamberfort, personal communication, 2008). The REE pattern of the low-Al edenites is dissimilar to any of the other amphiboles and other REE-bearing phases, suggesting these may have formed in a completely different melt, or that small amounts of hydrothermally alteration reduced and preferentially removed the MREE and. Texturally there is no indication for the latter, however, the low number of samples analyzed from the latite makes it difficult to truly understand the origin.

Geochemical modeling

Trace element concentrations vary between individual porphyry units and mineral phenocrysts contained therein. Figure 3.24 shows Sr/Y ratios versus Y for whole rock and mineral phases. The feldspar porphyries cluster at low values of Y (<15 ppm) and relatively high Sr/Y ratios (~50 to ~100). Exceptions include the quartz porphyry, and the L and A porphyries from M Gulch-Copper Hill which have Sr/Y ratios <40 ppm. 153

The A porphyry has a high Y value (32 ppm) relative to the other samples. The R porphyry displays a large range in Sr/Y as indicated by a sample with Sr/Y ratio of 20 collected from the center of the pit and a sample collected at the contact with the M

Gulch andesite breccia with a Sr/Y ratio of 80.

Rohrlach and Loucks (2005) proposed that plots of Y versus Sr/Y ratio can be used to define water content and pressure conditions for melt crystallization. Plagioclase crystallization is suppressed by high water pressure (PH 2O >3 kb) and amphibole stability is expanded; these conditions allow hornblende to crystallize first during cooling

(c.f. Rutherford and Devine, 1988). The magma can evolve to higher Sr/Y ratios and lower Y contents as Sr increases in the melt due to the suppression of plagioclase while removal of hornblende will deplete the melt in Yttrium. Defant and Drummond (1990) also proposed that high Sr/Y ratios (>20) are characteristic of adakite or slab melts as young hot eclogitic portions of the subducting slab melt.

Rayleigh fractionation models were calculated from the whole rock compositions assuming only amphibole fractionation. The A porphyry was chosen as the starting composition as this is the lowest silica content, although there is no evidence that this is similar to the parent composition. Amphibole partition coefficients were chosen from the experimental work of Ewart and Griffin (1994) (X Figure 3.24A) and Sisson (1994) (plus symbols Figure 3.24A). Both calculated models follow similar trends seen in the El

Salvador porphyries as they evolve to lower Y contents with age. This suggests that the porphyries at El Salvador formed under hydrous conditions at moderate high water pressures as amphibole came onto the liquidus while plagioclase crystallization was depressed. Alternatively, both amphibole and titanite crystallization may produce similar 154 trends due to the high partition coefficient Y in titanite (Tiepolo et al., 2002). The titanian pargasites and the low REE titanites in the latite dike sample have weak to no Eu anomaly and the pargasites are interpreted to have formed in a high temperature deep magma conduit (Figures 3.9, 3.21). It is possible that the low REE titanites crystallized within this lower conduit. The lower Y and Sr/Y values observed in the quartz porphyry is likely the result of plagioclase fractionation where Sr is removed decreasing the Sr/Y ratio.

Mineral phases define distinct trends of increasing Sr/Y ratios as Y decreases.

Apatite from the K and L porphyries contains low Sr/Y ratios (<1) with relatively high Y contents (200 to 1400 ppm), whereas apatite from the latite has low Y (<200 ppm) and shows an increase of Sr/Y from 2 to 11 with decreasing Y (Figure 3.24B). This potentially reflects removal of amphibole as the older K porphyry apatites are in equilibrium with a melt of higher Y content relative to the L and latite porphyries.

Titanite illustrates a similar behavior for the same three samples, however, the titanite in

L porphyry has a bimodal population of high Sr/Y ratios that are both high (>0.2) and low (<0.03) (Figure 3.24C). The titanites with the high Sr/Y ratios also are the ones that have a positive europium anomaly and potentially formed from the partial melting of a plagioclase-rich rock to acquire the elevated Sr values and Eu anomaly. The titanites with low Sr/Y and negative Eu anomaly reflect the removal of plagioclase from the melt.

The relatively high partition coefficients for both Y and Sr and crystallization temperatures between 700-800 ºC for titanite (Tiepolo et al., 2002) would suggest that they formed from a melt with low Sr composition. The bimodal population may be the result of mixing due to a mafic recharge event where the low Y and high Sr/Y titanites 155

Figure 3.24. Y (ppm) vs. Sr/Y for whole rock and mineral phases from the El Salvador porphyry suite. A. Whole rock analyses by ICP-MS. Crystallization models calculated arbitrarily using A ppy concentrations Cmelt = 500 ppm Sr and 32 ppm Y. Partition coefficients of Ewart and Griffin (1994) defined by X ticks and Sisson (1994) + ticks under dacitic compositions were used in the model. B. Apatites from the K, L, and latite porphyries from Turquoise Gulch. C. Titanites from the K, L, and latite porphyries from Turquoise Gulch. D. Amphiboles from the latite porphyry dike of Turquoise Gulch.

156 formed in equilibrium with a hydrous melt containing a fraction of plagioclase rich source, whereas the lower Sr/Y titanites formed in an upper crustal melt with low Sr and

Eu content due to plagioclase removal. The amphiboles from the latite dike support this hypothesis as the deep crust titanian pargasites have higher Sr (220 to 360 ppm) compared with the high-Al 2O3 edenites (50 to 170 ppm). Two titanian pargasites have higher Y concentration (19 and 23 ppm) than the main pargasite field and plot near the edenite points (Figure 3.24D). This may be due to the “resetting” of the amphiboles or formation from a melt that represents the mixture between the deep mafic source and the upper crust magma chamber.

Sm/Yb ratios have been used to estimate changes in silicic melts through time

(Kay et al., 1991). Garnet has a high partition coefficients with melt for the HREE (Lu &

Yb) and as garnet crystallizes and is removed from lower crustal melts the resulting melts will have increased Sm/Yb ratios (Johnson, 1998). At El Salvador the porphyry intrusions display a large range of both Sm/Yb ratios and La/Sm ratios (Figure 3.25A). The quartz porphyry the intrusions from M Gulch – Copper Hill have Sm/Yb ratios less than 4 and

La/Sm ratios that range from 3-7. The feldspar porphyries display a larger range of

Sm/Yb values but also show more scatter within a single lithology (i.e. L porphyries).

The overall trend shows that Sm/Yb ratios increase with decreased intrusive age for the

X, K, L porphyries and the latite porphyry dikes. It is interesting to note the A porphyry has a lower Sm/Yb ratio (~2) than all other samples.

Apatite displays a positive correlation of Sm/Yb with La/Sm that increases as age decreases from K porphyry to L porphyry to the latite dike due to the progressively decreasing Sm and Yb content with each progressive intrusion (Figure 3.25B). 157

Nonetheless, the REE ratios of titanite are complex. K porphyry displays low La/Sm

(<2) but a large range of Sm/Yb. The latite dike shows a similar Sm/Yb range that is negatively correlated with La/Sm, which ranges from 1 to 10. The apparent trend of low

Sm/Yb, high La/Sm to high Sm/Yb, low La/Sm seen in the L porphyry from Turquoise

Gulch spans the entire range of La/Sm and Sm/Yb of both K porphyry and latite. In the latite dike, the low-Al edenite grains have higher La/Sm ratios (>2.0) compared with the high-Al amphiboles (~0.5). The titanian-pargasites and high Al edenites (~5 kb, 15-18 km) show a wide range of Sm/Yb from 4 to 16.

Mathews et al. (2000) and Kay and Mpodozis (2001) argue that increasing La/Sm and Sm/Yb ratios reflect increasing crustal thickness and pressure as melts evolve from amphibole to garnet in the residue. Simple amphibole fractionation cannot explain the trend of increasing Sm/Yb from K ppy to latite observed as the Sm/Yb ratio would decrease due to the smaller partition coefficients for amphibole relative to melt for HREE compared to MREE (Sisson, 1994). Garnet and/or zircon with higher HREE partition coefficients relative to MREE would increase the Sm/Yb ratios during fractional crystallization. Zircon however, saturates in upper crustal settings under relatively low temperatures between 800 and 700 ºC (Finch and Hanchar, 2003; Hanchar and Watson,

2003). It also forms a very small volume percent of the melt (less than 0.1%) and while trace removal of zircon could potentially increase Sm/Yb it is difficult to model due to the low amount of La within the zircon structure (Sano et al., 2002; Hanchar and

Westrenen, 2007). Crystallization models were constructed to model the affect of garnet removal during crystallization using the partition coefficients of Johnson (1998) (Figure

3.25A). Models using both quartz rhyolite porphyry and A porphyry as starting 158

Figure 3.25. Sm/Yb vs. La/Sm plots for El Salvador whole rock and mineral analyses. A. Whole rock analyses from the El Salvador porphyry suite. Open circle represents value of quartz rhyolite porphyry (Gustafson, 1979). Garnet fractional crystallization models represented by + for quartz rhyolite starting composition and X for A porphyry starting composition. B. Apatites from the K, L, and latite porphyries from Turquoise Gulch. The increase in ratios is consistent with the whole rock values for each sample. Curve defined by the apatites from the latite porphyry could be produce by amphibole and/or titanite fractionation. C. Titanites from the K, L, and latite porphyries from Turquoise Gulch. Results are more complex than the apatite values. Curve defined by the titanites in the latite could be produced by amphibole/titanite fractionation. D. Amphiboles from the latite porphyry dike of Turquoise Gulch.

159 compositions suggest that up to 20% fractional crystallization of garnet could increase the

Sm/Yb content to the observed ratios but not the La/Sm ratios.

Alternatively the higher Sm/Yb ratios could reflect the assimilation of evolved upper crustal compositions. To test this, inherited zircon cores (Chapter two) with ages ranging 180 to 68 million years and believed to represent assimilated basement terrane potentially from the Sierra Fraga formation (Figure 1.2) were used to calculate melt concentration (Table 3.8). Zircon-melt partition coefficients were used from the experimental work of Sano et al., (2002), although the concentration of La is suspect due to the low concentration within zircon. Calculated melt concentrations vary from 1.8-

13.5 ppm for Sm and 1.7-7.9 ppm Yb with Sm/Yb ratios ranging from 0.4 to 2.2.

Samarium ranges from 1 to 5 ppm in the Turquoise Gulch porphyries and Yb ranges from

0.2 to 0.9 ppm Yb (Table 3.1). Mixing/assimilation of the country rock that hosted the various inherited zircon could explain the elevated Sm content within the El Salvador porphyries but not the low Yb values. Mesozoic inherited zircons were observed within the X porphyries and older Eocene inherited zircons within several of the feldspar porphyries (Chapter two) suggesting that at least partial assimilation did occur. It is possible that crustal shortening depleted the Yb content due to garnet formation and that assimilation of upper crustal material may account for at least part of the trace element budget within the El Salvador deposit.

Plagioclase-melt concentration

Plagioclase Sr and Ba compositions within the feldspar porphyries vary considerably between latite and the other porphyries (Figure 3.18). Singer et al. (1995) argue that changes of Sr, Ba, Fe, Mg, K, and Ti concentration within plagioclase 160

Table 3.8. Calculated melt compositions derived from inherited Mesozoic age zircons for La, Sm, and Yb. 2 1 Zircon concentration Calculated melt concentration Sample # Age Ma (1 σσσ) La Sm Yb La Sm Yb La/Sm Sm/Yb IT 10-10 187.2 (1.7) 0.042 2.5 198 90.4 3.2 1.7 2.74 1.84 ES 12811-12 180.9 (1.9) 0.037 6.6 464 79.8 8.2 3.7 0.93 2.21 ES 12782-3 180.8 (1.6) 0.033 10.8 1076 72.7 13.5 7.9 0.52 1.71 ES 12811-10 172.6 (1.2) 0.148 8.4 791 321.6 10.5 6.1 2.94 1.73 IT10-18 171.3 (1.7) 0.165 6.1 595 359.7 7.6 4.4 4.55 1.71 IT10-9 140.8 (1.3) 0.037 1.5 463 81.0 1.9 4.9 4.04 0.40 IT10-12 140.2 (2.3) 0.034 1.4 304 73.4 1.8 3.1 3.94 0.58 ES 12811-15 127.3 (1.6) 0.032 4.1 632 69.0 5.1 5.7 1.29 0.91 ES 12800-5 68.3 (0.6) 0.027 4.8 434 58.9 6.0 3.7 0.94 1.62

1Inherited zircon grains analyzed by SHRIMP-RG data from Chapter two and Appendix B. 2Melt concentrations calculated from Sano et al. (2002) where zircon-melt coefficients are: La - 0.00046 ± 0.00032, Sm - 0.80 ± 0.20, and Yb - 277 ± 55.

161 phenocrysts can be used to model the dissolution of plagioclase and the potential mixing/mingling of the melt during formation. We have applied the same technique to the El Salvador plagioclase phenocrysts using the following partitioning expressions to calculate equilibrium melt compositions (Bindeman et al., 1998), where R is the gas constant, T is the absolute temperature in Kelvin, D is the partition between plagioclase and melt, and X An is the mole fraction of An component in the plagioclase (one standard deviation error given in parenthesis):

RT ln D Sr = 38.5(0.7) – 30.4(1.1)X An

RT ln D Ba = 19.1(1.3) – 55(2.4)X An

All melt calculations are a first order approximation only based on temperatures approximated by amphibole and zircon thermobarometry and An compositions determined by electron microprobe. The calculated melt compositions display a linear trend with increasing Ba and Sr for the A, K, and L porphyries, whereas the latite shows two potential compositions (Figure 3.26). As plagioclase crystallizes Sr concentrations should decrease with increasing Ba content due to the partitioning of Sr into plagioclase and incompatible behavior of Ba in plagioclase (Singer et al., 1995; Bindeman et al.,

1998). If crystallization takes place without any plagioclase present, the resultant melt should show a direct 1:1 increase in Sr and Ba concentration. The slight increase in Sr composition suggests that plagioclase is crystallizing although at a depressed level potentially due to a higher water content or crystallization from a plagioclase-poor melt.

The latite shows a complicated pattern as the sieved textured plagioclase has higher Sr concentrations than the non-sieved overgrowth zones (Figure 3.17) and the other porphyry samples. The overgrowth zones appear to show a potential mixing trend 162

Figure 3.26. Calculated melt equilibrium concentrations in equilibrium with measured plagioclase Ba and Sr compositions. Melt concentrations derived from temperature of 800 ºC and An content determined by electron microprobe of plagioclases from each porphyry. Symbols are the same as in Figure 3.18. The linear trend defined by the A, K, and L porphyries suggests crystallization within a plagioclase-poor melt. The latite shows two trends where the overgrowth zones display a mixing trend with a potentially more mafic parent with lower Sr and Ba compositions and the plagioclase with the sieved textures.

163 between a melt with lower Sr and Ba concentrations and the sieved plagioclase. The lower concentration melt could represent a mafic melt that mixed to form the textures seen in the latite porphyry. The varying Sr concentrations of the sieved plagioclase could reflect the melting of the plagioclase due to the mixing event elevating the An concentration and increasing Sr and decreasing Ba. The calculated Sr and Ba melt concentrations of the other feldspar porphyries also appear to extend back to the potential mafic parent melt which may represent the mafic melt composition that recharged the probable upper crustal magma chamber during the formation of the feldspar porphyries at

El Salvador (Matthews et al., 1994).

Formation of porphyries and copper mineralization

Gustafson (1979) originally described two distinct groups of Eocene intrusives at

El Salvador: 1) early intrusions of rhyolitic composition found in the Cerro Pelado center as well as the quartz porphyry intrusions that extend through out the district and 2) porphyries of granodioritic composition centered at Turquoise Gulch but also occurring at M Gulch – Copper Hill and south to Granite Gulch. Molybdenum mineralization is associated with the quartz rhyolite porphyry at Cerro Pelado and minor pyrite- chalcopyrite-bornite mineralization occurs with the quartz porphyry at Old Camp and M

Gulch-Copper Hill while the major ore mineralization is associated with the feldspar porphyries at Turquoise Gulch (Figure 3.1). Copper concentrations vary from 40 ppm to

1.0 wt. % within the porphyries sampled and potentially represent vein material incorporated during the sampling process (Table 3.1) 164

The slight negative Eu-anomaly and lower REE concentration of bulk rock analyses of the quartz porphyry and rhyolite porphyry (Gustafson, 1979) support the hypothesis that these units crystallized from a residual liquid dominated by plagioclase fractionation in the upper crust (Figure 3.3A). Questions arise as to the nature of the granodiorite porphyries centered at M Gulch – Copper Hill and their relation to the quartz porphyry and Turquoise Gulch porphyries. It is difficult to make an interpretation based on a few samples but chemically there is a distinct difference between the L and A porphyries from M Gulch – Copper Hill and those from Turquoise Gulch. The A porphyry represents the most mafic sample analyzed in this study and has chemical contains higher concentrations of MREE and HREE than the other porphyries (Figure

3.3A). The high Y and Yb content (Figure 3.3D; 3.25A) and low Sm/Yb ratios (Figure

3.25A) suggests little to no amphibole/garnet removal or assimilation of upper crust. It appears that the A porphyry represents an injection of mafic melt from a deep magma chamber into a shallow more silicic chamber as proposed by Cornejo et al. (1997; 1999).

The L porphyries from M Gulch – Copper Hill and Granite Gulch have significant geochemical differences from the X, K, and L porphyries from Turquoise Gulch (Figure

3.3). Zircon U/Pb dating gives ages of ~43.8 for the M Gulch – Copper Hill and Granite

Gulch porphyries whereas the L porphyries from Turquoise Gulch give ages of ~42 Ma

(Chapter two; Lee et al., 2007). While the M Gulch – Copper Hill L, A, and R porphyries are texturally similar to the Turquoise Gulch intrusions (Gustafson and Hunt,

1975; Gustafson et al., 2001), we suggest that the L and associated porphyries from M

Gulch – Copper Hill and Granite Gulch are earlier and separate intrusive events. 165

The feldspar porphyries from Turquoise Gulch display similar trace element compositions (Figure 3.3B, D). Zircon ages and chemical compositions of the Turquoise

Gulch porphyries suggest the possibility that at least partial assimilation occurred during the formation of the porphyries. Isotopic studies of Sr and Nd suggest that the feldspar porphyries have had little to no interaction with old radiogenic crust, whereas U-Pb isotopes suggest mafic crustal interaction (Gustafson, 1979; Tosdal et al., 2000). Trace element modeling and compositions suggest the porphyries at Turquoise Gulch formed from a complicated history whereby a potentially mafic source with garnet in the residue ascended and underwent several stages differentiation and mixed/assimilated with upper crustal material within an upper crustal chamber at ~6 to 10 km where plagioclase fractionation had occurred (Figures 3.23, 3.24, 3.25).

The latite porphyry dikes show clear petrographic evidence for magma mixing with the presence of sieved/wormy plagioclase (Figure 3.8) and the presence of at least two amphibole types. Dissolution and coarse sieved textures in plagioclase suggests a repeated history of heating and cooling of the host melt (Nelson and Montana, 1992;

Coombs et al., 2000; Longo, 2005). The titanian pargasite amphiboles within the latite likely reflect a hot, hydrous mafic magma that may be a sample of similar magmas that contributed to the earlier mineralizing granodiorite porphyry intrusions. Dungan and

Davidson (2004) suggest that assimilation of mafic plutonic roots rich in pyroxene and/or amphibole may occur in long-lived volcanic arcs and produce upper crustal melts with depleted REE signatures that differ from melts contaminated by mature upper crust. The late unmineralized mixed dikes appear to be common in porphyry type deposits and may 166 be useful in determining the original source of the mineralized intrusions (Lickfold et al.,

2007).

Mineralization occurs within all the major porphyry centers at El Salvador, however, the main and largest deposit is associated with the porphyries at Turquoise

Gulch. Copper was not observed within anomalous quantities in the mineral phases analyzed in this study (Appendix D). Amphibole varies in copper concentration from 3.1 ppm to below detection limit. Apatite varies from 12 ppm to below detection limit, although three samples from the L porphyry did yield values of 50 to 450 ppm. Biotite contains the highest copper concentration up to 1200 ppm due to the presence of copper inclusions as a result of weathering (Ilton and Veblen, 1988). Plagioclase varies from 30 to 2 ppm and titanite varies from 14 to 2 ppm. This potentially suggests that copper is acting as an incompatible element as observed in other porphyry copper plutons such as

Yerington batholith, Nevada (Dilles, 1987; Dilles and Proffett, 1995). Barium is an incompatible element found in relatively high abundance at El Salvador (Figure 3.3) and based on melt equilibrium studies increased during crystallization in the feldspar porphyries (Figure 3.26). Copper could also have potentially increased within the latter stages of melt formation if sourced from the deeper magma chamber and would be relatively enriched in the later intrusive events due to multiple recharging events (i.e.

Rohrlach and Loucks, 2005). Within the upper crustal chamber high water content/oxidation conditions, the late magmas that were potentially somewhat enriched in copper could have evolved hydrothermal fluids richer in copper than fluids associated with earlier intrusions. 167

Three stages of Eocene magmatic evolution occurred within the Indio Muerto district that culminated in two periods of ore mineralization (Figure 3.27). Initial Eocene

(~44-45 Ma) silicic intrusions formed first with the quartz rhyolite porphyry intruding at

Cerro Pelado and the sheet-like quartz porphyry intrusions intruding at Old Camp and further south down to Copper Hill and Turquoise Gulch (Figure 3.1). These intrusives associated with minor amounts of early copper and molybdenum mineralization formed from melts that had undergone plagioclase removal. The presence of ore mineralization potentially forming directly above the heat/melt source suggests the original source was rich in copper and molybdenum. As these silicic melts reacted with the upper crust as well as recharge events they evolved into the L porphyry granodiorite intrusions at M

Gulch – Copper Hill and Granite Gulch. Melting of the upper(?) crust below Turquoise

Gulch initiated the formation of a batholith(?) at ~6 to 10 km depth. Sm/Yb values suggest the lower crust was becoming garnet-rich due to the increase in crustal thickness

(Mathews et al., 2000; Kay and Mpodozis, 2001). As heat/melt flux increased the plagioclase-rich mid crust melted forming a chamber at ~ 20 km as evidenced by amphibole compositions. Repeated mafic pulses from the lower- and mid- crust ascended to mix with the upper crustal magma chamber below Turquoise Gulch forming the late Eocene (42-43 Ma) more evolved granodiorite intrusions. Volatiles and water content increased due to the breakdown of amphibole (Figure 3.6) increasing the oxidation state. At higher oxidation states sulfide crystallization is suppressed resulting in higher concentrations of copper and gold in the melt (Carroll and Rutherford, 1985;

Ballard et al., 2002). Copper will partition into the hydrothermal fluid phase as the melt becomes fluid saturated (Ulrich et al., 1999), allowing for the efficient transport and 168

Figure 3.27. Geologic evolution of the El Salvador porphyry copper deposit. South- southwest to north-northeast diagrams outlining the porphyry centers Granite Gulch (GG), Turquoise Gulch (TG), M Gulch – Copper Hill (MG-CH), Old Camp (OC), and Cerro Pelado (CP). A. ~43 Ma to 45 Ma outlining the intrusions of quartz porphyry rhyolite (QR) and quartz porphyry (QP) followed by minor mineralization at CP and OC. The quartz porphyry evolves(?) into L porphyry at OC and GG. Under TG melting of the crust initiates batholith(?) formation followed by X porphyry intrusions (XP). B. ~41.6 to ~43 Ma lower crust melts containing garnet ascend to interact with hornblende bearing andesite(?) which ascended to mix with the upper crustal batholith(?) forming the K porphyry (KP) and L porphyry (LP) and the main mineralization event at Turquoise Gulch. The final intrusive latite dikes (LaD) ascended from the lower/mid crust and mixed with the upper crustal batholith prior to intrusion at or near surface. Grey lines outline the earlier Eocene chambers. 169 deposition of copper (and gold) following the emplacement of the K and L porphyries.

The late (41.6 Ma) latite dikes potentially represent the mafic melt derived in the mid- crust that ascending and mixed with or partly assimilated the upper crustal El Salvador batholith.

Ore-mineralization at El Salvador appears to be dependant upon the amount and/or source of copper present within the porphyry intrusion. However, it appears that increasing mid- to upper-crustal interaction allows for an increasingly oxidized magma source potentially allowing for a higher volume of ore-mineralization as seen in the El

Salvador Turquoise Gulch deposit.

Acknowledgments

Analytical work for this project was funded by a 2007 Society of Economic

Geology (SEG) student research grant, a generous donation from Freeport McMoRan

Copper & Gold, Inc, and the Oregon State University Ore Geology Fund. We thank Lew

Gustafson and Enrique Tidy for initiating this project and supplying their samples. We also thank Richard Tosdal and Paula Cornejo for their insights into the geology of El

Salvador. Field work was partly funded and supported by the El Salvador division of

Corporacion Nacional del Cobre de Chile (CODELCO) with special thanks to Francisco

Camus, Walter Orquera, Ricard Santelices, Christian Rojas, and Eduardo Gonzalez. The following people also helped in one form or another to this study: Allison Weinsteiger,

Mark T. Ford, Barry Walker, and Anita Grunder.

170

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CHAPTER FOUR

THE HYDROTHERMAL ALTERATION ASSEMBLAGES AROUND ACTIVE GEOTHERMAL SYSTEMS IN LASSEN VOLCANIC NATIONAL PARK, NORTHERN CALIFORNIA

Robert G. Lee John H. Dilles David A. John Tanya L. Abela

This manuscript is in preparation for submission to the Journal of Volcanology and Geothermal Research 179

Abstract

Lassen Volcanic National Park hosts both the largest active hydrothermal system in the Cascade Range in association with recent dacitic volcanism centered on Lassen

Peak and fossil hydrothermal zones of Pleistocene age. The modern hydrothermal system includes fumaroles and acidic hot springs centered along an east-west fracture zone on the south flank of Lassen Peak and neutral chloride hot springs to the south and east. The older hydrothermal alteration zones are inactive but affect rocks in a four square kilometer area with nearly 500 m of relief that extends from Brokeoff Mountain to

Bumpass Hell in the east. These zones are exposed in the eroded core of the Pleistocene

Brokeoff volcano, and are spatially associated with a series of newly mapped andesite dikes and plugs which suggest that Brokeoff constituted a volcanic field rather than a single stratovolcano. Andesite lavas and breccias dip away from intrusive centers, and breccias are preferentially hydrothermally altered.

Hydrous silicate alteration minerals from active and ancient hydrothermal systems were identified using a portable infrared spectrometer within a two square kilometer area extending from Sulphur Works to Bumpass Hell. A subset of these samples was characterized in the laboratory in more detail via X-ray diffraction, petrography, scanning electron microscopy, and whole-rock geochemistry. Distribution maps were plotted for individual minerals, and serve as the basis for construction of generalized hydrothermal mineral assemblage maps.

The active hydrothermal system is dominated by steam-heated alteration produced where ascending H 2S-rich steam condenses at the water table near the surface.

The main east-west trend of hot springs from Sulphur Works (<150º C) to Bumpass Hell 180

(<170º C) and beyond the field area to Devils Kitchen is locally controlled by east-west striking faults. Subsidiary sets of hot springs aligned north to south in both Little Hot

Springs Valley and at Sulphur Works, and principally occur in Holocene post-glacial landslide, colluvial, and alluvial deposits. The active system is producing steam-heated wall-rock alteration to mixtures of kaolinite, alunite, opal, and cristobalite with accessory iron sulfates near surface and pyrite below the water table. The low pH (2-3) springs at

Bumpass Hell are apparently produced by surficial bacteriogenic oxidation of hydrothermal pyrite at 50º to 170º C, and these descending fluids produce the observed silicate and Fe-sulfate minerals.

The older and inactive hydrothermal systems produced a series of alteration assemblages that are zoned vertically and lateral to intrusions in Little Hot Springs Valley and near Sulfur Works. In the basaltic andesite lavas in the bottom of Little Hot Springs

Valley, alteration products consist of mixed layer illite-smectite, chlorite, calcite, quartz, pyrite, albite, and traces of potassium feldspar that here classified as propylitic alteration.

At higher elevations silicic andesites are altered to montmorillonite or illite-smectite with minor pyrite, here considered as intermediate argillic alteration. On the southeast flank of Pilot Pinnacle a separate hydrothermal center contains a similar zone of intermediate argillic alteration cored by advanced argillic alteration characterized by mixtures of pyrophyllite, dickite, alunite, kaolinite, and quartz. The presence of quartz, calcite, and pyrite-bearing veins within the intermediate argillic alteration suggests that condensed hydrothermal waters produced the inactive alteration zones when the water table was higher than at present. The advanced argillic alteration formed at lower pH, likely as a result of a larger proportion of magmatic gas, compared to the propylitic alteration. All 181 the fossil alteration zones formed at relatively low temperature (~50º to 300º C).

Hydrogen isotopic compositions of both active steam heated zones and fossil zones indicate local meteoric ground waters dominated all geothermal water. The fossil system produced no enrichment in economic metals.

Introduction

Active and fossil hydrothermal systems are present in many of the Quaternary

Cascades volcanoes, but the distribution, composition, and origin of hydrothermal alteration products are generally poorly known. These hydrothermal systems are the products of magmatic-hydrothermal fluid-rock interactions in shallow subvolcanic or geothermal environments. They are of interest because of the worldwide association with epithermal gold-silver deposits (Arribas, 1995; Hedenquist et al., 2000) that in some cases may root into base-metal deposits (Sillitoe and Hedenquist, 2003). Hydrothermal rock alteration can also weaken volcanic edifices and cause slope instability and structural collapse (Siebert, 2002). By studying the hydrothermal alteration it may be possible to determine what controls the distribution and mineralogy of alteration as well as how structure and lithology may control alteration.

Within Lassen National Volcanic Park (LNVP) northern California, the southern flank of the active Lassen Peak hosts the largest active magmatic-hydrothermal system in the Cascade Range. Here, both active and fossil hydrothermal systems are exposed in eroded Pleistocene rocks of the extinct Brokeoff volcano (Mount Tehama). The active systems extends approximately 12 km from the western boiling mud pots and fumaroles at Sulphur Works, eastward across Little Hot Springs Valley, to the largest thermal pools 182 at Bumpass Hell on the east, and eastward beyond the study area to Terminal Geyser

(Figure 4.1). The hydrothermal systems are characterized by steam-heated alteration

(Ingebritsen and Sorey, 1987) that is locally superimposed on alteration zones produced by older and inactive higher temperature and water-dominated hydrothermal systems

(Crowley et al., 2004).

The active Lassen hydrothermal system is characterized by a two-phase system with a vapor-dominated reservoir centralized beneath the Bumpass Hell area lying above a liquid-dominated system. Steam rises to discharge at the higher elevations as fumaroles and acid-sulfate springs, whereas alkali-chloride liquid discharges laterally to the south at

Morgan and Growler hot springs and south-southeast at Terminal Geyser. Ingebritsen and Sorey (1987) modeled the Lassen hydrothermal system as a liquid-dominated zone below Bumpass Hell with a parasitic vapor-dominated zone above the boiling liquid. Xu and Lowell (1998) suggest that the hydrothermal system is not static but oscillatory over a period of ~1000 years. This system controls the formation of steam-heated acid alteration in the active areas of hydrothermal alteration between Sulphur Works and

Bumpass Hell along the southern flank of Lassen Peak.

The alteration that resulted from older inactive hydrothermal systems is well exposed in a zone extending from Brokeoff Mountain east to Bumpass Hell and to the northeast near Pilot Pinnacle. Remote sensing spectral analysis has identified illite- smectite alteration in these zones (Crowley et al., 2004), parts of which are characterized with moderate oxygen isotopic depletion as documented by Rose et al. (1994).

This paper presents the results of fieldwork and lab studies conducted as a collaboration between Oregon State University and the U.S. Geologicaly Survey in order 183

Figure 4.1. A: Tectonic setting of the Cascade Arc with rectangular insert denoting location of Lassen volcanic region. B: Map of the Lassen volcanic region showing the major normal vaulting in the area. Irregular lines outline the vent fields of Lassen volcanic center (LVC) and Caribou volcanic field (CVF). Stars denote the locations of the other major volcanic centers: L, Latour; Y, Yana; D, Dittmar; and M, Maidu. Brokeoff volcano (BV) is dashed circle. Figure modified from Ingebritsen and Sorey (1985) and Guffanti et al. (1996). C: Southeast section of the Lassen region showing active hydrothermal systems in red and fossilized systems in green. Modified from Clynne et al. (2002). Solid rectangle marks location of Figure 4.2. 184 to describe and understand the fossil and active hydrothermal systems in LNVP; it is part of a larger USGS project addressing the hydrothermally altered rocks of the Cascade

Range. We present detailed mineral distribution and assemblage maps of the southern flank of Lassen Peak based on field mapping and mineral identifications by portable inferred mineral analysis (PIMA), X-ray defraction (XRD), and scanning electron microscopy (SEM). Geochemical analyses of unaltered host andesite rocks and the various alteration assemblages allow for modeling the volume gains/losses of the alteration assemblages at LVNP. We conclude with a geologic model for how the Lassen

Geothermal systems evolved to produce the observed distribution of the hydrothermal minerals.

Geological and volcanological setting

The Lassen volcanic region is located at the southern extent of the Cascades volcanic arc in northern California (Figure 4.1a). Volcanism is related to the northwestward subduction of the Gorda plate, part of the Juan de Fuca plate system

(Guffanti and Weaver, 1988). The Lassen region lies along the western margin of the

Basin and Range extensional province that lies east of the Cascades (Pezzopane and

Weldon, 1993). This extensional system transects the Lassen area and is characterized by normal and right-oblique slip normal faults (Figure 4.1b) and volcanic vents that are aligned in a north-northwest direction (Guffanti et al., 1990; Guffanti et al., 1996).

Volcanism has occurred in the Lassen region for approximately the last 7 million years and can be characterized on two scales (Clynne, 1990). On a regional scale hundreds of small, short-lived, mafic to intermediate composition volcanoes occur throughout the 185

Lassen region. Superimposed over this are a few larger, longer-lived, basaltic to rhyolitic volcanic centers. The Caribou volcanic field (CVF; Figure 4.1b) consists of approximately 50 km 3 of erupted material from over 100 small cones and shields at 700 to 20 ka (Clynne and Muffler, 1990; Guffanti et al., 1996). These cones are constructed of olivine-pyroxene basaltic andesites and andesites, olivine basalt, and pyroxene andesites (Guffanti et al., 1996). The Lassen volcanic center (LVC; Figure 4.1b) is the youngest of five volcanic centers including Latour, Dittmar, Yana, and Maidu. These volcanic centers generally evolved from an initial cone-building episode of basaltic to andesite lava flows and a late-stage emplacement of dacite to rhyolite domes and flows on the flanks of the main composite cone (Clynne, 1984; 1990). The LVC began with the construction of Brokeoff volcano, which is described as an andesitic stratocone active from 600 to 400 ka (Clynne, 1990). The Brokeoff volcano is overlain by three successively erupted sequences of dacitic to rhyolitic lava flows: the Rockland sequence at ~400 ka; the Bumpass sequence from 250 to 200 ka; and the Loomis sequence from

100 ka to present (Clynne, 1990). Lassen Peak is a dacitic dome complex within the

Loomis sequence and represents the youngest stage of silicic eruptions in the LVC.

Lassen Peak formed at 26 to 28 ka (Turrin et al., 1998), and the most recent eruptions occurred in 1914 and 1915 (Clynne, 1999).

Fossil hydrothermal systems and hydrothermal alteration mineralogy have been described in the Lassen region at Maidu (Wilson, 1961; John et al., 2005) and at Brokeoff volcano (Rose et al., 1994; Crowley et al., 2004). The late Pliocene Maidu volcanic center hosts a fossil acid-sulfate magmatic-hydrothermal system within its eroded core.

Both active and fossil systems are found at Brokeoff volcano (Figure 4.1c), with fossil 186 systems concentrated in the deeply eroded center extending from Brokeoff Mountain to

Little Hot Springs Valley. Active hydrothermal systems occur at several sites within the

Brokeoff Volcano as well as to the south and southeast.

Geology of Brokeoff Volcano

Brokeoff volcano is located in the southeast part of the Lassen Volcanic Center, and has been described as an eroded andesitic stratocone (Williams, 1932: Figure 4.1c).

The general stratigraphy of the volcano consists of two sequences of volcanic rocks, which host both the ancient and active hydrothermal alteration. The first stage is the

Mill Creek sequence erupted between 600 and 475 ka and consists multiple flows of glassy basaltic andesites and two-pyroxene andesites, along with pyroclastic and other fragmented deposits with variable (5 to 40 vol. %) phenocrysts (Clynne, 1990). The second stage, the Diller sequence, erupted from 475 to 400 ka and consists of thick andesite flows with 30-40 vol. % phenocrysts of plagioclase, hypersthene, augite, and titanomagnetite. Approximately 500 m of the first sequence is exposed in the glacial and fluvial valleys and ridges between Brokeoff Mountain and Sulphur Works and in Little

Hot Spring Valley, whereas the second sequence crops out at higher elevations mainly to the north and west of these locations (Figure 4.2). Volcanic flow-breccias between most of the andesite flows provided the conduits for hydrothermal fluid flow and host the majority of alteration minerals for the ancient hydrothermal system.

To the northeast and at higher elevations above Bumpass Hell are a series of two- pyroxene-hornblende dacite domes that postdate the older hydrothermal system and make up the Bumpass sequence. Vent breccias as well as dacitic lava flows cut the older hydrothermally altered andesite wall-rocks along the edge of Bumpass Hell. The dacite 187 rocks have been hydrothermally altered by the active steam-heated alteration centered on the Bumpass Hell thermal pools and fumaroles and do not contain the older alteration minerals seen within the andesite rocks.

Clynne (1990) proposed that Brokeoff Volcano forms a stratocone centered on

Diamond Peak which is composed of dikes and plugs as well as lava flows and brecciated flows that dip away from the central intrusions. Brokeoff Mountain, Mount Diller, Pilot

Pinnacle, and Mount Conard are believed to represent intrusions and eruptive centers on the flanks of the main volcano (Clynne, 1990; Clynne et al., 2002). Maximum elevation of the original cone was approximately 3400 m (Williams, 1932) and the basal diameter is estimated to be about 12 km (Figure 4.1C) so that eruptive products include roughly 80 km 3 volume (Clynne, 1990).

The volcano has been deeply eroded by glacial and fluvial processes to create both an irregular, bowl shaped depression south of Lassen Peak and the deeply incised

Mill Creek canyon. Little Hot Springs Valley is located in the northern part of Mill

Creek canyon and cuts into the center of the Pleistocene Brokeoff Volcano exposing hydrothermally altered rocks of the inactive fossil system. Numerous landslide and glacial deposits occur in the main valley and side drainages, and active fumaroles and acid-sulfate springs are concentrated within these Holocene deposits. Locally intense and widespread active sulfataric hydrothermal alteration zones occur throughout a 6 to 7 km diameter bowl that makes up the center of Brokeoff volcano with the largest areas located at Bumpass Hell and Sulphur Works (Figure 4.1C). These active areas of hydrothermal alteration are the result of a vapor-dominated acid-sulfate system (Muffler et al., 1982;

Ingebritsen and Sorey, 1985). Additionally, Little Hot Springs Valley hosts an older 188

Figure 4.2. Geologic map of the Brokeoff Volcano region showing rock sequences, structure, active fumaroles and intrusive dikes and plugs. A. Index map from west edge of Sulphur Works to Cold Boiling Lake with enlarged inset B. Geology from Clynne and Muffler (in press) and this study. 189 liquid-dominated system (Crowley et al., 2004) and Brokeoff Mountain host an older acid-sulfate alteration currently being investigated in detail by D. John and co-workers.

During mapping of the area several plugs and radiating andesite dikes have been found throughout the area (Figure 4.2B). These dikes extend northeast and east away from Diamond Peak into Little Hot Springs Valley. Petrographically, these dikes are similar to the two-pyroxene andesites of both the Mill Creek sequence and the Mount

Diller sequence, and it seems likely that these dikes may be the feeders for some of these lavas.

Methods and analytical techniques

Geologic and hydrothermal alteration minerals were mapped on topographic and digital orthophoto quadrangle (DOQ) base maps. Over two hundred and fifty rock samples were collected with permission from the National Park Service for laboratory analysis and located to (±5 m) with a GPS unit. A Portable Infrared Mineral Analyzer

(PIMA) was used in the field for rapid identification of hydrous alteration minerals

(excepting Fe-hydroxides and oxides). Short-wave infrared spectrometers can identify hydrous minerals present at the 5 to 10 volume percent or more, and these minerals are particularly useful in order to characterize high-sulfidation and low-sulfidation epithermal environments (Thompson et al., 1999). The spectra were analyzed in order to identify minerals present using characteristic absorption features of wavelength position, depth, and width (Figure 4.3), which are a function of molecular bonds present in the mineral (Thompson et al., 1999). The computer database software

FEATURESEARCH™ and SPECMIN™ were used to identify absorption features by 190 comparison with mineral reference libraries. Figure 4.4 details representative spectra and alteration assemblages of samples analyzed in the field.

X-ray powder diffraction patterns were collected on forty-seven samples using a

Phillips XRG 446 X-ray diffractometer, run at 40 keV and 30 mA using a Cu K α radiation source. These samples were chosen for a detailed analysis of clay mineralogy and to confirm initial PIMA identification. Analyses were performed on bulk rock powders, <15 µm size fractions, and <2 µm size fractions. The mineralogy of samples was identified using the characteristic mineral d-spacing of X-ray emission lines according to procedures detailed in Moore and Reynolds (1997) and using the Jade™ 3.0 software.

Ten samples were analyzed on an Amray 3300 field emission scanning electron microscope (FESEM) housed at the Oregon State University electron microscope facility.

Samples were broken into small chips approximately 2-3 cm in diameter and glued to stands. The samples were then coated with a 60% Au 40% Pd mixture and vacuum- sealed in the machine. An X-ray energy dispersive spectrometer was used to identify semi-quantitatively the major element concentrations within image.

Sixteen whole rock and <15 µm samples were analyzed for D/H isotopic composition using a TC/EA furnace operating at 1450ºC on line with a gas chromatograph and continuous flow mass spectrometer at Oregon State University.

Whole rock and <15 µm samples were weighed out to approximately 2 mg and placed in silver capsules. The samples were heat treated in a vacuum oven at 50-70 ºC for approximately 2 hours to evaporate excess water. Samples were standardized using an in

191

Figure 4.3. A: Infrared spectra of dickite and kaolinite (samples CALV053 and CALV262) showing the distinguishing characteristics for identification including the hull, feature depths, position, and the full width half-maximum. Dickite has doublet feature depths at 1.384 and 1.414, while kaolinite has doublet feature depths at 1.396 and 1.414. Kaolinite also has a higher full width half-maximum (inset). B: Spectra patterns of sample CALV262 vs. USGS Denver kaolinite standard. C: Spectra patterns of sample CALV053 vs. USGS Denver dickite standard. Large absorbance at 1.9 in CALV053 is from excess water in the sample as opposed to the standard.

192

Figure 4.4. Representative infrared spectra “stack plots” from Bumpass Hell, Pilot Pinnacle, and samples from northern and southern Little Hot Springs Valley. Numbers to right of pattern indicate sample name and bold face mineral name/mixture above pattern indicates sample type. Stack plot reflectance percent is not to scale. 193 house National Bureau of Standard biotite (NBS-30, -65 ‰) and reported in permil notation relative to VSMOW. Analytical reproducibility on unknowns is ± 2 ‰ (n = 5).

Seventy-three samples of altered and unaltered rocks were analyzed at the USGS geochemical laboratories in Lakewood, CO, following protocols described by Arbogast

(1996). Major, minor, and trace elemental concentrations were determined by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). Samples were digested using mixtures of hydrochloric, nitric, perchloric, and hydrofluoric acids at low temperature and then aspirated into the ICP-AES. A full list of elements analyzed by this method including lower detection limits is given in Woodruff et al. (2002).

Mercury was analyzed in sixty-four of the total analyzed samples by cold-vapor atomic absorption technique by dissolving the samples in acids, spiking the solution with various salts and analyzing the solution in a cold-vapor atomic absorption mercury analyzer with a detection limit of 0.02 ppm (Brown et al., 1997). Gold was analyzed in the same samples using fire assay collection and with analysis by atomic absorption spectrophotometry. The lower detection limit for gold is 5 ppb. Selenium was measured in forty of the total samples analyzed. The samples were heated and cooled in an acid mixture and then analyzed using atomic absorption spectrophotometry with a lower detection limit of 0.2 ppm.

Major elemental compositions were measured by X-ray fluorescence technique for nine unaltered andesite to basaltic andesites. All whole rock major, minor, and trace elemental geochemical data are reported in Appendix E.

All analytical data has been digitized within a geographical information system database using the geospatial software ArcView™ and ArcMap™. A digital map of 194 alteration assemblages was constructed based on mineral(s) present at sample location.

The data set is presented within the CD appendix.

Hydrothermal alteration mineralogy

Intensely and pervasively altered rocks are located in the valleys and bowls near

Sulphur Works, Pilot Pinnacle, Little Hot Springs Valley, and Bumpass Hell. Active fumaroles and mud pots within Sulphur Works and Bumpass Hell have formed steam- heated advanced-argillic alteration as part of the largest active hydrothermal system in the

Cascades. Sulphur Works lies within andesites of the Mill Creek Sequence and

Quaternary landslide material. Bumpass Hell is confined to a bowl-like depression within dacite lavas and vent breccias from the Bumpass Sequence as well as Quaternary colluvial deposits. The lower slopes of Pilot Pinnacle have active fumaroles within landslide deposits whereas the higher slopes host intermediate argillic and locally higher temperature advanced argillic alteration. Altered wall-rocks in Little Hot Springs Valley extends from the Mill Creek stream channel to midway up the slopes and cliffs to the east and west. This older system is concentrated within basaltic andesite flow breccias of the

Mill Creek sequence and extends upwards into andesite flow breccias and lavas of the

Mount Diller sequence. Active hot springs are confined to the streambed of Mill Creek in the center Little Hot Springs Valley and also occur along the southwest slopes of the valley.

Hydrous minerals were identified in the field using a PIMA II and representative spectra for samples from Bumpass Hell, Pilot Pinnacle, and Little Hot Springs Valley are presented in Figure 4.4. PIMA spectra, particularly where the samples contained several 195 hydrous minerals, sometimes did not allow identification of all hydrous minerals. The

PIMA spectra allowed for the identification of kaolinite, dickite, pyrophyllite, alunite, illite-smectite mixed layer clays, smectite, and chlorite. The distribution of these minerals within the 250 samples from within the field area is plotted in Figure 4.5.

Based on field relations, petrography, PIMA, XRD, and SEM data, minerals that occur together in the same sample and appear to have formed at the same time are grouped together into four distinct hydrothermal alteration assemblages (Table 4.1).

These assemblages are based on the associated mineralogy as described by Simmons et al. (2005). The active geothermal systems produce steam-heated advanced argillic with a characteristic mineral assemblage of kaolinite, alunite, ± montmorillonite, ± opal, ± cristobalite. Iron and sulfur species are accessory phases. Three fossil mineral associations were identified, and classified as advanced argillic, intermediate argillic, and propylitic alteration. Advanced argillic alteration is characterized by a mineral assemblage of pyrophyllite, alunite, dickite, quartz, ± kaolinite, with accessory iron phases and illite. Intermediate argillic alteration is characterized by smectite, pyrite, mixed layer illite-smectite, illite, quartz, ± feldspar. The propylitic alteration is associated with chlorite, calcite, montmorillonite, quartz, ± epidote.

Bumpass Hell

Bumpass Hell consists of superheated steam vents and acid-sulfate hot springs

(Janik et al., 1983) that are related to zones of steam-heated advanced argillic or acid- sulfate alteration that are forming today. The acidic alteration covers approximately 1 km from east to west and approximately 0.5 km from north to south at Bumpass Hell and is centered on and surrounds a zone of active steam venting extending approximately 200m

196

Figure 4.5. Sample maps denoting major mineral locations defined by PIMA for the Brokeoff volcano area. Geology contacts same as in Figure 4.2.

197

Figure 4.6. Representative XRD spectra for selected Brokeoff Volcano samples. Peaks identified using the software Jade™ 3.0: A – alunite; C – chlorite; Cr – cristobalite; D – dickite; H – hematite; I – illite; J – jarosite; K – kaolinite; M – montmorillonite; N – natroalunite; O – orthoclase; Op – opal; P – pyrophyllite; Q – quartz; T – anatase. A: Spectal patterns of whole rock powders from 5-60º 2 θ from Bumpass Hell. Sample CALV200 comes from the central area of the active thermal pools and contains mixtures of alunite, jarosite, hematite, and silica phases of quartz and opal. CALV201 is located on the periphery of the active zone at a higher elevation is dominated by alunite and cristobalite, and lacks the Fe-species. B: Spectra for clay fractions scanned from 2 to 40º 2θ from Sulphur Works (CALV196), Little Hot Springs Valley (CALV147), and Pilot Pinnacle (CALV053, CALV069).

