Geochemistry and Reaction Path Modeling of the Beowawe

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GEOCHEMISTRY AND REACTION PATH MODELING OF THE BEOWAWE

HYDROTHERMAL SYSTEM, NEVADA: A BARREN END-MEMBER

EPITHERMAL SYSTEM

______

A Thesis Presented to

the Faculty of the Graduate School

University of Missouri-Columbia

______

In Partial Fulfillment

of the Requirements for the Degree

Master of Science

______

Mark Leatherman

Dr. Martin Appold, Thesis Supervisor

December 2010

The undersigned, appointed by the Dean of the Graduate School, have examined the thesis entitled.

GEOCHEMISTRY AND REACTION PATH MODELING OF THE BEOWAWE HYDROTHERMAL SYSTEM, NEVADA: A BARREN END-MEMBER EPITHERMAL SYSTEM

Presented by Mark Leatherman

A candidate for the degree of Master of Science

And hereby certify that in their opinion it is worthy of acceptance

ACKNOWLEDGEMENTS

I would like to thank Carol Nabelek for her assistance with the ICP-AES analysis at the

University of Missouri—Columbia. Many thanks go to my colleagues Dr. Albert Hofstra and Dr.

Donald Sweetkind of the United States Geological Survey-Denver, and Dr. Mark Person and

Amlan Banerjee at the New Mexico Institute of Mining and Technology. Particular thanks go to

Dr. Kevin Shelton and Dr. Baolin Deng for their valuable reviews that have contributed significant improvement of this manuscript.

Many thanks go to my advisor, Dr. Martin Appold, for his patience, expertise, encouragement, and wisdom for the various twists and turns the research process underwent.

Special thanks go to my wife, Rebecca, who has greatly helped me along the way, as well as the rest of my family.