198

Figure 4.7. Scanning electron microscope images of hydrothermal alteration textures and minerals at Brokeoff Volcano. A: CALV202 from Bumpass Hell at 1000x showing fine grained (<3-4 µm) alunite crystals growing on kaolinite. B: CALV202 at 1500x magnification. C: CALV104 from Little Hot Springs Valley at 500x magnification showing pyrite crystals in an illite/smectite groundmass. D: CALV104 at 3000x showing illite/smectite crystals. E: CALV147 from Little Hot Springs Valley at 1000x magnification showing montmorillonite crystals growing on coarse orthoclase. F: CALV069 at 1000x magnification from Pilot Pinnacle. Jarosite crystals occur as fine grained crystals growing along the surface. Pyrophyllite occurs as 5-10 µm platy crystals within cavities. G: CALV097 from Little Hot Springs Valley at 1000x magnification showing coarse vuggy calcite. H: CALV003 from Little Hot Springs Valley at 500x magnification showing intermixed chlorite and smectite alteration of mafics in the groundmass around feldspar grains. Scale bars are at 10 µm. 199 on an NW-SE trend (Figure 4.2). Surrounding the steam-heated alteration is a region of weakly acidic to near-neutral smectite-rich alteration. Major alteration minerals within

Bumpass Hell characteristic of the acid-sulfate alteration include kaolinite, alunite, cristobalite, and opal (Figures 4.4, 4.6a). Alteration is pervasive, and most of the original rock host has been completely altered with few relict textures remaining. Kaolinite is present in most of the samples in Bumpass Hell and occurs in great abundance within the western edge of the area (Figure 4.5). Kaolinite is typically fine grained ( ≤20 µm) and commonly associated with opal. Alunite occurs within the altered slopes to the north and west of the central Bumpass Hell area and is commonly associated with kaolinite, ferric and ferrous hydroxides and sulfate minerals, and cristobalite (Figure 4.6a). Alunite typically forms fine-grained ( ≤10 µ m) tabular crystals with a sugary texture in hand specimen. SEM images show alunite as platy to tabular, mica-like crystals ≤5 µ m long filling vugs and growing on and around kaolinite grains (Figure 4.7a, b). PIMA and

XRD spectral data suggest that alunite compositions range from K-rich alunite to Na-rich alunite throughout the Brokeoff volcano region. At Bumpass Hell the composition of alunite is K-rich whereas Na-bearing alunites occur in samples located distally from the more active steam-heated regions. Alunite appears to be the dominant mineral in the slopes surrounding Bumpass Hell whereas kaolinite and opal mixtures are dominant in the central zone of hot spring venting (Figures 4.6a, 4.8). Silica phases are extensive within the area and include quartz, cristobalite, and opal. Opaline silica is the most abundant phase in the central part of the region where the greatest steam venting occurs.

Microcrystalline quartz, cristobalite, and chalcedonic silica are found in the northern and 200 , , Sulphur 1 eration in the field area. thefield in eration 1 Bumpass Hell, LHSV, Sulphur Works, LHSV, Hell, Bumpass Pilot Pinnacle Bumpass LHSV Hell, Bumpass Locations Works site, goethite, illite goethite, site, LHSV Pilot Upper Pinnacle, lcano, lcano, California. anatase anatase, goethite, jarosite, hematite, hematite, jarosite, goethite, anatase, native sulfur minerals, Fe-sulfate Accessory Minerals Accessory anatase, smectiteanatase, LHSV Sulphur alt heated Works steamwithassociation in epidote ± montmorillonite, pyrite, illite- montmorillonite,pyrite, smectite, quartz albite, kaolinite, montmorillonite,alunite, cristobalite natoralunite, opal, quartzdickite,alunite, pyrophyllite, jaro anatase, Major Minerals Major chlorite, calcite, illite, calcite, chlorite, quartz, pyrite, Hydrothermal alteration assemblages at Brokeoff Vo Brokeoff at assemblages alteration Hydrothermal Travertine deposits are located in LHSV, and and lower LHSV, in located depositsare Travertine Intermediate Intermediate argillic Table4.1. Assemblage Steam-heated argillic advanced Advanced argillic Propylitic 1 201 southern slopes at elevations above the Bumpass Hell hot spring vents. Other minerals present include anatase, hematite, goethite, jarosite, native sulfur, copiapite and iron- sulfate minerals. Goethite, hematite, and jarosite were all observed petrographically and in XRD analysis (Figure 4.6a), with goethite staining occurring as wide (1-2 m) bands surrounding the active center of Bumpass Hell but distinctly lacking in the central area near the thermal pools. Native sulfur and sulfate minerals occur near the active steam regions. Montmorillonite is generally abundant in the slopes surrounding Bumpass Hell, but also occurs in the center of the system with kaolinite and opal (Figure 4.4).

Little Hot Springs Valley

Little Hot Springs Valley cuts through the center of the eroded Brokeoff Volcano and contains both active and fossil hydrothermal alteration. The north end of the valley encompasses an area that has both active and abandoned travertine deposits first noted by

Muffler and Clynne, (personal communication, 2005) (Figure 4.2). To the west of these carbonate springs are zones of steam-heated advanced argillic alteration that extend west to Highway 89. South of the travertine deposits are deposits of intermediate argillic alteration. An outcrop of andesite breccia from the Mill Creek sequence to the southwest of the travertine deposit, contains both pyrophyllite and smectite clay minerals (Figures

4.4, 4.5).

Alteration in the southern end of the valley encompasses approximately two square kilometers and extends from Mill Creek up to the ridges bounding both sides of the valley. Active steam vents and boiling mud pots occur in the central part of the valley and on the southern slope of a small side valley southwest of Bumpass Hell at 626,000 m

E and 4,497,000 m N extending from creek east to the ridge line (Figure 4.8A). Major 202 hydrothermal minerals in this small valley include kaolinite, alunite, and opal. PIMA spectra indicate that much of the kaolinite is associated with smectite as summarized in the mineral distribution map (Figure 4.5). Crowley et al. (2004) noted this mixture and suggested that steam-heated alteration is currently overprinting an older alteration assemblage. The steam-heated alteration is confined in landslide and slump deposits

(Figure 4.8A). In the center of the steam-heated alteration is a series of at least five travertine pools. One of the pools sampled in the summer of 2005 had a temperature of

87.5ºC and a pH of 6.25 (Muffler, personal communication, 2005). Fumaroles and steam vents are located both 10 to 20 m to the north and west of the travertine deposits. Within the central section of the valley, advanced argillic alteration of steam-heated origin is confined to the active steam vents and is surrounded by smectite-bearing rock characteristic of intermediate argillic alteration.

The major hydrothermal minerals along the slopes of the valley include montmorillonite, pyrite, feldspar, mixed layer illite-smectite, chlorite, calcite, and quartz.

Adularia has been found in this assemblage in trace amounts but is rare. We suggest that this alteration assemblage is an intermediate argillic alteration that formed when the water table was higher than it is currently. The intermediate argillic alteration occurs in flow breccias that are capped by weakly smectite altered andesite lava flows. Original rock textures are typically preserved, but in some cases complete replacement of phenocrysts and groundmass has occurred. Montmorillonite replaces the groundmass and partially replaces plagioclase and mafic mineral phenocrysts, and is associated with pyrite and microcrystalline quartz. Up to 5 vol. % pyrite occurs in some areas as fine, to very-fine disseminated grains within the groundmass (Figure 4.7B). Pyrite is typically 203

204

Figure 4.8 (previous page). Photographs outlining alteration and hydrothermal features within Lassen Volcanic National Park. A. Looking towards the east edge of Little Hot Springs Valley. Left section of photograph shows alternating andesite lava flow and altered flow breccias. Lava flows have weak to no smectite alteration; breccias have pervasive smectite, pyrite, illite-smectite, chlorite, albite, orthoclase, quartz, and calcite alteration. Pyrite is fine-grained and forms small veins locally but not stockwork. To the right of the photo landslide and slump deposits have been completely altered to kaolinite/alunite/opal. Active steam vents occur throughout the area as well as in the base of the valley. Smectite also occurs with steam-heated kaolinite suggesting possible overprint of younger steam heated alteration on the older near-neutral alteration. Rectangular insert denotes location of photo B. B. Upper section of Little Hot Springs Valley with heavy set line marking the upper limit of chlorite and calcite. Alteration above line consists of montmorillonite, pyrite, illite/smectite, and quartz. C. Photograph of Bumpass Hell looking to the northwest. Central part of the active vents and thermal pools is opal/kaolinite dominant, whereas the altered slopes above the main active zone are alunite/cristobalite dominant. D. Southeastern edge of Little Hot Springs Valley showing a recent landslide outlined with black line. Head wall of the slide is completely smectite altered.

205 fine-grained ( ≤50-60 µ m diameter), but in may form narrow veins within the alteration.

Pyrite is the only sulfide mineral identified rare cases grains have been found in excess of

3-4 mm. Grains are typically euhedral and in the area. Albite is the common feldspar mineral in the alteration assemblage but orthoclase has been found in XRD and SEM analyses (Figures 4.6B, 4.7E). Orthoclase forms small tabular crystals commonly found with platy montmorillonite growing around it. Illite replaces the groundmass and is typically associated with smectite and pyrite (Figure 4.7C,D). Chlorite is associated with montmorillonite as a replacement of primary igneous mafic minerals in the groundmass

(Figures 4.6B, 4.7H). Both illite and chlorite are fine grained ( ≤20 µ m) and are generally disseminated. Calcite fills both vugs and porous spaces in lava flows and is disseminated throughout the groundmass in the brecciated layers (Figure 4.7G). At lower elevations along the stream channels in the valley small narrow (2-4 mm) veins of calcite have been observed. At higher elevations (~2350 m), the intermediate argillic alteration is mineralogically distinct due to the lack of chlorite and calcite (Figure 4.8B). The main silica phase is microcrystalline quartz typically associated with pyrite.

Pilot Pinnacle

Areas of hydrothermally altered rock in the Pilot Pinnacle area extend from the ridge below Pilot Pinnacle southeast down to the State Highway 89. Active steam vents and boiling mud pots occur in glacial and colluvial deposits at the base of Pilot Pinnacle and are associated with steam-heated advanced argillic alteration similar to Bumpass Hell and Little Hot Springs Valley. In the upper slopes and along the roadside, the alteration minerals include pyrophyllite, dickite, and natroalunite with accessory quartz, illite, and

Fe-oxide minerals. Pyrophyllite is present in one sample on the slope below Pilot 206

Pinnacle where it is associated with natroalunite, kaolinite, and jarosite (Figures 4.4,

4.6B, 4.7F). Pyrophyllite is fine-grained ( ≤10 µ m) and forms platy grains on the edges of cavities and vugs. Dickite occurs in the lower areas of Pilot Pinnacle and forms a large outcrop (3-4 m high) along the road. The outcrop is completely altered with no relict textures or minerals. The dickite is fine-grained ( ≤10 µ m) and is associated with illite, anatase (Figure 4.6b), alunite, and quartz. The dickite and pyrophyllite bearing assemblage do not appear to be associated with active steam vents and rather likely formed in an ancient fossil hydrothermal system.

Sulphur Works

We have split Sulphur Works into two areas, upper Sulphur Works and lower

Sulphur Works for discussion purposes based on elevation and relative location. Steam- heated advanced argillic alteration is associated with active fumaroles and boiling springs in both upper and lower Sulphur Works along a north-south trend. Located at the base of altered zone at the south side of lower Sulphur Works in the main discharge stream are two large (3-4 m diameter) travertine deposits associated with hot springs having a temperature at 84ºC (Muffler, personal communication, 2005). Steam-heated alteration is typically pervasive with little to no relict textures remaining in the host material. Acid- sulfate alteration assemblages in both upper and lower Sulphur Works are similar to those that occur in Little Hot Springs Valley and Bumpass Hell; kaolinite, alunite, opal, anatase, and/or rutile minerals (Figure 4.6B) are associated with the steam-heated zones.

Montmorillonite, illite, and pyrite characterize the intermediate argillic alteration that lie adjacent to and surrounding the acid-sulfate alteration near active vents.

207

Structural features

Major structural features include altered dikes and plugs, faults, quartz/chalcedony veins, calcite veins, and hydrothermal breccias. These are broadly distributed throughout the area of study. The dikes and plugs are distributed throughout the central and peripheral parts of Brokeoff Volcano (Figure 4.2). They are petrographically similar too and occur within the andesites of both the Mill Creek and

Mount Diller sequences. Based on their location and their composition these dikes potentially represent the feeder dikes responsible for the lava flows.

To the west of Sulphur Works are a series of elongate silicified zones composed of microcrystalline to fine-grained quartz, alunite, and Fe-oxide minerals. These features have not been observed in the Little Hot Springs Valley or Bumpass Hell areas. The distinctive silica-rich ledges most likely represent locations of upward fluid flow of low pH condensed fluid.

Landslides

Landslides and debris avalanches were observed in Little Hot Springs Valley and

Sulphur Works. In Little Hot Springs Valley, slump and slide deposits occur within smectite altered andesites (Figure 4.8D). Both old and recent slides were observed in rocks that are associated with intermediate argillic alteration. In several of the older landslide deposits and currently active creep deposits active venting and boiling mud pots occur. This suggests that the weak porous materials associated with the debris deposits act as conduits for the uprising steam, or that the resulting sulfataric decomposition of the 208 lavas is promoting slope instability in these areas. Based on recent active land failures observed in the field, it would appear that the former statement is the case.

Geochemistry

Rocks for geochemical analyses were sampled based on alteration mineralogy, texture, structure and several unaltered samples were also submitted for control of elemental distribution during alteration. Assuming Ti is immobile during most hydrothermal alteration (e.g. Laughnan,1969), most of the alteration assemblages are depleted in major element components such as Fe, Ca, Na, and K (Figure 4.9). Steam- heated advanced argillic samples have been stripped of most elemental components and are enriched in S, as expected by the presence of sulfur species during formation.

Intermediate argillic alteration is associated with increased potassium relative to the unaltered samples.

Mercury content varies within each alteration type with steam-heated zones containing with the highest content (0.05-31 ppm) compared to the fossil systems

(intermediate argillic 0.03-6.5 ppm; propylitic below detection limit (BDL)-0.23 ppm; and advanced argillic 0.04-0.37 ppm).

Precious metal contents were generally low in all samples analyzed with gold contents ranging from BDL to 28 ppb. One sample (CALV104) contained 114 ppb gold.

Copper and nickel are depleted relative to unaltered rock in the alteration assemblages related to low pH fluids (Figure 4.9). The intermediate argillic and propylitic zones show similar metal contents to unaltered host rock values.

209

Figure 4.9. Geochemical plots of major and trace elements vs. titanium (Wt. %). Most of the alteration assemblages are depleted in major element components relative to the unaltered samples (outlined by shaded region). The steam-heated advanced argillic samples are enriched in sulfur relative to the other samples as this alteration results from the direct condensation of H 2S and SO 4.

210

Hydrogen isotopes

Acid water and steam from active thermal springs in the Brokeoff volcano area have low pH and high sulfate concentrations and define a kinetic isotope fractionation trend on a δD versus δ18 O diagram (Muffler et al., 1982; Janik et al., 1983; Thompson,

1985). Hydrogen isotopic composition ( δD) for both active and inactive hydrothermally altered minerals and rocks range from -133 to -107 per mil (Table 4.2). The lower isotopic values are confined to the center of Little Hot Springs Valley, whereas the higher isotopic values form in the active steam-heated alteration around Bumpass Hell with oxygen values of ~8‰ (Figure 4.10). This is consistent with previous work where acid sulfate waters are associated with high δD and δ18 O values (Janik et al., 1983; Rose et al.,

1999). The hydrogen isotopic values suggest that hydrothermal fluids associated with both active and fossil alteration systems were strongly dominated by local meteoric water.

Discussion

Advanced argillic alteration around Pilot Pinnacle and the northern end of Little

Hot Springs Valley suggests higher temperature acid-sulfate fluid may have been centered in this area. The presence of pyrophyllite-alunite suggests temperatures ≥ 230º

C with pH ≤ 2, however, the presence of dickite, quartz, and illite suggests temperatures between 200º and 260º C (Reyes, 1990; Arribas, 1995; Hedenquist et al., 2000). Both kaolinite and montmorillonite occur peripheral to the zone of advanced argillic alteration similar to well described high-sulfidation epithermal gold deposits (Arribas, 1995).

211 D D δ δ δδ 2 ‰) (± Quartz, IlliteQuartz, -123 hlorite, hlorite, Kaolinite -128 te -128 te, Anatase, JarositeAnatase, te, -133 Kaolinite -118 alite, Orthoclase alite, -107 Jarosite,Goethite -120 , Natroalunite, -118 tmorillonite,Mg-Smectite, -125 Chlorite, Montmorillonite -124 g-smectite -125 arosite, Kaolinite, arosite,Pyrophyllite -114 e, Illite, Quartz, Hematite Albite,Quartz, Illite, e, Hematite Albite,Quartz, Illite, e, -127 -128 PIMA XRD m size fractions size Brokeoff from m Volcano, California µ

08 Smectite71 Smectite Montmorillonite, Illi Quartz, Orthoclase, C Mg-Fe Mont, Illite, Orthoclase, Quartz, 40 SmectiteChlorite, Mg-Fe Albite, Mont, Orthoclase, (mg) Amount Amount System Geothermal Geothermal ActiveActiveActive 0.983Inactive Kaolinite/Smectite 1.120Inactive Smectite 1.700Inactive 1.310 AluniteInactiveKaolinite, Albite,Mon Pyrophyllite/Na-alunite 1.015Inactive J Natroalunite, Kaolinite/Smectite 1.940Active Dickite 2.130Active Calcite/Chlorite/Smectite 1.860 Chlorit Mg-Fe M Quartz, Kaolinite, ActiveMontmorillonite, Albite, Cristob Calcite/Chlorite/Smectite Chlorit Mg-Fe 1.580Natroalunite Cristobalite, Kaolinite 1.370 Alunite 1.210 N/AInactiveQuartz, Dickite, AnataseInactive 1.375Cristobalite, Kaolinite, Quartz Chlorite/Smectite 1.340 N/ANatroalunite, Kaolinite, Quartz, Mg-Fe Albite, Quartz, Montmorilloni Illite, Albite, Quartz, -109 Cristobalite, Quartz, Natroalunite, -126 m m m m m m m m m m m m m µ µ µ µ µ µ µ µ µ µ µ µ µ type Sample Sample <15 <15 <15 <15 <15 <15 <15 <15 <15 <15 <15 <15 <15 Location UTM Hydrogenisotopic of composition rock whole and <15 North East Name Sample Sample Table 4.2. Table CALV017 4479309 627052Hell Bumpass CALV075 4480149CALV086 4480315 624984 Upper LHSV 624826 PilotPinnacle CALV121 4478899 626421 LHSV Lower CALV069 4480749 624492 PilotPinnacle CALV097 4479061 625461 LHSV Lower CALV098 4479027CALV115 4478916 625464 LHSV Lower 626026 LHSV Lower CALV138 4479122 625843 LHSV Lower CALV184 4479350 624026 Sulphur Works CALV148 4479305CALV149 4479306CALV153 626040 4479371 LHSV Lower 626055 rock whole LHSV Lower 626250 Inactive rock whole LHSV Lower Inactive 1.1 1.6 CALV147 4479299 626018 LHSV Lower rock whole Inactive 1.1 CALV025 4479706 626707Hell Bumpass CALV013 4479408 627012Hell Bumpass 212

Figure 4.10. Distribution of hydrogen isotopic values and oxygen isotope contours along the south flank of Lassen Peak. Circles represent all sample locations with filled black circles representing samples analyzed for hydrogen isotopes, value given next to sample. Heavy dashed line outlines oxygen isotope contours of Rose et al. (1994). Solid lines represent the same geologic contacts as in Figures 4.2 and 4.5.

213

The presence of propylitic and intermediate argillic alteration in the center of the

Brokeoff edifice likely formed within a liquid-dominated reservoir characterized by near- neutral pH conditions (Muffler et al, 1982). We have found altered areas with chlorite, smectite, and illite mixtures, but mixed layer illite-smectite alteration is dominant in the permeable flow top breccias. Chlorite occurs with calcite and appears to be confined to lower elevations of the Brokeoff edifice and could be partly stratigraphically controlled.

The lack of chlorite/calcite in intermediate argillic alteration above 2350 meters in Little

Hot Springs Valley suggests this may be a transition zone with the location of the water table during active alteration.

The presence of smectite within the lower elevations of Little Hot Springs Valley as well as throughout the field area may have formed as the result of descending and laterally flowing steam-heated waters that have been neutralized as they move away from the fluid source (Simeone et al., 2005). Smectite is a relatively low temperature mineral

(<170º C), compared with the higher temperature chlorite and mixed layer illite-smectite

(Reyes, 1990). The presence of chlorite/smectite mixtures and massive smectite within the propylitic alteration supports the hypothesis that oxidation of downward percolating advanced argillic fluids formed the smectite, overprinting the older propylitic alteration.

The acid-sulfate steam heated alteration formed from a shallow vapor-dominated reservoir beneath areas of active solfataric systems (Ingebritsen and Sorey, 1987). The mineral assemblage of alunite/cristobalite surrounding the main thermal pools forms at higher temperatures (~120º to 170º C) compared to the kaolinite/opal mineral assemblage

(<120º C) that occurs within the center of Bumpass Hell (Reyes, 1990) (Figure 4.8C).

Oxidation of pyrite due to surficial bacteriogenic effects under low pH (2-3) conditions 214 produces the hydrothermal fluids that descend to form the observed hydrothermal mineral assemblage.

The presence of kaolinite and montmorillonite mixtures in Little Hot Springs

Valley and in areas of Bumpass Hell likely represents an overprinting of the two hydrothermal environments as previously suggested by Crowley et al. (2004). This overprinting is most likely due to a drop in the water table as the kaolinite-alunite alteration in Little Hot Springs Valley is currently active. The change in the propylitic chlorite alteration at roughly the same elevation to the north of the kaolinite- montmorillonite mixtures in Little Hot Springs Valley is further evidence for a drop in the water table. The presence of both quartz and chalcedony surrounding the active systems suggests formation within a near-neutral liquid-dominated alteration.

The fossil hydrothermal alteration at Lassen Volcanic National Park formed within the andesitic lava flows of Brokeoff Volcano (Figure 4.11). Ascending magmatic fluids produced the observed advanced argillic alteration which may have produced steam-heated alteration at or near the summit of the eroded volcano. The magmatic hydrothermal fluids interacted with local meteoric water and descended laterally to produce the near-neutral intermediate argillic and propylitic alteration observed in Little

Hot Springs Valley. Erosion of the volcano during the last ice age dropped the water table and exposed the now fossil hydrothermal alteration. Magmatic fluids still produced by a potential magma chamber at depth are ascending to form vapor-dominated zones below the active fumaroles and thermal springs within the park. Steam-heated advanced argillic minerals are produced as H 2S vapor condenses near the surface and flows

215

Figure 4.11. Simplified sketch from southwest to the northeast outlining the geothermal systems on the south flank of Lassen Peak.

216 laterally away from the pools. Chloride springs located to the south and east are produced as the laterally flowing hydrothermal fluid is neutralized.

Conclusions

Over two hundred and fifty samples were collected from Lassen Volcanic

National Park and were analyzed using a variety of methods. Alteration products were mapped and define four distinct alteration assemblages in the park. Inactive fossil alteration assemblages are the result of two different hydrothermal systems of acid- sulfate and near-neutral argillic alteration. Active vapor-dominated advanced argillic alteration defines the current alteration at the surface of the Brokeoff volcano region.

Hydrothermal and major mineralogical features of Brokeoff volcano area can be defined by four alteration assemblage types: 1) steam-heated advanced argillic alteration with kaolinite, alunite, cristobalite, and opal; 2) advanced argillic alteration with pyrophyllite, dickite, and associated Fe-oxides; 3) intermediate argillic alteration with smectite, pyrite, and mixed layer illite-smecite; and 4) propylitic alteration with chlorite, calcite, illite, quartz, pyrite, ± epidote (Table 4.1). Figure 4.12 details the alteration assemblage map we have determined from the results of our mapping and analysis. 217

Figure 4.12. Map of the hydrothermal alteration assemblages in the Brokeoff Volcano region. Geologic contacts are same as in Figure 4.2.

218

Acknowledgements

This report is based on research conducted by Oregon State University in collaboration with the Mineral Resource Program of the U.S. Geological Survey. The

Oregon State University research was supported by a grant from the Mineral Resource

External Research Program of the US Geological Survey. We would like to thank

Patrick Muffler, George Breit, and Jim Crowley for their support in the field and for additional comments to this study. We also thank Frank J. Tepley III for reviewing and commenting on this project.

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CHAPTER FIVE

CONCLUSIONS

The overall goal of this study is to determine the geochronology and geochemistry of porphyries from the El Salvador porphyry copper district and their relation to ore mineralization. An additional section of this thesis studied the fossil and active epithermal distribution along the southern flank of Lassen Peak in Lassen Volcanic

National Park, California. The second chapter of this dissertation focuses on the U-Pb geochronology and trace element composition of zircon sampled from fourteen rock types in the El Salvador district. The third chapter continues the study of the El Salvador deposit through the detailed chemical analysis of rock samples and their mineral phases.

In the fourth chapter, mineral assemblages associated with varied epithermal-type alterations were determined through detailed field mapping coupled with infrared spectrometry and X-ray diffraction. An alteration map was synthesized from the resulting data outlining the location of paleo-systems and currently active steam-heated alteration.

Over two hundred analyses were conducted on zircons from fourteen El Salvador porphyry samples using a sensitive high-resolution ion microprobe with reverse geometry

(SHRIMP-RG). The age of the deposit was determined using the U-Pb geochronological method with zircon crystallization ages spanning approximately 5 million years from

~41.5 Ma to ~46.5 Ma. Porphyries analyzed in this study were emplaced over a 3 million year period from 41.6 Ma to ~44 Ma. Older Eocene age zircon grains outside of the statistical mean age in individual rock samples are interpreted to represent inherited grains from the recycling of prior intrusions or magma chamber(s) at depth. The 45-46 222

Ma inherited zircon grains potentially represent the early rhyolite porphyry intrusions not analyzed in this study. Porphyry samples from Granite Gulch and M Gulch – Copper

Hill that are texturally similar to the L porphyry centered at Turquoise Gulch were apparently emplaced ~1 million years prior to the intrusion at Turquoise Gulch.

Two apparent ages of ore mineralization are identified from the results. One at

43.6 ± 0.3 Ma associated with volumetrically minor chalcopyrite-bornite ore at the Old

Camp center and probably associated at the same time as the Cerro Pelado and M Gulch

– Copper Hill centers. The main ore body at Turquoise Gulch occurred at ~42 Ma just prior to or congruent with emplacement of L porphyry.

Trace element compositions of zircons from the porphyry samples define a complex history. Early Eocene age zircons (43-46 Ma) contain high U and Th concentrations, high negative Eu-anomalies, and relatively enriched MREE and HREE concentrations, whereas young Eocene zircons (41-42 Ma) contain low U and Th concentrations with constant Th/U ratios, moderate Eu-anomalies, and varied REE content. Using increasing Hf content as a proxy for progressive zircon crystallization and magma cooling, two distinct evolutionary paths are evident with zircon Eu-anomalies.

With increasing hafnium, Eu-anomalies in the 43-44 Ma intrusions evolve from 0.8 to

0.3, whereas the younger 41-42 Ma intrusions evolve from 0.8 to 0.65. This suggests a similar composition for the source/recharge for all samples with the older samples crystallizing/cooling in a plagioclase dominant melt. The younger intrusions crystallized in a melt where plagioclase is depressed due to a higher oxidation state of the magma.

Thermal conditions Ti-in-zircon geothermometer indicate that temperatures for zircon crystallization in the granodiorite porphyries were between 750º and 620º C 223 whereas the final latite dike intrusion contains a much larger range of temperatures from

850º to 630º C. Zircon saturation temperatures suggest similar crystallization temperatures for all other granodiorite porphyries; however the temperature variation in the latite reflects the mixing between a hotter more mafic magma and the cooler granodiorite magma chamber. The span of ages and variation in the zircon trace element concentrations suggest that the porphyry intrusions represent the tapping of one (or more) evolving granodioritic magma chambers that were periodically heated, locally remelted, and mixed with mafic magma during recharge events.

Amphibole and plagioclase phenocrysts from the latite porphyry dike define mixing between a mafic(?) melt with a mid to upper crustal magma chamber. Amphibole geobarometry and geothermometry suggests depths of ~20 km at ~930 ºC for the formation of the titanian pargasite and temperatures of ~785 to 869 ºC at pressures 3.9 to

1.7 kb for the edenite amphiboles. The presence of these amphiboles in the same sample suggests the mixing of a mafic melt derived in the mid-crust and the upper crustal El

Salvador granodioritic batholith. The mafic magma potentially represents the source of the previous porphyry intrusions and the source of volatiles and/or copper that produced the ore mineralization.

Major and trace element compositions of whole rock and accessory phases define three intrusive phases over a period of approximately five million years from 46 to 41.5

Ma. The Eocene quartz rhyolite and quartz porphyry intrusions at Cerro Pelado and Old

Camp represent the first phase and are associated with plagioclase fractional crystallization, minor copper (major molybdenum at Cerro Pelado) ore, and a relatively lower oxidation state than the later granodiorite porphyry intrusions. The second phase 224 includes the porphyry intrusions at M Gulch – Copper Hill and Granite Gulch, which cut the quartz porphyry intrusions. While texturally similar, these intrusions are less evolved than the third phase of granodiorite porphyries at Turquoise Gulch that are associated with the main ore mineralization event. Complexities with this hypothesis include variability in chemical composition from the L and X porphyries from Turquoise Gulch.

The X porphyry also yields zircon crystallization ages similar to the earlier intrusions at

M Gulch – Copper Hill and Old Camp and contains inherited Mesozoic age zircons. A large dynamic magma chamber or multiple chambers may account for the multiple intrusions found in the El Salvador deposit.

The main conclusion from this study at El Salvador is that copper mineralization is not solely restricted to the build up of magmatism followed by one mineralization event. The main ore body at El Salvador however, is directly linked to the intrusion of a mafic recharge event into a relatively higher oxidized magma chamber. This allowed the extraction of large amounts of copper, sulfur, and magmatic-hydrothermal aqueous fluids from the magma to produce the main large ore-body as opposed to the minor copper mineralization associated with the less oxidized quartz porphyry intrusions.

The final chapter of this dissertation utilized infrared spectrometry, x-ray diffraction, scanning electron microscopy, and geochemical analytical techniques to determine the mineral phases associated with hydrothermal alteration at Lassen Peak.

Four distinct alteration assemblages were identified and mapped within the eroded

Pleistocene Brokeoff volcano. These include: 1) the currently active steam-heated advanced argillic alteration with mineral phases of kaolinite, alunite, montmorillonite, 225 cristobliate, ± opal, ± Fe-oxides, ± Fe-sulfates, ± native sulfur 2) inactive advanced argillic alteration with pyrophyllite, dickite, alunite, ± quartz, ± Fe-oxide 3) intermediate argillic alteration with montmorillonite, illite, pyrite, alibite, and quartz 4) propylitic alteration with associated chlorite, calcite, montmorillonite, ± quartz, ± pyrite.

Intermediate argillic and propylitic alterations are pervasive throughout the center of the Brokeoff edifice in the field area with intermediate argillic confined to higher elevations relative to the propylitic alteration. The transition between the lower propylitic and the higher argillic alteration most likely represents the level of the water table prior to erosion. These alteration types within the center of the volcano suggest they were derived from a near-neutral liquid-dominated reservoir at temperatures of ~50º to 300º C.

The currently active steam-heated alteration is associated with fumaroles and iron-dominated thermal pools. They form within north-south erosional valleys that extend eastward from Sulphur Works to Little Hot Springs Valley to the largest vents and thermal pools at Bumpass Hell. This system formed as the water table dropped, forming a shallow vapor-dominated reservoir beneath areas of active solfataric systems. Acid- sulfate steam-heated minerals were produced by descending hydrothermal fluids at temperatures between 60º to 120º C.

226

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Appendix A

El Salvador samples

Three weeks were spent at the El Salvador porphyry copper deposit in northern

Chile during January and February of 2006 to collect samples for analytical study from the subterranean mine, open pit benches, and drill core. Twenty-six samples of the porphyry intrusions and breccias were analyzed for geochemical composition, while fourteen of these samples were additionally analyzed by SHRIMP-RG for zircon U/Pb geochronology. Whole rock geochemical analyses were conducted at the Washington

State University Geoanalytical laboratory. Approximately twenty grams of sample were crushed to powder using an automated agate mortar and pestle crusher. The powders were mixed with dilithium tetraborate (2:1 ratio for XRF and 1:1 ratio for ICP-MS) and fused at ~1000 ºC in a muffle furnace. The resulting fused beads are cooled and reground to powder with the XRF powders refused a second time in the oven and the cooled glass beads are then loaded into the XRF spectrometer. The ICP-MS powders after being reground are dissolved into solution and run in the mass spectrometer. Results for the

XRF analyses are given in Table A1 and results from the ICP-MS are given in Table A2.

The twenty-six samples analyzed are listed below with a brief description of rock type and location. El Salvador mine sample numbering was used in identifying all samples collected. Locations are given in both UTM coordinates and El Salvador mine site coordinates.

242

ES-12781 UTM: 444,247E 7,097,210N MINE: 21346N 8274W Elev: 2616m Sample of R porphyry collected on the west upper bench of the M Gulch pit. Quenched contact with late collapse breccia with a dark grey groundmass, and phenocrysts of quartz, plagioclase and biotite.

ES-12782 UTM: 444,306E 7,097,266N MINE: 21376N 8189W Elev: 2579m Sample of R porphyry from the center of the M Gulch pit. Coarser grained with rounded quartz phenocrysts, plagioclase, biotite, and hornblende with fine-grained disseminated pyrite. Propylitically altered with biotites altering to chlorite. One of the samples analyzed by SHRIMP-RG for zircon U/Pb geochronology.

ES-12783 UTM: 444,568E 7,097,125N MINE: 21255N 7935W Elev: 2630m Sample of A porphyry along the eastern edge of the M Gulch pit near contact with M Gulch – Copper Hill L porphyry. Sample has a dark mafic groundmass with plagioclase, biotite, and hornblende pheocrysts. One of the samples analyzed by SHRIMP-RG for zircon U/Pb geochronology.

ES-12785a UTM: 444,410E 7,096,410N MINE: 19832N 7744W Elev: 2440m Sample of K porphyry collected in the Inca Norte 2440 level of the subterranean mine. Fine grained groundmass with pheoncrysts of plagioclase, quartz, and biotite with potassic alteration. One of the samples analyzed by SHRIMP-RG for zircon U/Pb geochronology.

ES-12786 UTM: 444,400E 7,096,418N MINE: 19840N 7760W Elev: 2440m Sample of L porphyry collected near contact with K porphyry sample ES-12785a in the Inca Norte 2440 level of the subterranean mine. Sample is coarse-grained near equigranular with phenocrysts of quartz, plagioclase, biotite, and amphibole.

ES-12787 UTM: 444,390E 7,096,420N MINE: 20030N 7856W Elev: 2440m Sample of the same L porphyry collected further up the tunnel from previous sample. One of the samples analyzed by SHRIMP-RG for zircon U/Pb geochronology.

ES-12789a UTM: 443,412E 7,094,339N MINE: 20058N 7844W Elev: 2454m Sample of L porphyry collected in Granite Gulch. Sample has a fine-grained groundmass with phenocrysts of quartz, plagioclase, biotite, and amphibole. Sample was run as a repeat (R) in analytical runs. One of the samples analyzed by SHRIMP-RG for zircon U/Pb geochronology.

ES-12789b UTM: 443,412E 7,094,339N MINE: 20058N 7844W Elev: 2454m Quartz-sericite-hematite breccia in contact with the previous L porphyry sample.

ES-12790 UTM: 444,864E 7,097,558N MINE: 21382N 7679W Elev: 2657m Sample of L porphyry collected from Copper Hill, with plagioclase and biotite phenocrysts in a dark gray aplitic groundmass. The sample contains fine-grained yellow montmorillonite and slight supergene clay alteration. 243

ES-12791 UTM: 444,950E 7,098,730N MINE: 21996N 7336W Elev: 2711m Sample of late quartz porphyry collected on the southwest upper bench of Old Camp that was collected from a narrow dike that cut andesite and quartz porphyry breccias. Contains feldspar and quartz pheonocrysts within a highly clay altered fine-grained groundmass.

ES-12792 UTM: 443,800E 7,096,245N MINE: 19259N 8320W Elev: 2476m Sample of latite dike collected within the Inca centro oeste 2476 level of the El Salvador subterranean mine. Sample was collected from the center of a 20 meter long dike that cuts the X porphyry. It contains plagioclase and rare hornblende and quartz pheoncrysts within a pilotaxitic groundmass. One of the samples analyzed by SHRIMP-RG for zircon U/Pb geochronology.

ES-12793 UTM: 443,780E 7,096,240N MINE: 19251N 8313W Elev: 2476m Sample of latite dike collected within the Inca centro oeste 2476 level of the El Salvador subterranean mine along contact with X porphyry. Sample collected from same dike as sample ES-12792.

ES-12794 UTM: 444,822E 7,096,245N MINE: 19259N 8355W Elev: 2476m Sample of X porphyry collected within the Inca centro oeste 2476 level of the El Salvador subterranean mine. Porphyry sample cut by the latite dike contains equigranular plagioclase, quartz, potassium feldspar, and biotite in a fine-grained groundmass. High density quartz/pyrite D-veins present within the sample. Strongly potassic altered and returned high LOI and low XRF totals was not used in thesis chapters.

ES-12795 UTM: 444,820E 7,096,400N MINE: 20008N 8181W Elev: 2500m Sample of X porphyry collected within the Inca centro oeste 2500 level of the El Salvador subterranean mine. Sample is strongly mineralized including digenite. Only sample of X porphyry to yield low LOI totals and presented within thesis.

ES-12796 UTM: 444,860E 7,096,470N MINE: 20078N 8128W Elev: 2500m Sample of L porphyry collected within the Inca centro oeste 2500 level of the El Salvador subterranean mine. Near equigranular porphyry that contains plagioclase, quartz, and biotite pheoncrysts. Sample also contains mafic enclaves.

ES-12798 UTM: 445,191E 7,097,912N MINE: 21997N 7348W Elev: 2725m Sample of tourmaline breccia collected from M Gulch on same bench as sample ES-12791. Sample contains angular to subangular andesite and porphyry clasts within a fine-grained tourmaline matrix. Sample not used in thesis chapters.

ES-12800 UTM: 444,806E 7,098,950N MINE: 21290N 7639W Elev: 2700m Sample of L porphyry collected from M Gulch – Copper Hill above the A porphyry sample ES-12783. One of the samples analyzed by SHRIMP-RG for zircon U/Pb geochronology. 244

ES-12804 UTM: 443,560E 7,096,890N MINE: 20086N 8720W Elev: 2577m Sample of L porphyry collected from diamond drill hole 8261 from 134.5 to 136.8 m. Rock is comprised euhdral plagioclase and amphibole phenocrysts in a fine-grained dark grey groundmass.

ES-12807 UTM: 443,780E 7,095,770N MINE: 19198N 8426W Elev: 2384m Sample of K porphyry collected from diamond drill hole 1367 from 269 to 286 m. One of the samples analyzed by SHRIMP-RG for zircon U/Pb geochronology. Rock is comprised of amphibole, quartz, and plagioclase phenocrysts set in an aplitic plagioclase groundmass.

ES-12808 UTM: 445,110E 7,098,940N MINE: 22276N 7070W Elev: NA Sample of quartz porphyry collected from the base of the Old Camp pit. The sample contains quartz, plagioclase, and biotite phenocrysts in a microcrystalline groundmass. One of the samples analyzed by SHRIMP-RG for zircon U/Pb geochronology.

ES-12809 UTM: 443,877E 7,096,168N MINE: 19573N 8378W Elev: 2585m Sample of latite dike collected from diamond drill hole 8485 at 76 m. The rock is comprised of plagioclase and hornblende pheoncrysts within a pilotaxitic groundmass.

ES-12810 UTM: 443,884E 7,096,184N MINE: 19589N 8371W Elev: 2581m Sample of X porphyry collected from diamond drill hole 8485 at 93.6 m. Sample was highly potassicly altered and was not used in thesis. The rock is comprised of euhedral plagioclase phenocrysts set in a fine-grained equigranular groundmass.

ES-12811 UTM: 443,930E 7,095,950N MINE: 19355N 8325W Elev: 2573m Sample of X porphyry collected from diamond drill hole 8480 from 168.1 to 170 m. One of the samples analyzed by SHRIMP-RG for zircon U/Pb geochronology. The rock is comprised of euhedral plagioclase phenocrysts set in a fine-grained equigranular groundmass and is cut by quartz-pyrite veins with 6mm sericite halos.

ES-12812 UTM: 443,977E 7,096,131N MINE: 19526N 8278W Elev: 2578m Sample of latite dike collected from diamond drill hole 8471 at 135.2 m. The rock is comprised of plagioclase and hornblende pheoncrysts within a pilotaxitic groundmass.

ES-12813 UTM: 443,929E 7,096,123N MINE: 19518N 8326W Elev: 2586m Sample of X porphyry collected from diamond drill hole 8471 at 85.8 m. Sample was potassicly altered and was not used in thesis. The rock is comprised of euhedral plagioclase phenocrysts set in a fine-grained equigranular groundmass.

245

ES-12814 UTM: 444,218E 7,098,730N MINE: 19833N 8037W Elev: 2602m Sample of L porphyry collected from diamond drill hole 411 at 65.4 m. Rock is comprised euhdral plagioclase and amphibole phenocrysts in a weakly altered light grey aplitic groundmass.

246

Table A1. El Salvador whole rock X-ray fluorescence analyses. Sample ES-12781 ES-12782 ES-12783 ES-12785a ES-12786 ES-12787 Rock Type R ppy R ppy A ppy K ppy L ppy L ppy Major Elements (Weight %):

SiO 2 58.22 63.43 57.26 66.62 63.54 65.83

TiO 2 1.051 0.550 0.985 0.559 0.745 0.658

Al 2O3 16.80 16.37 18.77 14.36 17.33 16.37 FeO* 7.26 3.98 6.36 2.32 3.41 2.95 MnO 0.161 0.141 0.029 0.012 0.011 0.030 MgO 0.77 1.39 2.42 1.27 1.42 1.29 CaO 3.57 0.42 1.60 2.66 4.18 3.81

Na 2O 4.52 2.55 5.37 4.24 5.40 4.89

K 2O 2.04 7.22 1.82 3.68 1.77 2.39

P 2O5 0.331 0.198 0.326 0.170 0.235 0.202 Sum 94.72 96.26 94.94 95.89 98.04 98.43 LOI (%) 3.94 2.63 3.51 2.58 0.89 0.82

SO 3 ≥ 0.21 0.35 0.18 1.01 0.43 0.20

Trace Elements (ppm): Ni 24 6 9 6 6 7 Cr 11 5 7 6 7 8 Sc 7 5 10 5 5 5 V 113 72 139 72 88 73 Ba 496 1652 352 588 496 549 Rb 38 150 81 74 61 53 Sr 659 229 488 453 739 640 Zr 145 111 139 104 146 121 Y 9 11 32 6 8 8 Nb 7.6 5.6 5.7 5.4 6.5 6.3 Ga 23 18 23 18 22 21 Cu 49 80 3703 722 319 239 Zn 815 234 233 24 15 29 Pb 6 13 6 3 2 3 La 22 13 15 12 16 19 Ce 44 34 30 27 38 38 Th 1 2 2 2 2 3 Nd 24 15 17 13 20 18

Bi 1 0 0 2 2 1 Cs 14 2 11 3 2 3 As ≥ 4 6 2 1 0 4 sum Trace 2512 2662 5302 2145 2001 1847 Trace wt. % 0.25 0.27 0.53 0.21 0.20 0.18 sum m+tr 94.97 96.52 95.47 96.10 98.24 98.61 M+Toxides 95.02 96.57 95.60 96.15 98.28 98.65 with SO 3 95.24 96.92 95.78 97.15 98.71 98.85 247

Table A1. cont. Sample ES-12789a ES-12789aR ES-12789b ES-12790 ES-12791 ES-12792 ES-12793 Rock Type L ppy GG L ppy GG Breccia L ppy Late Qtz ppy Latite dike Latite dike Major Elements (Weight %):

SiO 2 61.99 61.65 75.64 61.63 66.84 60.08 62.90

TiO 2 0.745 0.739 0.228 0.869 0.597 0.881 0.774

Al 2O3 17.08 16.93 16.32 18.26 19.22 16.09 15.87 FeO* 5.54 5.59 1.22 3.63 0.98 3.85 3.61 MnO 0.033 0.033 0.011 0.023 0.001 0.063 0.025 MgO 1.73 1.71 0.13 2.62 0.11 1.62 1.63 CaO 3.46 3.42 0.27 2.47 0.29 5.11 2.63

Na 2O 4.98 4.95 0.68 5.73 3.91 4.33 3.24

K 2O 1.91 1.90 2.86 2.65 1.14 2.01 2.57

P 2O5 0.276 0.275 0.024 0.089 0.122 0.268 0.233 Sum 97.75 97.19 97.38 97.97 93.21 94.31 93.49 LOI (%) 1.13 1.13 2.31 1.15 6.38 4.96 5.13

SO 3 ≥ 0.10 0.08 0.01 0.10 0.17 0.09 0.65

Trace Elements (ppm): Ni 13 12 2 10 0 13 12 Cr 7 8 13 13 3 10 8 Sc 7 7 5 11 5 7 7 V 103 102 24 119 65 100 100 Ba 511 501 423 268 147 524 459 Rb 65 64 71 138 38 34 54 Sr 629 625 305 572 466 675 475 Zr 133 132 182 119 119 127 120 Y 11 11 10 8 8 8 8 Nb 6.1 5.7 22.5 6.1 7.2 6.7 5.5 Ga 21 22 18 23 21 22 18 Cu 1242 1223 193 1461 66 40 1107 Zn 201 198 29 171 21 75 168 Pb 7 9 12 3 5 3 32 La 20 17 15 19 14 20 15 Ce 39 38 24 38 33 41 33 Th 1 2 15 1 4 1 1 Nd 18 18 9 16 18 22 18

Bi 1 2 1 1 5 1 0 Cs 6 3 6 11 1 3 7 As ≥ 0 3 6 0 14 7 9 sum Trace 3042 3003 1387 3007 1059 1740 2656 Trace wt. % 0.30 0.30 0.14 0.30 0.11 0.17 0.27 sum m+tr 98.05 97.49 97.52 98.27 93.32 94.48 93.76 M+Toxides 98.12 97.56 97.55 98.34 93.34 94.52 93.82 with SO 3 98.22 97.63 97.56 98.44 93.51 94.61 94.47 248

Table A1. cont. Sample ES-12794 ES-12795 ES-12796 ES-12798 ES-12800 ES-12804 ES-12807 Rock Type X ppy X ppy L ppy Tm Bx L ppy L ppy K ppy Major Elements (Weight %):

SiO 2 56.09 57.33 62.67 61.89 63.22 60.66 64.19

TiO 2 0.872 0.843 0.727 0.486 0.650 0.752 0.582

Al 2O3 15.28 18.28 16.61 15.01 17.20 16.67 14.85 FeO* 5.01 2.66 3.21 6.18 3.72 5.65 3.10 MnO 0.016 0.009 0.029 0.016 0.027 0.019 0.011 MgO 1.67 1.88 1.49 2.27 1.67 1.44 1.47 CaO 4.54 5.46 3.82 0.59 1.80 2.56 4.00

Na 2O 3.69 5.62 4.81 1.75 5.87 3.97 4.35

K 2O 2.17 1.92 2.20 0.14 2.41 3.44 1.25

P 2O5 0.250 0.302 0.232 0.100 0.181 0.242 0.173 Sum 89.60 94.32 95.80 88.42 96.75 95.41 93.99 LOI (%) 6.98 2.83 2.55 10.06 2.05 2.80 3.99

SO 3 ≥ 2.29 2.09 1.03 0.68 0.12 0.61 1.45

Trace Elements (ppm): Ni 12 6 6 7 7 11 6 Cr 9 4 4 13 4 7 5 Sc 8 9 6 9 8 5 5 V 116 112 86 127 95 105 96 Ba 342 305 611 64 476 706 521 Rb 41 68 49 3 90 126 26 Sr 804 757 627 455 463 551 557 Zr 106 152 121 99 125 131 113 Y 11 11 7 17 14 8 8 Nb 5.2 5.0 5.6 8.3 5.7 6.9 5.1 Ga 15 21 21 21 21 22 20 Cu 3060 2163 518 302 3714 2464 407 Zn 35 20 50 31 187 161 22 Pb 4 3 4 12 10 4 3 La 18 15 17 17 19 37 17 Ce 34 33 36 25 45 71 36 Th 1 0 2 4 2 2 1 Nd 17 15 19 10 18 30 16

Bi 0 2 1 15 0 1 1 Cs 1 2 4 3 6 12 0 As ≥ 5 0 1 130 3 3 2 sum Trace 4642 3701 2195 1373 5313 4461 1865 Trace wt. % 0.46 0.37 0.22 0.14 0.53 0.45 0.19 sum m+tr 90.07 94.69 96.02 88.56 97.28 95.85 94.17 M+Toxides 90.18 94.77 96.06 88.59 97.41 95.95 94.21 with SO 3 92.47 96.86 97.09 89.27 97.53 96.57 95.66 249

Table A1. cont. Sample ES-12808 ES-12809 ES-12810 ES-12811 ES-12812 ES-12813 ES-12814 Rock Type Qtz ppy Latite dike X ppy X ppy Latite dike X ppy L ppy Major Elements (Weight %):

SiO 2 81.14 60.61 61.01 61.92 58.86 62.32 64.06

TiO 2 0.126 0.843 0.804 0.802 0.851 0.817 0.791

Al 2O3 5.38 16.18 21.12 22.12 15.72 19.13 17.91 FeO* 2.60 6.15 3.14 1.78 6.98 4.99 3.12 MnO 0.011 0.061 0.000 0.000 0.071 0.000 0.013 MgO 0.23 1.17 0.28 0.18 0.91 0.10 1.53 CaO 0.06 3.38 0.06 0.06 3.19 0.05 2.95

Na 2O 0.58 4.23 0.33 0.13 4.22 0.31 5.28

K 2O 3.26 2.12 3.22 1.59 2.05 2.15 1.89

P 2O5 0.026 0.258 0.154 0.192 0.254 0.317 0.248 Sum 93.41 95.00 90.11 88.77 93.12 90.18 97.79 LOI (%) 4.27 3.81 8.95 10.31 5.83 8.88 1.56

SO 3 ≥ 0.63 0.27 0.27 0.26 0.07 0.29 0.05

Trace Elements (ppm): Ni 3 16 7 13 14 1 9 Cr 5 12 5 6 9 9 8 Sc 2 5 9 7 7 4 6 V 19 92 147 94 99 77 92 Ba 600 562 408 273 525 233 532 Rb 35 36 67 38 39 38 53 Sr 43 571 188 477 575 209 659 Zr 29 128 131 139 125 134 145 Y 4 7 5 7 8 5 9 Nb 2.3 6.3 5.5 6.9 6.6 5.4 6.6 Ga 6 23 19 20 22 5 22 Cu 10517 87 1468 2403 48 11 342 Zn 39 218 21 51 137 10 43 Pb 4 8 4 3 5 1 4 La 5 16 12 24 18 14 20 Ce 11 45 25 62 37 30 41 Th 1 1 2 4 1 1 3 Nd 6 20 14 30 18 14 20

Bi 4 2 0 0 1 0 0 Cs 1 4 4 1 7 0 1 As ≥ 19 5 1 18 7 0 1 sum Trace 11352 1863 2540 3676 1706 801 2016 Trace wt. % 1.14 0.19 0.25 0.37 0.17 0.08 0.20 sum m+tr 94.54 95.19 90.37 89.14 93.29 90.26 98.00 M+Toxides 94.82 95.23 90.43 89.23 93.32 90.28 98.04 with SO 3 95.45 95.50 90.70 89.50 93.39 90.57 98.09 250 Tm Tm Yb Lu 49 0.09 0.22 0.03 0.20 0.03 analyses from same powder solution. powder same from analyses 64 1.72 1.62 0.29 0.27 0.63 0.640 0.08 0.08 1.58 0.49 0.50 0.30 0.07 0.08 0.8142 0.12 2.324 2.12 0.847 0.42 1.60 0.39 0.14 2.77 1.007 0.27 0.984 0.55 0.14 1.70 0.624 0.14 1.68 1.52 0.85 0.28 0.08 0.77 0.79 0.27 0.23 0.13 0.62 0.497 0.14 0.12 0.66 1.54 0.08 0.07 1.20 0.388 0.09 0.27 0.482 0.19 0.06 0.88 0.52 0.07 2.03 0.48 0.34 0.15 0.08 0.33 0.07 0.06 0.36 0.77 0.43 0.05 0.10 0.07 0.36 0.56 0.06 0.09 2 1.9692 0.32 2.16 7.04 0.74 0.39 1.32 0.09 1.03 3.24 0.49 0.15 0.43 0.08 0.88 2.35 0.14 0.33 26 1.30 0.22 0.54 0.07 0.42 0.07 47 2.80 0.55 1.54 0.24 1.50 0.23 .31.45 1.47 2.29.23 0.24 0.42 1.47 0.55 1.02 0.33 0.07 0.14 1.01 0.43 0.85 0.17 0.07 0.14 1.10 0.18 .43 2.02.26 0.33 7.22 0.75 1.33 0.10 3.24 0.53 0.43 0.08 2.40 0.33 0.27 1.31 0.22 0.56 0.08 0.43 0.07 6 0.45 2.29 0.43 1.03 0.14 0.88 0.14 .04.58 0.36 0.33 1.75 1.61 0.29 0.28 0.65 0.69 0.09 0.10 0.51 0.58.86 0.07 0.09 0.35.96 1.71 0.36 0.28 1.67 0.62 0.29 0.08 0.66 0.48 0.08 0.07 0.47 0.07 5.58 0.66 2.66 0.36 0.76 0.10 0.59 0.10 04 2.57 0.32 1.61 0.28 0.69 0.10 0.57 0.09 . 1 analyses from separate from powder solution.analyses ®1 repeat- All analyses given in partsin per given million. analyses All repeat ® - Table A2: ElTable A2: analyses Salvador wholeICP-MS rock LEE LEE ES-12787 LEE ES-12787® LEE ES-12789a ppy L ppy L LEE ES-12789a® ppy L ppy L LEE ES-12789b LEE ES-12790 Breccia 19.97 LEE ES-12791 18.02 40.90 LEE ES-12792 ppy L 37.03 19.15 19.27 LEE ES-12793 Qtz ppy Late 37.95 5.06 38.27 4.65 14.40 LEE ES-12793®1 dike Latite 14.26 19.98 18.26dike Latite 4.78 LEE ES-12794 22.58 dike Latite 4.84 32.54 19.65 LEE ES-12795 19.40 19.25 19.47 3.83 2.48 3.50 38.58 LEE ES-12796 16.48 ppy X 4.46 16.49 40.41 4.02 LEE ES-12798 1.13 ppy X 4.03 8.60 1.03 34.61 19.28 34.70 4.66 5.22 LEE ES-12800 ppy L 1.09 2.73 1.09 17.19 4.41 2.57 1.90 4.42Bx Tm 21.37 6.07 15.23 17.87 LEE ES-12807 3.24 ppy L 0.3 17.74 3.2 0 0.33 2.97 2.00 15.06 34.63 4.22 LEE ES-12808 0 3.54 16.26 31.80 3.55 LEE ES-12809 1.01 1.49 ppy K 4.73 14.52 1.22 34.78 LEE ES-12810 Qtz ppy 1. 4.15 1.03 0 2.22 23.19 19.87 26.92 LEE ES-12811 3 dike Latite 4.52 17.83 44.87 LEE ES-12812 2 0.3ppy X 3.06 4.21 18.50 18.16 LEE ES-12813 ppy X 19.19 5.42 11.47 3.72 5.03 37.17 1.15 LEE ES-12814 dike Latite 40.05 3.75 20.61 10.54 1.22 ppy X 2.94 4.61 3.27 5.14 1.16 ppy L 4.66 18.69 1.34 4.01 2.99 18.33 1.24 14.51 0.4 20.81 39.15 2.71 9.85 1.35 5.25 31.31 0.4 3.26 3.61 11.78 4.00 5.08 0.3 1.29 3.11 4.17 1.17 0.4 22.08 24.73 0.99 20.68 1.18 17.55 5.27 0. 45.69 0.31 3.12 2.75 4.05 2 3.88 5.76 12.22 1.10 1.00 0.3 1.21 22.89 1.01 0.33 0.1 2.25 2 4.51 2.46 0.82 0.66 1.36 0.2 0.11 1.50 3.42 0. 0.1 0.4 LEE LEE ES-12785a® ppy K LEE ES-12786 ppy L 11.47 25.56 17.54 3.39 38.68 13.91 5.06 2.80 20.72 0.83 4.08 2.10 1.24 2.96 LEE ES-12804 0.3 ppy L 40.02 73.09 8.12 29.35 4.97 1.47 3.32 0.3 Sample IDSample type Rock La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er LEE LEE ES-12781 LEE ES-12781® LEE ES-12782 ppy R ppy R LEE ES-12783 LEE ES-12783® ppy R LEE ES-12785a ppy A ppy A 20.30 21.38 ppy K 43.69 45.79 14.58 5.76 5.97 15.37 15.71 30.53 24.15 24.66 32.98 33.13 12.67 3.86 4.33 4.91 26.73 4.27 4.90 15.51 18.42 18.44 1.42 3.43 1.46 3.32 13.76 5.08 3.43 5.19 3.41 1.06 2.03 2.76 0.4 2.09 0 2.71 7.27 0.84 7.28 0.3 1.2 1.99 1 0. 1 251 Zr 464 6.3 110 1 11.76 653 5.4 135 24 4.82 2.24 724 616 4.2 3.9 131 104 5 2.84 6196 4.7 1.44 113 552 4.4 84 83 2.01 1.407 1266 371 0.88 7.0 4.42 5.3 194 103 641 102 3.9 5.3 85 109 9 0.25 440 9.7 92 .4 9.08.3 498 2.85 8.4 447 135 3.6 92 .7 10.02 562 10.3 113 .5.7 1.90 4.32 778 749.3 7.6 6.9 9.80 99 141 561 4.4 123 7.8 12.56 656 7.6 141 3.7 4.03 632 5.1 95 0.0 4.426.2 471 0.44 7.2 44 118 1.4 26 88.9 12.3277.6 481 2.94 11.2 48764.0 136 4.8 4.96 624 81 6.4 121 analyses from same powder solution. same from analyses 149.0 2.97 227 4.1 98 74 63.8 4.97 626 6.7 124 .79 70.2 4.17 298 3.8 169 .86 32.5 2.62 656 6.1 120 .35 34.3.96 2.19 38.2 573 9.98 5.5 567 124 5.7 117 4.16 36.9 1.27 452 4.6 96 6.23 51.5 5.94 463 6.3 109 analyses from separate powderfrom solution. analyses repeat ®1 - Latite dikeLatite 461 1.85 6.29 7.09 3.15 0.42 0.80 36.03 51.9 5.97 All analyses given in parts in pergiven million. analyses All repeat ® - Table Cont. Table A2: LEE LEE ES-12783ppy A 345 1.73 6.48 31.99 3.57 0.42 1.71 7.79 81 LEE LEE ES-12782 R ppy LEE ES-12783 ®ppy A LEE ES-12785a®K ppy 1671 345 2.83 LEE ES-12789a 1.75 627 6.42 ppy L 10.22 6.85 2.48 2.93 31.14 LEE ES-12790 5.84 LEE ES-12791 0.58 3.53ppy L 6.00 LEE ES-12792 505 1.15Qtz ppy Late 0.44 2.35 dike Latite 15.43 3.19 1.71 146 0.46 6.37 7.83 269 0.48 3.04 10.90 535 3.21 5.63 3.48 7.76 1.82 7.36 6.35 0.48 7.04 7.59 2.85 1.01 7.35 3.24 0.69 9.80 3.46 2.02 0.48 0.43 0.73 0.77 4.95 4 134 LEE LEE ES-12781 LEE ES-12781 ® R ppy R ppy LEE ES-12785a 486 500 Kppy LEE ES-12786 1.66 1.71 LEE ES-12787ppy L 7.54 LEE ES-12787 ® 7.85ppy L ppy L 8.27 8.51 588 LEE ES-12789a®L ppy 3.80 3.96 2.64 LEE ES-12789b 500 Breccia 0.46 0.48 6.09 545 534 0.65 2.68 0.63 5.81 3.49 510 2.96 7.68 8.82 7.12 LEE ES-12793 2.69 435 7.01 3.32 7.26 6.49 36. dike Latite 3 0.47 15.20 7.01 6.29 3.70 6.40 0.54 22.81 10.99 3.23 2.82 0.51 460 5.15 9.01 3.53 0.54 0.69 0.47 1.88 5.75 73 1.43 0.49 0.96 3.39 1.71 6.27 1.01 4.05 4.54 60. 2.59 7.06 9. 49. 6 12 3.12 0.42 0.82 3 Sample IDSample Rock type Ba Th Nb Y Hf Ta U LEE ES-12793 ®1 Pb Rb Cs Sr Sc LEE LEE ES-12794 Xppy LEE ES-12798 LEE ES-12800Bx Tm ppy L 326 LEE ES-12808 1.39 Qtzppy 59 5.74 10.67 480 4.92 2.69 2.81 8.20 589 0.38 16.05 6.93 1.86 13.75 0.63 2.74 3.36 5.15 3.35 0.73 4.00 0.54 39 2.81 1.46 0.96 12.22 11.76 0.36 1. 9 0.41 4.76 3 LEE LEE ES-12795 LEE ES-12796 Xppy ppy L LEE ES-12804 LEE ES-12807ppy L 304 Kppy 609 LEE ES-12809 1.72 2.34 dike Latite 5.37 10.16 708 6.65 517 3.56 6.97 557 2.26 1.87 3.25 0.37 1.80 6.39 0.35 5.92 0.47 6.89 7.03 7.58 0.59 4.49 6.73 3.49 2.60 5.47 66 3.64 0.49 0.41 2.13 48. 0.45 0.38 0.78 5.30 3.20 127 8 24. LEE LEE ES-12810 LEE ES-12811 Xppy LEE ES-12812 Xppy LEE ES-12813 dike Latite LEE ES-12814 Xppy ppy L 363 516 253 0.92 1.78 1.89 220 5.89 6.84 531 7.26 1.65 0.98 7.02 4.06 2.78 2.95 5.86 3.40 2.96 7.17 0.40 3.40 0.44 0.50 8.69 0.46 2.46 0.78 0.50 3.18 4.44 0.39 5 3.99 0.50 0.57 51. 0.78 30. 2.08 4.65 35. 51. 1 252

Appendix B

SHRIMP-RG analytical procedures and results

Fourteen samples were collected from the El Salvador district for zircon analysis via SHRIMP-RG technique. Zircons were separated by crushing the rock in a steel jaw crusher, and then pulverizing to powder using a steel disk grinder at the El Salvador mine. The powders were then sieved to <500 micron size and the heavy mineral fraction was concentrated using a Wilfley table, and then separated using a magnetic Frantz isodynamic separator at the Oregon State University mineral separation laboratory.

Euhedral, well-formed zircons were hand-picked under a binocular microscope. Lab procedures emphasize careful cleaning (with air, water, soap, alcohol), between samples to assure minimal possibilities of cross-sample contamination.

Zircons were mounted in a 2.54 cm diameter epoxy plug together with Stanford

USGS in house zircon standards. The plugs were polished to expose grain centers and photographed in reflected light and using a cathodoluminescence (CL) detection system at the Stanford University with a JEOL JSM 5600 scanning electron microscope operating at 15 kv accelerating potential. The CL images were used to screen the zircons;

“Cl-dark” areas of high uranium content were selected for analysis due to the low uranium content in the El Salvador samples. All zircon CL images and SHRIMP-RG spot locations are given in CD Appendix I. CL-images of the zircon in each sample display a range of textures including oscillatory growth zones, sector zoning, and rounded cores. In the current study, zircon rims displaying regular concentric (oscillatory) growth zones were sampled and interpreted to represent normal magmatic crystallization where zircon is saturated within the melt. Identifiable truncated or resorbed cores were typically 253 avoided although they were sometimes sampled in cases where the core represented the only “dark” portion of the grain. Inherited cores with ages >45-41 Ma were sampled but represent <5% of all spots analyzed.

SHRIMP-RG analyses

The U-Th-Pb and trace element concentrations of zircons were analyzed using a

SHRIMP-RG at the Stanford USGS Micro Analysis Center (SUMAC) housed at Stanford

University and jointly owned and operated by the U.S. Geological Survey. Samples were run over three sessions from February 2007 to February 2008. The zircon mount was Au coated and placed in the sample chamber where an 8nA 16 O2-primary ion beam removed surface contamination and the gold coat prior to collection of positive secondary ions. The U-Th-Pb ratios were corrected using the standard zircon R33 which has a 419 ±

1 Ma age and was analyzed approximately every fourth analysis during the run. Six mass

90 16 204 206 207 208 238 232 16 238 16 scans of peaks at Zr 2 O, Pb, Pb, Pb, Pb, U, Th O, and U O were collected for each analysis with beam tuning and centering conducted on the 238 U16 O peak. Count times of 8s and 24s were used for 206 Pb and 207 Pb respectively with average counts determined over the six scans per run.

Trace element concentrations were simultaneously analyzed and were corrected using an in house zircon standard Madagascar Green which was analyzed five to six times over the course of a twenty-four hour run. Concentrations of elements were derived from mass analyses of: 139 La, 140 Ce, 146 Nd, 147Sm, 153 Eu, 155 Gd, 163 Dy 16 O,

166 Er 16 O, 172 Yb 16 O, 180 Hf 16 O and were analyzed with 1 to 2 second count times averaged over six counting sequences. Analyses of Pr is considered unreliable due to peak 254 interference from 140 Ce 1H, Pr concentration is calculated by normalizing to ⅓ La concentration and ⅔ Nd concentration.

During the final session (February 2008) three samples (ES-12785a, ES-12783, and ES-12792) were reanalyzed for the entire trace element suite currently available for analysis on the SHRIMP-RG using masses: 7Li, 9Be, 11 B, 19 F, 23 Na, 24 Mg, 27 Al, 30 Si, 31 P,

32 S, 35 Cl, 39 K, 40 Ca, 45 Sc, 48 Ti, 49 Ti, 51 V, 52 Cr, 55 Mn, 56 Fe, 74 Ge, 89 Y, 93 Nb, 93Zr 1H, 96 Zr,

139 La, 140 Ce, 141 Pr, 146 Nd, 147 Sm, 153 Eu, 165 Ho, 157 Gd 16 O, 159 Tb 16 O, 163 Dy 16 O, 166 Er 16 O,

169 Tm 16 O, 172Yb 16 O, 175 Lu 16 O, 180 Hf 16 O, and Pb 206 . 49 Ti was selected for calculation of concentrations due to the 96 Zr peak interference with 48 Ti. Each mass peak was normalized to the 30 Si count rate to minimize instrumental drift and sputtering effects.

Normalized count rates were calibrated to the Madagascar green standard. Aluminum, calcium, and iron count rates were monitored to determine any contamination by inclusions or altered zones in zircon. Analytical results for both U/Pb and trace element concentrations are given in Table B1 and in CD Appendix II.

255 1 4 .6 .5 .4 .6 .5 .3 .4 0.6 0.3 0.5 0.5 0.7 err σ 1 U U 238 ppmppm Hf Pb / Age (Ma) Age 206

% % err Pb 206 Pb/ 207 % % err U 238 Pb/ 206 Pb C-Pb 206 r zircon zircon separates r Pb/ 207 U (ppm) Th (ppm) Pb 206 (ppm) La ppmppm Ce Ndppm ppm Sm ppm Eu Gdppm ppm Dy Erppm Yb Rad Sample # Sample Table B1. SHRIMP-RG analytical data from El Salvado El from data analytical SHRIMP-RG B1. Table ES ES 12808-1 ES 12808-2 ES 12808-3 ES 12808-4 ES 12808-5 1.93 ES 12808-6 2.07 ES 12808-7 3.11 ES 12808-8 0.61 351 ES 12808-9 3.54 362 ES 12808-10 1.21 515 ES 12808-11 6.53 101 ES 12808-12 1.84 230 610 ES 12808-13 4.17 222 1.80 203 1112 573 1.69 0.83821 0.27 0.83835 317 ES 12808-1 96 572 0.88 0.83851 700 ES 12808-2 0.00640 303 114 ES 12808-3 0.00667 994 0.83837 295 0.83839 ES 12808-4 0.00703 325 0.83842 45 ES 12808-5 0.17 0.83843 148 0.00706 274 ES 12808-6 1.4 0.00676 0.33 290 0.83838 ES 12808-7 1.3 0.00694 0.02 386 0.00683 0.83847 ES 12808-8 1.1 0.04 50.54 0.83845 0.0601 ES 12808-9 18 0.00675 0.03 106 52.30 0.83835 2.5 0.0532 ES 12808-10 0.8 0.00693 0.16 91.45 0.00693 0.0488 ES 12808-11 1.4 0.02 0.83840 37.96 0.83844 0.6 0.00667 1.10 117.39 ES 12808-12 0.0911 0.22 10.8 0.0524 1.22 ES 12808-13 1.1 0.02 32.04 0.00705 5.3 0.00693 0.0624 1.32 0.02 104.74 0.7 0.0479 4.5 1.1 1.22 0.04 4.28 64.94 2.32 1.2 40.5 0.0537 0.02 8.0 4.03 89.36 6.4 0.0499 0.53 0.02 35.34 42.5 4.38 0.0540 1.30 2.8 5.7 1.5 59.49 45.0 3.2 3.72 0.0521 12.01 2.21 7.94 8.71 42.9 5.2 1.81 0.99 31.73 43.1 0.0829 1.67 0.0555 0.60 3.5 2.42 5.26 0 43.7 7.2 2.82 17.71 43.8 2.39 0 5.5 59.5 3.64 0.26 43.0 47.5 4.39 0.71 1. 16.6 0.99 1.99 0 44.4 8.2 43.6 2.17 10.84 44.1 6.53 0 33.9 42.6 88.8 320 0.81 2.00 2.14 233 0 43.3 18.4 1.19 107.5 44.0 53.0 173 0 3.81 121 379 599 0.49 57.6 1.35 418 20.1 1 310 81 233 296 53.9 207 1032 630 7.7 23.4 315 731 79 512 155 394 536 182 11069 391 1053 11117 105 624 32 10952 146 936 307 687 297 11095 9126 1171 195 10808 12621 65 785 290 515 12841 379 10375 143 8750 9785 10458 256 3 4 6 8 7 9 0 .3 .3 .4 .3 err σ 1 U U 238 ppmppm Hf Pb / Age (Ma) Age 206

% % err Pb 206 Pb/ 207 % % err U 238 Pb/ 206 Pb C-Pb 206 Pb/ 207 U (ppm) Th (ppm) Pb 206 (ppm) La ppmppm Ce Ndppm ppm Sm ppm Eu Gdppm ppm Dy Erppm Yb Rad Sample # Sample Table B1. Cont. B1. Table ES ES 3239-1 ES 3239-2 ES 3239-3 ES 3239-4 ES 3239-5 0.99 ES 3239-6 6.70 ES 3239-7 0.45 ES 3239-8 4.12 ES 3239-9 170 0.85 1124 ES 3239-10 3.55 ES 3239-11 6.23 76 ES 3239-12 718 0.37 ES 3239-13 141 82 1.19 359 ES 3239-14 0.71 606 1042 ES 3239-15 0.78 0.83840 47 0.83848 126 0.65 68 0.48 206 63 120 ES 3239-1 0.00677 358 0.83843 0.00694 3.54 0.83838 420 141 ES 3239-2 4.95 0.83852 105 ES 3239-3 0.83842 0.00695 0.00668 35 0.83849 ES 3239-4 158 84 1.7 612 ES 3239-5 0.00705 42 0.6 0.00682 0.03 824 ES 3239-6 91 0.83821 0.00696 0.83838 0.01 ES 3239-7 41 0.83845 2.2 0.7 0.0504 0.02 0.0479 ES 3239-8 0.83827 0.00635 24 0.00673 653 0.02 30.40 1.7 ES 3239-9 0.83858 0.8 0.00688 0.06 373 80.63 ES 3239-10 0.0613 0.6 0.0456 0.00643 0.04 0.83839 15.08 0.83838 ES 3239-11 7.9 0.0481 0.00722 0.03 2.7 17.49 0.83850 ES 3239-12 0.0502 0.67 2.3 1.3 0.02 19.59 0.0458 ES 3239-13 0.00675 0.00672 0.73 1.8 0.02 94.16 9.5 ES 3239-14 3.3 0.00699 0.66 0.01 1.6 79.32 ES 3239-15 43.3 0.0556 44.5 0.0519 0.39 0.03 8.3 1.8 2.14 11.69 3.8 0.0470 0.49 0.01 2.8 3.34 43.55 2.2 0.8 0.0463 0.99 0.01 16.25 43.8 43.0 1.94 0.7 0.0520 0.77 0.04 23.28 10.6 2.44 0.8 45.2 0 6.1 1.37 0.30 0.02 11.83 43.6 0.0514 1.39 0.0494 9.0 44.8 1.03 0.86 11.21 3.71 0.0475 0.31 232.05 7.8 1.55 1.0 0. 3.41 1.84 128.07 40.3 8.6 0.81 43.0 23.7 0.94 0.37 0.8 10.1 0.92 0. 44.2 3.7 42.2 3.48 0.22 0 1.82 1.10 3.48 41.4 3.2 19.1 1.14 4.16 1.04 46.1 35.4 1.0 0.56 1.22 108 0. 43.1 14.2 43.1 1.92 0.70 228 0. 10.54 39.0 0.72 44.9 0. 40.8 2.29 75 4.43 277 0. 0.72 215 8.4 1. 40.2 66 0.40 6.72 0 442 10.9 175 0 30.0 2.01 210 145 563 10.9 433 104.9 43 182 132 7.1 839 320 55 61.8 101 392 293 1209 10596 52 12982 363 322 279 87 594 35 116 13831 7669 337 170 718 108 546 9107 10546 561 182 11186 255 75 652 324 10309 244 879 9129 10045 1166 178 9802 8895 9641 10969 10646 257

1 7 7 6 .5 .3 .5 .3 .7 71 0.4 0.5 0.3 0.3 0.3 0.6 0.5 0.5 0.3 err σ 1 U 6.9 0.2 238 ppm Hfppm Pb / Age (Ma) Age 206

%err Pb 206 Pb/ 207 %err U 238 Pb/ 206 Pb C-Pb 206 Pb/ 207 U U (ppm) Th (ppm) Pb 206 (ppm) Lappm ppm Ce Ndppm ppm Sm ppm Eu Gdppm ppm Dy Erppm Yb Rad Sample # Sample Table B1. Cont. B1. Table ES12791-1 ES12791-2 ES12791-3 ES12791-4 ES12791-5 0.04ES12791-6 0.02ES12791-7 0.05ES12791-8 0.02 40.48ES12791-9 0.02 39.91ES12791-10 0.03 85.09ES12791-11 0.05 24.43 0.46ES12791-12 0.02 26.99 0.41ES12791-13 0.02 22.94 0.08 1.41ES12791-14 62.72 0.03 0.29ES12791-15 31.89 1.49 0.02 0.35ES12791-16 13.73 1.92 0.02 0.38 20.35ES12791-17 5.06 0.02 0.98 75.42ES12791-18 0.88 0.03 0.35 0.82 53.35ES12791-19 1.26 0.02 0.32 0.85 22.60 1.14 0.25 0.04 1.86 83.69 5.55 0.76 0.03 0.42 34.95 1.36 16.4 0.54 0.02 0.60 33.08 1.04 24.9 0.36 0.54 47.05 0.82 53.7 1.45 155.73 2.11 3.66 0.39 8.9 0.59 80.54 2.14 13.2 0.41 69 0.83 1.16 149 0.76 0.43 9.8 6.27 1.44 267 73.9 1.40 1.28 13.3 1.59 1.00 44 1.31 127 10.8 0.75 62 302 3.40 8.9 1.77 6.81 514 39 43.9 451 0.55 8.63 25.4 0.68 70 248 13.4 87 140 1.68 50 595 67.8 2.87 46 983 235 900 13.0 75 2.35 129 11076 12.4 157 12875 195 318 37.3 58 102 13908 82.1 355 1583 104 458 106.7 159 59 237 11769 10658 361 53 185 108 218 13617 410 662 11211 237 870 680 118 11455 430 103 9372 345 216 1193 10603 746 12823 1318 11070 254 10558 231 13889 620 1279 2409 11730 11353 11328 1152 141 ES12791-1 ES12791-2 ES12791-3 ES12791-5 1.95ES12791-6 3.69ES12791-7 6.77ES12791-8 334ES12791-9 0.98 645ES12791-10 0.88 1148 5.55 1.08 250 174 0.48 235 1.67 151ES12791-14 814 0.83841 945 0.83836 193 0.83845 58 0.00678 86 288 5.11 98 0.00665 483 0.00687 0.83832 69 0.83839 0.83843 1.0 109 40 863 0.00659 0.8 0.83830 0.00675 0.8 0.00683 0.83840 0.83828 0.0478 0.00649 0.0486 338 0.0475 1.5 0.00678 0.00655 1.6 0.7 0.83845 5.1 0.0517 1.4 3.7 0.0487 2.8 1.1 0.00689 0.0478 2.0 0.0459 43.5 7.2 42.7 0.0520 0.0571 44.1 7.8 0.7 3.6 7.2 0 42.1 0 6.0 0.0489 8.8 43.3 43.9 41.8 0. 43.3 41.5 3.2 0. 0 0. 44.2 0.9 ES12791-4 1.21ES12791-11 216ES12791-12 ES12791-13 5.44ES12791-15 114 3.56ES12791-16 0.92ES12791-17 0.83830ES12791-18 931 1.57ES12791-19 610 1.61 0.00652 168 2.09 5.30 469 19.42 268 293 276 1.2 0.83842 357 95 0.83843 905 3093 127 0.00680 0.0498 0.83821 200 0.00679 220 0.83843 1220 0.00635 617 0.83840 0.83843 0.6 5.8 0.00682 0.83863 0.83842 0.8 0.00680 0.00682 1.6 0.0485 0.00731 0.00681 41.7 0.0439 1.2 1.2 0.0554 1.0 3.5 0.0463 0.3 0.7 0 3.8 0.0528 0.0470 7.1 0.0473 0.0502 43.6 6.2 43.8 6.8 40.4 5.1 1.6 3.4 43.8 43.4 43.8 0 4 43.6 258

4 9 1 6 .7 .9 .8 .7 .6 .6 .6 .7 .6 1.9 0.3 err σ 7809 1 6 1.2 U U 238 ppmppm Hf Pb / Age (Ma) Age 206

% % err Pb 206 Pb/ 207 % % err U 238 Pb/ 206 Pb C-Pb 206 Pb/ 207 U (ppm) Th (ppm) Pb 206 (ppm) La ppmppm Ce Ndppm ppm Sm ppm Eu Gdppm ppm Dy Erppm Yb Rad Sample # Sample Table B1. Cont. B1. Table ES ES 12811-1 ES 12811-2 ES 12811-3 ES 12811-4 ES 12811-5 0.13 ES 12811-6 0.06 ES 12811-7 0.03 ES 12811-8 0.02 57.99 ES 12811-9 0.02 77.82 ES 12811-10 0.05 7.22 ES 12811-11 0.02 24.08 9.33 ES 12811-12 0.15 36.66 10.68 220.85 ES 12811-13 0.01 0.05 ES 12811-14 0.24 8.22 0.01 0.38 18.61 ES 12811-15 32.32 28.22 0.01 0.46 ES 12811-16 14.75 12.84 0.01 29.58 0.72 0.01 31.72 10.82 0.41 1.12 18.36 0.01 0.45 14.47 37.24 1.42 0.02 0.22 25.66 0.58 20.38 112.8 0.44 0.50 172.3 1.08 0.65 16.99 26.80 1.34 0.51 0.71 56.62 0.70 0.37 1.69 0.22 261 1.51 5.4 0.72 305.9 10.9 0.20 419 0.59 1.31 15.7 0.58 0.38 1.22 0.81 0.84 0.97 368 0.82 838 537 8.2 20 13.3 0.72 45 2.20 0.61 67 6.4 18.9 0.41 16.3 632 1072 0.46 828 12.5 33 37 0.96 61 84 11.8 132 26 81 8.1 8701 1479 10.1 85 757 28.2 49 139 179 68 78 279 52 171 55 38 180 55 10688 141 12915 100 7732 331 157 100 373 128 388 75 11496 137 266 9166 227 11375 212 10996 10454 167 10764 347 493 12271 12222 11704 12991 ES ES 12811-1 ES 12811-2 ES 12811-3 ES 12811-4 ES 12811-5 0.97 ES 12811-6 0.55 ES 12811-7 0.14 ES 12811-8 1.05 166 ES 12811-9 1.37 ES 12811-10 1.62 97 ES 12811-11 0.32 24 175 ES 12811-12 0.97 248 235 ES 12811-13 0.51 5.58 275 ES 12811-14 144 0.88 0.83844 ES 12811-15 54 12 121 2.67 164 ES 12811-16 0.83831 123 1.08 0.00681 88 239 430 0.83822 0.76 0.83852 160 0.00654 1.48 0.83841 20 109 3.68 0.83843 0.00649 79 0.00701 180 1.6 0.00680 153 41 132 0.83848 0.00684 0.83844 2.1 67 86 0.84689 595 51 0.83837 0.0431 4.4 0.00693 1.6 0.00689 98 0.83825 1.5 0.0469 58 0.02712 0.84744 0.00670 1.3 0.0712 0.0434 0.83850 30 0.00644 305 8.5 0.0511 0.83836 2.4 0.02841 1.4 10.1 0.0492 0.00700 0.84388 0.83858 0.7 1.9 17.7 0.00671 0.0466 8.2 1.4 0.0518 44.0 0.01997 7.1 0.00720 1.0 42.0 0.0490 0.0512 6.4 1.4 40.5 0.0554 11.6 1.6 45.3 0.0482 6.6 0 43.4 1.2 0.7 0.0492 0 43.8 2.8 8.9 0.0536 1. 44.6 6.4 0 0.0495 0.0490 44.0 4.2 0 172. 6.5 42.8 0 7.2 41.0 1. 180.9 5.3 3.3 0. 44.9 0.8 42.8 0 127.3 46.1 0 0 1 259

err σ 1 U 238 ppmppm Hf Pb / Age (Ma) Age 206

% % err Pb 206 Pb/ 207 % % err U 238 Pb/ 206 Pb C-Pb 206 Pb/ 207 U (ppm) Th (ppm) Pb 206 (ppm) La ppmLa ppm Ce Nd ppm ppm Sm ppm Eu Gdppm ppm Dy Er ppm Yb Rad Sample # Sample Table B1. Cont. Cont. B1. Table IT 10-1IT 10-2IT 10-3IT 10-4IT 10-5IT 10-6 0.88IT 10-7 0.20IT 10-8 1.95IT 10-9 1.94IT 10-10 152 0.18IT 10-11 0.39 33IT 10-12 331 0.30IT 10-13 326 0.20IT 10-14 213 3.55 30IT 10-15 3.67 64 25IT 10-16 802 0.16 0.83836 49IT 10-17 265 1.01 34IT 10-18 0.83825 0.25 0.83841 187 0.00679 19 144 0.31 0.83846 42 0.19 24 0.00713 0.00685 35 0.83825 0.42 53 0.00692 15 0.83840 0.28 43 42 1.5 60 0.83849 2.94 53 0.00700 0.83834 3.2 31 0.00705 16 1.0 0.84477 0.0642 0.84787 68 0.00711 10 1.0 45 0.00703 30 0.83847 126 0.02210 0.1319 0.0572 3.3 16 0.02967 0.84474 0.0500 2.3 18 0.83825 20.1 0.00758 2.5 35 0.83828 0.02240 0.1180 3.1 21 14.0 0.83842 0.9 0.0816 0.00684 65 4.5 0.9 0.83839 0.00682 0.0628 5.8 42.7 0.83839 3.5 0.00727 0.0967 0.84680 34.1 0.0494 1.6 0.00712 41.0 0.0552 13.4 43.5 2.7 0.00710 13.5 0.02718 0.1186 44.3 2.5 1.0 11.7 0.0634 3.2 41.1 3.6 0.1017 1.7 2.2 43.4 3.3 0.5 0.0914 2.7 44.8 17.8 0.9 0.5 0.1014 42.4 6.2 140.8 0.0917 2.6 187.2 9.3 0.0903 1.2 11.3 0.0572 44.4 1.2 17.7 140.3 1.4 19.5 1.3 41.0 1.7 9.3 41.5 3.6 2.0 43.6 2.3 43.3 1.2 43.2 171.3 1.2 1.7 1.4 1.2 1.7 IT 10-1IT 10-2IT 10-3IT 10-4IT 10-5IT 10-6 0.15IT 10-7 0.03IT 10-8 0.57IT 10-9 0.03 49.35IT 10-10 0.01 11.02IT 10-11 139.48 0.02IT 10-12 0.03 39.25IT 10-13 7.96 0.01 11.10IT 10-14 2.26 34.15 0.01 12.04IT 10-15 0.01 11.10IT 10-16 0.02 1.78 16.76IT 10-17 8.50 1.04 0.01 51.40 3.61IT 10-18 7.90 0.02 1.07 11.63 0.01 1.38 10.40 4.63 8.09 0.02 30.40 0.64 1.81 5.29 2.06 0.02 10.70 0.06 1.90 0.18 0.01 116.0 2.42 9.12 0.05 2.77 1.48 273.8 9.05 1.34 1.21 0.06 15.20 22.5 1.44 0.31 1.23 0.51 8.10 298 1.47 0.15 13.44 40.4 2.73 1.11 620 0.86 12.8 0.29 0.85 2.48 0.17 14.2 0.25 62 0.20 16.5 0.37 0.42 412 1.51 142 1.90 747 0.16 1.79 9.8 1.53 44 4.5 0.53 4.7 50 95 0.23 1.22 696 17.1 55 238 1.20 1102 1.14 3.8 17.3 41 75 0.32 174 33 0.70 20 8426 92 3.0 7099 12.2 415 46 96 15.3 24 53 142 84 8550 5.2 13.8 100 195 43 9304 13 190 35 72 70 9726 66 186 10595 89 298 22 60 106 8540 27 139 60 152 8440 15896 188 176 15485 129 46 9305 65 127 320 12877 9278 272 108 12130 8980 8589 10077 11273 260 .6 .7 0.4 0.5 0.7 0.6 0.5 0.5 err σ 1 U U 238 ppmppm Hf Pb / Age (Ma) Age 206

% % err Pb 206 Pb/ 207 % % err U 238 Pb/ 206 Pb C-Pb 206 Pb/ 207 U (ppm) Th (ppm) Pb 206 (ppm) La ppmppm Ce Ndppm ppm Sm ppm Eu Gdppm ppm Dy Erppm Yb Rad Sample # Sample Table B1. Cont. B1. Table ES ES 12785a-1 ES 12785a-2 ES 12785a-3 ES 12785a-4 1.97 ES 12785a-5 1.06 ES 12785a-6 0.91 ES 12785a-7 1.92 ES 12785a-8 351 1.10 188 1.19 153 1.50 ES 12785a-1 325 1.67 ES 12785a-2 290 187 ES 12785a-3 195 90 ES 12785a-4 0.83827 256 61 0.03 ES 12785a-5 231 289 0.02 0.83825 ES 12785a-6 92 0.00652 0.02 0.83841 ES 12785a-7 111 0.83841 0.01 45.17 ES 12785a-8 0.00657 119 0.06 0.83838 32.75 0.00690 185 0.83837 0.00687 0.22 24.46 0.83837 0.9 0.02 38.99 0.00688 0.67 16.78 0.83833 0.00710 34.70 1.3 0.48 0.00683 30.43 1.5 0.0579 0.57 1.0 0.00674 49.46 0.53 67.29 0.0701 1.83 1.3 0.59 1.2 0.0626 1.24 0.0584 0.61 1.1 1.43 5.2 0.77 10.38 1.1 0.0671 1.57 0.0948 1.22 6.0 1.48 0.0652 0.81 5.8 1.32 5.6 0.0673 0.92 41.3 2.23 3.64 10.6 1.05 16.8 41.0 4.3 1.02 12.1 43.5 5.1 0.78 43.5 14.0 4.3 1.40 1.53 43.1 14.9 42.9 14.3 55 0 42.9 11.4 44 0 42.2 20.5 54 18.9 52 55 93 37 77 107 85 56 90 104 185 166 65 240 167 96 12124 182 217 12567 12505 135 355 11984 195 11003 11306 11550 11709 261

2 0 1 2 2 1 2 0 9 2 .6 .7 .1 .1 .8 .0 .8 .1 .2 0.9 err σ 1 U 238 ppmppm Hf Pb / Age (Ma) Age 206

% % err Pb 206 Pb/ 207 % % err U 238 Pb/ 206 Pb C-Pb 206 Pb/ 207 U (ppm) Th (ppm) Pb 206 (ppm) La ppm La ppm Ce Nd ppm ppm Sm Eu ppm Gd ppmppm Dy Erppm Yb Rad Rad Sample # Sample Table B1. Cont. Cont. B1. Table ES ES 12807-4 0.35 ES 12807-10 ES 12807-11 ES 12807-12 64 0.39 ES 12807-14 0.67 ES 12807-15 0.47 ES 12807-16 21 ES 12807-17 0.90 70 113 0.83816 0.39 ES 12807-19 0.63 82 ES 12807-20 0.50 0.00632 157 47 88 0.28 71 112 0.34 40 0.83823 0.83846 2.6 90 99 0.83829 0.00642 52 31 0.00692 0.0665 94 0.83834 54 0.00663 66 0.83824 0.83829 0.00665 2.5 24 11.0 1.9 0.83827 0.00647 26 0.00655 2.3 0.0576 0.83804 0.00649 0.0491 1.8 0.83840 39.7 0.0663 2.4 0.00624 1.9 0.00726 11.5 0.0519 10.0 2.2 0.0617 1. 0.0549 9.4 2.9 40.7 0.0546 2.6 8.2 44.3 10.2 0.0942 41.6 8.8 0.1053 1 9.9 42.4 40.8 10.1 41.6 1. 8.4 41.3 0 1 37.8 0 43.3 0. 1 1. ES ES 12807-2 ES 12807-3 ES 12807-5 ES 12807-6 0.42 ES 12807-7 1.48 ES 12807-8 ES 12807-9 0.31 0.32 80 260 0.38 0.27 ES 12807-13 1.15 54 55 39 264 69 51 0.83814 0.35 0.83831 200 23 ES 12807-18 23 0.00620 0.00662 48 0.83830 31 137 0.83830 61 0.83820 0.45 0.00658 0.83814 0.83836 2.4 ES 12807-1 0.00664 1.4 ES 12807-2 0.00639 ES 12807-3 0.00627 20 0.00668 0.0588 0.0566 2.8 82 ES 12807-4 2.8 ES 12807-5 0.17 0.83835 2.5 ES 12807-6 0.02 0.0560 2.9 ES 12807-7 10.8 1.5 0.02 0.00665 0.0641 6.2 ES 12807-8 62 0.02 12.81 0.0626 ES 12807-9 0.01 17.41 0.0689 0.0517 ES 12807-10 12.5 0.01 0.83825 54.75 39.2 ES 12807-11 11.9 42.0 0.01 12.12 2.6 0.46 ES 12807-12 10.8 0.02 11.67 0.00645 0.50 ES 12807-13 11.8 0.02 10.94 41.8 6.9 0.03 1.23 ES 12807-14 0.0495 15.28 1. 41.8 0.13 0.05 ES 12807-15 0 0.99 12.20 40.2 0.02 0.30 ES 12807-16 43.22 1.31 2.5 39.2 0.02 0.39 14.56 ES 12807-17 42.7 3.08 1. 12.0 0.02 1.69 23.37 ES 12807-18 0.35 1. 0.65 0.02 0.50 16.56 ES 12807-19 0.0550 0.80 1. 0.86 1.12 0.07 12.41 ES 12807-20 1.12 2.07 1. 0.06 2.15 29.60 0 42.6 3.40 2.62 0.22 0.04 15.23 1.19 0.56 17.1 8.1 0.50 0.01 24.47 11.6 2.84 0.13 0.02 0.69 18.55 3.76 29.9 1.06 1.88 17.76 4.88 1 0.20 3.1 0.74 1.26 10.98 41.0 3.99 6.4 1.93 28 0.33 7.70 2.14 2.30 43 8.2 2.69 104 21.4 2.87 2.50 0.60 0.86 0.42 8.8 12 6.50 1 28.0 0.21 0.42 24 22.3 4.14 51 1.90 80 171 28 30.8 4.27 0.46 55 11.4 1.04 3.95 26 23 102 0.99 3.1 2.37 110 25.8 42 58 166 2.53 313 52 80 6.0 0.67 78 40.5 41 177 0.59 24.0 9435 41 51 14 9513 9698 26.2 88 95 83 115 117 144 8.0 27 100 10955 74 325 7.0 10625 63 81 26 153 150 8958 67 11161 213 138 34 53 9160 151 9298 23 9314 90 291 62 9573 95 240 9122 130 65 10944 8851 163 42 168 12096 8685 147 9495 92 9572 9444 9723 ES ES 12807-1 0.31 59 26 0.83808 0.00618 2.8 0.0750 11.5 38.4 1. 262 6 6 6 6 .5 .5 .5 .4 .6 0.5 0.2 err σ 1 U U 238 ppmppm Hf Pb / Age (Ma) Age 206

% % err Pb 206 Pb/ 207 % % err U 238 Pb/ 206 Pb C-Pb 206 Pb/ 207 U (ppm) Th (ppm) Pb 0.320.87 53 149 21 91 0.83852 0.83843 0.00705 0.006830.030.00 2.4 1.4 8.12 22.38 0.0491 0.0485 0.36 0.46 11.4 6.8 0.99 1.21 45.2 43.8 0.71 0.60 1.1 0.6 8.9 10.7 40 46 84 92 199 212 10680 9289 206 (ppm) La ppmppm Ce Ndppm ppm Sm ppm Eu Gdppm ppm Dy Erppm Yb Rad Sample # Sample Table B1. Cont. B1. Table ES ES 12800-12 1.55 262 124 0.83845 ES 12800-12 0.00688 0.01 1.0 42.78 0.0480 0.54 5.0 1.75 44.1 0.87 18.9 85 171 360 11718 ES ES 12800-1 ES 12800-2 ES 12800-3 ES 12800-4 ES 12800-5 0.01 ES 12800-6 0.01 ES 12800-7 0.02 ES 12800-8 0.00 31.62 ES 12800-9 0.01 25.93 ES 12800-10 0.01 34.39 103.89 0.22 0.40 0.01 19.49 0.52 0.02 43.62 1.84 0.03 42.01 0.92 1.25 33.72 0.26 42.30 1.60 0.57 39.04 4.22 0.63 4.32 0.63 0.43 0.96 0.67 0.83 1.92 0.53 1.85 1.65 1.46 13.3 1.27 0.45 2.09 15.3 1.01 1.60 32.2 0.85 52.2 0.65 62 8.8 1.05 19.2 0.78 65 117 17.1 264 12.7 141 17.6 42 16.1 138 83 214 506 78 60 329 71 318 94 77 166 434 948 150 11333 127 11299 135 11468 227 165 344 13168 303 284 12538 11132 289 375 11580 11866 10967 11059 ES ES 12800-11.1 ES 12800-11.2 ES 12800-11.1 ES 12800-11.2 ES ES 12800-1 ES 12800-2 ES 12800-3 ES 12800-4 ES 12800-5 0.99 ES 12800-6 0.85 ES 12800-7 1.11 ES 12800-8 7.16 162 ES 12800-9 2.61 145 ES 12800-10 1.68 194 1.78 1153 1.20 285 67 2.05 1.15 279 80 119 303 484 0.83855 202 0.83840 0.83835 356 79 0.83859 196 0.00712 156 0.00680 170 0.00664 0.84002 0.00723 0.83849 89 324 0.83844 1.3 0.01065 93 0.00698 0.83847 1.4 0.83839 1.2 0.00684 0.5 0.83843 0.0474 0.00692 0.00672 0.0529 0.9 0.0498 1.0 0.00683 0.0481 1.0 6.3 0.0471 1.2 0.0473 6.6 0.9 5.8 0.0467 1.3 2.3 0.0477 45.7 0.0483 4.0 43.3 5.7 0.0500 42.5 4.9 46.4 6.0 0. 68.3 4.2 44.8 0. 6.0 0 44.0 44.4 43.1 0. 0 43.7 0 0. 0 0 263

7 9 7 6 9 9 .6 .6 .6 .6 .7 .4 .7 .0 .7 0.6 0.8 0.5 err σ 1 U 238 ppmppm Hf Pb / Age (Ma) Age 206