TABLE OF CONTENTS

ACKNOWLEDGEMENTS………………………………………………………………………….ii

LIST OF FIGURES………………………………………………………………………………….iv

LIST OF TABLES………………………………………………………………………………...... v

ABSTRACT…………………………………………………………………………………………vi

I. INTRODUCTION………………………………………………………………………1

II. GEOLOGIC BACKGROUND………………………………………………………....7

III. ICP-AES ANALYSIS………………………………………………………………...13

IV. FLUID INCLUSION MICROTHERMOMETRY…………………………………....17

V. GEOCHEMICAL REACTION PATH MODELING…..…………………………….24

i. COLE-RAVINSKY PROFILE (CR) MODEL………..………………..24

A. SEGMENT 1……………………………………………………….28

B. SEGMENT 2……………………………………………………….30

C. SEGMENT 3……………………………………………………….37

D. SEGMENT 4……………………………………………………….40

E. SEGMENT 5……………………………………………………….41

F. SEGMENT 6……………………………………………………….44

ii. PERSON ET AL. PROFILE (P) MODEL……………………………....46

iii. HIGH S MODEL………………………………………………………..52

VI. DISCUSSION.………………………………………………………………………..55

VII. CONCLUSIONS……………………………………………………………………...62

VIII. REFERENCES………………………………………………………………………..64

IX. APPENDIX I………………………………………………………………………….67

X. APPENDIX II………………………………………………………………………...73

XI. APPENDIX III………………………………………………………………………..90

XII. APPENDIX IV………………………………………………………………………107

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LIST OF FIGURES

Figure Page

1. Fumarole Photo………………………………………………………………………...2

2. Map of Field Area……………………………………………………………………...3

3. Sinter Terrace Photo………………………………………………………………...... 4

4. Stratigraphic Column……………………………………………………………….....8

5. Alteration Profile…………………………………………………………………...... 10

6. Hand Sample Photos…………………………………………………………………12

7. ICP-AES Trends…………………………………………………………………...... 16

8. Fluid Inclusion Photos…………………………………………………………….....18

9. Microthermometry Histograms………………………………………………………22

10. Conceptual Model-Cross Section………………………………………………...... 27

11. pH-Fugacity-TDS Data………………………………………………………….....32

12. CR Model Mineral Precipitation Data……………………………………………..33

13. CR Model Aqueous Concentration Data…………………………………………..34

14. CR Model Precious Metal-Porosity-Hydraulic Conductivity Data………………..35

15. P Model Aqueous Concentration Data………………………………………….....47

16. P Model Mineral Precipitation Data…………………………………………….....48

17. P Model Precious Metal-Porosity-Hydraulic Conductivity Data……………….....49

18. High S Model Data………………………………………………………………...53

19. Precious Metal Stability Plots……………………………………………………..57

LIST OF TABLES

Table Page

1. ICP-AES Data………………………………………………………………………...14

2. Microthermometry Data………………………………………………………………19

3. Initial Fluid Parameters……………………………………………………………….25

4. Spece8 Mineral Saturation States…………………………………………………….29

5. Hydrologic-Theoretical Ore Grade Calculations…………………………………...... 59

ABSTRACT

The Beowawe geothermal field in north-central Nevada is one of the hottest and

most active in the Basin and Range province of the western U.S. Prior to disturbances of

the field caused by geothermal power exploration and development beginning in 1959,

and culminating with the completion of a 16.7 MW power plant in 1986, Beowawe had

more active geyser activity than any other site in North America outside of Yellowstone

National Park. The Beowawe area also contains characteristics of low-sulfidation

epithermal, Au-Ag deposits including sinter deposits, banded chalcedony veins with

adularia, bladed calcite, slotted quartz pseudomorphs after calcite, pyrite, and discharging

low chlorinity fluid that is neutral to basic in pH. Despite these characteristics, Beowawe

appears to be only weakly mineralized with respect to gold and silver. Although

Beowawe is one of the hottest areas in the Great Basin, there is no evidence for a magma

body at depth.

Regional fluid flow is apparently channeled along the NNW- and ENE-striking

Muleshoe and Malpais faults, which serve as recharge and discharge pathways,

respectively. Numerical modeling suggests that rapid advection of meteoric recharge had

cooled the fluid-flow system to a near uniform temperature of <150°C about 5000 years

ago. This contrasts with the 70-80°C/km temperature gradients that are currently

observed at Beowawe. In addition, the amount of silica that could have been deposited

under predicted model conditions in 5000 years is far less than what is observed in the

field. Together, these observations suggest that fluid flow at Beowawe occurred

episodically over a much longer period of time, perhaps on the order of hundreds of

thousands of years. The purpose of this study was to look for evidence of episodic flow

in the sinter and vein deposits, and to use reaction-path modeling to determine if a

hydrothermal fluid sourced from a deep carbonate reservoir could produce mineral

alteration assemblages observed in the field and ore grade precious metal mineralization

along its ascent to the surface.

Stratigraphically-controlled Samples of Beowawe sinter from several different

stratigraphic levels were analyzed by ICP-AES. None of these samples showed

detectable quantities of Au and Ag, which is probably due to the low solubility of gold in

the discharging fluids. Elements that did exist in detectable concentrations include Li

(0.46-46 ppm), S (2.3-4900ppm), Fe (49-18,000 ppm), Zn (0.3-76 ppm), As (6.2-60

ppm), Ba (12-230ppm), and Tl (20-29ppm). The heterogeneous variation in sinter compositions supports episodic fluid flow with fluctuating composition rather than a progressive evolution in fluid composition as a result of cooling. Fluid inclusion microthermometry performed on sinter and vein samples indicate silica was precipitated from dilute fluids that ranged from 0 to 1.4 eq. wt.% NaCl, which is quite similar to current discharged waters at Beowawe. The fluid inclusions have highly variable homogenization temperatures that probably reflect heterogeneous entrapment of liquid and vapor in a geyser environment. Geochemical reaction-path modeling of fluid sourced from a hypothesized deep carbonate aquifer ascending along the Malpais Fault supports current discharge fluid chemistry, and observed alteration mineral assemblages.

The modeling predicts precious metal mineralization to be weak overall, but most concentrated at depths of >1700 m and at shallower depths of <400 m. The modeling predicted variable net mineral precipitation along the ascent path, from which porosity

and permeability change were calculated. The calculations showed that enough flow

vii

episodes could occur before the porosity was fully occluded and the flow system would

shut down to allow ore grade precious metal mineralization to occur along some intervals

of the flow path.

viii

INTRODUCTION

The Beowawe geothermal field in north-central Nevada is one of the hottest and most active in the Basin and Range province of the United States. Prior to disturbances of the field caused by geothermal power exploration and development beginning in 1959, and culminating with the completion of a 16.7 MW power plant in 1986, Beowawe had more active geysering than any other site in North America outside of Yellowstone National Park (White, 1998).