% % err Pb 206 Pb/ 207 % % err U 238 Pb/ 206 Pb C-Pb 206 Pb/ 207 U (ppm) Th (ppm) Pb 206 (ppm) La ppmLa ppm Ce Nd ppm ppm Sm ppm Eu Gdppm ppm Dy Er ppm Yb Rad Sample # Sample Table B1. Cont. Cont. B1. Table ES12783-1 ES12783-2 ES12783-3 ES12783-4 ES12783-5 1.03ES12783-6 0.67ES12783-7 1.19ES12783-8 1.14 175ES12783-9 1.46 116ES12783-10 1.51 199ES12783-11 0.63 204ES12783-12 1.36 255ES12783-13 85 1.98 0.97 262ES12783-14 43 1.75 105ES12783-15 81 0.83843 0.98 236ES12783-16 72 0.83837 185 1.56 322ES12783-17 0.83847 174 0.00683 147 0.86ES12783-18 0.83828 329 0.00670 2.81 0.83838 36 172 0.00692 125 0.47 0.83838 273 0.00651 187 0.83 0.00668 0.83847 152 1.6 92 0.51 0.83840 0.00674 465 2.0 67 0.83855 1.6 0.00696 77 0.83827 78 0.00674 0.0492 127 149 1.4 0.83817 1.3 0.00715 0.0492 109 0.83837 88 1.3 0.00649 0.0458 168 0.83834 0.00620 0.0541 0.83835 1.9 0.0462 37 7.6 1.2 0.00665 0.83852 83 0.0519 0.00665 9.0 1.2 0.00660 36 7.3 1.5 0.0507 0.83845 0.00704 0.0464 0.83828 6.5 1.0 43.7 7.9 0.0524 1.6 0.83837 0.00692 42.9 6.1 1.3 0.0531 0.00652 44.5 1.8 0.0481 9.3 0.00672 41.5 6.1 1.0 0.0432 43.0 0.0528 0. 5.5 43.0 0.0441 0. 2.2 7.1 1.7 0.0471 0. 44.5 4.8 43.3 2.0 0. 8.1 0 45.6 0.0524 5.9 0.0540 0 41.4 9.0 0.0511 39.8 4.8 0. 0 42.9 10.8 42.4 0 7.6 42.5 0 45.2 9.5 0 0 44.2 41.5 42.9 1 0 0. ES12783-1 ES12783-2 ES12783-3 ES12783-4 ES12783-5 0.02ES12783-6 0.04ES12783-7 0.03ES12783-8 0.03 26.24ES12783-9 0.04 15.36ES12783-10 0.04 33.51ES12783-11 0.02 31.16 0.40ES12783-12 0.02 33.27 0.35ES12783-13 0.45 41.15 0.02 0.45ES12783-14 16.94 0.02 0.40ES12783-15 32.47 1.16 0.50 0.02ES12783-16 1.11 40.41 0.02 0.73 30.54ES12783-17 1.45 0.02 0.37 18.11ES12783-18 1.39 0.59 0.48 0.03 32.70 1.59 0.58 0.03 0.71 46.81 2.04 1.14 0.04 0.69 15.33 1.28 0.38 0.02 0.69 56.76 11.4 1.67 0.53 0.89 11.64 10.2 1.77 0.62 1.19 26.74 3.63 15.6 0.37 0.76 14.84 1.57 14.4 0.52 0.87 1.78 15.4 0.46 52 0.92 2.05 20.9 1.70 0.41 50 1.23 11.1 0.71 0.41 75 1.57 16.2 1.06 75 1.22 112 18.0 0.99 59 29.8 1.24 105 0.75 88 18.5 1.19 166 0.82 56 17.9 164 0.84 77 256 21.3 111 0.70 75 111 243 10.3 188 0.88 141 376 17.9 121 10751 373 11.4 86 158 100 10289 226 13.0 139 193 12064 421 12.9 38 318 11199 272 96 10903 177 325 51 212 10220 276 364 60 10318 679 62 70 10485 240 381 12110 104 11075 458 127 10918 130 149 10919 610 11077 220 285 10222 11850 285 8560 11067 9727 264

4 7 9 .6 .6 .3 .6 .4 .0 .1 .7 58 1.6 0.8 0.5 0.3 0.8 err σ 1 8 0.3 U U 238 ppm Hf ppm Pb / Age (Ma) Age 206

% err Pb 206 Pb/ 207 % err U 238 Pb/ 206 Pb C-Pb C-Pb 206 Pb/ 207 U U (ppm) Th (ppm) Pb 206 (ppm) La La ppm Ce ppm Nd ppmppm Sm ppm Eu Gdppm ppm Dy Er ppm Yb Rad Rad Sample # Sample Table B1. Cont. Cont. B1. Table ES ES 12782-1 ES 12782-2 ES 12782-3 ES 12782-4 ES 12782-5 2.06 ES 12782-6 1.87 ES 12782-7 6.38 ES 12782-8 0.15 ES 12782-9 351 5.32 ES 12782-10 316 1.14 ES 12782-11 260 1.45 ES 12782-12 2.96 22 294 ES 12782-13 906 0.98 119 5.25 ES 12782-14 202 144 0.39 0.83838ES 12782-15 241 1.94 0.83843ES 12782-16 511 14 372 0.51 0.84744ES 12782-17 169 0.00682 896 107 4.38 0.00687 102 0.83836 0.96 0.83843 70 0.02853 354 152 0.44 0.83823 0.99 1116 0.83846 86 0.00768 72 1.3 0.00684 766 0.83838 1.3 0.00656 164 32 0.83843 0.9 0.00699 117 0.83835 0.0620 72 0.00674 168 0.0534 3.8 46 0.7 381 0.83818 0.00682 0.83821 0.00671 0.0521 1.3 66 1.3 0.83834 0.83835 0.00648 0.1558 9.2 0.00637 0.0486 41 0.9 56 5.5 0.0749 0.83835 0.6 1.5 0.00684 3.2 0.00665 0.0597 0.83841 0.0527 0.83840 18.8 0.00680 43.0 2.3 1.1 4.2 0.0484 0.0556 43.8 0.00710 7.8 180.8 0.00685 15.1 2.1 0.7 0.0801 0.0582 42.8 4.1 1.6 0 43.8 4.5 6.7 0 0.0760 40.7 0.0494 2.2 44.2 1.5 10.4 0.0673 43.0 4.8 2. 0 0.0859 43. 42.6 0.0588 8.5 0 4.2 40.0 11.2 40.4 0 11.2 0. 42.4 8.4 42.6 42.6 1 43.4 43.3 0. 1 0 ES ES 12782-1 ES 12782-2 ES 12782-3 ES 12782-4 ES 12782-5 0.02 ES 12782-6 0.02 ES 12782-7 0.01 ES 12782-8 0.02 57.49 ES 12782-9 0.06 27.96 ES 12782-10 0.04 33.73 ES 12782-11 0.02 7.11 2.29 ES 12782-12 0.02 67.19 0.58 ES 12782-13 0.03 35.81 0.04 0.71 ES 12782-14 37.67 0.11 ES 12782-15 0.34 42.59 6.62 0.08 0.84 ES 12782-16 25.68 1.77 109.43 0.01 0.80 ES 12782-17 2.16 0.25 0.65 9.34 1.04 0.01 0.35 4.26 20.46 3.00 0.03 0.43 0.81 14.96 2.34 2.13 0.03 0.92 53.62 1.76 0.41 26.33 0.81 0.91 59.6 0.28 1.39 12.21 1.36 18.3 0.37 9.24 0.94 22.77 26.0 0.64 0.97 0.81 0.36 0.53 1.33 219 9.3 38.2 0.78 0.78 1.28 3.92 19.0 0.35 86 2.09 116 19.0 0.44 1.29 10.4 0.39 367 1.60 199 103.7 37 14.8 0.83 1.01 179 0.92 74 232 0.77 90 7.4 17.1 1.01 69 682 387 482 12.8 68 0.58 67 384 25.5 146 485 12.8 201 103 9659 32 13.6 224 745 815 11361 11.4 54 144 145 10768 123 305 448 61 211 13101 1315 672 68 53 8397 103 318 56 8738 263 12793 121 132 12650 406 160 102 11235 225 125 538 12651 294 10541 10550 221 13166 295 12275 9820 11612 265 0 2 .2 .6 .1 .6 .6 .5 .0 .6 0.4 1.1 1.3 1.6 2.0 err σ 1 U U .3 0.2 238 ppmppm Hf Pb / Age (Ma) Age 206

% % err Pb 206 Pb/ 207 % % err U 238 Pb/ 206 Pb C-Pb 206 Pb/ 207 U (ppm) Th (ppm) Pb 206 (ppm) La ppmppm Ce Ndppm ppm Sm ppm Eu Gdppm ppm Dy Erppm Yb Rad Sample # Sample Table B1. Cont. B1. Table ES ES 12789a-1 ES 12789a-2 ES 12789a-3 ES 12789a-4 0.01 ES 12789a-5 0.01 ES 12789a-6 0.01 ES 12789a-7 0.03 10.70 ES 12789a-8 0.07 ES 12789a-9 6.77 0.02 ES 44.0412789a-10 0.01 ES 10.3412789a-11 0.22 0.03 31.70 ES 12789a-12 139.82 0.19 0.01 ES 12789a-13 0.44 0.02 ES 12789a-14 9.80 1.50 0.01 0.47 ES 12.4112789a-15 0.43 0.05 1.82 0.46 8.91 0.02 17.42 1.46 0.02 14.52 0.34 2.55 0.37 2.36 0.01 16.15 1.32 8.08 0.33 0.53 7.78 0.67 0.67 10.44 0.70 1.01 1.47 3.58 7.94 2.83 4.7 0.63 3.23 1.36 0.33 1.64 4.6 15.9 0.77 1.84 0.60 16.3 2.14 0.28 4.94 13.7 21 91.7 0.80 0.72 1.23 1.80 19 1.10 84 7.8 23.2 0.72 3.05 49 63 430 0.51 16.6 44 9.4 1.08 15.8 203 38 0.49 31.8 30 61 82 138 761 110 6.4 13.1 62 37 503 50 86 5.9 88 164 57 12374 97 1357 308 11897 114 23 40 11074 73 83 1458 9146 12112 129 22 129 185 227 42 153 65 165 9669 238 8974 42 9067 8573 11616 132 94 9448 95 11286 10614 11039 ES ES 12789a-1 ES 12789a-2 ES 12789a-3 ES 12789a-4 0.27 ES 12789a-5 0.21 ES 12789a-6 2.15 ES 12789a-7 0.22 ES 12789a-8 1.26 ES 12789a-9 48 9.16 ES 12789a-10 34 395 0.27 ES 12789a-11 0.30 ES 12789a-12 34 216 0.24 ES 12789a-13 18 1543 0.37 ES 12789a-14 13 149 0.33 ES 12789a-15 42 0.83828 0.39 49 21 0.83839 1510 0.21 0.83822 89 39 0.25 62 0.00660 0.83835 0.20 55 0.00739 0.83846 0.00635 0.83841 19 70 36 32 0.00757 0.00691 21 0.00679 0.83855 2.7 40 57 0.83839 3.2 30 34 1.0 0.83831 0.00741 58 0.83835 0.0640 3.1 0.00701 14 0.83838 0.5 1.3 0.1195 0.0527 0.00706 25 0.83818 0.00691 13 0.83843 0.1491 0.00701 2.8 0.0493 10.4 0.0482 0.83835 0.00646 2.7 11.7 0.83846 0.00782 4.6 3.0 2.4 0.00708 0.0799 18.1 2.5 41.5 0.0811 0.00772 2.4 6.1 2.3 43.3 0.1095 40.5 0.0810 3.2 20.9 0.0841 3.0 42.6 0.0769 44 1 9.9 3.3 43.5 13.0 0.1522 1 11.5 0.0999 45.7 14.7 0.1359 2 43.2 9.2 0 41.9 8.3 42.5 17.4 43.0 1 17.0 40.0 1. 1 43.8 42.6 44.2 1 1 266 3 err σ 1 U U 238 ppmppm Hf Pb / Age (Ma) Age 206

% % err Pb 206 Pb/ 207 % % err U 238 Pb/ 206 Pb C-Pb 206 Pb/ 207 U (ppm) Th (ppm) Pb 206 (ppm) La ppmppm Ce Ndppm ppm Sm ppm Eu Gdppm ppm Dy Erppm Yb Rad Sample # Sample Table B1. Cont. B1. Table IT 9-1IT 9-2IT 9-3IT 9-4IT 9-5IT 9-6IT 9-7 0.99IT 9-8 1.08IT 9-9 0.86IT 9-10 0.92 177IT 9-11 0.29 191IT 9-12 0.38 152IT 9-13 1.01 164IT 9-14 0.89 84 1.43 49 0.86 89 64 1.13 178 65 0.83826 5.92 155 67 0.83830 0.75 255 0.83830 31 151 0.00653 1.15 0.83829 14 199 0.00658 78 1031 0.00659 0.83844 74 125 0.00656 116 0.83838 0.83828 192 1.5 62 0.00700 0.83833 1018 1.4 93 0.83827 0.00702 1.5 0.00658 0.83834 0.0631 1.5 0.00670 49 0.83837 0.83833 0.00654 0.0566 103 2.6 0.00661 0.0575 0.83846 2.3 0.00668 0.00663 0.0583 0.83844 1.4 6.2 1.5 0.0665 1.2 6.9 0.00699 0.0850 0.00695 1.5 6.7 0.0632 0.6 1.3 6.5 0.0626 41.1 0.0599 10.9 41.8 0.0475 1.8 8.8 0.0483 41.8 1.4 0.0542 6.1 41.6 10.9 10.9 0.6 43.9 0.0596 12.6 0.0592 0.6 43.0 2.8 0.7 41.4 7.0 42.2 0.6 41.4 12.0 1.2 42.4 9.3 1.1 42.8 42.2 0.6 0.7 0.6 44.2 0.7 44.0 0. 0.6 0.9 0.7 IT 9-1IT 9-2IT 9-3IT 9-4IT 9-5IT 9-6IT 9-7 0.01IT 9-8 0.01IT 9-9 0.01IT 9-10 0.03 32.37IT 9-11 0.02 34.82IT 9-12 0.01 27.55IT 9-13 0.01 27.98 0.56IT 9-14 0.01 11.48 0.67 0.01 7.27 0.01 0.53 30.64 2.28 0.35 29.92 1.63 0.03 2.04 43.03 1.71 0.01 27.41 0.06 1.45 0.01 0.47 41.32 1.25 0.56 0.97 32.03 3.48 0.75 0.96 23.10 0.42 0.27 0.95 36.05 1.33 1.48 0.75 1.70 15.7 0.55 1.89 2.01 15.8 0.44 1.22 0.13 13.1 0.79 0.86 1.89 12.1 1.03 2.01 19.1 58 1.23 1.26 0.77 60 1.95 3.1 13.2 1.10 51 15.0 1.13 49 106 19.4 0.83 50 12.5 113 1.38 16.7 15 51 95 22.5 56 97 221 11.5 74 72 240 18.9 49 64 101 202 38 11032 75 101 211 11542 46 142 132 81 11181 95 120 226 11807 97 127 211 9598 300 90 148 11939 209 13088 253 11282 244 11377 11855 198 11627 296 11239 11679 10405 267

8 6 8 1 9 8 9 .7 .7 .1 .8 .8 .9 .0 0.6 0.6 0.6 1.0 err σ 1 U 238 ppmppm Hf Pb / Age (Ma) Age 206

% % err Pb 206 Pb/ 207 % % err U 238 Pb/ 206 Pb C-Pb 206 Pb/ 207 U (ppm) Th (ppm) Pb 0.060.010.02 33.920.01 10.390.02 32.350.03 13.940.01 0.97 55.870.02 0.43 46.620.27 0.69 18.720.02 0.19 2.55 34.260.01 0.74 1.08 29.040.02 0.72 1.89 21.130.04 0.34 0.51 43.18 1.670.02 0.60 2.01 47.03 0.640.01 0.72 1.91 56.13 1.100.02 1.81 0.95 32.86 0.340.01 0.61 21.3 1.91 27.23 1.170.04 0.81 1.43 7.5 22.35 1.19 2.72 16.4 3.91 26.16 0.57 0.69 1.76 4.8 28.16 1.07 0.53 19.5 69 2.17 0.89 0.39 18.1 6.05 24 2.05 0.39 60 1.76 8.8 1.06 0.55 15.9 1.32 16 105 1.25 14.1 72 0.92 3.75 25.7 60 1.25 40 107 1.03 15.0 1.49 34 0.80 17.9 61 197 28 124 0.52 45.6 50 0.73 16.2 68 98 220 81 0.85 10570 12.0 51 64 111 59 242 8.1 58 131 11900 10.6 89 195 9163 14.0 60 93 10969 42 84 141 227 100 9204 189 12010 28 182 37 106 171 11645 11207 47 168 74 204 10945 322 11241 47 62 215 11890 11720 83 10225 151 10999 97 128 12654 173 11666 11914 11905 206 (ppm) La ppmLa ppm Ce Nd ppm ppm Sm ppm Eu Gdppm ppm Dy Er ppm Yb Rad Sample # Sample Table B1. Cont. Cont. B1. Table ES12787-1 ES12787-2 ES12787-3 ES12787-4 ES12787-5 0.78ES12787-6 0.18ES12787-7 0.72ES12787-8 0.39 143ES12787-9 0.86ES12787-10 1.24 34 130ES12787-11 0.54ES12787-12 0.79 72 161ES12787-13 98 0.56 0.47 214ES12787-14 15 1.52 103ES12787-15 64 0.83823 1.46 141ES12787-16 29 104 0.83820 1.17 104ES12787-17 0.83825 0.00637 155 0.79 82ES12787-18 266 0.83822 0.67 0.83817 0.00635 39 258 0.00639 0.71 0.83838 66 217 0.58 0.00634 54 0.00625 0.83812 139 1.8 0.60 56 0.00675 208 0.83828 125 3.7 194 0.83816 125 2.0 0.00612 0.0527 186 0.83834 0.83835 103 0.00648 2.5 1.8 0.83832 109 0.00629 0.0586 69 1.5 0.0491 0.83820 0.00662 61 0.00663 2.2 0.0489 66 0.00658 0.0563 0.83834 8.1 1.9 64 0.0545 0.00626 0.83817 14.6 2.2 61 0.83836 8.7 0.00664 0.0547 2.4 1.3 0.83831 13.9 0.00625 0.0506 40.7 7.3 1.3 0.83824 0.0623 0.00665 40.2 6.2 1.6 0.00660 0.0509 0.0486 41.0 9.3 1.8 0.00641 0.0519 40.6 8.1 2.0 39.7 0.0477 0. 8.6 1.9 43.0 1. 12.5 0.0509 2.2 5.8 0. 38.9 0.0539 2.2 5.6 1. 41.5 0.0472 0 7.0 39.7 0.0543 0 42.3 7.6 0.0527 42.5 0. 8.3 42.0 0. 8.6 40.2 0. 9.3 1 42.5 15.8 39.8 42.7 42.0 40.9 0 0 0 1 ES12787-2 ES12787-3 ES12787-4 ES12787-5 ES12787-6 ES12787-7 ES12787-8 ES12787-9 ES12787-10 ES12787-11 ES12787-12 ES12787-13 ES12787-14 ES12787-15 ES12787-16 ES12787-17 ES12787-18 ES12787-1 268 .6 .3 .4 .4 .3 .3 .4 86 0.6 0.5 0.3 err 681 σ 1 4 0.3 U U 06 7077 238 ppmppm Hf Pb / Age (Ma) Age 206

% % err Pb 206 Pb/ 207 % % err U 238 Pb/ 206 Pb C-Pb 206 Pb/ 207 U (ppm) Th (ppm) Pb 206 (ppm) La ppmppm Ce Ndppm ppm Sm ppm Eu Gdppm ppm Dy Erppm Yb Rad Sample # Sample Table B1. Cont. B1. Table ES ES 12792-1 ES 12792-2 ES 12792-3 ES 12792-4 ES 12792-5 0.01 ES 12792-6 0.01 ES 12792-7 0.01 ES 12792-8 0.13 20.02 114.45 ES 12792-9 0.02 ES 12792-10 0.01 53.49 184.00 ES 12792-11 0.03 0.28 151.33 ES 12792-12 0.01 2.20 0.02 46.85 0.39 0.80 11.17 47.42 0.58 13.09 0.75 3.24 0.03 6.65 71.60 373.07 0.73 24.41 2.39 146.26 2.33 10.25 0.31 0.50 24.17 4.15 41.92 1.04 13.75 1.87 33.27 1.46 5.17 6.59 0.92 0.37 81.79 6.4 50.3 192.4 3.28 47.51 1.09 21.5 3.06 95.6 48.05 0.54 0.87 135 29.07 2.18 19 437 14.7 35.0 67 535.4 284 0.60 7.1 225.9 31.1 181 467 30 45 103 1063 92 380 8.2 431 23 278 612 96 62 1036 76 185 114 562 11171 444 23 92 39 12271 143 12547 12 151 10650 176 615 43 246 83 13387 12387 8 11911 11052 107 14401 ES ES 12792-1 ES 12792-2 ES 12792-3 ES 12792-4 ES 12792-5 1.73 ES 12792-6 3.60 ES 12792-7 2.19 ES 12792-8 1.81 325ES 12792-9 3.08 678ES 12792-10 3.43 378ES 12792-11 1.18 319ES 12792-12 0.33 188 558 1.95 619 3.32 606 261 1.61 0.83815 202 656 3.21 0.83814 56 363 0.83834 353 0.00622 581 470 0.83827 0.00618 287 115 0.83825 0.00675 574 0.83831 0.00659 24 273 1348 0.83836 1.4 0.00642 0.7 0.00658 401 0.83817 0.83823 0.83834 0.9 0.00679 337 0.0564 1.0 0.83825 0.0559 0.00685 0.8 0.00644 0.00665 0.83829 0.0659 0.7 0.00652 0.0670 1.2 5.2 0.00651 0.0536 3.2 0.0533 2.3 0.9 0.7 3.7 0.0638 1.1 4.0 39.5 0.1252 0.7 3.6 0.0603 0.0525 39.3 3.4 42.3 11.2 0.0645 41.3 0.0515 0 40.9 8.3 4.4 4.4 0 42.0 42.7 0 4.8 0 3.4 39.8 0 40.7 42. 0 41.0 41.6 1.1 0 269

Appendix C

Electron microprobe analytical procedures and results

Major element contents of minerals were analyzed at Oregon State University using a Cameca SX-100 electron microprobe. Data reduction was conducted online using a stoichiometric PAP matrix correction program (Pouchou and Pichoir, 1984).

Back-scattered electron (BSE) images were acquired using the Peak Site software.

Amphibole, plagioclase, mica, and titanite grains were analyzed using a focused 1 µm beam with 15 kV accelerating voltage and 30 nA beam current. Apatites were analyzed using a beam diameter of 2 µm with 15 kV acceleration voltage and 20 nA beam current.

Elements analyzed included the following:

Amphibole: Na, Mg, Si, K, Ca, Ti, Mn, Cr, Fe, F, Cl, Al.

Apatite: P, Fe, Ca, F, Mn, Cl, S, Ce, Na, Mg, Si.

Biotite: Na, Si, Al, Mg, K, Ca, Ti, Mn, Fe, F, K, Ca, Ti, Cl.

Plagioclase: Na, Fe, Ca, K, Ti, Si, Al, Mg, Sr.

Titanite: Si, Al, Ca, Mn, Fe, Na, Mg, F, K, Ti.

Full quantification settings and detection limits are given in Table C1. Analytical results for each of the minerals analyzed are given in Tables C2, C3, C4, C5, and C6.

Mineral formulas were calculated assuming ideal stoichiometry and are described in detail in the text. Worked calculations are presented in the CD Appendix II.

270 α α K K α α PET LPET PET LPET K K 1 127 197 1 129 201 α α K K α α K K α α K K α α α L K K α α α K K K '07)

'07) '07)

th

α α α th th K K K α α α K K K ses by electron microprobe electron ses by Mica (Nov. 19 (Nov. Mica Mica (Nov. 15 (Nov. Mica α α α Feldspar (Nov. 15 (Nov. Feldspar K K K α α α K K K α α α K K K α α α K K K α α α Na Si Al Mg K Ca Ti Mn Fe F KNa Ca Si Ti Al Cl Mg K Ca Ti Mn Fe F K Ca Ti Cl Na Fe Ca K Ti Si Al Mg Sr K K K Line Line Elements Spec.Crystal Sp2 LTAP LTAP LTAP Sp2 LTAP Sp2 PET PET Sp2Spec. PET Sp5Crystal LIF Sp5 (S)Peak LIF Sp5 (S)Bg. LTAP (ppm)Lim. Det. LPET Sp4 Sp2 LTAP LPET 213 LIF L 30 Sp4 Sp4 433 PET Sp2 Sp5 15Elements 40 LPET 311 LTAP Sp3 SP3 LTAP 20 154 10Spec. LTAP Sp5 Sp3 LTAPCrystal 212 LPET 5 SP2 30 Sp3 295 Sp2 Sp3 30 15 277 Sp2 Sp2 LTAP LTAP 10 15 139 Sp3 LTAP Sp2 LTAP 814 10 Sp2 PET 5 PET Sp2 10 PET 5 Sp5 30 LIF Sp5 5 LIF Sp5 LTAP 15 LPET Sp4 LPET L Sp4 Sp2 Sp3 Sp3 Sp3 Sp3 Table C1. TableQuantification C1. analysettingsfor mineral (S)Peak (S)Bg. (ppm)Lim. Det. 159 30 136 15Elements 10 208 5 213 10 186 10 5 161 30 127 5 10 488 15 495 30 1140 5 30 186 15 16 0 (S)Peak 15 (S)Bg. 20 (ppm)Lim. Det. 20 159 30 30 10 136 10 15 10 208 15 30 5 212 10 5 10 185 10 5 15 161 30 129 5 5 10 487 15 499 30 1106 5 30 185 15 16 0 15 20 20 30 10 10 15 30 5 10 15 5 Line 271 α K α α K K α α α L K K α α α L K K '07)

'08)

'07) th

th

α α α th K K K α α α K K K Apatite (Dec. 7 (Dec. Apatite α α α Feldspar (Nov. 19 (Nov. Feldspar Titanite (March 17 (March Titanite K K K α α α K K K α α α K K K α α α K K K α α α P Fe Ca F Mn Cl S Ce Na Mg Si Si Al Ca Mn Fe Na Mg F K Ti Na Fe Ca K Ti Si Al Mg Sr K K K Line Elements Spec.Crystal (S)Peak (S)Bg. (ppm)Lim. Det. Sp2 LTAP 216 LIF 30 Sp4 429 PET Sp5 15Elements 40 LPET 302 LTAPLine SP3 LTAP 20 155 10Spec. LTAP Sp5 LTAPCrystal 209 LPET 5 SP2 30 (S)Peak 302 Sp2 (S)Bg. 30 15 271 (ppm)Lim. Det. Sp2 Sp3 LPET 373 10 15 138 LIF Sp3 10 Sp4 912 828 PET 10 Sp5 5 5Elements 10 549 PC0Line Sp1 10 2949 10 LIFSpec. 5 5 Sp4 1147Crystal 30 PET 10 Sp5 272 (S)Peak LPET 5 5 Sp1 (S)Bg. 143 LIF 10 (ppm)Lim. Det. LTAP 15 1504 Sp4 Sp1 5 LTAP TAP 310 10 LTAP 566 10 Sp2 Sp1 TAP 245 5 145 PET 10 Sp2 Sp5 5 10 366 LIF 100 Sp2 Sp4 60 5 538 10 5 LIF Sp4 984 LTAP 10 30 5 Sp2 LTAP 5 LTAP 257 LPET 10 Sp2 10 30 PET 115 15 Sp2 10 10 175 5 Sp3 5 192 20 Sp5 5 501 5 30 5 10 10 15 10 5 5 Table C1. Tablecont. C1.

272 α K 6 α α K K α α K K α α K K α α L K '08) '08) st st α α K K α α K K α α Apatite (March 21 (March Apatite K K Amphibole (April 21 (April Amphibole α α K K α α K K α α K K α α P Fe Ca F Mn Cl S Ce Na Mg Si Na Mg Si K Ca Ti Mn Cr Fe F Cl Al K K Line Table C1. Tablecont. C1. Elements Spec.Crystal (S)Peak (S)Bg. (ppm)Lim. Det. Sp3 LPET 357 LIF 10 Sp4 1289 PET Sp5Elements 5 508 10 PC0 Sp1 2249 10 LIFSpec. 5 1079 Sp4Crystal PET 380 10 Sp5 (S)Peak LPET 5 241 (S)Bg. Sp1 LIF 10 1418 (ppm)Lim. Det. LTAP Sp2 Sp4 LTAP 5 LTAP 272 LTAP 541 10 LTAP 30 Sp2 Sp2 TAP 149 200 5 PET 10 Sp1 Sp2 15 20 373 18 PET Sp5 Sp2 60 10 5 312 20 PET Sp5 230 LIF 10 10 30 Sp5 5 237 LIF 10 Sp4 15 20 30 486 LIF Sp4 10 40 LTAP 20 594 LPET 5 SP4 TAP 40 714 30 Sp2 5 192 Sp3 15 20 139 Sp1 5 10 20 224 10 20 10 20 10 15 7.5 Line 273

Table C2: El Salvador amphibole composition by electron microprobe analysis.

Sample SiO 2 TiO 2 Al 2O3 FeO Na 2O K2O MgO CaO MnO Cr 2O3 F Cl Sum ES3081-1.1rim 50.98 1.08 4.54 10.15 1.11 0.40 17.32 11.17 0.42 0.00 0.00 0.08 97.26 ES3081-1.2rim 50.58 1.20 4.99 10.14 1.10 0.45 17.12 11.45 0.40 0.00 0.00 0.12 97.56 ES3081-1.3rim 51.69 1.03 4.17 9.99 0.82 0.44 17.03 11.49 0.40 0.03 0.00 0.08 97.15 ES3081-1.5core 51.64 1.04 4.34 10.01 1.01 0.39 17.63 11.06 0.44 0.00 0.00 0.11 97.68 ES3081-1.6core 51.68 0.93 4.18 10.07 0.97 0.36 17.46 11.50 0.42 0.02 0.00 0.08 97.66 ES3081-2.1rim 51.51 1.14 4.57 9.83 1.24 0.43 17.74 11.11 0.35 0.00 0.00 0.12 98.04 ES3081-2.2core 52.00 0.88 4.18 9.32 1.11 0.31 18.05 11.21 0.40 0.00 0.00 0.07 97.53 ES3081-2.3rim 51.51 1.03 4.47 9.61 1.19 0.43 17.59 11.15 0.38 0.02 0.00 0.12 97.51 ES3081-3.1rim 53.30 0.49 2.91 9.36 0.58 0.24 18.20 11.95 0.36 0.02 0.00 0.06 97.48 ES3081-3.2core 54.89 0.14 1.99 9.57 0.29 0.10 18.15 12.38 0.35 0.00 0.00 0.20 98.07 ES3081-3.3core 53.77 0.36 2.45 9.46 0.47 0.15 18.15 11.85 0.30 0.01 0.00 0.04 97.01 ES3081-3.4rim 54.34 0.23 2.15 9.35 0.49 0.10 18.37 12.03 0.36 0.00 0.00 0.04 97.46 ES3081-4.2rim 51.00 1.17 4.71 10.60 1.17 0.45 16.97 11.22 0.41 0.00 0.00 0.12 97.83 ES3081-4.4core 51.07 1.25 4.69 9.95 1.27 0.43 17.62 11.08 0.46 0.00 0.00 0.11 97.93 ES3081-4.5core 51.01 1.20 4.60 10.44 1.13 0.44 17.11 11.25 0.44 0.02 0.00 0.11 97.76 ES3081-4.6core 50.09 1.24 5.18 10.45 1.11 0.50 16.82 11.45 0.37 0.02 0.00 0.13 97.34 ES3081-5.1rim 51.60 1.01 4.30 9.70 1.15 0.39 17.77 11.05 0.39 0.01 0.00 0.12 97.49 ES3081-5.2core 51.36 1.10 4.58 9.85 1.16 0.47 17.66 11.01 0.37 0.00 0.00 0.12 97.67 ES3081-5.5rim 51.95 1.01 4.05 9.46 0.98 0.35 17.86 11.26 0.39 0.02 0.00 0.07 97.38

ES3076-1.1rim 54.00 0.50 2.64 8.87 0.72 0.19 18.39 11.85 0.40 0.00 0.00 0.05 97.61 ES3076-1.2core 51.33 1.05 4.40 10.06 1.25 0.39 17.33 11.10 0.41 0.01 0.00 0.12 97.45 ES3076-1.3rim 52.78 0.60 3.35 9.00 0.81 0.29 18.11 11.59 0.42 0.00 0.00 0.08 97.05 ES3076-3.1rim 52.09 0.82 4.14 9.71 1.13 0.31 17.84 11.37 0.41 0.00 0.00 0.07 97.88 ES3076-3.3core 51.52 1.04 4.43 9.85 1.24 0.37 17.66 11.33 0.42 0.01 0.00 0.07 97.93 ES3076-3.4core 53.71 0.50 2.83 8.83 0.82 0.22 18.60 11.76 0.41 0.00 0.00 0.05 97.73 ES3076-3.5core 51.40 0.98 4.21 9.93 1.15 0.33 17.57 11.34 0.39 0.02 0.00 0.08 97.39 ES3076-3.6rim 51.37 0.74 4.51 10.40 1.21 0.36 17.38 11.38 0.50 0.00 0.00 0.09 97.92 ES3076-3.8core 50.91 0.88 5.36 9.56 1.15 0.35 17.04 11.22 0.45 0.00 0.00 0.08 97.00 ES3076-3.9rim 51.15 0.89 5.29 9.56 1.07 0.37 17.22 11.28 0.36 0.00 0.00 0.09 97.28 ES3076-4.1rim 53.42 0.71 3.35 9.17 0.81 0.25 17.98 11.55 0.42 0.03 0.00 0.07 97.77 ES3076-4.2rim 52.92 0.86 3.89 9.47 0.95 0.34 18.04 11.58 0.40 0.02 0.00 0.07 98.55 ES3076-4.3core 52.30 0.80 3.77 9.30 0.94 0.30 17.70 11.30 0.35 0.05 0.00 0.07 96.87 ES3076-4.4rim 52.69 0.71 3.49 9.23 0.79 0.25 18.01 11.67 0.41 0.00 0.00 0.06 97.30 ES3076-4.5rim 49.17 1.26 5.87 11.15 1.39 0.48 16.01 11.30 0.45 0.00 0.00 0.10 97.16 ES3076-4.6rim 53.11 0.47 2.93 8.66 0.62 0.20 18.42 12.11 0.32 0.00 0.00 0.05 96.89 ES3076-4.7rim 53.90 0.52 2.93 8.67 0.85 0.19 18.89 11.56 0.36 0.00 0.00 0.05 97.92 ES3076-5.1rim 51.54 0.80 4.29 9.74 0.91 0.35 17.47 11.69 0.26 0.00 0.00 0.08 97.14 ES3076-5.2core 53.02 0.44 2.93 8.72 0.69 0.18 18.39 11.80 0.23 0.00 0.00 0.05 96.46 ES3076-5.4core 54.31 0.37 2.11 8.09 0.55 0.18 18.96 11.90 0.21 0.01 0.00 0.04 96.72 ES3076-5.5core 53.41 0.47 2.80 8.64 0.67 0.22 18.61 11.91 0.23 0.00 0.00 0.05 97.01 ES3076-5.6rim 53.40 0.54 2.84 8.16 0.67 0.21 18.42 11.88 0.22 0.00 0.00 0.05 96.39 ES3076-5.7rim 54.41 0.31 2.00 8.00 0.50 0.14 19.14 12.10 0.20 0.01 0.00 0.03 96.83 ES3076-5.8rim 52.71 0.56 3.26 8.84 0.79 0.22 18.37 11.86 0.22 0.00 0.00 0.05 96.88 ES3076-5.9rim 52.83 0.62 3.12 9.07 0.89 0.26 18.06 11.41 0.30 0.01 0.00 0.07 96.65

274

Table C2: Cont.

Sample SiO 2 TiO 2 Al 2O3 FeO Na 2O K2O MgO CaO MnO Cr 2O3 F Cl Sum ES12792_IMG10 41.04 3.46 13.58 12.59 2.51 0.41 13.39 10.45 0.08 0.00 0.10 0.02 97.63 ES12792_IMG8 41.64 3.28 13.41 12.58 2.45 0.46 13.31 10.41 0.12 0.00 0.10 0.04 97.80 ES12792_IMG8 43.00 3.56 14.63 12.42 2.79 0.47 14.35 10.35 0.12 0.00 0.15 0.03 101.87

ES12792Am-1.1 42.17 2.66 13.17 11.27 2.66 0.40 14.57 11.17 0.06 0.06 0.00 0.01 98.21 ES12792Am-1.2 42.03 2.80 12.95 10.67 2.57 0.39 15.00 11.33 0.10 0.11 0.00 0.01 97.96 ES12792Am-1.3 41.62 2.71 13.29 11.96 2.62 0.44 14.18 11.23 0.11 0.02 0.00 0.02 98.21 ES12792Am-2.1 40.57 2.74 13.80 12.90 2.60 0.43 13.50 10.98 0.13 0.00 0.00 0.01 97.65 ES12792Am-3.1 45.35 0.91 8.67 18.12 1.59 0.76 11.74 11.21 0.47 0.01 0.00 0.02 98.84 ES12792Am-4.1 40.80 2.86 13.38 13.78 2.61 0.43 12.93 11.09 0.09 0.00 0.01 0.02 98.00 ES12792Am-4.2 41.38 2.83 13.53 13.39 2.57 0.44 13.15 11.08 0.07 0.00 0.00 0.02 98.47 ES12792Am-6.1 42.02 2.88 13.27 10.97 2.63 0.38 14.53 11.15 0.13 0.07 0.00 0.02 98.05 ES12792Am-6.2 41.80 2.89 13.26 11.07 2.65 0.38 14.38 11.17 0.11 0.02 0.00 0.01 97.75 ES12792Am-7.1 44.99 0.85 10.67 15.72 1.98 0.53 12.47 10.35 0.28 0.02 0.00 0.03 97.88 ES12792Am-7.2 44.14 0.93 10.99 15.56 1.92 0.54 12.46 10.62 0.31 0.00 0.00 0.04 97.51 ES12792Am-8.1 42.04 2.37 12.10 13.96 2.38 0.51 13.28 11.33 0.21 0.00 0.00 0.03 98.21 ES12792Am-9.1 45.26 1.00 8.74 17.86 1.55 0.76 11.61 11.28 0.42 0.00 0.00 0.03 98.50 ES12792Am-9.2 45.19 0.95 8.51 17.93 1.58 0.70 11.82 11.29 0.41 0.00 0.00 0.03 98.41 ES12792Am-10.1 42.45 2.92 13.26 11.01 2.62 0.44 14.74 11.34 0.11 0.00 0.00 0.01 98.91 ES12792Am-11.1 41.44 2.94 13.57 12.44 2.62 0.38 13.91 11.25 0.10 0.00 0.00 0.01 98.65 ES12792Am-12.1 42.07 2.63 13.07 13.38 2.57 0.44 13.18 11.27 0.13 0.01 0.00 0.02 98.77 ES12792Am-12.2 42.20 2.94 13.29 11.23 2.57 0.48 14.22 11.26 0.08 0.11 0.00 0.01 98.38

275

Table C3: El Salvador apatite composition by electron microprobe analysis.

Sample CaO P2O5 FeO MnO SO 3 Ce 2O3 Na 2O MgO SiO 2 F Cl sum ES12781_Apatite-1.1 54.08 40.79 0.28 0.14 0.15 0.09 0.06 0.00 0.06 1.34 0.23 97.21 ES12781_Apatite-1.2 53.78 40.91 0.53 0.12 0.60 0.09 0.25 0.06 0.19 1.41 0.13 98.08

ES12785a_Apatite-1.1 54.63 41.03 0.06 0.02 0.11 0.27 0.12 0.00 0.04 4.02 0.17 100.47 ES12785a_Apatite-1.2 54.46 40.84 0.03 0.04 0.16 0.25 0.20 0.00 0.00 2.76 0.32 99.07 ES12785a_Apatite-1.3 54.44 40.93 0.17 0.03 0.17 0.26 0.20 0.03 0.14 2.54 0.24 99.15 ES12785a_Apatite-1.4 54.39 41.67 0.12 0.14 0.22 0.10 0.21 0.01 0.00 2.42 0.32 99.60 ES12785a_Apatite-1.5 54.16 40.80 0.09 0.07 0.10 0.16 0.17 0.00 0.02 3.81 0.19 99.58 ES12785a_Apatite-2.1 54.52 41.06 0.26 0.21 0.23 0.19 0.19 0.02 0.00 2.56 0.36 99.58 ES12785a_Apatite-2.2 54.02 40.74 0.26 0.10 0.49 0.16 0.34 0.02 0.00 2.62 0.41 99.17

ES12782_Apatite-1.1 55.29 41.77 0.01 0.05 0.03 0.00 0.00 0.00 0.00 2.58 0.18 99.91 ES12782_Apatite-1.2 54.95 42.06 0.12 0.03 0.00 0.00 0.01 0.00 0.00 2.69 0.14 100.00 ES12782_Apatite-2.1 55.20 42.02 0.04 0.14 0.01 0.08 0.00 0.00 0.00 2.84 0.18 100.52 ES12782_Apatite-2.2 54.83 42.02 0.04 0.07 0.00 0.00 0.06 0.00 0.00 2.93 0.17 100.13 ES12782_Apatite-2.3 54.48 41.42 0.13 0.15 0.00 0.03 0.01 0.00 0.02 3.42 0.13 99.80 ES12782_Apatite-3.1 54.87 41.19 0.18 0.20 0.14 0.00 0.03 0.02 0.11 2.12 0.32 99.18 ES12782_Apatite-3.2 54.18 41.04 0.07 0.14 0.32 0.01 0.17 0.03 0.13 2.32 0.33 98.75 ES12782_Apatite-4.1 53.96 41.07 0.09 0.09 0.09 0.26 0.04 0.00 0.15 1.83 0.15 97.72 ES12782_Apatite-4.2 54.43 41.15 0.08 0.29 0.13 0.21 0.07 0.00 0.14 2.01 0.20 98.71 ES12782_Apatite-4.3 54.10 41.33 0.06 0.19 0.09 0.17 0.07 0.02 0.11 2.21 0.26 98.60 ES12782_Apatite-5.1 53.85 40.88 0.11 0.19 0.13 0.16 0.14 0.05 0.08 1.36 0.81 97.75 ES12782_Apatite-5.2 53.71 40.75 0.19 0.18 0.24 0.15 0.15 0.02 0.11 1.44 0.85 97.80 ES12782_Apatite-5.3 53.63 41.03 0.19 0.18 0.18 0.24 0.12 0.03 0.15 1.20 0.84 97.79

ES12789a_Apatite-1.1 53.91 41.35 0.75 0.08 0.04 0.17 0.09 0.00 0.48 1.82 1.14 99.85 ES12789a_Apatite-2.1 55.02 41.97 0.04 0.00 0.01 0.05 0.03 0.00 0.05 1.67 0.78 99.63 ES12789a_Apatite-2.2 54.42 41.25 0.05 0.18 0.03 0.16 0.04 0.00 0.13 1.61 1.53 99.40 ES12789a_Apatite-3.1 55.34 41.97 0.00 0.01 0.02 0.13 0.03 0.00 0.01 2.61 0.53 100.65 ES12789a_Apatite-3.2 54.68 41.63 0.29 0.02 0.03 0.11 0.05 0.00 0.03 2.37 0.69 99.88

ES12787_Apatite-1.1 53.63 40.81 0.14 0.00 0.29 0.47 0.20 0.00 0.16 2.14 1.04 98.88 ES12787_Apatite-1.2 54.01 41.32 0.11 0.07 0.30 0.45 0.25 0.01 0.16 2.17 0.89 99.72 ES12787_Apatite-2.1 54.98 41.50 0.03 0.04 0.02 0.05 0.03 0.00 0.04 2.16 0.22 99.07 ES12787_Apatite-2.2 54.43 41.02 0.03 0.08 0.14 0.43 0.14 0.00 0.14 2.07 0.89 99.36 ES12787_Apatite-2.3 54.77 41.50 0.10 0.03 0.01 0.11 0.05 0.00 0.05 2.21 0.42 99.24 ES12787_Apatite-3.1 54.36 40.70 0.06 0.00 0.03 0.27 0.01 0.00 0.15 2.70 0.07 98.33 ES12787_Apatite-3.2 54.35 41.03 0.00 0.03 0.11 0.29 0.14 0.00 0.12 2.85 0.43 99.35

ES12792_Apatite-0.1 54.99 40.63 0.12 0.07 0.15 0.00 0.04 0.07 0.06 1.47 0.26 97.85 ES12792_Apatite-0.2 54.47 41.03 0.27 0.10 0.12 0.04 0.08 0.13 0.06 1.75 0.23 98.27 ES12792_Apatite-0.3 53.88 41.10 0.15 0.00 0.14 0.02 0.05 0.08 0.07 1.55 0.30 97.34 ES12792_Apatite-1.1 55.20 42.25 0.00 0.00 0.15 0.07 0.03 0.01 0.04 1.51 0.21 99.48 ES12792_Apatite-1.2 55.53 42.29 0.08 0.22 0.28 0.01 0.06 0.01 0.10 1.41 0.12 100.10 ES12792_Apatite-1.3 55.31 42.06 0.07 0.07 0.14 0.02 0.05 0.01 0.08 1.44 0.13 99.37

276

Table C3: Cont.

Sample CaO P2O5 FeO MnO SO 3 Ce 2O3 Na 2O MgO SiO 2 F Cl sum ES12792_Apatite-3.1 55.39 42.33 0.00 0.03 0.10 0.01 0.07 0.00 0.04 1.56 0.13 99.67 ES12792_Apatite-3.2 54.90 42.18 0.08 0.10 0.10 0.17 0.05 0.00 0.11 1.11 0.16 98.96 ES12792_Apatite-2.1 54.97 42.24 0.13 0.06 0.15 0.06 0.05 0.02 0.06 1.46 0.21 99.40 ES12792_Apatite-5.1 55.09 42.65 0.12 0.04 0.09 0.08 0.07 0.01 0.10 1.05 0.25 99.53 ES12792_Apatite-5.2 55.06 42.35 0.22 0.01 0.15 0.13 0.07 0.08 0.06 1.29 0.33 99.74 ES12792_Apatite-6.1 54.91 42.49 0.25 0.08 0.17 0.22 0.06 0.02 0.14 1.48 0.32 100.13 ES12792_Apatite-6.2 54.93 41.99 0.13 0.02 0.13 0.09 0.04 0.02 0.04 1.10 0.25 98.76 ES12792_Apatite-7.1 55.45 42.50 0.03 0.09 0.08 0.03 0.04 0.01 0.05 1.77 0.12 100.18 ES12792_Apatite-7.2 52.63 41.23 0.51 0.06 0.74 0.00 0.21 0.25 1.83 1.08 0.30 98.85 ES12792_Apatite-7.3 55.43 42.36 0.15 0.13 0.15 0.18 0.02 0.00 0.03 1.42 0.20 100.07 ES12792_Apatite-7.4 56.15 42.05 0.08 0.12 0.11 0.19 0.03 0.00 0.04 1.56 0.16 100.49 ES12792_Apatite-8.1 55.28 42.37 0.14 0.01 0.30 0.00 0.11 0.02 0.15 1.40 0.14 99.93 ES12792_Apatite-9.1 55.34 41.94 0.13 0.12 0.10 0.06 0.06 0.03 0.06 1.10 0.20 99.13 ES12792_Apatite-9.2 55.24 42.26 0.00 0.12 0.14 0.09 0.06 0.00 0.10 1.15 0.18 99.35 ES12792_Apatite-10.1 54.59 42.55 0.20 0.00 0.13 0.05 0.05 0.06 0.04 1.14 0.29 99.09 ES12792_Apatite-12.1 54.92 42.15 0.07 0.09 0.08 0.10 0.04 0.02 0.09 1.71 0.13 99.40 ES12792_Apatite-12.2 55.15 41.89 0.07 0.12 0.19 0.20 0.08 0.00 0.18 1.67 0.13 99.66 ES12792_Apatite-12.3 55.50 42.50 0.05 0.19 0.11 0.08 0.03 0.01 0.03 1.50 0.14 100.14 ES12792_Apatite-12.4 55.44 42.02 0.13 0.05 0.17 0.02 0.07 0.01 0.06 1.40 0.10 99.47 ES12792_Apatite-13.1 55.43 42.12 0.11 0.03 0.18 0.14 0.09 0.01 0.08 1.53 0.14 99.86 ES12792_Apatite-13.2 55.36 42.57 0.03 0.20 0.14 0.18 0.02 0.00 0.05 1.73 0.12 100.40 ES12792_Apatite-14.1 55.66 42.96 0.13 0.07 0.13 0.19 0.03 0.00 0.05 1.47 0.12 100.81 ES12792_Apatite-14.2 55.19 41.74 0.14 0.06 0.22 0.15 0.08 0.01 0.09 1.61 0.14 99.44 ES12792_Apatite-15.1 54.72 42.52 0.06 0.10 0.10 0.12 0.05 0.01 0.04 1.24 0.26 99.21 ES12792_Apatite-15.2 55.22 42.36 0.11 0.10 0.12 0.28 0.05 0.02 0.11 1.36 0.20 99.94 ES12792_Apatite-15.3 55.28 42.04 0.02 0.06 0.11 0.06 0.03 0.03 0.06 1.39 0.17 99.25 ES12792_Apatite-17.1 55.15 42.21 0.13 0.04 0.15 0.17 0.07 0.03 0.05 1.11 0.26 99.37 ES12792_Apatite-17.2 54.55 41.75 0.43 0.12 0.14 0.15 0.09 0.08 0.07 1.14 0.30 98.81 ES12792_Apatite-17.3 55.09 41.88 0.21 0.06 0.16 0.02 0.04 0.05 0.12 1.26 0.29 99.18 ES12792_Apatite-18.1 55.30 42.06 0.06 0.12 0.15 0.06 0.04 0.03 0.06 1.11 0.15 99.12 ES12792_Apatite-18.2 55.00 42.20 0.17 0.06 0.18 0.11 0.04 0.00 0.03 1.14 0.19 99.11 ES12792_Apatite-18.3 55.37 41.95 0.15 0.04 0.12 0.05 0.07 0.02 0.04 1.25 0.22 99.28 ES12792_Apatite-19.1 55.57 42.19 0.17 0.08 0.12 0.17 0.04 0.10 0.05 1.52 0.19 100.21 ES12792_Apatite-19.2 54.83 41.90 0.00 0.08 0.13 0.15 0.04 0.00 0.04 1.66 0.12 98.95 ES12792_Apatite-19.3 55.26 41.77 0.13 0.03 0.08 0.03 0.05 0.02 0.05 1.43 0.12 98.97 ES12792_Apatite-20.1 54.67 41.47 0.10 0.09 0.17 0.09 0.06 0.03 0.05 1.47 0.13 98.33 ES12792_Apatite-20.2 55.00 42.15 0.07 0.12 0.12 0.13 0.09 0.00 0.09 1.91 0.13 99.83 ES12792_Apatite-20.3 54.82 42.23 0.12 0.08 0.10 0.01 0.09 0.04 0.04 1.99 0.13 99.63 ES12792_Apatite-21.1 55.19 42.63 0.03 0.09 0.15 0.06 0.08 0.02 0.03 1.76 0.12 100.15 ES12792_Apatite-21.2 55.32 42.11 0.09 0.13 0.12 0.06 0.04 0.01 0.08 1.40 0.07 99.42 ES12792_Apatite-22.1 55.43 42.10 0.14 0.04 0.16 0.13 0.05 0.00 0.07 1.63 0.18 99.93 ES12792_Apatite-22.2 54.90 41.96 0.03 0.10 0.25 0.11 0.09 0.00 0.10 1.53 0.16 99.23 ES12792_Apatite-23.1 55.21 41.91 0.09 0.16 0.10 0.13 0.04 0.01 0.03 0.97 0.17 98.83 ES12792_Apatite-23.2 55.00 42.03 0.07 0.11 0.15 0.04 0.06 0.01 0.02 1.21 0.14 98.83 ES12792_Apatite-23.3 55.47 41.91 0.11 0.02 0.13 0.15 0.09 0.01 0.04 1.30 0.12 99.34

277

Table C3: Cont.

Sample CaO P2O5 FeO MnO SO 3 Ce 2O3 Na 2O MgO SiO 2 F Cl sum ES12792_Apatite-24.1 55.25 42.60 0.03 0.06 0.16 0.00 0.05 0.04 0.05 1.32 0.16 99.72 ES12792_Apatite-24.2 55.23 42.16 0.10 0.13 0.12 0.07 0.07 0.01 0.07 1.47 0.23 99.64 ES12792_Apatite-24.3 54.98 42.59 0.28 0.10 0.12 0.09 0.05 0.05 0.02 1.41 0.23 99.92 ES12792_Apatite-25.1 55.06 42.13 0.08 0.07 0.11 0.16 0.05 0.00 0.06 1.46 0.18 99.37 ES12792_Apatite-25.2 55.29 42.40 0.21 0.08 0.11 0.07 0.07 0.04 0.09 1.32 0.14 99.83 ES12792_Apatite-26.1 55.05 42.31 0.13 0.06 0.21 0.24 0.06 0.02 0.07 2.07 0.15 100.37 ES12792_Apatite-26.2 55.02 42.36 0.12 0.07 0.14 0.00 0.08 0.01 0.04 1.98 0.14 99.96 ES12792_Apatite-27.1 54.98 41.88 0.17 0.03 0.12 0.12 0.04 0.06 0.05 1.63 0.26 99.34 ES12792_Apatite-27.2 55.06 42.04 0.10 0.05 0.15 0.06 0.07 0.01 0.12 1.81 0.12 99.58 ES12792_Apatite-28.1 55.37 42.71 0.13 0.10 0.09 0.00 0.08 0.05 0.06 1.18 0.19 99.97 ES12792_Apatite-29.1 55.27 42.09 0.07 0.17 0.18 0.02 0.05 0.00 0.06 1.19 0.18 99.27 ES12792_Apatite-29.2 55.21 42.04 0.10 0.08 0.13 0.10 0.00 0.00 0.04 1.38 0.17 99.25 ES12792_Apatite-29.3 55.42 41.65 0.04 0.13 0.10 0.12 0.02 0.01 0.09 1.15 0.30 99.03

278

Table C4: El Salvador biotite composition by electron microprobe analysis.

Sample SiO 2 Al 2O3 MgO FeO K2O TiO 2 Na 2O CaO MnO F Cl Sum ES-12783-Biotite-1.1 40.04 14.58 15.06 15.06 9.01 2.80 0.11 0.01 0.07 0.16 0.26 97.16 ES-12783-Biotite-1.2 37.01 16.95 13.93 16.04 9.66 3.13 0.09 0.00 0.07 0.18 0.28 97.34 ES-12783-Biotite-1.3 37.26 16.84 13.29 16.96 9.71 3.08 0.05 0.00 0.10 0.20 0.26 97.76 ES-12783-Biotite-2.1 36.43 16.03 13.19 15.58 9.26 2.86 0.11 0.05 0.10 0.14 0.23 93.97 ES-12783-Biotite-2.2 39.00 14.11 14.71 14.05 8.58 2.67 0.12 0.08 0.11 0.32 0.23 93.96 ES-12783-Biotite-3.1 38.73 16.06 14.10 16.43 9.41 2.97 0.08 0.01 0.12 0.25 0.22 98.37 ES-12783-Biotite-3.2 41.37 13.70 14.96 15.14 8.74 2.53 0.06 0.00 0.05 0.30 0.22 97.08 ES-12783-Biotite-3.3 40.99 14.68 15.87 14.52 8.52 2.85 0.11 0.06 0.02 0.33 0.23 98.18 ES-12783-Biotite-4.1 42.09 13.58 17.21 13.85 8.54 2.61 0.08 0.00 0.08 0.36 0.25 98.65 ES-12783-Biotite-4.2 37.74 16.75 14.27 15.99 9.52 3.23 0.10 0.00 0.06 0.11 0.25 98.01 ES-12783-Biotite-4.3 38.98 14.90 13.96 15.86 8.83 2.85 0.11 0.09 0.07 0.20 0.23 96.08 ES-12783-Biotite-4.4 38.69 15.73 14.69 15.63 9.54 3.05 0.06 0.00 0.10 0.16 0.20 97.84

ES-12785a-Biotite-1.1 38.91 13.75 16.85 14.29 9.59 3.77 0.10 0.00 0.05 1.01 0.10 98.43 ES-12785a-Biotite-1.2 39.11 13.87 16.54 15.03 9.65 4.07 0.12 0.00 0.05 1.10 0.10 99.65 ES-12785a-Biotite-2.1 38.17 14.02 15.88 15.10 9.34 4.33 0.13 0.00 0.04 0.74 0.16 97.91 ES-12785a-Biotite-2.2 37.72 14.36 16.09 15.46 9.45 4.26 0.12 0.00 0.07 0.75 0.15 98.42 ES-12785a-Biotite-2.3 37.81 14.17 15.63 15.76 9.53 4.23 0.10 0.00 0.05 0.77 0.12 98.18 ES-12785a-Biotite-2.4 37.75 13.93 15.50 15.84 9.44 4.19 0.10 0.00 0.06 0.70 0.17 97.69 ES-12785a-Biotite-2.5 36.29 15.87 18.05 16.23 7.61 2.47 0.09 0.02 0.05 0.84 0.11 97.64 ES-12785a-Biotite-2.6 38.64 13.69 16.06 15.55 9.30 3.91 0.11 0.01 0.04 0.79 0.12 98.20 ES-12785a-Biotite-3.1 38.53 14.19 16.43 14.98 9.47 4.09 0.10 0.00 0.03 0.90 0.12 98.84 ES-12785a-Biotite-3.2 38.58 14.26 16.93 14.89 9.44 3.82 0.12 0.00 0.05 0.92 0.13 99.14 ES-12785a-Biotite-3.3 38.29 14.30 16.45 14.87 9.59 4.15 0.10 0.00 0.06 0.88 0.14 98.83 ES-12785a-Biotite-3.4 38.45 14.25 16.23 15.47 9.30 3.86 0.11 0.00 0.07 0.84 0.11 98.68 ES-12785a-Biotite-4.1 37.43 13.71 15.32 14.92 9.01 4.12 0.14 0.04 0.08 0.61 0.19 95.56 ES-12785a-Biotite-4.2 37.49 13.59 15.29 14.92 8.82 3.78 0.17 0.06 0.07 0.63 0.15 94.98 ES-12785a-Biotite-4.3 37.43 13.85 14.93 15.72 8.89 3.99 0.12 0.05 0.07 0.62 0.18 95.83 ES-12785a-Biotite-4.4 37.33 13.67 15.01 15.52 9.04 4.03 0.12 0.03 0.06 0.72 0.17 95.69 ES-12785a-Biotite-5.1 46.50 11.73 13.04 13.62 7.49 3.60 0.13 0.10 0.07 0.57 0.17 97.02 ES-12785a-Biotite-5.2 37.00 13.47 15.00 15.27 8.81 4.11 0.15 0.09 0.05 0.64 0.18 94.76 ES-12785a-Biotite-5.3 37.80 13.58 15.70 14.61 8.69 3.46 0.16 0.10 0.05 0.65 0.16 94.97

ES-12787-Biotite-1.1 38.95 13.32 15.73 15.58 9.35 3.91 0.09 0.00 0.07 0.39 0.16 97.53 ES-12787-Biotite-1.2 38.94 13.30 15.71 15.59 8.99 3.91 0.10 0.05 0.10 0.40 0.16 97.25 ES-12787-Biotite-1.3 38.69 13.24 15.77 15.11 9.42 4.18 0.09 0.04 0.04 0.46 0.17 97.21 ES-12787-Biotite-1.4 39.32 13.13 15.98 15.45 9.29 4.10 0.08 0.00 0.05 0.40 0.16 97.97 ES-12787-Biotite-1.5 39.03 13.19 15.81 15.65 9.32 4.21 0.09 0.00 0.08 0.42 0.16 97.96 ES-12787-Biotite-1.6 39.34 12.68 16.04 15.36 9.07 4.36 0.11 0.00 0.08 0.42 0.16 97.61 ES-12787-Biotite-1.7 37.65 13.97 14.91 16.33 9.49 4.42 0.11 0.00 0.08 0.25 0.16 97.37 ES-12787-Biotite-1.8 39.64 12.86 16.13 15.28 9.26 4.01 0.10 0.00 0.08 0.46 0.15 97.97

ES-12781-Biotite-1.1 38.19 14.67 14.06 15.89 8.44 3.61 0.47 0.04 0.20 0.52 0.05 96.12 ES-12781-Biotite-1.2 37.85 14.75 16.81 13.59 7.68 3.85 0.88 0.07 0.14 0.30 0.05 95.96 ES-12781-Biotite-2.1 36.67 13.87 12.26 19.50 8.40 3.58 0.37 0.06 0.25 0.18 0.04 95.18

279

Table C4: Cont.

Sample SiO 2 Al 2O3 MgO FeO K2O TiO 2 Na 2O CaO MnO F Cl Sum ES-12781-Biotite-2.2 36.60 14.01 12.41 19.09 8.61 3.53 0.38 0.05 0.30 0.17 0.05 95.19 ES-12781-Biotite-2.3 36.73 14.09 12.37 19.46 8.72 3.57 0.35 0.03 0.23 0.17 0.03 95.76 ES-12781-Biotite-2.4 37.33 13.99 13.64 18.03 8.46 3.63 0.47 0.04 0.20 0.25 0.05 96.10

ES-12789a-Biotite-1.1 38.74 14.14 15.97 14.56 9.39 4.38 0.11 0.02 0.09 0.19 0.38 97.95 ES-12789a-Biotite-1.2 39.45 13.82 16.42 14.54 9.11 4.34 0.08 0.01 0.14 0.21 0.38 98.51 ES-12789a-Biotite-2.1 38.50 13.97 16.23 14.20 9.40 4.62 0.10 0.01 0.12 0.26 0.38 97.78 ES-12789a-Biotite-2.2 38.63 14.08 16.21 14.32 9.46 4.65 0.08 0.02 0.15 0.27 0.32 98.19 ES-12789a-Biotite-2.3 38.74 13.88 16.29 14.51 9.53 4.59 0.10 0.01 0.10 0.23 0.32 98.30 ES-12789a-Biotite-2.4 38.67 14.04 16.50 14.16 9.55 4.59 0.08 0.01 0.15 0.23 0.35 98.32 ES-12789a-Biotite-2.5 38.54 13.85 16.15 14.18 9.35 4.59 0.11 0.03 0.14 0.26 0.34 97.54 ES-12789a-Biotite-2.6 38.47 13.17 16.06 14.16 9.11 4.42 0.10 0.05 0.13 0.18 0.37 96.22 ES-12789a-Biotite-2.7 37.98 13.60 14.80 15.67 9.22 4.56 0.09 0.08 0.16 0.17 0.36 96.70 ES-12789a-Biotite-2.8 38.15 13.65 15.63 14.25 8.94 4.52 0.08 0.06 0.15 0.16 0.34 95.92 ES-12789a-Biotite-3.1 38.60 14.03 16.10 14.43 9.32 4.52 0.12 0.02 0.14 0.29 0.33 97.89 ES-12789a-Biotite-3.2 38.38 13.77 16.13 14.22 9.31 4.46 0.12 0.02 0.14 0.22 0.37 97.12 ES-12789a-Biotite-3.3 39.08 13.73 16.46 14.13 9.41 4.50 0.12 0.02 0.13 0.21 0.37 98.16

ES-12800-Biotite-1.1 37.73 15.11 14.95 15.09 9.05 3.86 0.16 0.00 0.05 0.18 0.17 96.35 ES-12800-Biotite-1.2 37.88 15.24 14.99 14.90 9.19 3.88 0.18 0.00 0.09 0.24 0.17 96.74 ES-12800-Biotite-1.3 37.66 14.97 14.91 15.13 9.09 3.77 0.18 0.00 0.10 0.27 0.25 96.33 ES-12800-Biotite-1.4 37.74 14.93 14.95 15.29 9.08 3.90 0.22 0.00 0.09 0.17 0.15 96.53 ES-12800-Biotite-1.5 37.79 15.24 15.05 15.08 9.29 3.58 0.14 0.00 0.07 0.13 0.19 96.56

ES-12807-Biotite-1.1 37.88 15.76 12.88 16.76 9.08 4.04 0.15 0.03 0.10 0.95 0.17 97.81 ES-12807-Biotite-1.2 37.67 15.47 12.81 17.05 9.16 4.35 0.18 0.00 0.15 0.66 0.19 97.69 ES-12807-Biotite-1.3 36.64 17.12 14.05 17.30 5.45 2.63 0.14 0.10 0.12 0.53 0.14 94.22

280

Table C5: El Salvador plagioclase composition by electron microprobe analysis.

Sample SiO 2 Al 2O3 Na 2O CaO FeO K2O TiO 2 MgO SrO sum ES-12783-1.1rim 59.41 25.67 6.77 6.89 0.15 0.35 0.02 0.00 0.09 99.37 ES-12783-1.2rim 58.64 26.41 6.73 7.39 0.17 0.19 0.01 0.00 0.11 99.65 ES-12783-1.3core 58.76 26.06 6.64 7.23 0.19 0.33 0.00 0.00 0.13 99.33 ES-12783-1.4core 57.07 27.23 6.12 8.58 0.17 0.24 0.00 0.00 0.20 99.62

ES-12792-1.1 54.76 28.57 5.15 10.05 0.38 0.19 0.03 0.02 0.18 99.33 ES-12792-1.2 54.95 28.40 5.21 10.13 0.37 0.17 0.01 0.03 0.19 99.46 ES-12792-1.3core 54.62 28.51 5.09 10.15 0.31 0.17 0.01 0.03 0.23 99.12 ES-12792-1.4core 54.71 28.55 5.13 10.34 0.32 0.17 0.01 0.02 0.17 99.41 ES-12792-1.5core 55.60 28.11 5.37 9.64 0.36 0.21 0.01 0.01 0.28 99.59 ES-12792-2.1rim 54.99 28.25 5.23 9.99 0.32 0.17 0.01 0.02 0.21 99.18 ES-12792-2.2rim 55.22 28.22 5.26 10.05 0.30 0.17 0.05 0.02 0.21 99.51 ES-12792-2.3gz 58.05 26.62 6.28 7.89 0.19 0.33 0.02 0.01 0.20 99.60 ES-12792-2.4gz 57.19 27.13 5.83 8.54 0.21 0.24 0.00 0.01 0.19 99.36 ES-12792-2.5svcore 55.16 28.07 5.30 9.79 0.30 0.17 0.01 0.01 0.19 99.00

ES-12781-1.1rim 54.93 28.38 5.20 9.75 0.25 0.20 0.01 0.02 0.23 98.97 ES-12781-1.2rim 56.74 28.14 5.74 9.01 0.26 0.23 0.02 0.01 0.17 100.32 ES-12781-1.3core 56.21 27.71 5.59 9.19 0.26 0.21 0.03 0.02 0.30 99.52 ES-12781-1.4core 55.11 28.60 5.24 9.94 0.27 0.21 0.03 0.01 0.25 99.64 ES-12781-1.5rim 55.44 27.72 5.39 9.06 0.34 0.34 0.04 0.03 0.20 98.57 ES-12781-1.6rim 59.39 26.68 6.61 7.08 0.22 0.34 0.03 0.01 0.26 100.61 ES-12781-1.7rim 59.79 26.73 6.73 7.00 0.28 0.30 0.02 0.01 0.16 101.02

ES-12789a-1.1rim 59.52 24.85 7.02 5.86 0.23 0.45 0.00 0.00 0.15 98.09 ES-12789a-1.2rim 60.36 25.30 7.12 5.87 0.17 0.50 0.00 0.00 0.22 99.55 ES-12789a-1.3core 58.57 26.22 6.43 7.19 0.28 0.39 0.01 0.00 0.08 99.18 ES-12789a-1.4core 56.96 26.08 6.35 7.26 1.52 0.44 0.02 0.00 0.10 98.73 ES-12789a-1.5core 59.43 26.42 6.80 6.95 0.11 0.42 0.01 0.00 0.07 100.21

ES-12787-1.1rim 58.51 26.20 6.54 7.02 0.38 0.46 0.00 0.22 0.08 99.42 ES-12787-1.2rim 59.93 25.60 6.96 6.16 0.15 0.47 0.02 0.01 0.16 99.46 ES-12787-1.3core 60.51 25.11 7.27 5.89 0.19 0.47 0.00 0.00 0.12 99.57 ES-12787-1.4rim 60.31 25.62 7.23 6.01 0.16 0.46 0.01 0.00 0.18 99.98 ES-12787-2.1rim 57.58 27.25 6.15 8.36 0.22 0.22 0.01 0.00 0.19 99.98 ES-12787-2.2rim 57.92 27.00 6.23 7.63 0.20 0.26 0.01 0.00 0.19 99.45 ES-12787-2.3core 60.69 25.75 7.26 5.90 0.19 0.48 0.01 0.00 0.13 100.40

ES-12800-1.1rim 58.13 26.67 6.36 7.71 0.19 0.30 0.00 0.00 0.11 99.46 ES-12800-1.2rim 58.35 26.00 6.42 7.37 0.18 0.35 0.00 0.00 0.09 98.77 ES-12800-1.3rim 59.71 26.24 6.80 6.99 0.22 0.35 0.01 0.00 0.15 100.49 ES-12800-1.4core 59.79 25.84 6.90 6.76 0.13 0.39 0.02 0.00 0.15 99.98 ES-12800-1.5core 60.18 25.86 6.96 6.41 0.18 0.31 0.01 0.00 0.09 100.00 ES-12800-1.6core 59.94 25.92 7.09 6.39 0.19 0.28 0.00 0.00 0.15 99.97 ES-12800-1.7core 59.44 26.33 6.76 6.91 0.17 0.35 0.01 0.00 0.11 100.08

281

Table C5: Cont.

Sample SiO 2 Al 2O3 Na 2O CaO FeO K2O TiO 2 MgO SrO sum ES-12800-2.1rim 58.99 25.43 7.10 6.08 0.18 0.24 0.00 0.00 0.15 98.17 ES-12800-2.2rim 69.07 21.06 10.67 0.16 0.07 0.16 0.00 0.00 0.00 101.20 ES-12800-2.3rim 59.10 25.64 6.67 6.81 0.16 0.37 0.00 0.00 0.08 98.83 ES-12800-2.4core 59.80 25.55 6.83 6.69 0.17 0.37 0.00 0.00 0.10 99.52 ES-12800-2.5core 60.52 25.28 7.24 5.98 0.17 0.42 0.00 0.01 0.09 99.72 ES-12800-2.6core 59.73 25.72 6.84 6.73 0.19 0.40 0.00 0.01 0.11 99.73 ES-12800-2.7core 58.49 26.30 6.62 7.22 0.20 0.30 0.00 0.00 0.21 99.35 ES-12800-3.1rim 69.56 21.04 10.47 0.14 0.06 0.31 0.00 0.00 0.00 101.59 ES-12800-3.2rim 58.68 26.39 6.56 7.44 0.21 0.35 0.01 0.00 0.15 99.79 ES-12800-3.3rim 59.35 26.40 6.72 6.87 0.17 0.42 0.00 0.00 0.14 100.07 ES-12800-3.4core 59.12 26.23 6.73 7.08 0.18 0.38 0.01 0.00 0.14 99.87 ES-12800-3.5core 59.47 25.91 6.67 6.83 0.17 0.42 0.02 0.01 0.12 99.62 ES-12800-3.6core 59.06 26.12 6.78 6.96 0.16 0.34 0.01 0.00 0.11 99.53 ES-12800-3.7core 59.16 26.19 6.74 6.98 0.15 0.37 0.01 0.00 0.12 99.71 ES-12800-3.8core 59.61 25.77 7.20 6.37 0.21 0.41 0.01 0.00 0.07 99.64 ES-12800-3.9core 60.19 25.59 7.06 6.48 0.16 0.44 0.00 0.00 0.17 100.09 ES-12800-3.10rim 59.15 26.25 6.84 6.89 0.18 0.26 0.00 0.00 0.14 99.72 ES-12800-3.11rim 60.11 25.85 6.88 6.65 0.14 0.43 0.01 0.01 0.09 100.16 ES-12800-4.1core 60.65 25.28 7.38 5.82 0.15 0.37 0.00 0.01 0.15 99.80 ES-12800-4.2core 60.27 25.78 7.03 6.17 0.14 0.45 0.00 0.01 0.13 99.99 ES-12800-4.3core 60.81 25.20 7.22 5.55 0.18 0.50 0.00 0.01 0.13 99.61 ES-12800-4.4core 59.83 25.97 6.92 6.56 0.14 0.46 0.01 0.00 0.06 99.96 ES-12800-4.5core 59.05 26.03 6.75 6.84 0.18 0.40 0.01 0.00 0.19 99.45 ES-12800-4.6rim 59.55 25.81 6.84 6.62 0.18 0.44 0.02 0.00 0.08 99.53 ES-12800-4.7rim 57.64 26.98 6.26 7.71 0.20 0.32 0.00 0.01 0.10 99.22 ES-12800-4.8rim 58.60 26.56 6.52 7.44 0.20 0.33 0.00 0.00 0.20 99.86 ES-12800-4.9rim 69.28 21.26 10.57 0.17 0.09 0.16 0.02 0.00 0.00 101.54

ES-12807-1.1rim 61.65 25.81 7.46 5.70 0.21 0.51 0.00 0.00 0.18 101.52 ES-12807-1.2core 60.88 25.55 7.30 5.68 0.18 0.50 0.02 0.00 0.13 100.25 ES-12807-1.3rim 58.84 26.64 6.78 7.21 0.19 0.33 0.00 0.00 0.19 100.18 ES-12807-2.1rim 66.61 23.92 9.21 2.90 0.16 0.26 0.02 0.00 0.07 103.16 ES-12807-2.2rim 59.06 26.43 6.80 6.80 0.16 0.34 0.01 0.00 0.20 99.81 ES-12807-2.3core 60.27 26.10 7.09 6.31 0.19 0.47 0.01 0.02 0.12 100.59 ES-12807-2.4core 58.96 26.53 6.71 7.08 0.18 0.40 0.01 0.00 0.10 99.97 ES-12807-2.5rim 59.32 26.41 6.77 6.87 0.19 0.43 0.03 0.01 0.09 100.11 ES-12807-2.6rim 61.14 26.11 7.16 6.30 0.19 0.47 0.01 0.01 0.17 101.56 ES-12807-3.1rim 62.83 25.41 7.78 5.05 0.15 0.45 0.00 0.00 0.02 101.70 ES-12807-3.2rim 59.31 26.94 6.62 7.27 0.15 0.41 0.01 0.01 0.19 100.93 ES-12807-3.3rim 57.70 27.36 6.02 8.21 0.16 0.33 0.00 0.02 0.16 99.96 ES-12807-3.4core 60.55 26.50 6.98 6.53 0.18 0.45 0.01 0.00 0.12 101.34 ES-12807-3.5core 59.52 26.78 6.62 6.96 0.16 0.45 0.01 0.01 0.09 100.60 ES-12807-3.6core 59.54 26.81 6.69 6.82 0.15 0.38 0.01 0.01 0.10 100.50 ES-12807-3.7core 61.23 26.04 7.17 5.93 0.19 0.44 0.00 0.00 0.18 101.19 ES-12807-3.8core 58.12 26.95 6.21 7.82 0.17 0.38 0.00 0.00 0.18 99.83

282

Table C6: El Salvador titanite composition by electron microprobe analysis. sample SiO 2 TiO 2 CaO Fe 2O3 Al 2O3 MnO Na 2O MgO K2O F sum ES-12785a-1.1 30.47 39.20 27.02 1.52 1.21 0.15 0.01 0.00 0.00 0.01 99.60 ES-12785a-1.2 30.39 39.44 27.21 1.44 1.18 0.13 0.00 0.00 0.01 0.00 99.79 ES-12785a-4.1 30.06 39.70 26.96 1.76 0.38 0.04 0.02 0.00 0.00 0.01 98.92 ES-12785a-4.2 30.27 40.34 26.70 1.65 0.40 0.00 0.03 0.00 0.00 0.01 99.40 ES-12785a-4.3 30.47 40.14 27.53 1.64 0.38 0.01 0.04 0.01 0.00 0.01 100.23 ES-12785a-5.1 30.07 39.78 26.99 1.57 1.16 0.12 0.01 0.00 0.00 0.01 99.70 ES-12785a-5.2 29.97 39.68 26.94 1.27 0.96 0.12 0.03 0.00 0.00 0.01 98.99 ES-12785a-6.1 29.99 39.70 26.77 2.01 0.58 0.01 0.06 0.01 0.00 0.01 99.14 ES-12785a-6.2 30.07 39.39 26.37 1.99 0.57 0.02 0.05 0.00 0.01 0.01 98.49 ES-12785a-6.3 30.46 40.11 26.93 1.59 0.45 0.06 0.04 0.00 0.01 0.02 99.68 ES-12785a-7.1 30.04 39.40 26.88 1.52 1.22 0.09 0.01 0.00 0.00 0.00 99.17 ES-12785a-7.2 30.29 38.80 26.90 1.78 1.28 0.07 0.00 0.00 0.00 0.01 99.13 ES-12785a-9.1 30.34 40.00 27.77 2.04 0.51 0.02 0.03 0.01 0.01 0.01 100.75 ES-12785a-9.2 30.59 40.08 28.01 2.10 0.54 0.07 0.04 0.01 0.01 0.00 101.44 ES-12785a-9.3 30.63 39.97 27.73 2.05 0.52 0.04 0.03 0.01 0.00 0.01 100.99 ES-12785a-12.1 30.45 40.41 27.47 1.69 0.38 0.07 0.04 0.01 0.00 0.02 100.53 ES-12785a-12.2 30.43 40.20 27.36 1.59 0.37 0.04 0.06 0.00 0.01 0.01 100.07 ES-12785a-12.3 30.30 40.55 27.46 1.58 0.38 0.03 0.03 0.00 0.01 0.02 100.36

ES-12787-1.1 30.24 39.21 26.62 2.44 0.81 0.04 0.02 0.01 0.00 0.01 99.40 ES-12787-2.1 30.07 39.89 27.10 1.79 0.68 0.04 0.04 0.00 0.00 0.00 99.60 ES-12787-3.1 30.12 40.15 27.12 1.74 0.64 0.07 0.00 0.00 0.00 0.00 99.83 ES-12787-3.2 30.16 40.11 27.02 1.78 0.67 0.04 0.01 0.00 0.01 0.01 99.80 ES-12787-4.1 29.66 40.26 26.88 1.49 0.53 0.05 0.03 0.00 0.01 0.00 98.90 ES-12787-4.2 29.87 39.80 26.24 1.63 0.62 0.04 0.03 0.00 0.01 0.01 98.26 ES-12787-5.1 29.72 39.67 26.67 1.89 0.81 0.02 0.03 0.00 0.01 0.00 98.82 ES-12787-6.1 30.25 41.08 27.84 1.21 0.63 0.02 0.03 0.00 0.00 0.01 101.07 ES-12787-6.2 30.35 39.80 27.87 1.60 0.93 0.00 0.00 0.00 0.00 0.04 100.60 ES-12787-6R.1 30.45 41.97 28.01 0.86 0.37 0.05 0.02 0.00 0.00 0.02 101.75 ES-12787-6R.2 30.68 42.17 27.83 0.96 0.41 0.00 0.02 0.00 0.00 0.01 102.10 ES-12787-7.1 30.13 40.25 27.27 1.27 0.81 0.08 0.00 0.00 0.01 0.01 99.82 ES-12787-8.1 29.75 38.96 26.17 2.04 0.84 0.06 0.03 0.00 0.01 0.00 97.86 ES-12787-9.1 30.46 42.33 27.83 0.66 0.33 0.00 0.03 0.00 0.00 0.01 101.67 ES-12787-9R.1 30.40 40.13 27.24 1.65 0.50 0.09 0.04 0.00 0.01 0.01 100.07 ES-12787-9R.2 30.25 40.78 27.30 1.47 0.35 0.03 0.03 0.00 0.00 0.01 100.22 ES-12787-9R.3 29.61 39.93 27.14 2.00 0.56 0.03 0.01 0.00 0.00 0.00 99.29 ES-12787-10.1 29.82 40.16 26.72 1.61 0.55 0.04 0.06 0.00 0.00 0.01 98.98 ES-12787-12.1 29.42 39.89 25.78 1.54 0.78 0.00 0.03 0.00 0.01 0.01 97.47 ES-12787-12R.1 29.62 40.37 26.69 1.05 0.62 0.03 0.02 0.00 0.00 0.01 98.40 ES-12787-12R.2 29.63 39.57 26.09 1.31 0.82 0.00 0.03 0.00 0.01 0.01 97.48 ES-12787-12R.3 29.93 40.05 26.44 1.50 0.71 0.06 0.03 0.00 0.00 0.01 98.73 ES-12787-13.1 29.61 39.18 25.96 1.90 0.65 0.01 0.04 0.00 0.01 0.00 97.35 ES-12787-13R.1 29.26 38.52 25.50 2.19 0.82 0.04 0.05 0.00 0.01 0.01 96.40 ES-12787-13R.2 29.82 39.13 26.00 1.99 0.73 0.03 0.04 0.00 0.00 0.00 97.74 ES-12787-15.1 30.16 40.87 27.32 1.25 0.52 0.02 0.03 0.00 0.00 0.00 100.18

283

Table C6: Cont. sample SiO 2 TiO 2 CaO Fe 2O3 Al 2O3 MnO Na 2O MgO K2O F sum ES-12787-15R.1 30.69 40.87 27.91 1.44 0.74 0.02 0.00 0.00 0.00 0.00 101.70 ES-12787-15R.2 30.57 41.55 27.45 1.10 0.44 0.04 0.01 0.00 0.00 0.01 101.19 ES-12787-16.1 29.50 39.94 26.68 1.61 0.65 0.04 0.04 0.00 0.00 0.02 98.48 ES-12787-16.2 29.67 39.14 26.44 1.86 0.74 0.04 0.04 0.00 0.00 0.01 97.95 ES-12787-17.1 30.36 39.65 27.63 1.73 0.87 0.05 0.02 0.00 0.00 0.00 100.30 ES-12787-17R.1 30.87 39.83 27.38 1.65 0.86 0.02 0.04 0.00 0.00 0.00 100.65 ES-12787-19.1 30.02 39.79 26.88 2.01 0.76 0.09 0.04 0.00 0.00 0.01 99.60 ES-12787-20.1 29.32 39.59 26.32 1.85 0.75 0.03 0.05 0.00 0.00 0.02 97.94 ES-12787-20.2 29.49 39.05 25.69 1.91 0.70 0.04 0.04 0.00 0.00 0.01 96.94 ES-12787-20.3 29.62 39.77 26.16 1.76 0.67 0.03 0.05 0.00 0.00 0.01 98.08 ES-12787-20R.1 29.48 39.75 26.11 1.96 0.72 0.07 0.02 0.00 0.00 0.00 98.11 ES-12787-20R.2 29.34 39.11 25.65 2.12 0.71 0.05 0.06 0.00 0.00 0.01 97.06 ES-12787-20R.3 29.82 39.52 26.35 1.67 0.62 0.02 0.04 0.00 0.01 0.00 98.05 ES-12787-20R.4 29.50 39.23 25.49 1.96 0.71 0.04 0.06 0.00 0.00 0.00 96.99

ES-12792-1.1 29.81 40.43 27.33 1.15 0.89 0.03 0.02 0.00 0.00 0.02 99.69 ES-12792-1.2 30.11 41.03 27.63 0.93 0.84 0.09 0.01 0.00 0.00 0.01 100.67 ES-12792-2.1 29.96 39.81 27.49 1.54 1.17 0.10 0.00 0.00 0.00 0.02 100.09 ES-12792-2.2 30.15 39.97 27.61 1.32 1.01 0.10 0.00 0.00 0.00 0.00 100.17 ES-12792-3.1 30.11 40.44 27.86 1.37 0.95 0.08 0.01 0.00 0.00 0.01 100.83 ES-12792-3.2 30.39 40.17 27.66 1.30 1.06 0.14 0.01 0.00 0.00 0.01 100.74 ES-12792-3.3 30.46 40.14 27.97 1.48 1.10 0.18 0.02 0.00 0.01 0.00 101.35 ES-12792-4.1 30.51 40.25 27.67 1.35 0.91 0.12 0.00 0.00 0.01 0.00 100.83 ES-12792-5.1 30.40 40.35 27.33 1.48 1.09 0.11 0.03 0.00 0.00 0.01 100.79 ES-12792-5.2 30.54 40.06 27.59 1.45 1.15 0.10 0.02 0.00 0.00 0.00 100.93 ES-12792-5.3 30.46 40.24 27.65 1.31 1.09 0.10 0.03 0.00 0.00 0.01 100.89 ES-12792-6.1 30.28 40.48 27.58 1.44 1.00 0.14 0.00 0.00 0.00 0.00 100.92 ES-12792-7.1 30.57 40.11 27.77 1.28 1.08 0.09 0.02 0.00 0.00 0.00 100.92 ES-12792-8.1 30.34 39.85 27.53 1.67 1.20 0.13 0.01 0.00 0.00 0.01 100.74 ES-12792-9.1 30.39 40.37 27.45 1.14 1.03 0.07 0.02 0.00 0.00 0.02 100.49 ES-12792-10.1 30.37 40.29 27.16 1.10 1.07 0.05 0.01 0.00 0.00 0.02 100.06 ES-12792-11.1 30.32 40.37 27.34 1.06 0.97 0.11 0.01 0.00 0.01 0.02 100.20 ES-12792-11.2 30.26 40.60 27.67 1.27 1.08 0.09 0.01 0.00 0.01 0.00 101.00 ES-12792-11.3 30.63 40.22 27.61 1.33 1.12 0.11 0.01 0.00 0.00 0.01 101.03 ES-12792-12.1 30.31 40.32 27.23 1.17 1.06 0.12 0.01 0.00 0.01 0.01 100.24 ES-12792-13.1 30.23 39.73 27.15 1.50 1.15 0.07 0.01 0.00 0.01 0.00 99.84 ES-12792-13.2 30.12 40.73 27.72 1.12 0.93 0.10 0.03 0.00 0.00 0.02 100.78 ES-12792-13.3 30.36 39.73 27.30 1.49 1.18 0.11 0.03 0.00 0.01 0.00 100.20 ES-12792-14.1 30.42 39.69 27.71 1.60 1.14 0.08 0.02 0.00 0.00 0.01 100.68 ES-12792-15.1 29.64 40.27 26.76 1.24 1.03 0.08 0.02 0.00 0.00 0.02 99.06 ES-12792-15.2 29.97 39.66 26.61 1.08 1.15 0.04 0.01 0.00 0.00 0.00 98.53 ES-12792-17.1 30.18 40.99 27.50 1.00 0.78 0.07 0.03 0.00 0.00 0.01 100.56 ES-12792-17.2 30.69 39.89 27.55 1.46 1.15 0.09 0.02 0.01 0.01 0.01 100.88 ES-12792-18.1 30.62 39.92 27.86 1.78 1.19 0.11 0.00 0.00 0.00 0.01 101.50 ES-12792-18.2 30.81 40.63 27.60 1.31 1.09 0.08 0.02 0.00 0.00 0.00 101.55

284

Table C6: Cont. sample SiO 2 TiO 2 CaO Fe 2O3 Al 2O3 MnO Na 2O MgO K2O F sum ES-12792-19.1 30.47 40.65 27.61 1.33 1.02 0.08 0.02 0.00 0.00 0.01 101.19 ES-12792-20.1 30.41 39.76 27.55 1.39 1.07 0.09 0.02 0.00 0.00 0.00 100.30 ES-12792-21.1 30.36 39.50 27.09 1.46 1.28 0.08 0.01 0.00 0.00 0.01 99.79 ES-12792-21.2 30.45 40.24 27.53 1.46 0.99 0.09 0.03 0.00 0.00 0.00 100.80 ES-12792-21.3 30.53 41.27 27.67 0.96 0.79 0.08 0.02 0.00 0.01 0.01 101.34 ES-12792-21.4 30.69 40.74 27.70 1.05 0.98 0.11 0.02 0.00 0.01 0.02 101.32 ES-12792-22.1 30.38 40.96 27.46 1.01 0.84 0.08 0.01 0.00 0.00 0.01 100.75 ES-12792-22.2 30.65 41.28 27.88 1.01 0.82 0.12 0.01 0.00 0.00 0.02 101.79 ES-12792-23.1 30.04 39.24 26.95 1.52 1.04 0.08 0.03 0.00 0.00 0.02 98.92 ES-12792-24.1 30.33 40.40 27.73 1.34 1.17 0.11 0.02 0.00 0.00 0.01 101.12 ES-12792-24.2 30.65 39.87 27.42 1.50 1.21 0.14 0.02 0.00 0.01 0.01 100.84 ES-12792-24.3 30.22 39.69 27.29 1.41 1.13 0.08 0.02 0.00 0.00 0.00 99.84 ES-12792-25.1 30.47 40.18 27.45 1.15 1.13 0.13 0.02 0.00 0.00 0.02 100.55 ES-12792-25.2 30.44 40.55 27.49 1.14 1.13 0.12 0.01 0.00 0.00 0.01 100.90 ES-12792-25.3 30.36 40.80 27.36 1.16 1.10 0.07 0.00 0.00 0.00 0.02 100.86 ES-12792-26.1 30.12 40.31 27.06 1.40 1.02 0.09 0.04 0.00 0.00 0.01 100.05 ES-12792-26.2 30.36 40.41 27.26 1.43 1.05 0.13 0.02 0.00 0.01 0.00 100.67 ES-12792-26.3 30.70 40.49 27.86 1.28 1.12 0.11 0.01 0.00 0.00 0.00 101.58 285

Appendix D

LA-ICP-MS Analytical Procedures and Results

Trace element concentrations for phenocyrst phases amphibole, plagioclase, biotite, apatite, and titanite were conducted in the W.M. Keck Collaboratory for Plasma

Mass Spectrometry at Oregon State University using a NewWave DUV 193nm ArF

Excimer Laser with aperture-focused optics. Samples were mounted in a sample chamber as either thin sections or one inch diameter round epoxy plugs. During the ablation process He was used as the carrier gas for the ablated particulate, and this was mixed with Ar gas immediately prior to the entry into plasma torch. Background counts were measured for 40 seconds prior to each analysis and subtracted from the ablation measurement. Signal conditions for the plasma torch was optimized prior to analysis using standard protocols for the instrument where signal strengths of 43 Ca and 232 Th were maximized while maintaining ThO/Th ratios below 2.5% during ablation of NIST 610 glass. Analyses were preformed using 50 and 70 mm ablation spot sizes with pulse frequencies of 3 Hz and 5 Hz for thin sections and plug mounts respectively. A mass table consisting of 29 Si, 31 P, 43 Ca, 47 Ti, 65 Cu, 85 Rb, 86 Sr, 88 Sr, 89 Y, 90 Zr, 93 Nb, 137 Ba, 138 Ba,

139 La, 140 Ce, 141 Pr, 146 Nd, 147 Sm, 153 Eu, 157 Gd, 159 Tb, 163 Dy, 165 Ho, 166 Er, 169 Tm, 172 Yb,

175 Lu, 208 Pb, 232 Th, and 238 U with dwell time of 10 ms per mass peak. Trace element abundances were calculated relative to the NIST 610 glass standard, which was analyzed both prior to and after unknown analysis. Values of 29Si and 43 Ca were used as internal normalizing isotopes in conjunction with SiO 2 and CaO contents measured by electron microprobe. USGS glass BCR-2G was also analyzed to monitor accuracy and precision.