Although geyser activity at Beowawe has now ceased, several fumaroles (Figure 1) and hot springs still exist.

The Beowawe geothermal area is located within the Whirlwind Valley watershed of the

Shoshone Range (Figure 2). Outcroppings of Tertiary volcanic rocks bound the valley as the

Argenta Rim on the north and as the Malpais Rim on the south. Hydrothermal fluids discharge

along the fault scarp of the ENE-striking Malpais Rim at temperatures ranging from 57 to 98⁰C.

Fluid temperatures increase sharply to about 230° C at three kilometers below the surface (Smith,

1983; Rimstidt & Cole, 1983; Struhsacker, 1986). Discharging hydrothermal fluids are dilute, with total dissolved solids (TDS) contents ranging from about 900 to 1400 ppm consisting

predominantly of sodium, sulfate, bicarbonate, and silica. The fluids tend to be slightly to

moderately basic, with pH ranging from about 7 to 9 (Cole & Ravinsky, 1984; Rimstidt & Cole

1983; White, 1998; Day, 1987). Over time, the discharging hydrothermal fluids have deposited a

massive siliceous sinter terrace (Figure 3) that is approximately 1.6 km long, 1 km wide, and 65 m thick and estimated to contain about 1.28 × 1011 kg of silica (Rimstidt & Cole, 1983).

The anomalously high fluid temperatures at Beowawe raise the question of how the fluids

acquired their heat, given the absence of any evidence for concurrent magmatism. Support for

the amagmatic character of the hydrothermal system lies in the absence of any surficial igneous

rocks younger than 10 Ma (Coolbaugh et al., 2005), low 3He/4He ratios in the hydrothermal fluids

(White, 1998), and the meteoric hydrogen and oxygen isotope composition of the hydrothermal

Figure 1: Photograph of an active fumarole at Beowawe (note hammer for scale).

Figure 3: Photograph of the siliceous sinter terrace (white) formed by hydrothermal fluid discharge at Beowawe. Note the road going up along the lower right-hand side of the terrace for scale.

4 fluids (John et al., 2003). In addition, Person et al. (2008) have recently completed a numerical model of groundwater flow and heat transport along a 60 kilometer cross section across the

Shoshone Range and adjacent basins. Their work showed that groundwater entering the subsurface along the Argenta Rim could have descended along the Muleshoe fault until it reached karsted Paleozoic carbonates at a depth of several kilometers, whereupon it moved laterally before ascending back to the surface along the Malpais fault. The model predicted a high temperature-depth gradient with fluid reaching a temperature of 240° C at a depth of three kilometers within the first few hundred years after the onset of flow that is consistent with present-day observations (Smith, 1983; Olmsted & Rush, 1987). However, after only about 1600 years, the temperature gradient along the Malpais fault had become nearly uniform due to high rates of advective heat transport, and absolute fluid temperatures were progressively decreasing with time. Mass balance calculations show that this period of time is too small to deposit the amount of silica that is present in the Beowawe sinter terrace (Rimstidt & Cole, 1983), leading

Person et al. (2008) to conclude that hydrothermal fluid flow and silica deposition have occurred in multiple brief episodes each on the order of 1000’s of years or less in duration, on an overall time span of hundreds of thousands of years. One objective of the present study was to look for geochemical evidence of episodic fluid flow in the Beowawe silica deposits.

The Beowawe geothermal area also has many characteristic features of low-sulfidation epithermal Au-Ag deposits such as fault-controlled fluid flow, siliceous sinter deposits, bladed calcite replaced by silica, sulfides coexisting with banded chalcedony and adularia, and fluid discharge that is dilute and neutral to basic in pH. The area is however only weakly mineralized with respect to gold and silver. Struhsacker (1986) has documented a low grade Au-Ag-As anomaly centered on White Canyon, an area of silica veining located about 1.5 km east of the sinter terrace that may be an earlier product of the Beowawe hydrothermal system. Surface samples and drill hole cuttings from depths up to ~100 m commonly had gold concentrations on the order of 10’s to 100’s of ppb, with a maximum of 560 ppb. The gold tends to be most