All analytical results are given in Table D1. 286 σ 25 g/g) 1 µ ( σ 45 1379 19 2 55 1353 22 .0 3.0 70.4 4.2 0.2 0.1 0.8 0.3 g/g) 1 ES-12783 ES-12783 µ Feldspar5b Feldspar6a ( σ 6 0.18 2.30 0.44 2.74 0.59 .4 12.5 79.8 52.3 76.8 21.9 g/g) 1 µ ( σ 2 0.37 9.54 0.78 9.31 0.22 9.33 0.46 0 0.10 1.34 0.19 0.85 0.03 1.05 0.10 2 0.12 1.12 0.24 0.93 0.08 0.87 0.08 12783 ES-12783 63 0.70 6.08 0.69 7.81 1.19 10.80 0.79 g/g) 1 0.41 0.19 0.53 0.41 µ 10.24 0.55 13.32 0.39 11.37 0.68 11.12 0.56 ( σ g/g) 1 0.33 0.19 µ ( 2 269257 7499 249912 3680 297949 10359 296307 15050 281019 56 σ 0.4 0.1 0.3 0.1 0.4 0.2 0.8 0.1 g/g) 1 µ ( Feldspar 3b Feldspar3c Feldspar 4a Feldspar4b σ apole LA-ICP-MS analysis. apole LA-ICP-MS g/g) 1 µ ( σ g/g) 1 0.74 0.29 µ ( σ g/g) 1 µ ( σ 0.2 0.1 0.3 0.1 0.5 0.2 3.7 2.3 0.9 0.0 0.9 0.2 0.3 0.1 0.5 0.3 8.4 1.9 0.8 0.2 337329 4 4 327 311 9 7 432 450 16 20 295 301 16 5 293 298 6 3 301 305 5 3 285 285 4 5 363 357 13 340 8 338 8 12 376 28 376 40 g/g) 1 62.6 19.1 66.4 5.0 252.8 115.4 82.7 15.8 114.7 19.7 83.7 9.2 52 57.1 6.0 63.5 7.1 42.6 4.0 51.3 4.1 55.0 5.0 38.6 3.7 49.6 3.0 39 19.83.9 59.4 3.5 6.31.3 26.70.9 3.7 1.8 17.10.9 8.00 0.20 7.03 0.23 1.04 0.45 8.06 0.40 6.79 0.16 8.00 0.39 6.9 0.75 0.12 0.74 0.12 0.38 0.22 0.77 0.10 0.55 0.06 0.97 0.26 1.0 2.73 0.49 2.21 0.40 2.41 0.43 1.98 0.09 2.73 0.70 2.49 0.42 3.1 1.00 0.11 1.12 0.11 3.42 0.25 1.27 0.07 0.94 0.05 1.12 0.17 0.7 6.09 0.51 5.08 0.23 20.23 2.99 5.80 0.69 6.02 0.18 5.02 0.41 9. 12941314 27 23 1299 1343 17 20 1704 1670 94 51 1291 1309 38 28 1259 1311 20 15 1255 1296 15 1248 9 16 1288 1387 13 1422 52 139 40 1459 µ 10.84 0.46 9.03 0.34 1.31 0.51 10.37 0.59 9.17 0.37 10.31 0.62 ES-12783 ES-12783 ES-12783 ES-12783 ES-12783 ES-12783 ES- ( Feldspar1a Feldspar 1b Feldspar2 Feldspar3a 261595 6662 254065 4552 1820608 68970 269382 3293 270302 598 Table D1: El Salvador mineral compositions by compositions QuadrTable D1: Salvador El mineral Sample # Sample Phase # Si U P Ca Ti Y Cu Rb Sr Sr Zr Nb Ba Ba La Pr Ce Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Pb Th 287 2 σ 0.6 2 0.0 .0 6.5 7.0 0.5 471 66 g/g) 1 14.7 10.3 0.6 µ ES-12785a ( σ 0.04 67 0.20 220.9 6.6 g/g) 1 0.18 µ ( σ 0.07 1 0.01 0.11 0.02 31.5 1.4 .08 0.05 0.07 0.01 1539.3 21.7 g/g) 1 0.16 22.5 4.0 126.5 1.5 1.9 1.2 µ ( 0 69.9 14.8 61.9 9.8 158636 6905 σ 0.30 2107.1 14968.6 439.6 14728.6 338.1 4.4 1.2 5 0.12 0.19 0.04 0.25 0.04 44.4 1.1 g/g) 1 2.96 0.36 0.03 0.06 0.02 215.6 2.5 4.07 0.52 0.30 0.12 0.57 0.11 1009.1 19.0 0.21 0.03 0.13 0.09 595.0 9.2 2.05 0.41 0.00 0.48 0.11 245.9 3.9 0.500.72 0.050.08 0.200.35 0.07 0.03 0.02 0.18 0.12 0.02 32.7 1.1 86.13.1 11.70.5 74.22.8 0.27 0.26 µ ( σ 13 118.06 21.46 22.93 2.26 26.75 3.51 4.2 2.7 g/g) 1 µ Biotite 2b Biotite 3 Biotite 6a Biotite 6b Apatite 1a ES-12783 ES-12783 ES-12783 ES-12783 ( σ g/g) 1 µ ( σ 0.47 8.2 0.1 542.8 13.4 458.6 9.3 307.4 8.1 538.6 14.6 525.8 18.0 0. g/g) 1 Biotite Biotite 1 Biotite 2a 3.38 9.171.42 0.433.42 0.16 0.37 0.60 0.39 1.78 0.06 0.09 0.43 0.20 0.36 0.10 0.26 2.36 0.59 0.27 0.14 0.85 0.09 182 0.08 0.05 ES-12783 ES-12783 µ ( 192821225 1826 206 σ 0.4 0.10.1 23.5 0.1 0.9 17.7 1.7 0.5 0.1 7.7 0.2 0.4 0.1 10.1 0.8 6.6 12.1 0.5 1.6 0.9 11.2 0.0 0.1 1.1 20.3 0.1 1.2 848.9 14. g/g) 1 41.4 7.5 31574.8 1751.1 16878.0 187.7 14976.7 163.5 23113.7 0.61 0.34 6.20 1.17 µ ES-12783 ( σ 0.6 0.3 1.5 0.1 0.40.3 2.0 0.5 0.50.2 g/g) 1 30.5 15.8 4.1 2.1 6241.0 42.1 72.4 1.0 124.1 10.1 1241.7 36.7 1 0.74 0.19 10.77 0.84 0.95 0.53 0.56 0.16 3.14 0.58 0.92 0.13 0. 0.04 0.03 0.09 0.08 1.31 0.07 0.05 0.04 0.12 0.04 0.64 0.12 0.1 ES-12783 µ Feldspar 7b Feldspar 7c ( σ 338325 8 6 232 240 8 6 335 355 11 7 20 20 4 2 555 567 6 7 311 315 12 6 199 198 5 4 287 292 9 9 259 255 7 4 2 1 7 0 g/g) 1 50.5 8.7 78.4 21.0 4135.5 176.3 73.5 27.4 20.5 14.4 1068.9 61. 0.82 0.10 0.83 0.08 0.85 0.12 0.59 0.04 2.52 0.41 2.72 0.26 2.22 0.45 6.54 0.37 9.46 0.36 7.34 0.33 9.55 0.42 0.37 0.07 1.04 0.16 0.94 0.20 0.94 0.21 2.93 0.08 0.08 0.08 0.15 0.04 1.0 5.64 1.07 11.23 2.68 6.65 0.44 275.97 18.04 7.39 2.24 13.18 1. ES-12783 13141368 241115 19 1143 25126521 29 1322 21 52 49 5 4 2 0 6 4 1 1 20 19 2 1 2 0 2 0 386 10 38014 µ 12.02 0.41 9.86 0.35 11.31 0.23 2.27 0.18 0.05 0.03 0.56 0.11 0 Feldspar 7a ( 266338 12107 231585 11543 280884 6158 Table D1: D1: Table Cont. P Ca Ti Sample # Sample Phase # Si U Pr Nd Sm Cu Sr Sr Y Zr Nb Ba Ba La Rb Ce Eu Er Tm Yb Lu Gd Dy Ho Pb Tb Th 288 6 σ 1 0.1 g/g) 1 0.03 0.01 µ ( σ 8.4 27.0 12.8 .3 2.1 g/g) 1 µ Bioitite 2c Biotite 2d ( σ 4.5 286.8 14.6 292.5 13.6 g/g) 1 0.60 0.30 0.12 0.03 0.06 0.05 µ ( σ 85a ES-12785a ES-12785a ES-12785a 82 6.01 12.48 10.88 5.64 2.84 1.64 0.84 g/g) 1 0.09 0.04 0.82 0.14 0.17 0.04 µ ( 6235.4 703.5 25520.0 628.9 25217.5 651.1 24782.2 582.7 σ 0.04 1.42 0.08 0.04 0.02 0.11 0.03 g/g) 1 µ ( σ 285 187 184 112 811 154 476 30 g/g) 1 26.2 0.7 21.0 1.0 28.4 0.8 26.6 0.7 29.1 0.8 29.4 1.0 µ Biotite 1a Biotite 1b Biotite 2a Biotite 2b ( σ 2.0 0.6 0.4 0.2 0.8 0.1 1.0 0.1 1.5 0.1 1.1 0.3 1.4 0.2 g/g) 1 µ ES-12785a ( σ g/g) 1 µ ( σ 0.6 0.3 0.4 0.1 0.1 0.1 421.6 29.8 431.5 16.6 269.4 13.3 268.2 1 479 14 412 7 1 0 1676 56 963 66 4555 147 4725 159 4307 145 3737 129 g/g) 1 µ ( σ 7 0 481 10 403 7 9 1 1670 60 960 64 4578 147 4737 155 4268 127 3736 12 2.6 2.2 25.0 17.7 13.8 9.1 19.4 2.0 18.7 2.2 22.6 6.9 31.4 4.0 15 7.1 1.6 31.5 2.2 35.5 3.5 8.2 2.3 20451.2 472.7 21382.3 493.0 2 7.10.5 41.21 5.11 0.5 0.2 9.1 6.7 6.55 0.77 5.59 0.59 13.16 7.17 8.93 2.05 10.66 6.98 18. 734 70 268498 7911 264222 6350 879 374 375384 9130728134730 8134832138627 390 387 11 7 1 0 3 1 1 0 3 0 7 9 1 2 2 0 1 0 g/g) 1 10.2 0.4 31.21 1.41 44.2 0.6 1.01 0.18 0.82 0.09 44.77 2.57 33.3 1.335.594.4 1.312.5 3.578.2 0.511.2 3.3 0.5 53.00 3.43 50.24 130.27 2.86 15.69 8.34 99.31 1.49 13.11 6.80 1.22 µ 899.612.5 0.2 0.1 1430.0 66.8 0.2 0.1 0.2 0.1 0.3 0.1 0.2 0.1 0. 565.2 6.6 6.08 0.33 7.15 0.14 643.66 33.57 0.35 0.25 0.09 0.03 211.3 2.1 0.63 0.05 0.46 0.11 313.93 16.19 0.05 0.01 0.17 0.05 258.8 6.3 417.03 27.16 0.28 0.12 0.19 0.02 237.8 7.4191.8 0.75 5.9 0.25 390.47 20.12 285.08 19.72 Apatite 1b Feldspar 1a Feldspar 1b 2 Apatite ES-12785a ES-12785a ES-12785a ES-12785a ES-12785a ES-127 ( 1463.8 24.1 7.64 0.53 8.39 0.45 1943.48 102.46 0.69 0.46 0.10 1013.9 19.1 1.53 0.33 1.09 0.37 1598.77 88.04 0.20 0.11 1546417745 142410.69672.4 39.1 4.6 22.9 7.0 20.6 17.9 31.0 1 Table D1: D1: TableCont. Rb Cu Ca Ti Ce Sample # Sample Phase # Si P U Sr Sr Y Nd Ba Ba La Nb Pr Th Eu Sm Zr Tb Dy Ho Er Tm Yb Lu Pb Gd 289 2 σ 1 0.2 6.6 g/g) 79.6 13.9 µ ( σ 1 0.5 4 1704 208252 2277 .6 7.2 2088.0 21.7 g/g) 56.7 1.3 51.9 1.6 15.6 0.411.5 12.0 0.3 0.3 8.6 0.2 28.6 µ Titanite-1 Titanite-4a 122.9 2.4101.0 98.3 1.6 1.6 72.6 2.0 ES12785a ES12785a ( 143069 3112 143226 3588 σ 1 3 126 21 1 17 0 4 0.10 4198.2 69.3 4129.6 63.1 .2 0.9 979.1 8.8 1357.6 17.0 93 132 3 1 g/g) µ ( σ .6 184.7 42.8 13.2 3.3 3.2 0.6 .6 275.0 6.5 353.9 12.0 1 0.07 748 271 1087 698 g/g) 4.14 35.960.17 93.68 0.10 49.36 3.5 0.8 2.2 101.4 0.1 1.5 434.4 5.5 0.49 0.260.23 0.040.24 0.010.05 0.04 672.1 142.7 9.4 2.6 595.0 15.3 94.4 287.8 1.7 5.5 46.4 258.8 0.8 5.9 40.7 0.6 0.16 µ ( ES-12785a ES-12785a σ 1 7.1 300.3 17.5 345.6 18.4 0.6 0.2 0.1 0.1 85a g/g) µ ( σ 1 4b Biotite 5 Biotite 6a Bioitite 6b g/g) µ 874.1 626.3 25625.4 730.8 26310.0 694.5 24404.3 720.5 20530 ( σ 1 0.10 0.3 0.1 0.2 0.0 1.3 0.5 1335.427.01126.421.1 g/g) 0.41 0.22 0.11 0.01 0.33 0.16 1.42 0.89 3327.3 47.5 2907.0 60. 0.43 0.110.04 0.42 0.22 0.02 0.55 0.19 437.9 6.3 424.6 12.9 0.26 0.10 0.24 µ ( σ 1 210 115 g/g) 0.10 0.03 0.67 0.04 0.08 0.03 0.21 0.13 0.52 0.18 911.0 18.4 10 0.04 0.02 0.18 0.03 0.12 0.03 0.42 0.20 739.6 9.1 645.8 7.4 µ ( σ 1 g/g) µ ( σ 1 436210 20 20 82 51 20 51 717183410281 61 73420271 0.1 0.1 0.9 0.2 0.9 0.2 1.5 0.2 4.9 1.4 0.8 0.1 1.3 0.3 1.6 0.1 0.9 0.2 283 g/g) 10.7 2.1 4.7 1.0 24.9 7.8 152.4 13.2 14.4 1.7 104.0 10.6 70.3 16 31.7 0.8 27.7 1.0 28.7 0.8 36.4 6.0 35.4 1.0 28.4 0.8 33.2 0.8 34 0.08 0.02 0.18 0.03 1.55 0.50 0.04 0.06 0.49 0.22 1.85 0.73 0.1 0.25 0.06 0.43 0.15 0.65 0.34 2.35 0.22 9.68 1.09 6.46 0.84 67.32 28.19 6 32.1 13.2 28.0 6.9 34.4 4.0 36.0 7.0 42.0 8.4 24.3 5.1 549.1257 4285 139 4284 159 4431 168 2868 142 3223 151 4360 140 4212 134 34 4297 128 4251 138 4490 158 2792 98 3218 163 4290 133 4190 124 342 µ 307.3 13.7 270.7 10.3 275.8 10.4 344.3 19.6 349.7 14.4 308.2 1 Bioitite 3a Biotitie 3b Biotite 3c Bioitite 4a Biotite ( ES-12785a ES-12785a ES-12785a ES-12785a ES-12785a ES-127 25588.6 592.0 23756.8 739.7 25208.0 603.9 27836.7 1628.8 23 Table D1: Cont. Table D1: Rb Ba Cu Sr Sr Y Nb La Ce Ti Zr Ba Pr Nd Sm Th Ca Eu Gd Tb Ho Er Dy Tm Yb Lu Pb Sample # Sample Phase # Si U P 290 2 σ 0.2 7.6 g/g) 1 µ ( σ 1.4 5.9 5.5 0.4 2.5 5.6 4.3 7.2 2.1 0.2 2.0 0.1 g/g) 1 ES12787 ES12787 µ Apatite Apatite 1a1b Apatite ( 3 2.4 0.1 2.4 0.1 σ 0.3 .0 0.7 9.0 0.5 8.8 0.4 9.7 g/g) 1 µ ES12785a ( 3 62.2 0.6 12.9 0.6 13.1 0.6 1 98.8 1.1 24.69 0.7 112.2 26.9 1.0 1.1 21.3 1.2 20.3 1.2 5 79.9 0.9 13.5 1.0 13.8 1.2 σ 0.1 5 3.8 442.5 4.6 15.2 0.5 14.2 0.7 2.9 7.6 2.5 305.3 3.3 57.5 2.4 58.1 2.3 g/g) 1 µ 245.1 20.4 324.2 16.7 170453 6965 168464 7146 ( σ .5 391.1 5.6 668.9 6.5 280.0 6.5 302.5 8.5 .3 182.8 6.8 507.2 7.2 125.8 4.5 128.3 5.2 2.8 689.5 7.1 1411.0 12.0 9.0 644.7 16.8 1043.7 8.1 1098.4 38.8 1147.2 40.0 0.1 49.2 2669.9 113.6 2894.7 174.8 0.5 0.1 0.9 0.1 10.4 292.9 5.4 689.8 10.0 177.5 9.9 186.6 5.9 6 11.8 430.8 9.8 1302.0 12.3 260.5 13.8 260.4 11.9 3.8 g/g) 1 µ ( 07299 4743 201233 1669 209593 2506 11.0 2.2 11.9 1.9 30489 3959 127203 4307 138902 2417 791 29 1109 130 1 2379.1 44.3 2570.5 25.5 4050.5 31.1 2367.0 33.7 2538.7 73.3 σ .0 1512.3 46.7 1700.2 32.0 3122.2 37.2 1109.8 35.5 1169.6 40. 0.2 -9a Titanite-9b Titanite-12a Titanite-12b 3.7 g/g) 1 µ ( σ 0.6 g/g) 1 32.7 µ ( σ 0.8 g/g) 1 27.1 µ ( σ 0.2 100041101000 10 0.6 0.1 0.1 0.0 0.4 0.1 0.1 0.0 0.2 0.1 0.1 0.0 4.7 g/g) 1 µ ( σ 0.3 2425 1 0 25 24 2 1 42 40 1 1 102 105 6 8 37 34 1 1 35 33 2 1 37 38 3 3 24 27 1 0 247 261 7 5 250 261 6 7 12 0 15 1 20 0 28 1 12 0 10 0 11 0 17 0 11 0 12 1 4.4 0.5 9.5 1.0 2.1 0.3 4.0 0.7 3.2 0.6 5.3 0.5 4.2 0.3 3.3 0.2 3.0 6.0 0.2 26.0 0.8 23.7 0.4 26.0 0.6 4.5 0.6 2.7 0.1 4.7 0.1 13.4 0. 3.3 4.9 0.2 18.1 0.5 14.5 0.3 15.1 0.3 3.6 0.4 1.9 0.1 3.9 0.1 8.7 0.2 1.2 0.1 2.2 0.2 1.3 0.2 4.8 0.3 0.8 0.0 1.9 0.9 7.6 2.7 2.1 0.1 4.7 g/g) 1 19.5 0.5 88.9 2.7 85.2 2.0 93.0 2.5 14.3 1.8 10.0 0.5 15.0 0.2 47 25.1 0.6 106.4 4.2 114.9 3.2 131.9 2.7 19.5 2.6 13.5 0.7 20.3 0. 48.7 1.2 216.7 8.9 199.6 3.4 222.9 4.3 37.6 4.4 25.4 2.1 37.5 0. 68.2 0.9 130.1 3.9 252.8 3.2 296.6 4.9 68.6 1.9 66.4 1.6 64.0 1. 36.6 1.0 157.7 6.2 134.6 2.8 150.7 3.6 28.1 2.6 17.6 1.2 31.1 0. µ 874.5 36.7 538.1 19.2 1110.7 40.3 1829.3 31.9 236.0 3.4 216.9 567.7 9.9 2378.8 45.7 2143.4 54.6 2256.8 57.8 415.2 54.7 265. 347.4 6.3 990.0 33.7 1265.9 27.5 1462.9 30.7 274.8 26.9 245.1 429.8 6.2 677.1 21.7 968.9 21.7 1101.5 20.1 392.9 10.0 359.6 6 731.4 11.0 768.1 16.2 996.1 24.1 1137.1 24.0 714.6 12.0 585.3 312.6 9.7 261.5 9.4 287.6 21.3 349.8 15.3 169.8 8.8 182.0 16.3 127.1 1.2 552.9 19.5 566.5 14.9 643.4 12.6 94.4 12.4 63.5 1.8 9 230.1 2.8 819.2 22.2 893.0 24.5 1036.2 18.4 175.9 20.2 140.8 7 235.3 6.0 267.2 12.1 120.4 2.0 166.5 3.5 87.2 4.5 43.4 2.4 182. ES12785a ES12785a ES12785a ES12785a ES12785a ES12785a ES12785a ( Titanite-4b Titanite-6 Titanite-7a Titanite-7b Titanite 2947.1 57.9 1995.3 64.0 413.7 18.7 359.7 10.1 418.4 4.5 982.1 1904.5 30.7 3629.7 128.6 4947.0 108.3 5746.9 102.6 1636.9 76 2774.5 40.4 3527.7 101.2 5226.3 135.4 6163.2 96.2 2667.2 45. 206323 2454 201309 4649 208639 1799 188891 5068 208273 1838 2 136050 1840 129110 3090 138260 3295 118071 3885 149319 2222 1 Table D1: Cont. Table D1: Zr Nb Cu Sr Sr Y Rb Nd Sm Ca Ti Pr La Ba Ba P Ho Tb Er Eu Sample # Sample Phase # Si U Dy Gd Tm Ce Yb Lu Pb Th 291 1 σ 37 g/g) 1 µ ( 9 0.9 0.2 σ 0.2 0.1 0.1 0.0 g/g) 1 0.56 0.17 µ ( σ 7 7.0 67.6 28.1 35.5 5.0 12787 ES12787 ES12787 g/g) 1 1.04 0.18 1.08 0.14 0.99 0.14 µ ( 72809 7984 237332 9922 295171 7141 σ .97 0.16 5.33 0.97 4.23 0.42 5.07 0.60 g/g) 1 0.70 0.14 0.42 0.11 0.58 0.04 0.51 0.02 µ ( σ 45 7.76 0.47 6.46 0.35 6.96 0.35 5.94 0.70 spar1 Feldspar 2a Feldspar 2b Feldspar 3a Feldspar 3b 09 0.54 8.73 0.46 7.12 0.50 7.51 0.17 5.99 0.21 07 0.20 1.21 0.20 1.18 0.17 1.36 0.21 1.30 0.32 g/g) 1 60.1 14.1 69.5 19.0 40.2 15.9 µ ( σ 0.4 5.7 g/g) 1 µ ( σ 0.2 0.3 g/g) 1 µ ( σ 1.9 5.7 g/g) 1 µ ( σ 0.6 2.9 0.9 5.0 g/g) 1 µ ( σ 0.3 2 1 44 9 27938 411 15 42811 39910 36711 471 7 11 0 54 10 277 19 4 0 8 0 425 9 416 12 404 4 381 8 479 7 0.3 0.1 115.2 29.2 10.9 1.5 0.3 0.1 1.6 0.2 0.7 0.1 0.6 0.2 1.4 0. 3.7 0.23.1 3.6 0.1 0.4 2.6 1.2 0.2 0.6 2.9 2.8 0.7 0.2 1.2 4.5 0.4 0.3 3.8 0.3 1.1 0.2 0.4 0.4 3.3 1.5 0.5 0.1 4.8 230 13 237 6 225 30 202 12 212 8 1327 52 1395 53 1340 41 1161 36 1417 230 13 247 4 222 12 188 3 210 3 1362 39 1434 39 1388 23 1206 27 1443 2 971 58 27278 5763 14019 4243 1050 178 238907 9696 249763 6433 2 g/g) 1 14.3 2.3 2467.2 583.0 76.4 25.3 13.3 1.6 76.2 3.0 38.1 10.4 39. 10.6 0.9 17.2 1.0 6.9 1.0 2.5 0.4 9.9 0.5 50.8 26.2 66.2 19.5 452.1 31.7 307.9 32.2 2.4 1.6 15.172.5 0.810.7 3.4 19.727.4 0.4 95.7 1.5 1.2 14.222.0 5.2 30.2 20.4 0.9 0.8 87.674.3 1.8 1.2 30.0 20.7 15.3 6.9 18.7 30.6 1.7 63.4 1.1 78.1 0.9 4.3 15.1 14.1 6.7 16.1 22.4 24.7 214.4 0.9 102.7 2.5 16.6 0.8 4.0 3.6 17.7 122.1 15.7 14.0 39.7 0.7 2.3 1.6 25.3 24.4 23.5 1.1 4.12 0.58 4 29.5 1.8 25.5 3.8 22.5 0.7 21.7 2.0 19.2 1.3 0.92 0.25 0.83 0.13 µ 337.3 17.3 391.1 23.3 398.4 36.9 384.3 22.2 459.4 20.6 941.1 41.1 837.3 34.2 659.9 33.8 224.1 10.4 529.3 15.6 8.16 0. 302.5 19.7 277.2 10.5 267.1 28.0 148.3 4.4 259.5 6.7 0.73 0.04 139.0 8.4 183.7 8.0 165.0 15.3 149.1 12.8 185.9 7.7 199.4 8.2 241.9 15.8 227.0 27.6 176.1 13.9 243.8 8.2 0.54 0.34 ( Apatite 2Apatite 3 Apatite 4a Apatite 4c Apatite 5 Apatite Feld ES12787 ES12787 ES12787 ES12787 ES12787 ES12787 ES12787 ES 2297.9 58.0 2129.7 45.6 1792.4 43.9 826.3 46.4 1772.2 53.9 8. 1136.4 37.7 1251.2 85.7 1172.4 59.0 739.6 45.5 1157.6 38.6 2. 153493 6150 135551 10794 154385 7220 134342 6483 175325 7260 Table D1: Cont. D1: Table Ca Ti Th Sr Y Rb Cu Dy Ho Er Tm Yb Lu Pb Tb P Nb Zr Ba Ba La Sr Ce Sample # Sample Phase # Si U Pr Gd Nd Sm Eu 292 σ .1 3.6 8.9 5.6 .6 21.9 g/g) 1 76.5 8623 1666 µ ( σ 1.1 12787 ES12787 3.4 146.4 2024.2 21.6 3.2 0.3 2.8 0.2 g/g) 1 72.7 µ ( σ 5.1 145.1 7.8 266.5 11.4 1.5 g/g) 1 34.0 µ ( σ .1 0.8 0.1 0.9 0.0 1.4 0.2 1.2 12.1 738.9 9.6 982.6 13.3 992.6 7.9 0.3 0.1 0.2 0.0 0.2 0.0 g/g) 1 64.4 µ ( σ 3.2 12 1 21 3 10 1 7 1 12 1 g/g) 1 84.0 4.023.9 56.8 1.516.2 1.1 16.4 0.6 51.2 0.6 11.9 2.6 14.7 0.3 79.5 0.8 10.5 3.8 22.2 0.5 16.1 1.2 14.6 0.5 5.4 0.7 0.2 4.4 0.1 87.6 Titanite-1 Titanite-2 Titanite-3 Titanite-5 Titanite-7 µ 193.0 5.5 163.2 1.9 131.4 8.8 195.3 5.1 42.1 0.9 120.6568.3 6.4 29.6 77.7200.5 379.5 11.0 1.0 4.2137.4 136.9 338.1 67.6 2.3 8.3 17.9 3.3 121.9 527.1 99.5 110.9 22.9 6.2 2.6 5.9 188.0 99.9 87.2 20.7 2.4 9.4 4.3 0.6 41.3 129.7 1.2 6.5 34.3 1.2 254.9 7.9 147.5 3.9 130.7 1.9 213.9 3.0 248.6 9.4 ( 1541.9 77.3 938.6 15.2 768.9 43.4 1343.5 49.4 234.3 5.8 7113.6 291.5 4490.3 69.9 3487.9 227.0 6353.3 141.7 1080.5 18 1006.1 55.8 634.1 11.3 552.7 32.1 907.6 39.5 170.5 3.7 145156 2756 136607 1395 149992 4805 147808 5035 137555 2444 σ 0.3 0.1 2092.2 85.2 1486.7 17.6 1288.0 53.0 1961.5 90.5 432.9 g/g) 1 0.14 0.08 2348.00.04 55.5 0.01 1982.7 1512.9 23.4 50.5 1466.4 995.9 13.1 10.5 2518.0 30.8 767.3 46.8 987 1375.5 25.7 248.3 06.3 721.6 207117 2802 218308 2893 220256 1197 212997 2086 21 ES12787 µ ( σ 2.0 0.2 478.7 14.5 336.7 2.6 317.6 4.0 265.6 6.0 1752.9 36.7 g/g) 1 0.04 0.02 0.18 0.06 9990.7 393.5 7606.0 74.1 4878.5 188.5 988 µ ( σ g/g) 1 µ ( σ 500 52 360 30 g/g) 1 0.07 0.01 0.05 0.02 µ ( σ 20 20 10 20 10120214 90 90110 5 1 4 1 5 1 0.6 0.1 293304 9 13 588 592 19 13 393 391 14 10 4905132 4892106 374 360 10 7 1 39 0 1 1 30 0 1 20 1 38 0 1 0 9 0 0 0 g/g) 1 20.4 0.9 34.6 1.5 33.8 1.5 25.4 1.0 37.0 1.7 1037.7 29.3 1010.6 0.39 0.12 8.49 1.23 11.18 0.71 4.89 4.05 1.53 0.61 4.58 1.36 1.3 0.1 1.3 0 16.2 3.5 26.2 5.0 6.7 5.1 8.8 0.5 18.3 8.1 5.2 1.3 7.0 0.5 2.8 0.5 51.6 5.0 25.8 4.0 18.7 14.7 40.1 11.4 187.7 8.7 121.4 3.2 124.7 ES12787 ES12787 ES12787 ES12787 ES12787 ES12787 ES12787 ES µ Biotite Biotite 1a Biotite 1b Biotite 1c Biotite 2 Biotite3 738.4 27.2 749.6 37.6 761.1 19.7 324.6 10.2 771.1 24.4 0.2 0.0 ( 22295.5 644.0 24667.5 632.4 25139.8 743.9 27370.9 789.2 265 Table Cont. D1: Nb Sm Eu Gd Ba Ba La Pr Nd Ce Tb Dy Ho Er Tm Yb Lu Pb Th Sr Zr Y Cu Rb Sample # Sample # Phase Si P U Ca Ti Sr 293 σ .1 1 3.3 0.1 ite-20 1 155.0 g/g) µ 117.1 ( σ 1 1.8 1.3 2.1 0.3 0 1 5 0.2 2.2 0.2 g/g) 68.4 µ ( σ .1 22.2 0.5 28.2 1.3 .6 15.6 0.3 21.9 0.5 1 2.4 .9 4.3 83.4 2.6 95.5 5.8 12787 ES12787 ES12787 7.9 5.9 114.5 1.7 128.3 8.3 g/g) 74.7 µ ( 4 114.1 8.8 139.4 2.0 175.5 6.6 σ .2 193.5 9.2 204.0 3.1 238.1 6.3 .5 313.1 4.8 200.5 2.9 510.4 11.3 1 5.7 4.2 157.0 9.8 193.0 2.9 236.4 13.7 g/g) 96.8 61.4 46.3 421.0 29.8 541.1 10.9 627.9 39.0 µ 317.0 14.6 251.2 16.3 149.2 22.3 345.2 16.6 064.1 58.5 1365.6 15.9 303.8 4.1 476.1 7.5 ( 1699.5 69.9 710.4 49.4 938.5 13.6 1084.5 66.3 σ .3 2376.6 70.1 1001.8 74.7 1398.3 17.5 1530.6 85.9 1 1.4 5.0 2108.8 36.0 1039.8 48.7 1422.8 10.8 1619.8 35.1 8.4 3003.0 139.4 1635.2 24.2 877.0 18.8 2358.6 45.5 2.7 3648.8 104.8 1590.0 72.2 2035.6 37.4 2404.4 98.2 21.4 3166.0 122.5 2256.3 17.3 2349.8 27.9 3261.5 56.3 g/g) 49.2 05.1 121.4 10235.4 175.2 4736.7 297.9 6626.3 84.8 7376.8 248 µ ( 37563 5794 136269 3800 139916 3631 130675 2152 140384 4794 12200 1685 206757 2154 210191 1652 204891 5893 208718 1598 6610.7 287.4 13925.1 297.9 7839.1 239.1 8895.4 335.6 11898. σ 1 0.4 10 Titanite-12 Titanite-13 Titanite-16 Titanite-19 Titan g/g) 27.0 µ ( σ 1 0.4 g/g) 12.3 µ ( σ 1 1.9 g/g) 98.5 µ ( σ 1 7.3 2 1 0 0 1 1 0.4 0.2 1.0 0.3 0.1 0.0 0.1 0.0 0.5 0.1 0.3 0.1 0.1 0.1 0.1 0.1 0.2 g/g) µ 117.8 ( σ 1 2.2 40 90 35 0 90 33 1 25 0 50 1 31 1 35 1 45 1 1314 0 0 60 58 5 3 11 11 0 0 27 26 1 1 17 17 1 0 10 12 1 1 15 13 1 0 12 11 1 0 12 10 1 0 12 11 1 0 3.1 0.5 5.9 0.8 8.3 1.8 3.2 0.2 2.6 0.3 4.7 0.8 2.7 0.1 3.3 0.7 8.2 6.7 0.9 25.7 1.1 222.2 4.3 11.6 1.3 149.7 3.5 474.2 10.0 388.8 1 2.8 0.3 10.5 0.3 90.6 2.6 4.6 0.4 59.5 1.2 176.0 2.8 161.4 6.2 65 3.2 0.2 12.9 0.4 124.4 2.7 6.4 0.6 80.4 1.9 199.0 2.5 214.0 8.5 8 0.9 0.1 3.3 0.2 25.8 0.7 1.4 0.2 18.2 0.4 60.7 1.0 45.4 1.8 18.4 1 1.0 0.1 3.2 0.1 17.9 0.6 1.5 0.1 14.5 0.5 48.2 1.0 31.1 0.8 14.6 0 6.5 0.4 20.6 0.6 155.3 2.3 10.0 0.8 117.4 4.5 386.6 6.5 273.6 9. 0.7 0.3 10.3 0.6 1.8 0.2 0.5 0.0 0.7 0.1 0.7 0.2 2.5 0.1 1.3 0.1 1. g/g) 16.4 0.4 38.8 0.5 199.8 4.5 42.1 2.1 184.2 3.4 313.0 9.1 325.6 5 47.8 4.2 157.8 4.1 1507.4 34.2 106.5 6.6 1036.1 22.3 1909.1 20 15.7 2.2 64.2 1.7 606.7 16.0 28.1 1.8 388.8 10.4 1052.9 17.2 10 63.7 7.1 267.7 7.4 2198.8 56.1 100.1 7.8 1569.0 28.6 4351.5 11 89.7 2.5 204.7 3.3 1383.5 29.2 248.7 13.8 1205.5 22.9 1281.6 1 29.9 3.4 108.5 4.1 1034.2 28.5 60.8 4.3 683.5 16.6 1479.5 21.7 25.8 1.6 108.8 2.3 291.1 4.4 9.7 0.6 141.3 3.4 82.7 3.7 456.4 12 ES12787 ES12787 ES12787 ES12787 ES12787 ES12787 ES12787 ES µ 116.1 342.4 8.0 373.3 10.0 153.9 10.5 126.5 7.5 156.5 4.7 109.1 10.3 322.4 13.6 823.8 19.0 6712.1 137.5 832.7 48.6 5393.9 122.4 69 822.3 12.8 1654.9 32.6 9255.8 110.3 2358.2 75.5 8369.1 110.5 489.5 9.6 723.8 16.1 2158.7 42.3 975.3 14.0 1851.3 21.1 950.4 319.9 6.0 560.8 13.4 999.6 10.0 252.4 5.0 1660.7 40.7 1209.8 1 191.8 3.6 471.7 20.3 445.5 6.3 60.8 4.0 1262.6 23.8 146.7 3.2 1 Titanite-6a Titanite-6b Titanite-8 Titanite-9 Titanite- ( 139851 2743 132984 2133 139692 2804 144669 4280 141949 3712 1 228010 2707 249878 4493 210478 3122 217617 2082 213692 1655 2 Table D1: Cont. D1: Table Sample # Sample Phase # Si U Ca Ti P Cu Eu Er Sm Ho Nd Dy Rb Sr Sr Y Pr Tb Ce Gd Tm La Ba Ba Nb Zr Lu Yb Th Pb 294 4 σ 1 dspar 2e g/g) µ ( σ 1 0.0 35.7 6.0 1 26 1961 36 7 37 1882 27 g/g) µ ( σ 1 0.06 0.7 0.21.3 0.3 0.3 0.0 g/g) 0.11 0.03 0.39 0.24 0.33 0.19 0.10 µ 446.4 85.1 68.8 6.0 58.3 4.5 ( σ 1 7 0.33 7.77 0.37 2.06 0.23 2.75 0.46 9 0.04 1.14 0.12 0.61 0.16 0.68 0.16 1 0.14 13.80 6.57 1.19 0.11 1.53 0.37 5 0.09 2.67 1.12 0.41 0.06 0.50 0.06 8 0.42 22.27 6.68 4.65 0.29 6.29 0.41 2 0.28 12.59 2.34 3.11 0.09 5.41 0.25 12792 ES-12792 ES-12792 ES-12792 g/g) µ ( σ 1 g/g) µ ( 16587 10895 238966 8077 270143 11983 161058 6998 234773 1112 σ 1 0.05 r 1e Feldspar2a Feldspar 2b Feldspar 2c Feldspar 2d Fel g/g) 0.08 µ ( σ 1 g/g) 0.28 0.15 µ ( σ 1 g/g) µ ( σ 1 9.30.2 1.9 0.1 0.90.3 0.1 0.0 2.81.3 10.5 2.7 2.70.4 0.50.2 0.4 0.2 23.8 6.6 0.4 0.2 g/g) 0.27 0.24 0.69 0.19 0.39 0.31 0.41 0.06 0.34 0.08 0.74 0.13 µ ( σ 1 0.1 0.1 0.4 0.4 0.2 0.1 0.4 0.1 2.71.9 7.12.4 2.02.2 16.5 3.5 146140 8 4 198 198 10 8 174 168 5 3 190 185 7 4 162 157 7 5 176 182 5 6 198 189 3 5 275 281 13 14 104 109 4 4 195 196 9 6 g/g) 2.04 0.24 5.50 0.68 2.21 0.19 2.22 0.37 2.36 0.21 2.04 0.34 2.6 0.57 0.10 1.09 0.19 0.76 0.15 0.69 0.13 0.60 0.17 0.90 0.12 0.9 1.73 0.42 2.54 0.61 2.24 0.31 1.70 0.17 1.83 0.17 1.74 0.28 2.1 0.60 0.07 0.88 0.05 0.44 0.03 0.56 0.08 0.71 0.08 0.43 0.10 0.5 5.44 0.18 6.50 0.41 6.01 0.32 6.22 0.25 5.61 0.25 5.98 0.43 6.5 4.42 0.31 5.13 0.28 3.97 0.24 4.39 0.32 3.76 0.18 4.65 0.20 4.9 40.5 8.1 53.7 14.9 61.9 11.7 74.8 15.0 60.0 15.2 76.3 6.8 29.3 1 87.3 3.3 135.1 21.6 63.8 1.7 55.0 1.7 88.2 3.5 66.8 6.7 89.8 3.3 1838 24 1890 37 1896 29 1932 13 1942 29 1765 56 2008 15 1945 68 156 1783 27 1810 36 1824 45 1841 33 1910 54 1701 53 1909 29 1869 68 149 µ ES-12792 ES-12792 ES-12792 ES-12792 ES-12792 ES-12792 ES- ( Feldspar 1a Feldspar1b Feldspar 1c Feldspar 1d Feldspa 210019 7998 245571 5889 218548 8901 227152 8111 225399 4301 2 Table D1: Cont. D1: Table Th Gd Tb Dy Ho Er Tm Yb Lu Pb Sm Eu Nd Pr Ce Zr Nb Ba Ba La Y Sr Sample # Sample Phase# Si U P Cu Rb Sr Ca Ti 295 σ 1 ar9a 0.1 0.0 g/g) µ ( σ 1 0 56 1971 41 3 56 1896 37 2.9 0.7 g/g) µ ( σ 1 15.7 68.221.4 g/g) 0.58 0.31 µ ( 1 95.1 8.2 64.5 3.1 102.6 6.4 σ 1 7 0.27 1.65 0.37 1.43 0.20 1.47 0.51 8 0.17 0.81 0.03 0.87 0.10 0.51 0.01 6 0.25 1.93 0.44 1.80 0.39 1.58 0.58 8 0.06 0.71 0.05 0.44 0.07 0.48 0.02 8 0.27 4.25 0.28 4.46 0.28 3.24 0.20 12792 ES-12792 ES-12792 ES-12792 01 0.50 5.78 0.33 5.72 0.18 5.09 0.39 g/g) 0.08 0.04 0.37 0.16 µ ( σ 1 g/g) µ ( 192170 10478 187661 8004 205018 5522 206752 9571 202548 9916 σ 1 6 Feldspar 7a Feldspar 7b Feldspar8a Feldspar 8b Feldsp g/g) µ ( σ 1 g/g) µ ( σ 1 0.7 0.1 3.0 0.9 0.6 0.2 0.4 0.2 3.7 0.2 g/g) 0.21 0.07 0.05 0.03 0.35 0.24 18.4 1.5 0.6 0.4 6.8 0.3 µ ( σ 1 0.3 0.1 1.1 0.2 0.1 0.0 0.1 0.1 1.4 0.2 0.3 0.1 g/g) 0.500.12 1.21 0.36 0.34 0.29 0.80 0.38 µ ( σ 1 1.7 0.8 5.6 1.5 150146 4 3 139 142 5 4 249 251 5 12 162 159 5 6 147 150 7 4 137 140 3 5 163 164 5 5 141 140 6 3 154 152 5 6 150 149 7 3 g/g) 2.07 0.36 2.13 0.28 6.09 0.21 1.61 0.42 1.72 0.56 2.27 0.23 2.3 0.52 0.18 0.82 0.17 1.10 0.14 0.75 0.06 0.72 0.07 0.77 0.12 1.0 2.03 0.40 1.64 0.12 5.59 0.13 2.29 0.32 3.60 0.22 2.23 0.38 3.3 0.71 0.04 0.40 0.02 1.26 0.29 0.62 0.09 0.64 0.06 0.59 0.07 0.6 6.35 0.15 5.40 0.36 13.48 0.46 6.69 0.16 5.34 0.33 6.02 0.32 6. 4.48 0.26 4.52 0.23 8.43 0.52 4.15 0.20 3.75 0.23 4.77 0.30 4.1 91.4 4.2 51.3 3.5 240.4 15.6 98.4 4.9 146.4 6.2 84.5 6.3 67.7 3. 38.9 16.4 48.9 10.2 89.8 10.5 41.6 5.7 76.6 24.3 39.5 14.7 75.6 1915 29 2146 47 1845 20 2010 35 1875 38 1853 45 1621 31 1982 35 194 1881 45 2057 37 1821 40 1970 53 1822 53 1801 39 1577 38 1928 36 186 µ ES-12792 ES-12792 ES-12792 ES-12792 ES-12792 ES-12792 ES- ( Feldspar3a Feldspar 3b Feldspar 4 Feldspar 5 Feldspar 200517 8611 208644 5762 265944 5500 211750 9443 192641 11088 Table D1: Cont. Table Th Er Tm Yb Lu Pb Tb Dy Ho Gd Sm Eu Nd Pr Ce Nb Zr Y Ba Ba La Sr Cu Ca Ti Sample # Sample Phase# Si U P Rb Sr 296 σ 189 17.0 g/g) 1 µ ( σ r 1e Feldspar2a 9 103 2219 92 90 104 2312 100 g/g) 1 µ ( σ .55 2.55 0.22 2.37 0.26 g/g) 1 µ ( 5 68.4 4.6 109.0 4.6 73.7 3.4 σ 3 0.38 6.06 0.49 4.33 0.24 5.97 0.63 5 0.51 7.80 0.91 6.79 0.42 8.20 0.55 1 0.05 0.76 0.11 0.93 0.13 0.64 0.16 3 0.29 2.97 0.72 2.20 0.24 2.57 0.60 7 0.21 0.96 0.22 0.89 0.18 1.22 0.09 g/g) 1 µ ( σ 0.23 0.2 0.1 0.1 0.0 0.4 0.4 0.7 0.2 g/g) 1 0.740.20 0.71 0.39 µ ( σ g/g) 1 µ ES ES 12792 ES 12792 ES 12792 ES12792 ES12792 12792 ES ( 90475 2947 75138 1701 87765 2888 85175 3684 85343 3552 75954 4 Feldspar1a Feldspar 1b Feldspar 1c Feldspar1d Feldspa σ g/g) 1 µ ( σ 0.7 0.2 2.8 0.4 1.9 1.5 0.7 0.3 g/g) 1 10.5 11.1 27.0 26.3 7.5 2.5 µ ( σ 0.1 0.0 g/g) 1 0.37 0.07 µ ( σ 1.60.6 0.9 0.5 0.40.4 9.61.9 1.5 0.9 1.4 0.9 185183 4 4 189 191 5 5 276 280 9 6 147 149 4 4 178 172 14 9 206 11 206 208 8 6 201 238 9 24 230 179 19 190 8 237 9 14 233 9 g/g) 1 5.10 0.25 5.76 0.47 5.96 0.45 4.57 0.23 5.31 0.34 5.38 0.32 4.8 6.42 0.35 7.68 0.28 8.00 0.33 5.87 0.13 6.83 0.34 6.81 0.45 7.1 98.6 7.2 65.4 7.6 78.2 4.7 81.7 5.3 107.1 7.4 141.2 20.7 77.7 7. 0.57 0.11 0.84 0.05 0.74 0.02 0.68 0.10 0.79 0.08 0.91 0.05 0.6 67.7 5.4 44.5 14.2 43.5 15.4 52.5 2.4 80.8 15.8 66.1 15.8 111.8 1.92 0.36 1.83 0.21 2.53 0.47 2.11 0.27 1.93 0.39 2.58 0.61 2.5 0.88 0.11 0.65 0.12 1.23 0.19 0.70 0.12 0.64 0.07 1.15 0.21 0.8 2.82 0.28 4.85 0.68 8.59 6.18 12.2010.11 0.73 2.60 0.19 2.79 0 1966 32 1731 32 2207 68 1779 41 2169 99 1873 60 2140 68 2164 94 223 2033 24 1790 26 2261 51 1826 42 2246 100 1961 53 2232 71 2305 89 22 µ ES-12792 ES-12792 ES-12792 ES-12792 ( Feldspar 9b Feldspar9c Feldspar10a Feldspar10b 225888 8616 220225 7595 248320 9604 203532 5143 TableD1: Cont. Ba Ba La Y Zr Nb Cu Rb Sr Ce Ca Ti Sr Pr Sample # Sample Phase # Si P U Nd Sm Eu Th Gd Tb Dy Ho Er Tm Yb Lu Pb 297 σ ar 7a g/g) 1 µ ( σ 513 84 2621 78 g/g) 1 2412 88 2525 86 µ ( σ g/g) 1 µ ( σ 11.3 47.4 7.8 114.6 38.9 2 0.16 0.72 0.15 0.83 0.09 0.87 0.06 0 0.19 0.97 0.15 0.92 0.15 1.02 0.15 8 0.50 2.08 0.65 2.69 0.72 3.27 0.77 12792 ES 12792 ES 12792 ES 12792 .8 18.0 119.4 5.6 193.0 13.5 124.6 11.3 91 0.77 4.92 0.49 5.23 0.41 6.45 0.78 25 0.74 2.68 0.49 4.28 0.28 3.21 1.00 6.3 1.2 3.2 0.8 0.5 0.2 0.6 0.2 0.8 0.2 .90 0.57 7.70 0.38 7.17 0.63 8.59 0.58 g/g) 1 20.2 3.0 0.7 0.5 0.17 0.08 µ ( σ 247 66108 2406 87050 3766 99041 4559 91565 3432 g/g) 1 0.47 0.16 1.24 0.32 1.040.74 µ ( σ r 3a Feldspar 3b Feldspar 4 Feldspar 5 Feldspar 6 Feldsp g/g) 1 µ ( σ g/g) 1 µ ( σ g/g) 1 µ ( σ 0.06 1.2 0.5 0.89.2 0.3 1.7 0.5 0.7 0.2 0.6 0.30.1 1.0 0.2 0.20.2 g/g) 1 0.10 16.9 4.0 17.6 5.8 0.6 0.2 0.47 0.15 0.10 0.02 µ ( σ 216214 6 11 260 276 5 11 179 186 3 6 218 221 6 7 192 191 5 8 171 178 4 4 242 248 11 5 195 200 10 7 204 200 9 9 198 198 8 6 g/g) 1 51.8 14.4 62.7 5.7 51.9 13.2 49.5 17.1 48.3 12.3 31.1 10.4 92.3 5.60 0.43 12.43 2.17 5.42 0.45 5.85 0.25 5.70 0.41 5.60 0.23 7. 7.65 0.43 21.36 6.55 8.10 0.65 7.33 0.99 8.30 0.45 6.60 0.31 12 0.63 0.14 2.75 0.90 0.70 0.04 0.65 0.08 0.86 0.14 0.50 0.03 1.4 2.37 0.38 13.16 5.03 2.01 0.44 1.66 0.37 2.27 0.40 2.22 0.09 5. 1.18 0.13 1.20 0.25 1.20 0.16 0.78 0.14 0.63 0.07 1.20 0.18 1.1 3.18 0.28 7.61 0.49 3.12 0.64 2.64 0.64 2.28 0.42 2.37 0.52 5.1 ES ES 12792 ES 12792 ES 12792 ES 12792 ES 12792 ES 12792 ES 2104 81 1870 97 2556 88 2104 104 2443 110 2550 79 1693 53 2383 102 2229 97 1948 100 2669 92 2210 107 2488 98 2666 74 1748 38 2415 83 2 µ 102.0 6.3 428.5 100.3 124.1 6.2 68.3 6.2 117.6 8.6 67.4 9.5 251 Feldspar 2b Feldspar 2c Feldspar 2d Feldspar 2e Feldspa ( 80254 2825 70368 1653 97640 3851 78822 3278 93179 3547 89649 3 Table D1: D1: Table Cont. Ti Cu Rb Sr Sample # Sample Phase # Si P U Sr Ca Nb Ba Ba La Y Zr Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Pb Th 298 σ g/g) 1 µ ( 9 314 6 σ 5.7 114.8 3.6 6 7 314 3 2.1 0.1 2.4 0.1 1.7 0.3 g/g) 1 5.43 0.42 5.83 0.28 5.47 0.53 5.13 0.37 0.67 0.02 0.80 0.03 3.12 0.280.44 0.031.06 4.14 0.170.07 0.35 0.52 0.020.61 0.04 1.60 0.080.07 0.12 0.20 0.02 0.06 1.13 0.24 0.09 0.02 ES12792 ES12792 µ Amph-1a Amph-1b ( 204759 7283 203772 3517 σ 0.2 0.1 12.4 0.4 14.0 0.2 g/g) 1 µ ( σ 3 0.431 5.76 0.05 0.41 0.86 2.90 0.10 0.08 2.36 3.08 0.05 0.08 3.03 0.11 9 0.81 3.02 0.41 16.18 0.31 18.68 0.44 6 2.7 99.9 5.5 15244 373 15708 160 0 0.21 0.80 0.31 1.85 0.11 1.74 0.03 6 0.28 2.76 0.57 0.42 0.12 0.28 0.08 12792 ES 12792 55 0.55 7.56 0.24 12.54 0.29 14.13 0.35 1.0 0.4 0.8 0.1 1.1 0.1 g/g) 1 µ ( σ 2147 70245 2009 84052 1823 g/g) 1 µ ( σ 2.5 0.7 1.1 0.5 41.3 1.8 45.7 1.2 g/g) 1 µ ( Feldspar 9b Feldspar 9c Feldspar 10a Feldspar 10b σ 0.1 0.1 0.1 0.1 g/g) 1 µ ( σ 4.1 1.5 g/g) 1 µ ( σ g/g) 1 µ ( σ 2.9 0.7 0.4 0.1 5.7 0.6 262256 24 15 174 177 6 5 197 192 8 9 198 196 6 7 216 214 11 6 225 224 12 5 289 296 8 5 186 190 6 4 85 86 3 2 94 91 3 1 g/g) 1 13.8 3.7 6.76 0.931.24 5.45 0.19 0.62 0.93 5.81 0.10 0.39 0.57 0.13 4.55 0.23 0.61 5.87 0.09 0.30 0.70 6.93 0.11 1.08 0.94 6.2 0.08 0.8 39.8 7.8 94.038.8 96.6 23.9 84.6 19.4 60.8 18.0 35.0 8.9 101.4 6.61 1.59 2.66 0.59 2.44 0.43 2.45 0.82 1.81 0.43 2.27 0.42 3.0 1.64 0.72 1.48 0.33 1.08 0.05 1.23 0.17 0.60 0.08 1.00 0.18 0.73 0.37 1.5 0.18 0.07 0.48 0.14 3.73 0.32 1.69 0.34 1.58 0.14 1.36 0.27 3.06 0.47 5.13 0.31 2.5 2380 70 2510 82 2452 85 2551 104 2360 87 2107 82 2377 62 2331 60 30 2268 80 2417 90 2356 86 2454 97 2278 88 2044 80 2320 74 2268 65 303 µ ES 12792 ES 12792 ES 12792 12792 ES ES 12792 ES 12792 ES 106.9 5.5 123.3 10.3 84.8 5.4 133.1 4.5 115.8 12.8 80.0 9.2 81. 10.19 1.01 7.64 0.25 7.30 0.52 7.34 0.50 7.20 0.36 9.33 0.50 8. ( Feldspar 7b Feldspar 8a Feldspar 8b Feldspar 9a 109270 9117 91303 3088 87423 4372 95458 3494 82261 3696 86720 Table D1: D1: TableCont. Zr Sr Ba Ba La Pr Nb Sample # Sample Phase # Si U P Y Ti Ce Nd Ca Sr Sm Eu Cu Rb Gd Tb Dy Ho Er Tm Yb Lu Pb Th 299 σ 1 g/g) µ Amph-9a ( σ 1 0.1 1.2 0.1 0.3 3.4 0.0 g/g) µ ( σ 1 7b Amph-8 3 0.8 24.5 0.4 9.8 0.5 3 0.05 0.22 0.03 0.10 0.02 .5 1.4 64.3 1.1 22.7 0.9 1.2 0.2 2.1 0.2 2.9 0.2 g/g) ES12792 ES12792 ES12792 µ ( σ 00 9169 268 12911 180 5495 62 1 3.0 61.0 3.8 52.6 6.0 27.2 6.4 1 0.11 3.59 0.18 3.47 0.20 1.42 0.13 2 0.05 1.22 0.07 1.20 0.05 0.54 0.06 5 0.48 7.22 0.47 5.65 0.30 2.67 0.18 7 0.03 1.12 0.05 0.99 0.03 0.32 0.02 0 0.29 2.49 0.27 2.01 0.05 0.86 0.13 2 0.28 1.56 0.10 1.30 0.21 0.62 0.07 3 0.05 0.17 0.03 0.17 0.03 0.11 0.03 2 0.07 0.86 0.13 0.65 0.05 1.23 0.07 71 0.3536 8.91 0.07 0.6264 8.42 0.28 8.69 0.26 0.15 13.97 8.17 0.90 9.90 0.16 0.23 14.67 0.46 4.33 0.06 5.00 0.83 18 1.08 11.47 0.73 10.14 0.92 3.99 0.40 g/g) ES12792 µ ( σ 1 .69 51.69.69 0.80 57.68 44.03 1.29 2.36 47.45 39.66 0.45 3.46 28.41 48.22 0.69 0.53 20.78 0.76 g/g) µ ( 93946 3738 202550 6845 201153 3545 199222 4413 211853 5312 σ 1 g/g) µ ( σ 1 g/g) µ ( σ 1 g/g) µ ES12792 ES12792 ES12792 ES12792 ( σ 1 0.02 g/g) 0.02 µ ( σ 1 0.8 0.1 1.7 0.24.9 0.1 0.8 0.1 2.3 0.2 1.0 2.6 0.2 0.2 1.0 2.4 0.1 0.2 0.7 0.1 1.9 0.1 0.8 0.1 2.3 0.1 0.9 0.1 5.7 0.2 0.9 5.0 0.4 7.5 1.2 0.4 315309 5 4 23116 26116 1 3 1 2 357 360 37 6 39 6 2 305 2 327 114 116 2 3 3 3 320 327 99 101 7 5 5 327 1 336 15 90 88 17 2 53 2 53 4 93 92 3 130 4 6 134 5 38 5 41 227 2 223 1 4 3 62 64 35 34 3 2 0 1 112 109 2 1 40 43 1 1 g/g) 2.56 0.19 0.86 0.05 2.07 0.12 1.95 0.22 1.56 0.09 1.61 0.16 3.8 19.4 0.6 7.4 0.96.02 0.17 12.55.17 9.07 0.11 0.3 0.178.38 3.12 12.4 0.48 3.65 0.11 0.28 0.5 3.84 3.60 0.60 3.85 11.5 0.09 6.64 0.11 0.5 3.65 0.56 2.70 12.8 0.08 6.89 0.12 0.4 2.42 0.49 3.07 0.12 34.2 0.23 5.67 0.7 2.68 0.91 10. 0.17 26. 5.31 10. 0.60 16. 0.91 0.01 0.45 0.07 0.71 0.05 0.71 0.04 0.54 0.05 0.62 0.03 1.7 7.64 0.65 2.95 0.52 6.39 0.50 6.35 0.43 4.54 0.47 5.37 0.42 13. 61.4 2.4 19.8 0.7 42.9 0.8 49.8 2.8 31.5 0.9 39.9 1.7 29.3 0.6 40 4.53 0.31 2.04 0.15 3.61 0.36 3.13 0.35 2.94 0.30 3.65 0.33 7.7 0.73 0.06 0.24 0.04 0.47 0.04 0.45 0.06 0.43 0.06 0.49 0.07 1.2 1.92 0.20 0.67 0.17 1.08 0.09 0.92 0.12 0.97 0.16 1.19 0.08 3.6 0.20 0.03 0.16 0.03 0.10 0.04 0.10 0.03 0.09 0.02 0.40 0.02 0.3 1.22 0.29 0.49 0.05 0.77 0.19 0.44 0.10 0.44 0.11 0.74 0.12 2.0 0.17 0.04 0.03 0.02 0.08 0.02 0.13 0.04 0.06 0.02 0.11 0.03 0.2 0.53 0.11 1.10 0.06 0.39 0.09 0.38 0.05 0.41 0.09 0.29 0.06 0.5 Amph-2 Amph-3 Amph-4 Amph-4b Amph-6a Amph-6b Amph-7a Amph- ES12792 ES12792 µ 25.76 0.7630.58 20.04 0.45 0.69 14.58 17.12 1.44 0.47 22.61 17.23 1.34 0.32 23.51 11.06 0.75 0.27 14.91 13.68 0.99 0 16.86 0 198.4 23.4 20.9 3.2 110.9 3.1 115.2 9.2 91.3 2.9 106.0 7.4 40.7 ( 14199 215 4678 65 15831 113 15207 221 15159 252 15573 425 5055 2 192673 4321 221711 2725 196978 3146 196585 4503 200260 2586 1 Table D1: Cont. Table D1: Ce Nd Eu Sr Sr Y Ba Ba La Pr Sm Tb Rb Nb Gd Zr Cu Dy Ca Ti Sample # Sample Phase # Si U Ho P Er Tm Yb Lu Pb Th 300 σ 0.14 0.0 0.0 2.4 1.0 2.7 g/g) 1 µ ( σ 0.2 2792 ES12792 3.1 g/g) 1 µ ( σ .1 0.3 0.1 6.9 3.3 0.3 .3 1.2 4.1 0.9 8.8 1.6 .9 4.6 82.6 2.5 117.3 8.9 2.6 g/g) 1 µ ( 2 4.4 0.2 4.4 0.2 6.2 0.59 1 3.0 0.2 2.8 0.1 4.1 0.27 2 6.1 0.2 6.7 0.3 9.1 0.71 1 0.7 0.1 0.7 0.1 1.0 0.14 3 3.5 0.3 3.8 0.2 4.4 0.31 1 0.5 0.0 0.5 0.1 0.7 0.03 1 2.1 0.1 2.2 0.0 1.7 0.06 σ 1.0 60.7 3.2 66.3 2.3 93.6 8.49 0.2 10.5 1.0 11.5 0.4 17.1 1.24 0.1 1.9 45.3 1.4 49.2 1.1 63.3 3.16 0.9 19.1 0.8 19.3 0.8 27.1 2.55 5 2.0 87.6 4.1 92.1 1.8 130.0 9.20 .0 8.5 413.9 21.3 417.6 7.6 488.2 8.63 3.4 g/g) 1 µ ( 54775 4529 158658 4574 154863 4174 131385 5054 σ 8.8 474.3 7.7 372.3 18.6 395.6 12.2 563.1 50.30 1.4 1004.3 17.3 764.7 34.4 785.6 17.8 1024.1 46.99 0.2 74 36 835 55 344 72 563 71 821 71 2.9 4.9 0.2 10.5 0.4 5.2 0.7 5.7 0.3 5.3 0.31 g/g) 1 Apatite 1 Apatite Apatite 2 Apatite 3 Apatite 5 Apatite 6a µ ( σ g/g) 1 µ ( σ g/g) 1 µ Amph-12a Amph-12b ( σ g/g) 1 µ ( σ 2.6 0.4 3.1 0.6 g/g) 1 µ ( σ 361361 86 86 4 1 953 974 82 84 11097 21107 10 50 2 6 0 0 2 5 0 0 20 50 2 6 0 0 3131 0 1 314 316 5 3 319 326 13 13 331 332 5 2 362 363 14 16 464 462 15 10 489 496 7 8 470 467 7 7 457 454 6 7 569 565 23 24 2.6 0.1 2.2 0.1 2.0 0.1 3.9 0.1 3.3 0.2 1.1 0.05.0 0.9 0.2 0.1 13.2 0.9 0.6 0.1 14.5 0.7 0.7 0.1 14.6 0.7 1.0 0.0 14.9 0.4 88.6 4.0 101.5 2.2 82 g/g) 1 18.8 0.3 42.4 2.9 54.6 1.7 65.9 2.1 59.3 4.9 0.4 0.1 0.7 0.0 0.2 0 2.22 0.07 5.92 0.13 5.81 0.50 5.60 0.38 6.66 0.12 62.2 3.4 76.6 2.56 0.12 2.56 0.24 3.03 0.11 2.82 0.18 3.59 0.23 85.2 3.1 115. 15.2 2.5 101.4 6.5 120.8 8.1 137.0 5.7 161.3 14.3 153931 4302 1 0.59 0.04 1.80 0.17 1.67 0.14 1.99 0.17 2.07 0.23 12.9 0.8 13.7 8.27 0.27 3.35 0.33 3.40 0.26 3.33 0.12 3.92 0.30 374.5 4.8 553 2.16 0.30 5.61 0.34 5.43 0.33 4.98 0.18 6.15 0.48 46.9 3.1 55.3 0.25 0.03 0.66 0.04 0.70 0.10 0.77 0.05 0.75 0.06 4.7 0.3 5.5 0. 1.07 0.15 3.14 0.06 3.79 0.18 3.15 0.40 4.61 0.37 20.7 1.1 24.7 0.17 0.02 0.47 0.05 0.53 0.06 0.57 0.05 0.66 0.03 3.3 0.2 3.5 0. 0.49 0.07 1.18 0.22 1.30 0.11 1.04 0.21 1.52 0.11 7.4 0.2 8.5 0. 0.10 0.01 0.11 0.01 0.16 0.02 0.14 0.04 0.15 0.01 0.8 0.1 0.8 0. 0.36 0.08 0.66 0.11 0.90 0.24 0.80 0.11 0.77 0.04 3.6 0.1 4.4 0. 0.08 0.04 0.13 0.02 0.10 0.01 0.10 0.03 0.12 0.04 0.6 0.1 0.7 0. 1.09 0.11 0.34 0.05 0.20 0.08 0.26 0.05 0.57 0.10 2.3 0.2 2.1 0. 5154 67 16057 201 16351 235 15476 117 15962 183 5.9 1.0 3.6 0.8 6 ES12792 ES12792 ES12792 ES12792 ES12792 ES12792 ES12792 ES12792 ES1 µ Amph-9b Amph-10 Amph-11 11.04 0.44 17.59 1.04 19.56 0.78 18.47 0.48 22.73 1.75 373.3 1 19.00 0.58 13.70 0.54 15.37 0.80 13.81 0.45 17.26 1.31 712.2 1 ( 210162 5423 197259 7462 199018 6583 200266 5093 192075 5890 6 Table D1: Cont. Table D1: Zr Nb Sm Pr P Eu Ba La Ba Nd Ca Ti Gd Ce Cu Tb Sample # Sample Phase # Si U Sr Y Rb Sr Dy Ho Er Tm Yb Lu Pb Th 301 σ 0.1 2.1 600 72 g/g) 1 µ ( σ 0.1 0.4 0.1 0.2 1.9 0.1 0.1 0.5 0.0 0.3 3.4 0.3 0.1 0.6 0.0 0.1 2.7 0.1 0.2 5 0.3 4.2 0.1 0 0.1 4.6 0.2 .6 0.9 6.5 0.9 7.7 0.2 6.7 0.2 3.3 g/g) 1 µ ( σ 0.8 11.8 0.2 12.1 0.4 0.1 .6 1.1 22.4 0.6 20.0 0.6 12792 ES12792 ES12792 0.1 0.1 5.1 2.3 52.8 1.2 47.6 1.0 2.7 g/g) 1 µ ( σ .5 92.5 3.5 69.7 1.2 69.0 3.1 4.1 123.4 3.8 102.2 1.4 94.6 3.3 3.4 115.1 3.5 98.7 1.5 84.5 2.2 0.1 2.8 g/g) 1 µ 576.2 20.6 549.0 18.5 435.5 6.2 413.6 16.0 491.4 7.1 481.4 10.2 497.9 6.5 390.0 6.5 ( σ 0.2 .1 100.0 1025.0 21.9 979.9 27.9 883.0 13.7 765.7 23.8 tite 12a Apatite 12b13 Apatite 14 Apatite 15 Apatite 3.2 g/g) 1 µ ( 57516 4297 159453 4743 157760 4301 157560 4388 157242 4550 σ 0.1 2.8 g/g) 1 µ ( σ 0.1 2.9 g/g) 1 µ ( σ 0.2 0.1 0.1 0.1 0.0 0.1 0.0 0.1 0.0 0.3 0.2 7.1 2.5 2.4 g/g) 1 µ ( σ 0.1 5.3 3.1 1.1 0.4 2.5 g/g) 1 µ ( σ 0.2 2070 20 50 10 50 20 50 20 60 10 80 20104 60154 10 50 10 50 0.7 0.1 0.4 0.2 0.4 0.1 0.4 0.1 0.7 0.1 0.8 0.0 1.0 0.1 1.8 0.5 0.6 5.4 0.3 4.6 0.3 4.6 0.2 6.3 0.2 7.7 0.2 12.8 1.0 9.9 0.3 5.1 0.3 8. 1.5 0.1 2.1 0.2 2.3 0.1 2.0 0.2 2.1 0.1 2.1 0.1 2.2 0.3 2.6 0.1 2.3 0.6 0.1 0.5 0.0 0.5 0.0 0.6 0.0 0.7 0.1 1.4 0.1 1.1 0.1 0.7 0.1 0.6 5.7 0.3 3.4 0.2 3.5 0.1 3.4 0.2 5.5 0.3 9.3 1.4 6.3 0.3 4.7 0.4 4.7 2.6 6.4 1.4 5.7 1.0 5.6 0.9 5.7 1.6 3.7 0.8 3.7 1.1 4.7 0.9 72.2 28.2 5 1.0 0.1 0.6 0.0 0.8 0.1 0.6 0.1 0.9 0.1 2.0 0.0 1.3 0.1 0.9 0.0 0.8 5.0 0.5 2.6 0.1 3.0 0.2 2.4 0.1 4.3 0.2 7.9 0.6 5.2 0.2 3.9 0.1 3.3 7.3 0.4 3.9 0.2 4.7 0.4 3.6 0.1 6.8 0.2 11.4 0.9 7.8 0.4 6.2 0.3 5. 585596 22 22 451 445 9 7 449 445 16 18 459 468 6 6 485 499 8 7 431 429 8 6 495 500 22 23 512 515 11 11 430 435 7 7 529 534 7 7 770 143 918 115 527 31 648 78 687 44 1023 99 815 46 89953221 726 75 g/g) 1 20.2 1.3 9.7 0.4 12.4 0.9 9.3 0.2 16.4 0.5 27.6 2.0 18.2 0.3 16.8 77.2 6.2 37.6 1.6 47.5 2.9 38.8 1.2 72.5 1.4 117.4 9.0 77.0 2.4 6 10.8 0.6 6.0 0.3 6.8 0.3 6.0 0.1 9.6 0.3 18.2 1.1 12.6 0.5 9.0 0.5 32.0 1.9 16.3 0.5 20.4 1.0 15.5 0.5 30.1 0.6 52.5 4.3 32.8 1.0 27 µ 668.1 40.5 325.4 8.8 422.2 32.2 328.4 7.6 560.1 6.9 922.3 61.5 108.9 5.6 55.6 1.8 69.3 4.9 51.7 2.1 97.1 1.8 163.8 11.0 102.3 3 513.4 11.7 416.4 5.3 403.3 16.9 459.6 8.5 502.6 9.7 662.2 46.6 152.3 6.7 77.2 1.5 98.5 7.8 80.2 1.6 127.3 1.7 206.0 13.0 129.9 137.7 7.4 79.0 1.5 87.7 4.1 73.9 1.7 126.0 2.3 221.9 14.8 153.1 ( ES12792 ES12792 ES12792 ES12792 ES12792 ES12792 ES12792 ES 1165.5 33.0 683.2 13.2 810.1 47.3 750.8 15.4 1029.8 16.9 1529 Apatite 6bApatite 7a Apatite 7b Apatite 8 Apatite 9 Apatite Apa 140954 5886 124502 3386 155882 4227 157844 4572 157555 4257 1 Table D1: Cont. D1: Table Nd Sm Nb Ba Ba La Zr Eu Ce Pr Th Pb Lu Cu Rb Sr Sr Y Yb Ca Ti Tm Gd Sample # Sample Phase # Si U Er Ho Dy P Tb 302 8 σ 0.1 e24 2.3 1.0 0.2 g/g) 1 µ ( σ 0.1 0.0 0.2 0.0 1.0 4.4 0.7 0.1 3.4 0.1 0.1 2.2 0.1 0.2 4.6 0.3 0.0 0.5 0.1 0.2 3.0 0.2 0.0 0.5 0.1 0.1 2.0 0.2 0.2 4.7 0.3 2.9 g/g) 1 µ ( 4 8.2 0.2 9.2 0.7 σ 0.1 .2 0.9 42.2 2.1 48.2 3.3 .0 1.2 31.7 1.1 34.0 1.8 .0 0.4 12.3 0.3 15.3 0.9 12792 ES12792 ES12792 3.3 g/g) 1 61.4 1.4 65.9 1.4 71.1 3.5 64.4 1.3 74.0 1.2 70.2 4.1 µ ( σ 0.1 2.3 0.0 0.0 0.0 0.0 g/g) 1 55.4 13.5 254.1 4.6 290.5 7.1 296.8 19.4 µ 452.9 11.7 425.2 6.4 463.0 6.4 395.1 9.6 ( σ .6 961.0 24.7 642.7 13.6 733.1 18.4 642.4 27.2 0.0 2.8 g/g) 1 µ ( 58169 4228 159921 4533 156994 4362 157993 5047 159321 4660 σ 0.1 20b Apatite 2122 Apatite 23a Apatite 23b Apatite Apatit 2.5 g/g) 1 µ ( σ 0.1 2.6 0.1 0.0 0.1 0.0 0.1 0.1 g/g) 1 µ ( σ 0.2 2.5 g/g) 1 µ ( σ 0.1 2.9 0.8 0.2 1.0 0.2 0.6 0.2 g/g) 1 µ ( σ 0.1 1050 10 50 20 40 20 70 201010202010 404060405040 2.5 0.3 0.1 0.3 0.1 0.3 0.1 0.4 0.2 0.3 0.0 0.1 0.1 0.5 0.0 0.4 0.1 0.3 5.5 0.9 5.0 0.9 6.4 1.6 5.2 1.4 5.5 0.3 5.2 0.8 6.1 0.7 4.4 0.4 4.0 3.8 0.1 3.6 0.2 2.8 0.2 6.4 0.3 2.9 0.1 2.3 0.1 6.7 0.1 2.7 0.1 3.1 2.6 0.1 2.7 0.1 1.9 0.1 3.9 0.3 2.0 0.1 1.7 0.0 4.2 0.2 2.0 0.1 2.2 6.1 0.3 5.9 0.3 4.9 0.3 9.2 0.3 4.6 0.2 4.1 0.1 9.4 0.2 4.4 0.2 5.2 0.6 0.0 0.7 0.0 0.5 0.0 0.9 0.0 0.5 0.0 0.4 0.0 0.8 0.0 0.5 0.0 0.5 3.3 0.2 4.0 0.2 2.9 0.3 4.3 0.4 3.3 0.1 2.3 0.2 4.4 0.2 2.8 0.2 2.8 0.5 0.0 0.6 0.1 0.5 0.1 0.8 0.0 0.4 0.0 0.4 0.0 0.7 0.1 0.4 0.0 0.5 2.1 0.2 2.0 0.1 2.2 0.2 2.2 0.1 1.8 0.1 2.0 0.1 2.1 0.1 2.2 0.1 2.0 5.0 0.2 6.4 0.2 5.2 0.3 6.7 0.2 5.0 0.1 5.2 0.2 4.9 0.2 6.4 0.2 6.5 486 39 666 62 529 57 521 43 522 59 558 52 641 30 2391 733 517 41 453 5 482489 8 7 469 480 6 6 425 434 6 6 502 500 8 6 452 456 7 7 463 462 6 6 498 503 8 6 435 434 8 8 442 443 6 6 457 456 7 8 g/g) 1 79.5 1.6 86.1 1.9 62.2 2.3 116.2 4.3 61.3 1.2 54.3 0.9 120.6 2.7 85.6 1.3 92.7 1.4 70.3 2.6 140.0 4.8 68.8 0.8 61.4 0.9 123.3 2.5 58.3 1.6 57.1 1.4 40.1 1.2 95.2 2.1 42.4 0.6 34.0 0.7 96.5 2.3 40 10.7 0.3 10.7 0.4 8.3 0.4 16.0 0.7 8.1 0.1 7.1 0.1 17.3 0.4 8.0 0. 43.9 1.3 38.7 0.8 31.1 1.9 65.6 3.8 30.1 1.1 25.0 0.9 69.4 1.5 29 17.4 0.8 16.5 0.4 12.2 0.8 26.4 1.1 11.8 0.3 10.6 0.2 29.4 0.9 12 ES12792 ES12792 ES12792 ES12792 ES12792 ES12792 ES12792 ES µ 746.3 13.3 842.5 12.5 682.8 26.2 1169.4 40.6 654.1 9.9 618.3 9 362.9 6.8 372.9 7.0 276.8 10.1 593.8 16.6 276.6 5.5 236.4 3.1 5 421.7 6.0 498.2 10.1 434.9 16.2 586.0 21.6 394.9 5.2 392.2 5.0 ( Apatite 18aApatite Apatite 18b Apatite 1920a Apatite Apatite 158202 4624 158222 5261 156919 4594 159026 4615 158801 4601 1 Table Cont. D1: Sample # Sample # Phase Si U Ce Sr Sr Y Rb P Pr Zr Nd Ca Ti Sm Eu Gd Nb Ba Ba La Tb Cu Dy Ho Er Tm Yb Lu Pb Th 303 σ 1 0.4 0 0 g/g) itanite 7 itanite 31.1 µ ( σ 1 0.7 0.2 4.3 0.2 0.1 3.7 0.2 0.3 1.4 0.1 4 10.9 418.6 8.6 g/g) 25.3 µ ( 7 26.5 2.3 38.6 1.7 8 10.8 1.0 16.4 0.7 4 14.3 1.3 22.69 1.3 21.1 1.1 26.5 1.1 σ .1 80.0 2.3 108.5 4.2 1 0.5 5 2.5 42.5 4.3 63.1 3.4 g/g) 23.9 72.9 7.9 271.2 8.1 270.7 4.2 68.9 6.9 70.8 6.9 106.0 4.8 µ ( σ .0 502.6 7.4 250.4 11.5 333.2 6.1 .7 423.6 14.0 180.0 15.5 272.5 13.5 .1 304.7 11.5 132.4 10.6 196.2 10.0 1 0.3 7.2 680.8 15.7 289.7 17.2 411.8 17.8 2 2251 215148 1875 216708 996 221675 2234 310 2525 147232 1824 144187 4526 146126 2585 g/g) 23.3 µ ( σ .9 995.1 20.2 1108.5 25.1 977.7 13.9 1106.4 24.7 .3 1081.0 119.2 2187.3 47.5 997.4 54.8 1416.6 35.3 1 0.4 57.8 2346.5 66.7 3433.1 56.4 2199.8 58.0 2607.4 42.9 6.1 8.2 195.1 3.9 241.3 15.0 242.4 7.8 285.4 15.6 g/g) 24.0 µ ( σ 1 1.2 g/g) 41.6 Titanite 1Titanite 2 Titanite Titanite 35 Titanite 6 Titanite T ES ES 12792 ES 12792 ES 12792 ES 12792 ES 12792 ES 12792 µ ( σ 1 0.2 2.6 g/g) µ ( σ 1 0.1 3.2 0.7 0.2 5.92.5 0.1 0.1 0.1 0.0 0.1 0.1 0.0 0.0 0.1 0.1 1035.4 34.0 337.7 10.9 343.2 8.5 524.6 6.6 337. g/g) µ ( σ 1 0.1 2.6 0.9 0.3 2.3 0.4 3.0 0.3 2.4 0.4 5.7 0.5 2.7 0.3 3.0 0.4 1.9 0.4 g/g) µ ( σ 1 0.3 10 20 8318238 00 10 5 0 5 0 11 2 18437 12 0 10 0 11 0 15 0 10 0 11 0 2.2 6.4 1.0 3.1 0.6 9.1 0.9 47.8 16.8 219207 2419 211071 1447 21589 0.8 0.2 0.4 0.1 0.8 0.2 4.3 2.4 356.5 10.4 269.8 5.3 315.2 16.0 2 0.6 0.1 0.6 0.0 0.8 0.1 0.3 0.0 5.4 0.1 3.2 0.2 3.6 0.3 7.2 0.2 3.2 6.3 0.2 6.1 0.4 7.0 0.2 3.3 0.4 48.2 0.6 26.9 0.5 31.0 3.7 61.2 1. 2.9 0.2 2.7 0.1 3.1 0.1 1.6 0.1 19.9 0.4 10.2 0.2 11.8 1.6 26.0 0. 0.5 0.1 0.5 0.0 0.7 0.0 0.3 0.1 4.1 0.2 3.1 0.1 3.1 0.2 5.0 0.2 2.9 4.6 0.2 4.1 0.13.7 0.2 4.5 0.2 3.5 0.4 2.3 0.1 4.0 27.2 0.1 0.5 1.4 13.3 0.2 0.3 32.7 16.4 0.8 2.4 22.6 35.5 1.1 1. 23.9 2.1 42.0 0. 2.1 0.2 1.7 0.1 2.1 0.1 3.5 0.3 2.0 0.1 1.4 0.2 2.5 0.4 1.1 0.2 1.4 4.4 0.4 4.7 0.1 7.1 0.3 4.2 0.2 149.8 4.2 73.3 1.6 72.7 3.0 74.8 3 489493 9 9 502 503 7 9 455 450 6 6 48313 47816 39 42 1 0 36 38 1 0 34 36 1 1 40 39 1 1 37 37 2 1 39 37 1 1 569 105 586 46 3766 1219 31627 5656 146297 2773 144237 2849 141 g/g) 96.0 3.7 87.7 2.1 95.0 1.4 49.9 1.3 383.6 7.0 279.5 7.1 272.4 21 90.0 2.7 81.8 1.6 95.1 1.5 43.1 1.1 539.1 10.5 293.6 6.6 311.4 3 69.5 3.6 58.5 1.0 68.6 1.6 29.6 0.7 311.2 3.7 170.6 6.0 195.0 28 47.6 2.3 39.2 1.1 47.7 1.4 20.7 0.9 232.2 0.9 118.9 3.8 137.1 20 12.5 0.5 10.5 0.3 12.3 0.3 6.3 0.4 70.4 0.8 39.0 1.2 47.9 7.4 93. 20.7 0.5 18.4 0.4 19.9 0.6 8.9 0.6 135.5 2.8 64.7 1.3 78.8 12.4 1 ES12792 ES12792 ES12792 ES12792 µ 796.6 32.3 766.0 12.1 813.6 11.8 510.0 8.0 2947.8 59.7 2434.0 414.5 16.5 424.2 4.7 451.4 5.8 331.1 4.3 1072.0 22.7 1040.7 24 414.7 15.7 362.0 8.4 407.5 4.8 197.6 3.0 1632.6 23.7 1053.5 27 ( Apatite Apatite 26a26b Apatite Apatite 2729 Apatite 160188 4670 161064 4411 157132 4912 145613 4396 485.8 26.5 23 Table D1: Cont. D1: Table Ba Pr Ce P Cu Rb Sr Sr Y La Ba Ca Ti Sm Nd Sample # Sample Phase # Si U Nb Zr Tm Gd Er Eu Ho Dy Lu Tb Yb Pb Th 304 3 σ 1 0.7 g/g) 22.7 itanite itanite 21a µ ( σ 1 0.1 1.3 0.1 0.8 3 0.1 6.8 0.1 3 0.1 11.9 0.3 7 0.5 1.6 0.1 g/g) 29.3 µ ( σ 1 0.5 7 0.4 9.0 0.2 49.7 0.7 .6 0.9 12.6 0.2 74.5 0.9 8.9 1.4 16.6 0.9 62.5 1.6 5.2 1.2 20.1 0.2 110.6 2.1 g/g) 34.6 2.0 31.9 0.8 182.3 1.7 18.3 µ ( σ 1 2.2 71.5 4.4 59.8 1.5 340.9 3.7 0.7 4 4.4 57.7 1.3 103.6 2.9 81.5 1.2 12792 ES12792 ES 12792 ES 12792 1.3 26.3 128.9 5.4 111.2 1.1 629.3 9.9 4.6 3.9 399.4 10.1 720.6 51.1 316.6 1.5 g/g) 55.0 µ 530.6 15.1 227.1 11.2 356.5 26.2 241.7 12.0 ( 1333.7 39.9 166.7 10.3 142.8 1.9 887.6 18.5 2175.1 14.3 286.0 13.5 219.1 3.8 1238.9 18.8 1250.0 34.9 216.2 10.9 160.0 3.8 768.2 12.3 σ 1 4.6 54.9 2624.4 86.6 316.7 24.7 318.5 7.3 596.8 7.7 0 0 0 0 1 1 0.8 57.3 1717.3 40.5 912.2 21.0 995.5 20.4 1168.1 15.6 g/g) 53.7 µ 952.2 66.2 6077.3 178.4 851.4 46.4 666.2 15.2 3810.6 55.5 ( 35702 2236 134182 2123 145529 1627 132960 3480 146411 3799 14444 3866 209504 1297 209870 1183 208528 1212 214873 1482 4126.4 225.5 7997.7 276.1 1953.8 82.7 1638.2 36.4 4346.5 65. σ 1 0.9 e 13ae Titanite13b Titanite 15 Titanite17 Titanite 18 T 0.1 0.0 0.3 0.1 g/g) 39.0 µ ( σ 1 0.3 g/g) 23.9 µ ( σ 1 0.3 g/g) 24.2 µ ( σ 1 4.5 g/g) 50.1 µ ( σ 1 0.7 3937 1 1 40 42 2 2 35 37 2 0 41 42 1 1 42 46 1 1 45 46 3 1 40 44 1 0 39 36 1 0 30 30 1 0 42 41 1 1 100 15 1 100 100 211 19 1 29 1 9 0 70 18 0 1.1 0.1 1.7 0.2 1.5 0.2 1.3 0.1 1.5 0.1 2.9 1.1 2.1 0.2 1.5 0.1 1.7 2.8 0.2 4.6 0.3 2.9 0.1 2.7 0.2 5.9 0.2 4.7 0.1 13.0 0.3 2.5 0.0 2. 2.5 0.2 5.4 0.6 3.5 0.1 3.0 0.2 8.6 0.3 5.5 0.2 22.8 0.5 3.1 0.1 2. 7.5 0.4 24.7 1.7 14.9 0.8 13.3 0.5 46.7 1.6 24.4 1.1 116.6 2.8 15 6.4 0.3 18.6 1.2 11.4 0.5 10.1 0.5 32.8 1.0 18.3 1.0 87.5 2.4 10. 2.5 0.3 3.6 0.5 3.5 0.6 3.5 1.0 1.9 0.5 14.3 9.6 2.0 0.3 3.1 0.8 2. g/g) 78.8 1.6 156.2 15.7 77.5 2.3 68.1 1.3 164.9 3.6 211.8 13.7 196. 17.0 1.0 33.0 2.4 21.2 1.1 18.7 0.9 50.5 1.8 35.6 1.7 126.6 3.1 1 17.0 0.8 44.3 3.5 28.6 0.8 26.1 1.2 81.1 4.1 44.4 2.4 206.1 4.7 2 36.8 2.0 118.0 9.9 74.6 2.9 65.6 3.2 217.8 2.9 117.6 4.5 573.5 1 61.7 2.8 218.9 16.8 134.4 7.8 116.1 5.7 417.7 10.5 226.6 4.6 98 22.9 1.2 73.6 5.5 44.9 2.7 39.9 2.3 128.7 2.5 75.0 2.2 283.1 8.5 99.3 6.1 309.2 26.1 187.5 13.8 172.0 5.8 588.6 16.4 324.1 12.6 25.6 µ Titanite8 Titanite 9 Titanite11a Titanite11b Titanit ES ES 12792 ES 12792 ES12792 ES 12792 ES12792 ES 12792 ES 183.8 5.5 511.7 45.2 311.6 8.0 279.7 8.2 877.2 25.5 473.3 12.2 267.2 3.7 521.0 42.4 251.2 3.9 243.8 3.2 399.5 3.7 494.9 5.3 70 349.7 8.7 1320.8 128.3 334.7 2.2 319.4 3.6 1131.1 11.0 1120.9 996.2 28.2 1409.8 111.2 986.2 22.0 879.0 14.9 1702.1 26.2 177 233.8 6.9 456.8 46.3 222.6 6.8 294.2 9.2 459.0 12.4 460.9 19.5 220.0 8.3 442.0 33.5 270.6 7.9 265.1 5.3 722.8 19.9 515.8 18.8 711.5 17.5 1756.1 129.1 1069.8 46.2 1034.7 22.9 3148.8 89.5 1 ( 2191.9 75.6 3499.3 257.9 2297.3 40.9 2165.5 39.0 4924.6 97.7 141232 2055 140766 1605 140433 2594 149925 1934 155463 2188 1 215564 1516 216239 1563 212758 2697 213057 2922 219322 1056 2 Table D1: Cont. D1: Table Pb Th Lu Yb Tm Er Tb Dy Gd Eu Ho Rb Sr Sr Y Zr Sm Nb Ba Ba La Ce Sample # Sample Phase# Si U P Ca Ti Cu Pr Nd 305 9 σ 1 g/g) µ ES-12800 ( Feldspar1a σ 1 0.5 0.3 0.0 4.85 0.19 8 0.3 g/g) µ ( σ 1 .7 1.1 50.9 2.0 .8 0.8 23.9 0.3 .5 3.3 145.7 4.1 0.91 0.14 .4 0.8 50.6 2.2 .1 1.6 84.1 4.2 .5 0.7 36.4 1.1 58 14 1 0 252 12 g/g) µ ( σ 1 3 7.8 99.3 6.8 87.0 3.0 12792 ES 12792 ES 12792 9.5 6.9 115.2 3.4 241.9 11.5 g/g) 34.5 39.4 282.6 3.8 289.7 2.0 98.8 13.2 334.8 13.7 657.4 22.8 0.99 0.36 01.3 9.0 224.4 10.2 435.9 16.9 µ 467.1 20.8 528.0 11.6 988.2 22.0 0.6 0.3 407.8 17.9 505.6 21.6 697.4 12.2 1.23 0.30 ( σ .6 826.1 36.1 313.8 13.0 249.4 12.5 330.4 54.5 1 8.9 1255.7 108.7 607.7 31.4 748.3 8.5 g/g) µ 043.5 15.8 1052.1 39.2 1285.6 58.5 1168.1 30.0 8.36 0.32 Titanite Titanite 25b Titanite 25c Titanite 26a Titanite26b ( 10858 2246 208090 2114 214542 2487 206064 2281 34.3 3.9 34762 2205 137472 3075 163753 4358 136520 3384 225545 9331 1863.4 21.7 1674.0 77.3 2005.0 94.5 3208.0 67.1 3.76 1.06 0 3150.2 51.5 2982.8 134.8 3668.9 164.5 4149.2 79.7 13.06 1.0 σ 1 g/g) µ ( σ 1 g/g) µ ( σ 1 g/g) µ Titanite23 Titanite 24 Titanite 25a ( σ 1 g/g) µ Titanite Titanite 22 ( σ 1 1 1 0 0 4543 1 0 46 46 1 0 36 34 1 0 39 38 1 1 42 42 1 1 41 44 2 1 47 48 2 1 54 55 5 4 39 40 1111149 1112838 17 1 15 0 23 0 15 1 13 0 13 0 13 1 73 15 17 0 249 8 2.8 0.4 2.9 0.4 3.3 0.2 2.8 0.3 3.6 0.9 2.6 0.2 2.0 0.4 2.6 1.0 2.4 0.2 0.1 0.1 0.0 0.3 0.2 0.1 0.0 0.1 0.0 5.5 0.8 0.2 0.1 5.0 0.3 3.5 0.1 8.9 0.2 4.5 0.2 4.9 0.2 4.5 0.1 3.6 0.2 4.2 0.2 5.9 1.6 0.2 1.8 0.1 3.1 0.4 1.5 0.2 1.2 0.0 1.6 0.2 1.6 0.1 2.6 0.4 1.0 6.7 0.5 4.9 0.1 10.8 0.3 5.8 0.1 6.5 0.2 6.0 0.2 4.5 0.2 5.3 0.2 9. g/g) 38.4 3.1 29.8 0.9 68.3 2.3 35.9 1.4 38.2 1.5 34.9 0.8 29.0 2.2 32 26.7 0.8 44.9 0.9 79.0 1.9 24.3 0.6 36.9 1.1 35.4 0.7 33.4 3.1 25 81.7 4.7 84.1 0.9 85.9 2.4 75.9 4.4 83.1 1.0 78.7 0.6 68.3 2.0 75 29.4 1.8 27.3 0.4 35.2 0.6 27.3 1.3 29.2 0.2 27.1 0.4 23.5 0.9 24 55.9 3.6 43.6 0.9 81.9 1.6 49.3 2.2 54.4 0.7 50.0 1.4 39.6 1.6 44 22.6 1.4 19.1 0.2 29.8 0.9 21.0 0.6 22.0 0.5 19.9 0.3 16.9 0.7 18 ES ES 12792 ES 12792 ES12792 ES 12792 ES 12792 ES12792 ES µ 634.2 38.7 508.1 8.4 969.7 17.4 553.9 16.2 614.9 6.1 569.5 4.8 469.6 26.7 299.6 5.6 878.2 3.6 305.6 2.6 534.0 2.0 587.0 6.4 10 652.5 41.3 519.1 10.8 2402.3 41.9 403.5 8.1 1032.1 9.5 1049.3 366.7 22.3 502.7 17.5 584.8 33.9 193.4 8.5 929.5 53.8 922.8 31 363.5 20.1 351.4 5.9 421.1 9.0 335.9 20.0 344.2 4.5 337.5 4.0 2 512.8 23.3 448.2 7.9258.6 680.7 18.2 11.2 245.6 468.0 2.1 14.2 301.2 446.0 8.0 7.2 232.0 443.7 13.6 244.6 6.3 1.9 235.6 2.6 2 142.0 10.1 128.6 2.6 178.8 4.2 126.8 7.8 142.2 1.6 131.0 1.8 10 102.6 1.7 180.6 4.2 254.7 4.9 84.8 1.8 116.6 1.8 117.8 2.1 109. ( Titanite Titanite 21b 1328.8 18.3 1534.8 27.3 1820.7 27.6 1198.2 20.1 1006.6 16.8 1 2090.3 110.7 1907.9 26.8 2540.9 43.3 1884.8 62.8 1907.6 30.6 3767.9 117.7 3457.3 63.7 5207.3 106.8 3425.3 84.5 3155.2 57. 216755 1893 213028 2676 214509 2017 212722 3056 212256 1622 2 146225 3277 146933 4441 132826 1734 134322 1651 139383 4185 1 Table D1: Cont. Table Ca Ti Cu Rb Sr Sr Y Zr Lu Yb Nb Sample # Sample Phase# Si U P Ba La Ba Pb Sm Pr Gd Eu Dy Tm Nd Tb Er Th Ho Ce 306 σ g/g) 1 0.58 0.17 µ 207.7 21.1 ( σ 43 1105 30 8 41 1135 35 0.1 0.1 g/g) 1 µ ( σ .7 1.4 27.9 2.1 30.5 2.7 g/g) 1 ES-12800 ES-12800 ES-12800 µ ( σ .7 28.5 14.4 6 0.56 8.03 0.54 8.84 0.45 8.51 0.30 7 0.10 0.84 0.12 0.76 0.07 0.71 0.04 8 0.36 1.40 0.40 1.85 0.33 2.51 0.66 1 0.08 1.06 0.16 1.15 0.16 0.87 0.13 10 0.44 6.61 0.30 7.95 0.88 8.78 1.26 .99 0.60 10.36 0.44 10.16 0.44 11.34 0.34 g/g) 1 µ ES-12800 ( Feldspar 3a Feldspar3b Feldspar 3c Feldspar 4 σ g/g) 1 µ ( 269394 8993 236951 6983 232887 8979 253297 13126 247291 9786 σ 1.6 0.5 10.0 4.2 g/g) 1 µ ( Feldspar 2b Feldspar2c σ g/g) 1 0.38 0.21 µ ES-12800 ES-12800 ES-12800 ( σ 0.3 0.1 0.3 0.1 0.3 0.0 0.3 0.1 0.1 0.0 0.2 0.1 0.3 0.1 g/g) 1 µ ( σ 0.7 0.2 0.4 0.1 0.4 0.1 0.8 0.1 5.1 1.0 0.9 0.2 0.5 0.4 0.8 0.2 g/g) 1 µ ( σ 0.4 0.1 978 37 1017 47 1070 39 1009 46 1034 37 1027 33 1097 31 1036 31 1077 246246 9 13 313 310 12 11 331 318 13 10 278 283 12 11 299 288 19 13 385 389 24 17 324 320 12 9 289 294 10 8 367 372 14 10 378 14 386 10 g/g) 1 85.1 3.8 21.1 6.2 52.2 10.4 23.9 8.8 59.5 9.7 31.1 6.3 45.3 17.7 38.0 19.1 70.2 18 43.6 2.0 18.6 0.5 30.6 3.8 26.2 4.1 30.9 1.3 29.6 2.5 31.9 1.4 28 7.47 0.30 7.29 0.30 7.22 0.26 8.18 0.43 7.28 0.58 6.96 0.30 8.3 0.57 0.07 0.68 0.17 0.62 0.05 0.71 0.09 1.15 0.09 0.66 0.05 0.8 8.41 0.41 8.49 0.75 8.88 0.56 9.61 0.44 10.11 0.51 9.07 0.53 10 2.35 0.56 1.93 0.47 2.21 0.31 2.18 0.64 2.86 0.17 2.48 0.20 2.8 0.250.07 0.59 0.39 1.11 0.15 0.98 0.09 1.21 0.14 0.87 0.16 0.95 0.10 1.37 0.27 1.0 0.39 0.36 6.38 0.42 6.74 0.54 6.48 0.36 5.72 0.24 5.58 0.64 13.52 0.96 7. 1028 40 1045 40 1116 39 1055 39 1039 37 1080 39 1153 37 1089 35 114 µ ES-12800 ES-12800 ES-12800 ( Feldspar 1b Feldspar1c Feldspar 1d Feldspar2a 217892 6308 252838 11543 270911 7440 213770 5280 223460 7316 TableD1: Cont. Cu P Sr Ca Ti Sr Sample # Sample Phase # Si Rb U Y Ba Ba La Zr Nb Pr Ce Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Pb Th 307 1 σ 1 88 6 g/g) 0.35 0.37 µ ES-12807 ( Feldspar 3c σ 31 1153 21 40 1103 30 1 g/g) 0.47 0.31 µ ( σ 1 0 0.400 4.27 0.053 0.27 0.13 0.330 0.09 0.93 5.35 0.04 0.12 0.39 0.22 0.40 0.10 0.36 0.04 0.19 0.46 0.11 0.2 0.0 g/g) µ ( σ 1 4 0.67 6.01 0.36 4.83 0.31 6.15 0.48 g/g) 42.7 3.3 50.3 3.4 35.0 2.6 34.5 2.4 µ ( 206274 4067 227307 8663 261677 8695 251536 6631 σ 1 9 1.13 3.78 0.27 4.67 0.46 6.10 0.63 4.25 0.26 0.1 0.0 0.1 0.0 g/g) ES-12807 ES-12807 ES-12807 ES-12807 µ Feldspar 2b Feldspar 2c Feldspar 3a Feldspar 3b ( σ 1 g/g) 43.2 14.4 27.7 2.7 71.6 5.8 µ ( σ 1 1c Feldspar 2a 0.3 0.1 0.2 0.1 g/g) 0.48 0.09 0.50 0.06 µ ( σ 1 g/g) µ ( σ 1 g/g) 6.85 0.330.58 6.97 0.142.60 0.36 0.52 0.740.63 1.50 6.58 0.13 0.06 0.23 0.28 0.54 0.71 5.87 0.14 2.15 0.15 0.20 0.73 0.53 0.55 5.60 0.13 1.50 0.15 0.47 0.52 0.78 0.79 1.35 4.83 0.20 0.06 0.27 0.37 0.68 0.48 5.3 0.06 2.33 0.15 0.35 0.5 0.72 1.2 0.05 0.7 µ ES-12807 ES-12807 ES-12807 ES-12807 ( 215965 4122 228324 5911 208867 6406 246481 4971 255578 14038 σ 1 g/g) 0.04 0.01 8.02 0.34 9.29 0.50 8.96 0.40 7.70 0.31 7.31 0.36 6.3 µ ( σ 1 9 0 15 0 1236 34 1357 28 1245 22 1214 16 1251 41 1129 30 1286 18 1134 7 1 20 1 1166 29 1291 25 1175 29 1170 22 1186 31 1089 19 1260 23 1061 0.8 0.1 2.9 0.2 0.1 0.0 0.1 0.0 g/g) 4.11 1.46 3.38 1.75 4.24 0.46 4.11 0.79 3.55 0.24 4.78 0.51 6.4 21.6 0.3 22.2 0.1 28.3 9.7 ES12800 ES12800 Biotite 1a Biotite 1b Feldspar 1a Feldspar 1b Feldspar 4434 136 4418 127 323 9 345 6 330 9 411 10 330 11 290 14 351 7 285 11 2 4443 68 4498 72 325 11 345 9 326 8 423 10 343 13 300 7 355 8 287 8 300 7 µ 256.8 6.9 251.9 9.1 0.3 0.2 0.4 0.2 1.0 0.1 0.6 0.3 0.4 0.1 0.4 0. ( 21726 520 21765 476 39.0 1.4 44.1 4.6 38.9 1.8 32.9 1.8 43.5 4.0 1146.8 9.7 481.4 9.4 Table D1: Cont. TableD1: Tb Dy Ho Er Tm Yb Lu Pb Th Zr Nb Ba Ba La Ce Pr Nd Sm Eu Gd Y Sr Sr P Sample # Sample Phase # Si U Ca Ti Cu Rb 308

Appendix E

Lassen Peak

Two summers during 2004 and 2005 were spent at Lassen Volcanic National Park located in northern California collecting samples and mapping the hydrothermal alteration. Over two hundred and sixty samples were collected at the park of which 212 were analyzed by a portable infrared mineral analyzer (PIMA), 48 were analyzed by X- ray diffraction (XRD), and 73 were analyzed at the USGS analytical laboratory for major and trace element concentration. A PIMA analyzes the molecular bonds present within hydrous minerals and all analyzed spectra are presented within the CD appendix. The computer database software FEATURESEARCH™ and SPECMIN™ were used to identify absorption features by comparison with the USGS mineral reference libraries.

The Oregon State University Phillips XRG 446 X-ray defractometer, run at 40 kev and

30 mA using a Cu K α radiation source was used to qualitatively identify minerals present within bulk rock powders, <15 µm size fractions, and <2 µm size fractions. Sample locations and mineral identifications by both PIMA and X-ray diffraction are presented in

Table E1.

Geochemical analyses were conducted at the USGS geochemical laboratories in

Lakewood, CO using an inductively coupled plasma-atomic emission spectrometer.

Samples were digested using mixtures of hydrochloric, nitric, perchloric, and hydrofluoric acids at low temperature and then aspirated into the spectrometer. Mercury was analyzed in sixty-four of the total analyzed samples by cold-vapor atomic absorption technique by dissolving the samples in acids, spiking the solution with various salts and analyzing the solution in a cold-vapor atomic absorption mercury analyzer with a 309 detection limit of 0.02 ppm. Gold and selenium were analyzed using fire assay collection after heating and cooling the samples within an acid mixture and then analyzed by atomic absorption spectrophotometry with a lower detection limit of 5 ppb for gold and

Mineral identifications and field mapping were digitized into the geographic information software MapInfo®. The geographic database is presented in the CD appendix.