5 concentrated in sulfide-bearing margins of chalcedony veins. Silver anomalies are less widespread than gold, but reach a higher maximum concentration of 15 ppm. The maximum arsenic concentration found was 484 ppm. Struhsacker (1986) speculated about the reasons for the weak gold-silver mineralization and suggested that it was a result of the amagmatic character of the hydrothermal system, high permeability of the Malpais fault, and low gas contents in the fluids that prevented overpressuring and episodic hydrothermal eruption (steam explosions) and

brecciation. A second major objective of the present study was to investigate further the reasons

for the weak gold-silver mineralization at Beowawe by modeling the solubility and reactivity of

gold and silver in a hypothetical hydrothermal fluid as it ascended from a deep carbonate aquifer

to the surface.

GEOLOGIC BACKGROUND

The Beowawe geothermal field is located on the southwestern margin of Whirlwind

Valley at the intersection of the NNW-trending Northern Nevada Rift and the NE-trending

Shoshone Range (Figure 2). The Northern Nevada Rift is a result of Basin and Range extension, which stretches from near the Nevada-Oregon-Idaho border to southeast Nevada (John et al.,

2000). The rift is Middle Miocene in age and is thought possibly to reflect the passage of the

Yellowstone hot spot through northern Nevada during that time (John et al. 2003). The rift is exposed in the Argenta and Malpais Rims, two forks of the Shoshone Range that were uplifted between the Late Miocene and the Quaternary as a result of Basin and Range extension that form the northern and southern boundaries of Whirlwind Valley, respectively (Faulder et al., 1997;

John et al., 2003). Most of the hydrothermal discharge at Beowawe occurs at the base of the

Malpais Rim, apparently focused along the Malpais fault scarp. Additional hydrothermal fluid

focusing may have been caused by the NNW-trending Dunphy Pass fault, which parallels the

Northern Nevada Rift boundary and intersects the Malpais fault near Beowawe.

The stratigraphy of the Beowawe area is shown in Figure 4. The deepest rocks identified

are autochthonous early Paleozoic carbonates that lie approximately 3 to 5 km below the ground

surface (Zoback, 1979; Olmsted & Rush, 1987). These rocks may have undergone karst

dissolution and served as an important reservoir for circulating hydrothermal fluids. The

carbonate rocks are overlain by rocks of the Roberts Mountain thrust. The stratigraphically

lowest and thickest member of the thrust package is the Ordovician Valmy Formation, which

consists of at least 1700 m of predominantly siliciclastic rocks. In the Beowawe area, the Valmy

Formation consists mainly of gray to red siliceous siltstones that can grade into quartzite, with

lesser amounts of conglomerate, chert, chalcedony, sandstone, and shale (Zoback, 1979). Active

Paleozoic tectonics have significantly fractured this formation allowing the intrusion of Tertiary

diabase dikes (Struhsacker, 1980; Cole & Ravinsky, 1984). The Valmy Formation is

Figure 4: Simplified stratigraphic column of the Whirlwind Valley area of Beowawe.

8 unconformably overlain by about 45 to125 m of felsic tuffaceous sediments dated to be Late

Eocene in age, and interbedded by hornblende biotite lavas (Struhsacker, 1980). The sediments consist of clasts of the Valmy Formation, and felsic and mafic volcanic rocks in a matrix of feldspathic sand and quartz, feldspar, glass, and mafic mineral pyroclasts, largely cemented with calcite. Overlying the tuffaceous sediments are about 1200 m of Middle Miocene volcanic rocks.

The rocks consist predominantly of basaltic andesite and pyroxene dacite with lesser basalt, tuff, and tuffaceous sedimentary rock (Struhsacker, 1980; Zoback, 1979; Cole & Ravinsky, 1984).

These volcanic rocks are prominently exposed in the Argenta and Malpais Rims. Overlying the volcanic rocks in Whirlwind Valley are several tens of meters of Tertiary and Quaternary gravel, landslide, and alluvium deposits. These deposits are primarily clastic weathering products of the

Tertiary volcanic rocks and Valmy Formation.