310

Table E1: PIMA and XRD Mineral Identifications from Lassen Peak samples. Sample # Latitude Longitude PIMA XRD CALV001 40.456848 -121.506574 Smectite CALV002 40.457947 -121.517506 Smectite CALV003 40.457336 -121.516095 Chlorite/Smectite CALV004 40.457336 -121.516095 Chlorite/Smectite CALV006 40.455201 -121.514411 Smectite/Illite Chlorite, Quartz, Illite, Mont, Albite, Anatase CALV007 40.455201 -121.514411 Smectite/Illite CALV010 40.457695 -121.505259 Smectite CALV013 40.455641 -121.502068 Kaolinite/Smectite Albite, Kaol-Mont, Mg-Smectite, CALV014 40.455641 -121.502068 Kaolinite/Smectite CALV015 40.455474 -121.501622 Alunite Cristobalite, Quartz, Anatase, Natroalunite CALV016 40.454750 -121.501370 Smectite CALV017 40.454750 -121.501595 Smectite Albite, Montmorillonite, Cristobalite, Orthoclase CALV021 40.456241 -121.504380 Smectite CALV022 40.457942 -121.505624 Smectite CALV023 40.457695 -121.505672 Smectite/poor ID CALV024 40.457073 -121.505286 Smectite CALV025 40.458355 -121.505581 Alunite Cristobalite, Natroalunite CALV026 40.459111 -121.505222 Smectite CALV027 40.460179 -121.504460 Smectite CALV028 40.458081 -121.506284 Smectite CALV029 40.457556 -121.509143 Smectite CALV031 40.458210 -121.505662 Alunite CALV032 40.458736 -121.506118 Smectite/poor ID CALV033 40.457540 -121.513601 Smectite CALV035 40.459310 -121.513719 Smectite Quartz, Cristobalite, Albite, Montmorillonite, min Kaol CALV036 40.459321 -121.513596 Smectite CALV037 40.459321 -121.513596 Smectite CALV038 40.459272 -121.513392 Smectite CALV039 40.459755 -121.513333 Smectite CALV040 40.459846 -121.513462 Smectite CALV041 40.459782 -121.513295 Smectite CALV043 40.464615 -121.518810 Alunite/Smectite CALV044 40.465511 -121.519513 Smectite/poor ID CALV045 40.465575 -121.520033 Smectite CALV046 40.465983 -121.520290 Smectite CALV047 40.466090 -121.520993 Smectite CALV048 40.466090 -121.520993 Smectite CALV049 40.465849 -121.525403 Smectite CALV050 40.465951 -121.525821 Smectite CALV051 40.464626 -121.527050 Smectite/poor ID CALV052 40.463998 -121.527473 Dickite Quartz, Dickite, minor Natroalunite CALV053 40.464331 -121.527441 Dickite Dickite, Illite, Anatase, Quartz CALV054 40.463886 -121.526985 Smectite/poor ID CALV055 40.458789 -121.524491 Smectite CALV056 40.460216 -121.522576 Chlorite/Smectite CALV057 40.460801 -121.521948 Calcite CALV058 40.461515 -121.521658 Organic CALV059 40.461413 -121.521733 Smectite CALV060 40.461627 -121.522855 Kaolinite CALV061 40.461676 -121.522324 Kaolinite Kaolinite, Anatase, Quartz, Dickite CALV062 40.462802 -121.522635 Kaolinite CALV063 40.464336 -121.527296 Dickite/Alunite CALV064 40.465602 -121.528568 Smectite CALV065 40.465602 -121.528568 Smectite CALV066 40.465736 -121.529034 Smectite CALV067 40.465736 -121.529034 Smectite CALV068 40.467163 -121.530440 Kaolinite

311

Table E1: Cont. Sample # Latitude Longitude PIMA XRD CALV069 40.468086 -121.531491 Pyrophyllite/Na-alunite Natroalunite, Jarosite, Kaolinite, Pyrophyllite CALV070 40.468086 -121.531491 Pyrophyllite/Na-alunite CALV071 40.465028 -121.531770 Kaolinite CALV072 40.464438 -121.530789 Kaolinite Kaol, Na-alunite, Quartz, Opal, Cristobalite, sulfur CALV073 40.464256 -121.530338 Kaolinite CALV074 40.464261 -121.529662 Kaolinite CALV075 40.462609 -121.525821 Kaolinite/Smectite Kaolinite, Quartz, Mg-smectite CALV076 40.467351 -121.532264 Alunite/Smectite/Illite CALV077 40.463322 -121.532913 Kaolinite Kaol, Na-alunite, Cristobalite, Quartz, illite-smec CALV078 40.463220 -121.532832 Kaolinite CALV080 40.463145 -121.532162 Kaolinite/Smectite Kaolinite, Mg-smectite, Cristobalite, Quartz CALV081 40.462925 -121.531465 Kaolinite CALV082 40.462469 -121.530923 Kaolinite CALV083 40.463558 -121.530097 poor spectra CALV084 40.463939 -121.527479 Smectite CALV085 40.464562 -121.527527 Dickite/Kaolinite CALV086 40.464138 -121.527645 Dickite Dickite, Quartz, Anatase CALV088 40.458564 -121.523075 Pyrophyllite/Smectite Pyrophyllite, Kaolinite, Quartz, minor Alunite CALV089 40.455383 -121.522409 Smectite CALV090 40.453624 -121.521814 Smectite CALV091 40.453693 -121.521063 Smectite CALV092 40.453629 -121.520537 Chlorite/Smectite CALV093 40.453130 -121.520714 Smectite CALV094 40.453017 -121.520897 Smectite CALV095 40.453017 -121.520897 Smectite CALV096 40.452256 -121.519770 Chlorite/Smectite CALV097 40.452728 -121.520376 Calcite/Chlorite/Smectite Mg-Fe Chlorite, Illite, Quartz, Albite, Hematite CALV098 40.452433 -121.520382 Calcite/Chlorite/Smectite Mg-Fe Chlorite, Illite, Quartz, Albite, Hematite CALV099 40.452433 -121.520382 Calcite/Chlorite/Smectite Mg-Fe Chlorite, Illite, Quartz, Albite, Hematite CALV100 40.451548 -121.519620 Chlorite/Smectite CALV101 40.451548 -121.519620 Chlorite/Smectite CALV102 40.451548 -121.519620 Chlorite/Smectite CALV104 40.450941 -121.520403 Chlorite/Smectite CALV105 40.450941 -121.520403 Chlorite/Smectite CALV106 40.450995 -121.520478 Smectite CALV107 40.454396 -121.515243 Chlorite/Smectite CALV109 40.450013 -121.515044 Smectite CALV110 40.450174 -121.514475 Smectite/Illite/Cholrite/Kaolinite Albite, Qtz, Kaol, Mont, illite, chlorite, anatase, hem CALV111 40.450174 -121.514475 Smectite/Illite/Cholrite/Kaolinite CALV112 40.450174 -121.514475 Smectite/Illite/Cholrite/Kaolinite CALV113 40.450737 -121.514722 Smectite CALV114 40.450754 -121.513778 Chlorite CALV115 40.451338 -121.513724 Kaolinite Kaolinite, Cristobalite, Quartz, Natroalunite CALV116 40.451306 -121.512587 Calcite/Smectite CALV117 40.451306 -121.512587 Calcite/Smectite CALV118 40.451392 -121.512394 Smectite CALV119 40.451569 -121.511815 Smectite/Illite Albite, Quartz, Kaolinite, Hematite, Mont, illite? CALV120 40.450078 -121.510608 Smectite CALV121 40.451134 -121.509116 Alunite Quartz, Kaolinite, Natroalunite, Jarosite, Goethite CALV123 40.455705 -121.518204 Smectite CALV124 40.455812 -121.518273 Smectite CALV125 40.455340 -121.518311 Smectite CALV126 40.454648 -121.518783 Smectite CALV127 40.453688 -121.518526 Chlorite/Smectite CALV128 40.453484 -121.517308 Smectite CALV129 40.453484 -121.517308 Smectite CALV130 40.453114 -121.517329 Kaolinite

312

Table E1: Cont. Sample # Latitude Longitude PIMA XRD CALV131 40.452411 -121.516814 Smectite CALV132 40.451987 -121.518016 Chlorite/Smectite CALV135 40.451113 -121.517184 Smectite CALV136 40.450915 -121.516728 Smectite CALV137 40.453162 -121.515870 Smectite/Illite CALV138 40.453232 -121.515886 N/A Quartz, Albite, Illite, Montmorillonite, Anatase, Jaros CALV139 40.453860 -121.515527 Chlorite/Smectite CALV140 40.453860 -121.515527 Smectite CALV141 40.460731 -121.523423 Kaolinite/Smectite CALV142 40.460688 -121.520763 Smectite CALV143 40.458441 -121.516857 Smectite CALV146 40.457357 -121.515581 Chlorite/Smectite CALV147 40.454814 -121.513794 Smectite Mont, Albite, Orthoclase, Mg-Fe Chlorite, Quartz, Illit CALV148 40.454825 -121.513515 Smectite Montmorillonite, Orthoclase, Quartz, Illite? CALV149 40.454825 -121.513360 Smectite Quartz, Orthoclase, Mont, Illite, Mg-Fe Chlorite, Kaol CALV150 40.454476 -121.513483 Smectite/poor ID CALV151 40.455227 -121.512389 Chlorite/Smectite CALV152 40.455866 -121.511686 Chlorite/Smectite CALV153 40.455399 -121.511037 Chlorite/Smectite Quartz, Albite, Mg-Fe Chlorite, Montmorillonite CALV154 40.454493 -121.507056 Smectite CALV155 40.453758 -121.508280 Smectite CALV156 40.453742 -121.509186 Alunite CALV157 40.453742 -121.509186 Alunite Kaolinite, Natroalunite, Quartz CALV159 40.456134 -121.525682 Chlorite/Smectite CALV160 40.456134 -121.525682 Chlorite/Smectite CALV161 40.456091 -121.525263 Chlorite/Smectite CALV162 40.455571 -121.524797 Smectite CALV163 40.455877 -121.524614 Smectite CALV164 40.456064 -121.524625 Smectite CALV165 40.456633 -121.524657 Smectite CALV166 40.451698 -121.521562 Smectite CALV167 40.451054 -121.521583 Smectite/Illite CALV168 40.451349 -121.520956 Smectite CALV169 40.451156 -121.520516 Chlorite/Smectite/Illite CALV170 40.451156 -121.520516 Chlorite/Smectite/Illite CALV171 40.451156 -121.520516 Chlorite/Smectite/Illite CALV175 40.457668 -121.551222 N/A Kaolinite, Mont, Alunite, Quartz CALV178 40.459422 -121.550744 N/A Kaolinite, Natroalunite CALV180 40.459964 -121.551924 N/A Crist, Kaol, Natroalun, hematite, Albite, Mg-smect, ill CALV183 40.457931 -121.540707 N/A Natroalunite, Quartz, Kaolinite/Dickite? CALV184 40.455555 -121.537258 N/A Natroalunite, Quartz, Cristobalite, Kaolinite CALV187 40.454316 -121.534973 N/A Illite, Chlorite, Quartz, Kaolinite CALV189 40.454026 -121.534222 N/A Montmorillonite, Quartz, minor Anatase CALV190 40.453457 -121.534141 N/A Quartz, Anatase CALV194 40.454900 -121.530869 N/A Quartz, Kaolinite, Anatase CALV195 40.449691 -121.533267 N/A Quartz, Albite, Orthoclase, Kaolinite, Mg-Smectite CALV196 40.448420 -121.534576 N/A Opal, Anatase, Kaolinite, Alunite CALV199 40.456665 -121.500367 N/A Quartz, Cristobalite, Anatase, Hematite? CALV200 40.456585 -121.500061 N/A Jarosite, Hematite, Quartz, Opal, Anatase, Alunite CALV201 40.457550 -121.502470 N/A Alunite, Cristobalite CALV202 40.458682 -121.504546 N/A Cristobalite, Kao-Mont, Alunite, Calcite, Albite, Kaol CALV203 40.459449 -121.503537 N/A Kaolinite, Natroalunite, Cristobalite, Albite, Rutile + CALV204 40.459793 -121.502781 N/A Cristobalite, Natroalunite, Kaolinite, + ? CALV205 40.457400 -121.508601 N/A Albite, Montmorillonite, Kaolinite, Mg-Smectite, Quartz CALV207 40.455067 -121.506037 N/A Albite, Kaolinite, Mg-Smectite CALV208 40.458419 -121.501660 Alunite

313

Table E1: Cont. Sample # Latitude Longitude PIMA XRD CALV209 40.458248 -121.500979 Alunite poor kaolinite CALV210 40.458108 -121.501032 Alunite poor kaolinite CALV211 40.458097 -121.500388 Smectite CALV212 40.457175 -121.502132 Smectite CALV213 40.456976 -121.501488 Smectite CALV214 40.455517 -121.497889 Kaolinite CALV215 40.455464 -121.497186 Kaolinite poor CALV216 40.455925 -121.497288 Kaolinite CALV217 40.456220 -121.496344 Kaolinite CALV218 40.456059 -121.493978 Kaolinite/Smectite CALV219 40.456343 -121.494665 Kaolinite/Smectite CALV220 40.456880 -121.495147 Kaolinite CALV221 40.457073 -121.495915 Kaolinite CALV222 40.458038 -121.496467 Kaolinite poor CALV223 40.457786 -121.497545 Kaolinite/Alunite CALV224 40.457148 -121.498527 poor spectra CALV225 40.456869 -121.498774 poor spectra CALV226 40.458773 -121.501472 Kaolinite/Alunite CALV227 40.458494 -121.500909 Smectite CALV228 40.458623 -121.501692 Smectite poor CALV229 40.458452 -121.502357 Smectite CALV230 40.455979 -121.501944 Smectite/Opal CALV231 40.455689 -121.501697 Opal CALV232 40.455399 -121.502175 Water/organic CALV233 40.455726 -121.502604 Chlorite/Calcite/Smectite CALV234 40.455780 -121.502609 Smectite CALV235 40.455683 -121.502373 Smectite CALV236 40.455925 -121.501644 Kaolinite/Opal CALV237 40.457030 -121.505452 Smectite CALV239 40.456075 -121.510930 Chlorite/Smectite CALV240 40.456075 -121.510930 Chlorite/Smectite CALV241 40.449412 -121.538186 Smectite? CALV242 40.452642 -121.521401 Smectite CALV243 40.452556 -121.521723 Chlorite/Smectite CALV245 40.451456 -121.510205 Smectite CALV247 40.452288 -121.505833 Kaolinite/Smectite CALV248 40.451526 -121.506391 Kaolinite/Smectite CALV249 40.451242 -121.507443 Kaolinite/Smectite CALV250 40.451692 -121.507303 Kaolinite/Smectite CALV252 40.451719 -121.509395 Kaolinite/Smectite/Opal CALV253 40.451472 -121.509943 Kaolinite/Smectite/Opal CALV254 40.465801 -121.527393 Water CALV255 40.466246 -121.527988 Smectite CALV256 40.464674 -121.533589 Smectite CALV257 40.462604 -121.532961 Kaolinite CALV258 40.461987 -121.532972 Dickite CALV259 40.461370 -121.532409 Water CALV260 40.460141 -121.530976 Smectite CALV261 40.458409 -121.533267 Illite/Smectite CALV262 40.456268 -121.528219 Kaolinite CALV263 40.452374 -121.534399 Smectite CALV264 40.450571 -121.533653 Water CALV265 40.446253 -121.536357 Alunite CALV266 40.444295 -121.536073 poor spectra LAD018 40.450523 -121.520135 Smectite LAD019 40.455683 -121.525413 Smectite

314

Table E2: Whole Rock Geochemical Analyses for Lassen samples. Sample CALV001 CALV003 CALV006 CALV009 CALV010 CALV011 CALV012 CALV013 Longitude -121.50657 -121.51610 -121.51441 -121.51413 -121.50526 -121.50245 -121.50245 -121.50207 Latitude 40.45685 40.45734 40.45520 40.45191 40.45770 40.45647 40.45647 40.45564 Alteration 1 IA PR PR UA IA UA UA SHAA

Al 2O3 16 16.4 CaO 2.66 3.88

Cr 2O3 <0.01 <0.01

Fe 2O3 4.6 3.6

K2O 2.95 2.64 LOI 2.8 1.4 MgO 2.39 2.14 MnO 0.04 0.05

Na 2O 2.59 3.75

P2O5 0.18 0.12

SiO 2 65.1 64.8

TiO 2 0.71 0.78 Al 8.19 11.2 7.8 7.8 10.6 7.62 8.42 11.6 Ca 1.26 4.55 3.17 1.62 0.31 1.42 2.42 0.27 Fe 3.71 4.34 3.66 3 2.56 4.72 2.34 0.91 K 4.76 0.6 1.63 2.36 1.51 2.2 2.07 0.59 Mg 0.38 3.19 1.99 1.33 0.53 0.25 1.08 0.92 Na 1.52 3.37 1.72 1.75 0.33 2.18 2.63 0.07 S 0.35 0.06 0.52 0.02 0.14 0.4 0.07 0.01 Ti 0.42 0.54 0.36 0.27 0.39 0.42 0.42 0.52 Au 0.013 0.011 <0.005 <0.005 <0.005 0.007 Hg 0.84 <0.02 0.04 0.06 2.46 1.08 Ag <1 <1 <1 <1 <1 <1 <1 <1 As 3 4 6 2 3 3 2 3 Ba 1250 277 495 1100 522 659 774 434 Be 0.9 1.4 1 1 0.9 1.1 1.2 0.9 Bi <0.04 0.07 0.1 0.05 0.16 0.09 0.05 0.11 Cd <0.1 0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 Ce 31.2 55.3 30.1 52 39.4 44.7 35.1 66.2 Co 0.8 21.2 17.6 13.3 7.8 1.7 6.8 1.3 Cr 45 58 21 23 62 47 24 23 Cs <5 <5 0.72 0.62 <5 <5 1.59 <5 Cu 34.6 61.7 47.6 38.9 40 25.7 26.2 10.7 Ga 17.3 23.7 13.9 15.1 22.6 16.6 17.9 20.9 In 0.07 0.07 0.05 0.04 0.04 0.04 0.05 0.03 La 17.4 33.1 13.6 23.5 20.2 22.4 18.5 30.7 Li 3 8 13 13 3 8 9 4 Mn 83 1040 639 327 194 247 396 66 Mo 1 0.1 0.12 0.62 1.71 1.62 1.58 1.54 Nb 9 16.3 5.3 7.9 8.1 9 9.8 12.3 Ni 3.3 44.3 42.2 31.4 27.7 5.5 16.7 6.2 P 800 1550 705 760 430 4370 530 540 Pb 10.7 3.8 8.9 7.3 14.1 11.9 7.2 12.9 Rb 117 13.8 55.4 76.3 48.9 62.1 75.2 20.7 Sb 0.57 0.19 0.38 0.29 0.68 0.65 0.4 0.59 Sc 15.5 22.8 13.5 12.8 13.2 16.4 15.6 15.4 Se <0.2 <0.2 <0.2 <0.2 <0.2 Sn 1.9 2.8 0.9 1.4 1.7 2.1 1.6 2.9 Sr 477 552 353.1 340 130 301 356 206 Te <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 Th 6.6 6.5 4.2 8.3 9.5 8 8.2 7.9 Tl 0.3 0.1 0.2 0.5 0.5 0.4 0.4 0.6 U 2 1.9 1.4 2.9 2.7 2.9 2.8 3.5 V 100 143 124 106 73 181 103 107 W 0.6 1.3 0.3 0.6 0.8 0.6 0.8 0.2 Y 23 23 13 19 12 14.5 15.7 29.1 Zn 7 93 52 52 22 6 26 14 1 IA = Intermediate argillic, PR = Propylitic, AA = Advanced argillic, SHAA = Steam-heated advanced argillic. Oxides and major elemental concentrations given in Wt. % all other analysis in ppm.

315

Table E2: Cont. Sample CALV014 CALV015 CALV016 CALV017 CALV019 CALV025 CALV026 CALV029 Longitude -121.50207 -121.50162 -121.50137 -121.50160 -121.50301 -121.50558 -121.50522 -121.50914 Latitude 40.45564 40.45547 40.45475 40.45475 40.45439 40.45835 40.45911 40.45756 Alteration 1 UA SHAA IA IA UA SHAA IA IA

Al 2O3 16.1 CaO 5.23

Cr 2O3 <0.01

Fe 2O3 4.76

K2O 2.4 LOI 1.9 MgO 3.01 MnO 0.08

Na 2O 3.37

P2O5 0.17

SiO 2 62.1

TiO 2 0.72 Al 9.14 0.57 8.85 9.22 8.54 2.59 9.04 8.96 Ca 2.65 0.01 3.07 0.88 3.57 0.08 0.61 1.69 Fe 2.21 0.39 2.56 4.64 3.23 0.62 1.5 1.97 K 2.23 0.17 1.84 2.42 1.95 0.74 1.19 2.38 Mg 0.53 <0.01 1.57 0.85 1.73 0.02 0.71 0.38 Na 2.7 0.02 2.54 0.54 2.39 0.31 0.66 1.63 S 0.4 0.44 0.14 0.06 0.03 1.41 0.98 0.02 Ti 0.4 0.44 0.42 0.52 0.38 0.47 0.34 0.29 Au 0.012 <0.005 <0.005 0.005 <0.005 <0.005 0.025 Hg 0.12 1.54 0.09 6.48 1.4 0.36 0.05 Ag <1 <1 <1 <1 <1 <1 <1 <1 As 2 6 3 4 2 4 2 2 Ba 719 489 718 610 810 606 794 684 Be 1.5 <0.1 1.4 1 1.3 0.4 0.9 1.5 Bi 0.07 0.06 0.04 0.05 <0.04 0.14 0.08 <0.04 Cd 0.2 <0.1 <0.1 <0.1 0.1 <0.1 <0.1 <0.1 Ce 55.4 30.2 47.3 38.4 46.5 20.3 32.4 51.2 Co 9.2 0.3 13.9 2.1 13.7 0.3 8.2 10.2 Cr 31 10 29 58 26 23 16 36 Cs <5 0.2 <5 <5 2.76 1.17 <5 <5 Cu 45.1 2.4 11.9 30.5 32.5 6.6 45.9 31.2 Ga 18.2 9.24 20.9 23.6 16.1 13.5 20.8 18.3 In 0.05 <0.02 0.04 0.04 0.04 0.02 0.04 0.04 La 27.2 15.8 23.2 19.3 23.1 10.1 17 25.5 Li 8 <1 8 5 8 <1 3 13 Mn 288 13 540 107 629 24 216 142 Mo 0.9 0.85 1.96 1.53 2.17 1.22 1.71 0.78 Nb 8.8 7.2 9.4 10.8 8.8 7.5 6.9 4.7 Ni 22.1 1.2 24.9 7.4 33.5 1 17.5 20.8 P 920 330 870 1270 770 492 400 580 Pb 11.2 10.1 12.3 17.6 8.2 11.6 9.1 11.6 Rb 63.8 3 102 86.5 80 27.6 69.8 63.8 Sb 0.42 0.3 0.56 0.64 0.47 0.83 0.52 0.39 Sc 15.1 5.6 16.4 21 15.2 4 15 15.8 Se <0.2 <0.2 <0.2 <0.2 <0.2 Sn 1.9 1.1 1.8 2.1 1.6 1.3 1.5 1.1 Sr 439 166.9 427 227 420 313.1 262 501 Te <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 Th 7.7 9.3 10 10.7 8 6.1 7.6 4.4 Tl 0.3 <0.1 0.4 0.5 0.5 0.1 0.4 0.2 U 2.5 3.3 3.4 3.5 2.8 1.4 2.8 1.1 V 110 30 84 146 115 36 94 76 W 0.6 0.6 0.9 0.3 0.9 0.7 0.7 0.5 Y 24.1 7.5 18.2 15.1 22.2 3.6 10.4 20.1 Zn 41 2 43 11 61 4 25 35 1 IA = Intermediate argillic, PR = Propylitic, AA = Advanced argillic, SHAA = Steam-heated advanced argillic. Oxides and major elemental concentrations given in Wt. % all other analysis in ppm.

316

Table E2: Cont. Sample CALV031 CALV036 CALV039 CALV043 CALV051 CALV052 CALV053 CALV054 Longitude -121.50566 -121.51360 -121.51333 -121.51881 -121.52705 -121.52747 -121.52744 -121.52699 Latitude 40.45821 40.45932 40.45976 40.46462 40.46463 40.46400 40.46433 40.46389 Alteration 1 SHAA IA IA SHAA IA AA AA IA

Al 2O3 CaO

Cr 2O3

Fe 2O3

K2O LOI MgO MnO

Na 2O

P2O5

SiO 2

TiO 2 Al 7.45 8.42 7.46 8.88 8.57 0.96 13.2 8.84 Ca 0.37 0.57 1.29 2.13 3.21 0.11 0.01 2.41 Fe 1.78 3.24 3.42 2.41 3.02 0.07 0.05 1.89 K 0.73 3.51 3.49 1.52 1.94 0.07 0.38 2.45 Mg 0.6 0.57 0.29 0.7 1.62 0.02 0.03 0.16 Na 0.6 0.6 1.56 1.95 2.78 0.02 0.02 2.49 S 0.44 0.07 0.03 0.9 0.03 0.24 0.03 0.75 Ti 0.39 0.45 0.37 0.47 0.43 0.54 0.59 0.49 Au 0.012 0.028 <0.005 0.006 <0.005 <0.005 <0.005 <0.005 Hg 0.66 0.3 0.33 0.35 <0.02 0.23 0.04 0.07 Ag <1 <1 <1 <1 <1 <1 <1 <1 As 1 7 15 4 2 18 10 10 Ba 404 1840 593 921 642 740 599 983 Be 0.5 1.2 1 1.5 1.2 0.2 0.1 1.2 Bi <0.04 0.05 0.05 0.06 0.06 10.3 0.59 0.25 Cd <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 Ce 20.3 39.8 26.9 51.5 36.7 65.9 21.2 36.6 Co 6.2 3 4.7 7.2 18.1 0.4 <0.1 3.9 Cr 45 39 30 40 32 24 55 23 Cs <5 <5 <5 <5 <5 <0.05 <0.05 <5 Cu 17.3 14.4 38.7 17.2 29.4 4.3 9.8 14.8 Ga 21.2 18.6 17.8 22.2 23 2.63 19.4 21.1 In 0.04 0.05 0.04 0.02 0.04 <0.02 <0.02 0.04 La 11.1 22.1 16.5 26 18.2 30.5 9.8 20.1 Li 2 6 11 4 5 2 18 2 Mn 197 114 72 290 614 13 <5 221 Mo 1.08 2.09 1.42 2.2 1.24 2.77 2.48 1.69 Nb 6.8 8.7 6.2 9.3 8.4 8.7 7.9 10.1 Ni 13.5 3.8 5.5 18.1 36.6 0.7 0.8 12.5 P 360 840 620 1110 690 1240 143 640 Pb 10.4 14.9 9.3 11.3 8 14 4.8 13 Rb 25.5 108 91.8 53.6 49.3 1.8 12.3 62.7 Sb 0.49 1.02 0.84 0.61 0.43 2.82 2.04 0.65 Sc 10.6 19.4 16.6 16.2 17.6 3.9 5.5 15.4 Se <0.2 0.4 0.7 <0.2 <0.2 0.5 Sn 0.9 1.3 1.1 2.1 1.7 2.2 1.5 2.1 Sr 175 140 258 502 504 736.7 44.3 399 Te <0.1 <0.1 <0.1 <0.1 <0.1 0.5 0.3 0.2 Th 7.2 8.8 5.7 8.8 8.1 8.6 2.6 9.3 Tl 0.2 0.7 0.4 0.2 0.3 <0.1 0.3 0.5 U 2.6 3.1 1.6 2.9 2.6 1.3 0.5 3.3 V 85 130 89 126 114 47 188 115 W 0.6 0.5 0.8 0.8 0.6 0.6 0.8 0.8 Y 6.6 13.4 9.4 17.3 18.7 4.1 1.7 13.7 Zn 18 16 18 41 55 5 9 47 1 IA = Intermediate argillic, PR = Propylitic, AA = Advanced argillic, SHAA = Steam-heated advanced argillic. Oxides and major elemental concentrations given in Wt. % all other analysis in ppm.

317

Table E2: Cont. Sample CALV063 CALV066 CALV067 CALV069 CALV072 CALV075 CALV076 CALV077 Longitude -121.52730 -121.52903 -121.52903 -121.53149 -121.53079 -121.52582 -121.53226 -121.53291 Latitude 40.46434 40.46574 40.46574 40.46809 40.46444 40.46261 40.46735 40.46332 Alteration 1 SHAA IA IA AA SHAA SHAA SHAA SHAA

Al 2O3 CaO

Cr 2O3

Fe 2O3

K2O LOI MgO MnO

Na 2O

P2O5

SiO 2

TiO 2 Al 6.84 8.78 8.78 6.76 9.37 2.62 7.46 8.35 Ca 0.02 2.73 0.35 0.3 0.08 0.06 0.16 0.16 Fe 0.05 3.14 0.78 9.34 0.09 0.05 2.18 0.22 K 1.02 1.74 0.58 0.87 0.1 0.11 1.84 0.53 Mg 0.04 1.6 0.46 0.13 0.03 0.08 0.08 0.19 Na 0.09 2.46 0.25 0.81 0.05 0.02 0.68 0.51 S 0.74 0.32 0.12 3.46 0.34 0.16 5.05 0.34 Ti 0.39 0.47 0.82 0.28 0.46 0.6 0.32 0.53 Au 0.008 <0.005 0.009 <0.005 <0.005 0.006 <0.005 0.006 Hg 0.08 0.03 4.33 0.37 0.25 30.7 0.25 1.58 Ag <1 <1 <1 <1 <1 <1 <1 <1 As 7 15 8 19 10 5 27 53 Ba 441 677 1880 669 453 952 326 537 Be 0.2 1.4 1.7 1.4 0.4 1 0.4 0.8 Bi 1.21 0.05 0.13 0.09 0.11 0.19 0.14 0.13 Cd <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 Ce 24 38.5 84.4 35.5 42.5 25.1 45.7 50.9 Co <0.1 15.3 1.4 0.9 <0.1 <0.1 0.9 0.2 Cr 49 35 34 43 53 14 29 55 Cs <5 <5 5 1.79 1.17 <5 <5 1.52 Cu 1.2 27.2 5.3 30.1 5 1.4 31.8 2.6 Ga 20.2 22.7 29.3 12.9 12.5 6.58 16 12.8 In 0.03 0.05 0.05 0.02 <0.02 0.05 0.02 0.04 La 13.4 19.3 43.1 15.8 19.6 13.2 23.4 21.1 Li 9 4 4 8 73 10 4 13 Mn 6 551 119 52 6 11 14 69 Mo 2.55 1.8 3 1.44 1.61 1.38 1.74 1.22 Nb 6.1 9.1 13.6 5.5 8.2 8.5 6 8.4 Ni 0.9 27.3 4.3 4.6 1.9 1 3.2 1.5 P 410 690 810 2920 1020 360 1650 2010 Pb 6.9 10.5 20.7 10.3 9.6 29.8 9.5 16.4 Rb 12.6 57.6 29.8 21.7 7.4 4.4 7.9 20.1 Sb 2 0.58 0.76 0.81 0.74 1.28 0.59 1.32 Sc 6 19.4 25.1 10.4 8.8 9.4 13.6 8.1 Se 2.5 1.2 0.9 1.6 1.3 Sn 1.8 1.9 2.7 1.1 1.2 1.7 1.8 1.1 Sr 179 439 365 1331.3 968.6 285 992 1215.2 Te 0.6 0.2 0.1 1.1 <0.1 0.2 1.1 0.9 Th 2.3 8.6 12.2 6 6.4 8.8 6 5.4 Tl 0.4 0.9 0.6 0.5 <0.1 <0.1 0.3 0.5 U 0.5 3 3.4 1.9 1.3 2.2 1.6 1 V 117 122 141 147 132 62 91 134 W 0.4 0.8 1.1 0.7 0.9 0.6 0.5 0.5 Y 1.4 18.3 30.7 7.3 5.7 10.3 8.4 3.9 Zn <1 56 9 21 7 4 7 33 1 IA = Intermediate argillic, PR = Propylitic, AA = Advanced argillic, SHAA = Steam-heated advanced argillic. Oxides and major elemental concentrations given in Wt. % all other analysis in ppm.

318

Table E2: Cont. Sample CALV081 CALV082 CALV085 CALV086 CALV088 CALV097 CALV104 CALV111 Longitude -121.53146 -121.53092 -121.52753 -121.52765 -121.52307 -121.52038 -121.52040 -121.51448 Latitude 40.46293 40.46247 40.46456 40.46414 40.45856 40.45273 40.45094 40.45017 Alteration 1 SHAA SHAA SHAA AA AA PR PR PR

Al 2O3 CaO

Cr 2O3

Fe 2O3

K2O LOI MgO MnO

Na 2O

P2O5

SiO 2

TiO 2 Al 8.91 6.46 7.33 5.66 9.99 3.4 9.82 10.58 Ca 0.21 0.11 0.1 0.03 0.17 20.9 2.29 1.79 Fe 0.15 0.07 3.14 0.26 1.77 1.89 3.95 4.82 K 0.21 0.11 0.08 0.05 2.18 0.64 0.83 0.87 Mg 0.02 0.02 0.02 0.04 0.15 0.78 1.87 1.87 Na 0.05 0.04 0.06 0.02 0.33 0.75 2.31 2.15 S 0.61 0.29 0.18 0.2 0.2 0.93 2.79 0.02 Ti 0.33 0.37 0.39 0.35 0.51 0.17 0.52 0.58 Au 0.012 0.009 0.008 0.009 <0.005 <0.005 0.114 <0.005 Hg 1.13 0.26 0.89 0.22 <0.02 <0.02 0.04 0.23 Ag <1 <1 <1 <1 <1 <1 <1 <1 As 18 3 16 14 111 5 5 3 Ba 847 522 422 383 907 243 313 390 Be 0.7 0.2 0.3 0.3 0.6 0.5 1.4 1.1 Bi 0.15 <0.04 0.13 3.46 0.2 0.05 0.08 0.07 Cd <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 Ce 44.3 29 28 28.4 38.1 18 42.1 45.6 Co <0.1 <0.1 <0.1 1.8 0.4 8 23.9 20.5 Cr 25 15 27 11 68 17 38 31 Cs <5 <5 <5 <5 0.36 0.29 <5 1.01 Cu 1.6 1 17.3 3.2 9.5 21 35 74.8 Ga 21.4 16.1 19.6 12.4 14.9 6.07 24.2 18.5 In 0.04 0.02 0.02 <0.02 0.03 <0.02 0.05 0.06 La 21.4 14.5 13.1 15.5 16.9 8.9 21.4 21 Li <1 2 22 20 16 3 4 13 Mn <5 8 13 5 38 866 524 842 Mo 1.74 0.99 2.56 2.88 1.41 0.18 0.35 0.56 Nb 6.6 5.3 8.3 6 6 2.5 8.8 8.6 Ni 1.6 1.6 2 4.2 2.7 16.3 37.1 39.6 P 2410 1110 650 290 2020 383 1360 1180 Pb 21.5 10.6 4.7 5.4 9.5 4 8.4 6.6 Rb 2.8 3.5 2.4 1.5 40.5 17.7 27.7 26.6 Sb 2.28 0.41 2.04 1.44 8.39 0.17 0.34 0.22 Sc 14.9 11.3 7.7 6.8 6.6 6.8 24.5 19.9 Se 0.4 0.2 4.4 2.9 <0.2 Sn 1.6 1.4 1 1.5 1.1 0.4 1.3 1.2 Sr 1050 694 237 150 613.8 458.3 525 382.2 Te 0.8 <0.1 1.7 0.7 1.1 <0.1 <0.1 <0.1 Th 7.7 5.1 7 4.7 5.4 1.8 5.9 6.4 Tl <0.1 <0.1 <0.1 0.1 0.3 <0.1 0.2 0.1 U 2.2 1.2 1.6 1.3 0.8 0.6 1.8 2.1 V 169 110 125 92 190 60 157 166 W 0.6 0.5 0.8 0.5 0.8 0.2 0.5 0.8 Y 6.1 3.7 4.3 4.5 4.1 8.2 19.8 20.4 Zn <1 3 2 <1 28 24 74 91 1 IA = Intermediate argillic, PR = Propylitic, AA = Advanced argillic, SHAA = Steam-heated advanced argillic. Oxides and major elemental concentrations given in Wt. % all other analysis in ppm.

319

Table E2: Cont. Sample CALV115 CALV122 CALV138 CALV144 CALV147 CALV148 CALV149 CALV153 Longitude -121.51372 -121.50950 -121.51589 -121.51651 -121.51379 -121.51352 -121.51336 -121.51104 Latitude 40.45134 40.45084 40.45323 40.45854 40.45481 40.45483 40.45483 40.45540 1 Alteration SHAA UA IA UA IA IA IA PR

Al 2O3 17.1 16.2 CaO 6.3 6.03

Cr 2O3 <0.01 <0.01

Fe 2O3 5.76 5.49

K2O 1.98 1.94 LOI 0.85 2.15 MgO 2.78 2.69 MnO 0.08 0.07

Na 2O 3.52 3.15

P2O5 0.23 0.21

SiO 2 60.2 61.2

TiO 2 0.79 0.74 Al 6.09 8.96 6.67 8.37 8.03 5.56 6.8 8.17 Ca 0.56 4.32 1.51 4.08 0.18 0.07 0.04 3.14 Fe 1.56 4.14 2.46 3.85 1.07 0.64 0.21 3.32 K 0.84 1.61 2.01 1.54 3.48 3.59 2.27 0.75 Mg 0.47 1.69 0.79 1.64 0.41 0.27 0.37 1.91 Na 0.57 2.57 1.36 2.27 0.56 0.11 0.08 2.45 S 0.86 0.02 0.78 0.05 0.17 0.02 0.07 0.09 Ti 0.54 0.44 0.37 0.37 0.31 0.48 0.32 0.34 Au 0.011 0.009 <0.005 <0.005 <0.005 0.008 Hg 1.95 0.1 0.24 0.06 1.08 <0.02 Ag <1 <1 <1 <1 <1 <1 <1 <1 As 3 2 4 1 4 10 5 2 Ba 468 603 755 716 1160 1700 471 308 Be 0.6 1.1 1 1.1 0.8 0.6 1 1.3 Bi 0.09 <0.04 0.12 <0.04 <0.04 <0.04 <0.04 0.06 Cd <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 Ce 35.7 53.8 29.3 41.4 38.6 39.5 48.2 26.1 Co 8.3 15 11.3 14.1 0.2 0.2 0.2 22.8 Cr 23 33 22 16 4 3 3 16 Cs <5 1.2 0.8 0.79 1.5 0.97 1.68 <5 Cu 26.2 34.7 48.8 28.5 2.8 9.6 3.9 41.3 Ga 21.6 17.7 14 16.9 19 12.4 13.2 18.5 In 0.04 0.04 0.04 0.04 0.03 0.03 <0.02 0.04 La 18.3 23.3 15.6 21.2 19.3 20.5 23.1 12.8 Li 3 10 10 8 3 3 6 14 Mn 170 656 258 601 30 31 61 641 Mo 1.09 1.29 0.21 0.96 0.08 1.95 0.5 0.12 Nb 8.6 8.7 5.4 8.5 8.4 11.3 6.8 4 Ni 15.2 30.7 21.1 22.5 1.1 0.9 0.7 23.1 P 730 1020 589 930 296 <50 138 630 Pb 9.7 5.9 9.2 5.8 26.8 9.3 13 6 Rb 28.1 45.2 58.7 42.6 130.3 127.2 95.5 27.4 Sb 0.54 0.28 0.4 0.3 0.59 0.92 0.73 0.24 Sc 16.8 20.4 12.5 15.8 8.2 11 7 18.5 Se <0.2 <0.2 Sn 1.9 1.5 1.3 1.5 1.1 1.4 1 1.4 Sr 251 479 444.4 450 83.3 61.4 30.7 488 Te <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 Th 8.8 5.7 3.7 6.7 8.9 11.7 8.3 4.3 Tl 0.4 0.1 0.3 0.3 0.5 0.3 0.3 0.1 U 3.2 2 1.2 2.5 1.4 4.6 2.6 1.3 V 106 161 121 130 57 46 44 112 W 0.8 0.7 0.4 0.6 0.4 1.1 0.7 0.7 Y 12.1 21.8 8.9 19.5 12 12.4 10.5 14.4 Zn 23 55 30 59 7 6 7 48 1 IA = Intermediate argillic, PR = Propylitic, AA = Advanced argillic, SHAA = Steam-heated advanced argillic. Oxides and major elemental concentrations given in Wt. % all other analysis in ppm.

320

Table E2: Cont. Sample CALV159 CALV160 CALV161 CALV175 CALV177 CALV178 CALV184 CALV187 Longitude -121.52568 -121.52568 -121.52526 -121.55122 -121.55122 -121.55074 -121.53726 -121.53497 Latitude 40.45613 40.45613 40.45609 40.45767 40.45767 40.45942 40.45555 40.45432 Alteration 1 UA UA UA SHAA IA SHAA SHAA SHAA

Al 2O3 16.9 16.1 15.7 CaO 7.65 6.57 5.65

Cr 2O3 0.02 <0.01 <0.01

Fe 2O3 7.22 5.38 5.03

K2O 1.25 1.91 2.02 LOI 0.75 3.8 2.55 MgO 5.45 2.96 3.17 MnO 0.13 0.09 0.08

Na 2O 3.28 2.73 3.09

P2O5 0.18 0.19 0.19

SiO 2 56.2 59.7 61.4

TiO 2 0.74 0.68 0.73 Al 8.79 8.13 8.27 8.72 10.5 8.6 9.73 9.66 Ca 5.07 4.19 3.81 0.28 0.1 0.21 0.09 0.02 Fe 4.94 3.63 3.65 0.57 7.05 0.3 2.41 0.4 K 1 1.47 1.61 1.94 0.04 1 1.8 2.16 Mg 3.23 1.76 1.9 0.25 0.04 0.11 0.09 0.12 Na 2.35 1.92 2.31 0.64 0.02 0.19 0.5 0.3 S 0.31 0.11 0.09 4.39 0.01 0.94 4.63 0.3 Ti 0.37 0.31 0.34 0.41 0.44 0.51 0.39 0.14 Au <0.005 <0.005 <0.005 <0.005 <0.005 Hg 0.14 <0.02 1.46 1.99 0.09 Ag <1 <1 <1 <1 <1 <1 <1 <1 As 15 5 2 5 4 14 11 11 Ba 417 621 613 393 17 575 422 768 Be 0.9 1 1.2 0.4 0.5 0.7 0.3 0.5 Bi 0.17 <0.04 0.13 0.08 0.06 0.26 0.08 1.3 Cd <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 Ce 26.5 38.6 39.8 21.7 11.2 35.5 195.9 10.2 Co 24.8 14.7 13.1 2.8 13.5 1.4 1 1.1 Cr 96 22 23 196 171 24 42 31 Cs 0.54 1 1.16 0.56 <5 2.11 0.4 0.75 Cu 53.6 32.8 31 26 53.2 11.3 50.8 23.6 Ga 16 16.3 16.3 22.7 22.4 14.2 15.9 12.1 In 0.04 0.04 0.04 0.04 0.1 <0.02 0.05 0.03 La 13.3 20.1 20.1 9.3 5.3 15.5 78.9 4.5 Li 7 8 10 15 78 58 1 4 Mn 1020 694 684 25 60 35 36 18 Mo 1.23 1.19 1.49 0.56 0.95 1.53 1.3 1.25 Nb 5.3 7.2 7.8 3.3 4.2 5.7 6.1 2.5 Ni 78.1 26.6 27.2 6.6 37.8 3.6 3.5 4.7 P 760 810 840 836 140 1070 2420 1210 Pb 2.7 6.1 7.7 8.8 3.1 7.6 15.1 13 Rb 30.2 44.1 49.5 12.9 2.4 40.7 29.6 45.4 Sb 0.79 0.54 0.51 0.38 0.34 0.63 0.43 1.39 Sc 24 15.8 14.2 20.1 55.1 19.3 22.9 9.6 Se 0.2 Sn 1 1.3 1.2 1.1 1.1 0.9 1 1.4 Sr 404 382 380 783.9 14.9 557.5 1142.8 341.1 Te 0.1 <0.1 <0.1 0.5 <0.1 <0.1 <0.1 0.2 Th 2.9 5.1 5.5 2.2 4.1 5 6.8 1.4 Tl 0.1 0.2 0.2 0.2 <0.1 0.4 0.1 1.3 U 0.7 1.3 1.8 0.4 0.8 1.8 2.7 0.2 V 172 122 131 231 302 191 204 135 W 0.4 0.6 0.8 0.4 0.2 0.7 0.5 0.4 Y 18 17 17.9 1.5 1.1 5 9.8 1.4 Zn 57 53 54 13 12 9 11 6 1 IA = Intermediate argillic, PR = Propylitic, AA = Advanced argillic, SHAA = Steam-heated advanced argillic. Oxides and major elemental concentrations given in Wt. % all other analysis in ppm.

321

Table E2: Cont. Sample CALV195 CALV196 CALV198 CALV200 CALV202 CALV203 CALV204 CALV207 Longitude -121.53327 -121.53458 -121.50097 -121.50006 -121.50455 -121.50354 -121.50278 -121.50604 Latitude 40.44969 40.44842 40.45717 40.45658 40.45868 40.45945 40.45979 40.45507 Alteration 1 SHAA SHAA SHAA SHAA SHAA SHAA SHAA IA

Al 2O3 CaO

Cr 2O3

Fe 2O3

K2O LOI MgO MnO

Na 2O

P2O5

SiO 2

TiO 2 Al 6.37 0.68 0.31 1.66 8.92 6.86 2.2 4.61 Ca 0.28 0.07 0.13 0.05 1.13 0.28 0.12 0.85 Fe 2.81 0.09 0.03 10.5 1.53 0.55 0.34 0.72 K 1.31 0.05 0.03 1.97 1.46 1.65 1.07 0.15 Mg 0.41 0.02 0.02 <0.01 0.83 0.22 0.02 0.33 Na 0.59 0.01 0.01 0.44 1.65 0.89 0.14 0.78 S 0.09 0.1 0.03 4.99 0.22 3.94 0.09 0.1 Ti 0.51 0.77 0.35 0.4 0.34 0.35 0.41 0.24 Au <0.005 0.006 <0.005 <0.005 <0.005 0.006 <0.005 <0.005 Hg 4.4 0.39 2.96 5.58 0.08 1.01 2.18 1.36 Ag <1 <1 <1 <1 <1 <1 <1 <1 As 4 <1 3 5 4 <1 6 9 Ba 499 128 207 131 599 141 676 436 Be 0.6 0.1 0.4 0.1 1.1 0.4 0.8 0.5 Bi <0.04 0.11 0.06 0.11 0.08 0.06 0.08 0.05 Cd <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 Ce 11.7 7.99 0.33 34.9 28.4 37.6 17.3 24.6 Co 2.2 0.4 <0.1 0.5 6.7 2.4 0.3 4.1 Cr 28 22 4 82 26 12 3 27 Cs 0.62 <5 0.07 <5 1.07 <5 3.09 0.69 Cu 18 3.8 3.9 <0.5 25.8 4.3 9 11.9 Ga 14.2 2.85 0.34 51.3 16.1 25.8 4.12 9.02 In 0.03 <0.02 <0.02 0.03 0.04 0.04 <0.02 0.02 La 6.1 4.8 <0.5 19.3 13.2 18.5 7.9 11.7 Li 3 <1 <1 <1 7 1 1 3 Mn 206 7 18 <5 255 61 42 57 Mo 1.52 0.77 1.13 1.59 0.91 0.97 2.18 0.93 Nb 4.5 10.3 3.9 8 6 7 7.7 4.5 Ni 7.2 1.8 <0.5 3.7 21.1 6.6 1 10.8 P 291 80 <50 980 407 640 72 173 Pb 7.1 3.7 1.9 12.6 9.8 9.1 9.7 5.7 Rb 43.7 5.7 1.8 10 40.8 20.4 56 5.3 Sb 0.26 0.5 0.16 0.31 0.43 0.42 0.65 0.38 Sc 11.6 3.9 0.7 6 10.9 15.7 1.9 6.3 Se <0.2 <0.2 <0.2 Sn 1.2 1.4 0.7 2.1 1 1.5 1.3 0.7 Sr 103.3 26.8 37.9 528 305.2 427 36.5 175.8 Te <0.1 0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 Th 5 1.2 0.2 8 6.6 6.8 6.5 1.3 Tl 0.2 <0.1 <0.1 0.4 0.3 <0.1 0.3 0.2 U 1.7 0.7 0.3 2.4 2.6 2.4 2.5 0.8 V 123 50 8 98 91 68 13 56 W 0.5 1.3 0.1 0.5 0.5 0.5 1 0.3 Y 5.6 4.7 0.2 3 12.2 8.3 7.1 8.6 Zn 17 <1 2 <1 29 7 8 16 1 IA = Intermediate argillic, PR = Propylitic, AA = Advanced argillic, SHAA = Steam-heated advanced argillic. Oxides and major elemental concentrations given in Wt. % all other analysis in ppm.

322

Table E2: Cont. Sample CALV214 CALV218 CALV222 CALV223 CALV243 CALV250 CALV252 CALV258 CALV268 Longitude -121.49683 -121.49292 -121.49539 -121.49647 -121.52172 -121.50622 -121.50833 -121.53192 -121.48342 Latitude 40.45564 40.45619 40.45817 40.45792 40.45256 40.45183 40.45186 40.46211 40.45567 Alteration 1 SHAA IA IA SHAA UA SHAA SHAA SHAA IA

Al 2O3 16.6 CaO 7.65

Cr 2O3 0.01

Fe 2O3 6.95

K2O 1 LOI 4.35 MgO 5.13 MnO 0.1

Na 2O 2.39

P2O5 0.22

SiO 2 54.4

TiO 2 0.89 Al 10.2 10.2 9.55 10.6 8.48 11.8 12.9 10.2 10.4 Ca 0.05 0.54 0.13 0.1 5.02 0.1 0.08 0.04 0.12 Fe 0.24 2.73 0.96 0.23 4.73 1.24 0.79 0.09 2.05 K 0.05 1.97 0.82 0.31 0.78 0.76 0.87 0.06 0.06 Mg 0.06 0.96 0.09 0.04 3.07 0.33 0.28 0.03 0.04 Na 0.02 1.5 0.05 0.13 1.72 0.07 0.06 0.03 0.02 S 0.12 0.05 0.07 0.6 0.1 0.09 1.07 0.11 0.21 Ti 0.41 0.39 0.38 0.39 0.42 0.46 0.57 0.45 0.48 Au <0.005 <0.005 0.009 <0.005 <0.005 0.006 <0.005 <0.005 Hg 1.11 0.13 0.3 0.69 0.34 3.58 0.05 0.87 Ag <1 <1 <1 <1 <1 <1 <1 <1 <1 As 2 2 3 1 <11 2 122 Ba 709 629 1980 523 607 525 866 126 661 Be 0.3 1.1 0.8 0.8 0.9 1 0.8 0.5 1.6 Bi 0.17 0.13 0.07 0.05 <0.04 0.05 0.05 1.6 <0.04 Cd <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 Ce 38.5 32.3 21.3 32.5 30.7 42.7 44.8 34.4 99 Co 0.6 12.8 0.8 0.3 22.9 3.7 1.9 0.6 0.6 Cr 20 38 39 37 61 33 55 19 41 Cs <5 <5 <5 <5 0.22 <5 <5 <5 <5 Cu 0.7 43.3 7 6.6 47 5.1 3.8 2.1 6.4 Ga 19.1 20.8 24.3 25.7 16.6 22.1 29.4 37.4 22.6 In <0.02 0.05 0.04 0.11 0.04 0.04 0.06 <0.02 <0.02 La 19.4 17.6 11 16.1 14.9 18.1 22.9 17.4 44.4 Li <1 6 <1 <1 15 4 4 31 7 Mn 11 395 65 22 794 55 50 <5 16 Mo 0.46 0.25 1.87 1.84 0.34 1.03 1.93 1.1 0.76 Nb 7.1 9 7.7 7.5 6.7 8.8 9.9 6 7.1 Ni 2.5 26.3 3 2.8 49.7 13.8 12 1.8 2.4 P 460 560 340 780 990 1070 1000 370 1500 Pb 11.3 11 10.9 12.1 1.9 10.2 14.8 7.8 7.5 Rb 2.1 59.7 44.9 5.6 17 14.6 15.9 1.6 1.8 Sb 0.24 0.48 0.59 1.07 0.12 0.23 0.59 1.91 0.29 Sc 16.2 27.4 12.7 14.4 22.3 13.2 15.6 6.9 29.2 Se na <0.2 <0.2 <0.2 <0.2 <0.2 0.8 <0.2 Sn 1.4 1.2 1.2 1.3 0.9 1.5 1.4 2.4 0.9 Sr 297 211 47.2 209 446 173 337 280 856 Te <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 0.1 <0.1 Th 5.2 8.6 8.9 6.8 3 5.9 9 4.7 12.4 Tl 0.1 0.1 0.4 0.2 0.1 0.1 <0.1 <0.1 <0.1 U 1.7 2.1 2.2 2.9 1 1.6 2.8 0.5 1.9 V 138 72 79 106 169 134 142 119 131 W 0.6 0.5 0.7 0.7 0.4 0.4 0.9 0.4 0.3 Y 10.1 10 7.6 6.7 18.9 4.6 6.7 1.5 9.6 Zn <1 43 10 4 60 13 2 <1 <1 1 IA = Intermediate argillic, PR = Propylitic, AA = Advanced argillic, SHAA = Steam-heated advanced argillic. Oxides and major elemental concentrations given in Wt. % all other analysis in ppm.