Figure 5 shows how hydrothermal fluid flow at Beowawe has produced a zoned alteration of the host rocks to a depth of at least 2800 m (Struhsacker, 1980; Rimstidt & Cole,

1983; Cole & Ravinsky, 1984). Listed in order of increasing depth, zone I is characterized by zeolite, zone II by smectite, zeolite, and enrichment of Au, zone III by smectite, chlorite, and enrichments of Zn, Au, Ag, and Hg, and zone IV by chlorite, epidote, and enrichments of Zn, Cu,

Ag, and As (Figure 5a). The presence of some alteration minerals at temperatures lower than expected thermodynamically based on the present-day thermal profile, and the presence of hematite in the upper three alteration zones led Cole & Ravinsky (1984) to suggest that the

Beowawe hydrothermal system is currently in a state of thermal collapse (Figure 5b). In this scenario, a hot, reducing sodium chloride-fluid that dominated the system earlier is being progressively displaced by a cooler, more neutral, oxidizing sodium-bicarbonate-sulfate fluid.

Significant hydrothermal alteration is also observed in the rocks of White Canyon, located about 1.5 km east of the Beowawe sinter terrace. This discharge site is now inactive, possibly indicating that the locus of hydrothermal activity has shifted westward over time. The mineral alteration assemblage at White Canyon consists of multi-colored banded chalcedony with

Figure 5: (a) Major hydrothermal alteration zones as a function of depth for the Beowawe area, including prominent element anomalies within each zone (after Cole & Ravinsky, 1984). (b) Alteration mineral distribution and intensity (H = high, L = low) with depth. The solid curved line marks the measured thermal profile of Beowawe whereas the dashed curve is a reference boiling temperature for pure water (after Cole & Ravinsky, 1984).

10 adularia, slotted-habit calcite replaced by quartz (Figure 6), and minor pyrite with dark red and gray friable sulfides. Struhsacker (1986) suggested that hydrothermal fluids at White Canyon eventually precipitated enough silica to seal up most proximal open space. However, the permeability of the Malpais fault west of White Canyon was high enough to allow fluid flow to shift to its present location at Beowawe. The absence of brecciation at White Canyon supports this interpretation, indicating the presence of permeable flow conduits that prevented fluid pressure build-up and resultant steam explosions.

The hydrology of the Beowawe area has been studied by Day (1987), Olmsted & Rush

(1987), Faulder et al. (1997), and Person et al. (2008). The present day water table slopes

downward from west to east across Whirlwind Valley toward the Humboldt River. Groundwater

recharge is focused in the uplands bordering the western end of Whirlwind Valley. Faults such as

the Muleshoe Fault appear to channel much of the recharge to kilometer-scale depths, allowing

groundwater to reach the high observed discharge temperatures observed at Beowawe. Much of

the descending groundwater is likely to be intercepted by porous and permeable, possibly karsted carbonates immediately underlying the Roberts Mountains thrust, where the groundwater is temporarily sequestered and equilibrates with its host rock before ascending to the surface via the

Malpais Fault. This conclusion is supported by the Beowawe discharge waters’ light oxygen and hydrogen isotope composition, which has been interpreted to reflect a meteoric source of

Pleistocene age, unexpectedly old given Person et al.’s (2008) modeling prediction that groundwater can traverse the hypothesized flow path on the order of 100’s of years, and the waters’ heavy carbon isotope composition and high bicarbonate to chloride ratios, which indicate greater interaction with carbonate rocks than siliciclastic rocks (Zoback, 1979; Mariner et al,

1983; Day, 1987). On the basis of electric self-potential data, Zoback (1979) has inferred the existence of a second, smaller reservoir at an approximate depth of one kilometer, possibly created by increased fracturing from the intersection of the range front faults with the Northern

Nevada Rift graben-bounding faults.

Figure 6: Hand samples of bladed calcite replaced by quartz (top), and banded chalcedony- adularia from White Canyon (bottom).

ICP-AES ANALYSIS

Geochemical evidence for the episodicity of the Beowawe hydrothermal system was sought by measuring the bulk composition of siliceous sinter from twelve discrete stratigraphic positions in the sinter terrace. All of the samples were analyzed using inductively coupled plasma-atomic emission spectroscopy (ICP-AES) in the Department of Geological Sciences at the

University of Missouri—Columbia. Samples were prepared for analysis by powdering 0.2 g of material and heating it at 1,050°C for 30 minutes to drive off volatiles. The ashed samples were then mixed with 1.5 mL of 3% HF solution in separate Teflon bombs and heated in a 1400 W microwave oven at low power for 20 minutes to break silicate bonds. To aid in the dissolution of metals, 1 mL of 4% aqua regia was added to each sample solution and heated for ten minutes in a microwave oven at low power. Fifteen mL of 30% boric acid solution were then added to each sample solution followed by 10 more minutes of low power heating in a microwave oven to break up any fluoride complexes that may have formed by secondary reactions. The final step consisted of diluting the sample solutions to 50 mL with deionized water. An accompanying acid blank was prepared using the above procedure for instrument calibration, along with three other check standard solutions. These three standards were used to calibrate the instrument with intensities of

0.1 mg/l, 1.0 mg/l, and 10 mg/l. Elements chosen for analysis were based on the reported composition of Beowawe discharge waters from Cole & Ravinsky (1984), Day (1987), Rimstidt

& Cole (1983), and White (1998) as well as typical low-sulfidation alteration assemblages which included Li, S, Fe, Cu, Zn, As, Se, Mo, Ag, Sb, Te, Ba, Au, Tl, and Pb.

Elemental concentrations determined from the ICP-AES analyses and detection limits are shown in Table 1. The elements that registered above their detection limits in every sample were

Fe, Ba, and As with concentrations ranging from 113 to 17,800 ppm, 13.2 to 225 ppm, and 6.17 to 60 ppm, respectively. The elements that registered below their detection limits in every sample analyzed included Au, Ag,

Table 1: Minor and trace element composition of Beowawe sinter samples as determined by ICP-AES.

ICP-AES Concentrations (ppm) Sample ID Elevation (ft.) Li S Fe Zn As Ba Tl B11 1,667 46.3 1,120 17,800 17.5 60.0 45.4 ---- B10 1,554 18.4 4,480 803 ---- 7.26 225 ---- B9 1,568 ------103 ---- 14.0 19.0 ---- B8 1,538 14.3 ---- 551 6.36 12.8 50.8 ---- B7 1,538 6.73 27.4 1,780 ---- 8.6 95.7 ---- B6 1,538 5.17 ---- 113 3.1 11.6 13.2 14.0 B5 1,568 ------349 ---- 14.8 15.5 29.1 B4 1,557 10.9 226.0 764 75.5 6.71 89.9 ---- B3 1,565 2.33 ---- 358 12.5 8.98 52.1 19.8 B2 1,488 18.2 184.0 6,880 30.0 9.11 148.0 ---- B-1c 1,488 12.4 9.97 2,540 7.62 9.84 97.9 ---- B-1b 1,488 19.2 30.5 4,820 ---- 6.17 177.0 ----

“----“indicates that the concentration of the element in the sample was below the detection limit.

*Detection limits for the analyzed elements are as follows: 0.2 ppm for Tl, 0.09 ppm for Pb, 0.08 ppm for Se, 0.05 ppm for As, 0.04 ppm for Te, 0.03 ppm for Sb and Au, 0.02 ppm for S, 0.01 ppm for Li, Fe, Cu, Mo and Ag, 0.004 ppm for Zn, and 0.001 ppm for Ba.

Cu, Se, and Mo. Maximum concentrations found for the remaining elements were 46.3 ppm for

Li, 4,880 ppm for S, 75.5 ppm for Zn, and 29.1 ppm for Tl.

The elements Li, S, Fe, Zn, As, and Ba existed in detectable concentrations in enough sinter samples to allow trends to be sought as a function of elevation (Figure 7). Although concentrations can vary considerably within stratigraphic horizons, with the exception of As, all of the elements show a general pattern of decreasing concentration from an elevation of about

1490 to 1540 m, increasing concentration from about 1540 to 1555 m, decreasing concentration from about 1555 to 1560 or 1570 m and increasing concentration about 1560 or 1570 to 1667 m.

The pattern of As concentration with elevation is largely antithetical to that of the other elements.

The interpretation of these elemental concentration patterns is equivocal, but given the mineralogical homogeneity of the sinter terrace as a function of elevation, variations in sinter composition could plausibly reflect variations in parent hydrothermal fluid composition. This would indicate that hydrothermal fluid composition at Beowawe was not constant over time, which is consistent with the episodic fluid flow proposed by Person et al. (2008).

None of the elements detected is particularly enriched in the Beowawe sinter compared to average continental crust (Taylor and McLennan, 1985), with the exception of As, which is enriched by about an order of magnitude, and Tl, which when detected is enriched by about two orders of magnitude. Thus, the Beowawe hydrothermal fluid did not appear to have had strongly mineralizing character when it discharged at the surface, though it was capable of strong mineralogical alteration at greater depths.

Figure 7: Concentrations of Li, S, Fe, Zn, As, and Ba in the Beowawe sinter terrace as a function of elevation, as determined by ICP-AES. The solid line in each plot indicates the trend of variation of the concentrations. At elevations where more than one sinter sample was analyzed, the trend line connects to the mean value of the measurable concentrations.

FLUID INCLUSION MICROTHERMOMETRY

In order to understand more of the fluid temperature and salinity history of the Beowawe hydrothermal system, microthermometry was performed on fluid inclusions hosted by opaline sinter from Beowawe, and on quartz-chalcedony-adularia veins from within and extending eastward from White Canyon. The microthermometry was conducted using a Linkam THGMS

600 heating-cooling stage in the Department of Geological Sciences at the University of

Missouri--Columbia. A total of 60 fluid inclusions, half from older White Canyon veins and half from younger opaline sinter, were analyzed. Petrographic observations showed quartz replacements of bladed calcite not to contain any usable fluid inclusions. All of the fluid inclusions analyzed are considered to be primary, based on the criteria of Goldstein & Reynolds

(1994). Inclusions found in White Canyon vein quartz display a prismatic to ovoidal habit with an average liquid-vapor ratio of 7:1 whereas those found in younger siliceous sinter tend to possess irregular, spicule-type habits with an average liquid-vapor ratio equaling 4.5:1 (Figure 8).

For each sample chip, homogenization temperatures for all fluid inclusions were recorded before last-ice-melting temperatures so as not to risk stretching the inclusions, which would cause falsely elevated homogenization temperatures. In addition, because heating can also cause fluid inclusion stretching, liquid-vapor ratios were always compared to original, pre-microthermometry photographs of the fluid inclusions once the first homogenization temperature measurement in a sample chip had been performed to ensure that no changes in liquid-vapor ratio had occurred and that subsequent homogenization temperature measurements in the sample chip were accurate.

Microthermometry results are displayed in Table 2 and in Figure 9. Most of the fluid inclusions in the samples were composed of a single liquid water phase. The remainder consisted of liquid and vapor in highly variable proportions. No daughter minerals were observed in any of the fluid inclusions. Petrographic assemblages of liquid-vapor fluid inclusions of clear primary origin and sizes large enough for microthermometry analysis were rare in the samples studied.

17 a) b)

Figure 8: (a) Primary fluid inclusion assemblages oriented along growth bands in vein quartz from White Canyon, and consisting mostly of liquid-only fluid inclusions. (b) Possible assemblage of randomly oriented fluid inclusions lacking any clear association with growth features in quartz vein host from White Canyon. Most of the fluid inclusions in the photograph consist of a single liquid aqueous phase, with the exception of a two-phase aqueous liquid-vapor fluid inclusion visible in the center. (c) Large, two-phase, spicule-shaped fluid inclusion hosted by opaline sinter from Beowawe. Note characteristic banding of sinter matrix.

Table 2: Fluid inclusion microthermometry data from White Canyon silica veins and Beowawe siliceous sinter.

Sample ID Inclusion ID Sample Dimensions Th (°C) Tm (°C) Eq. Wt.% NaCl Type (µm) Qtz.-chal.- EVBV-1 1-1 adul. vein 7 3 129.4 −0.4 0.72 Qtz.-chal.- EVBV-1 1-2 adul. vein 5.5 3.5 255.0 0 0 Qtz.-chal.- EVBV-1 1-3 adul. vein 5.25 3 100.0 0 0 Qtz.-chal.- EVBV-1 1-1 adul. vein 8.5 3.25 127.3 −0.4 0.72 Qtz.-chal.- EVBV-1 1-2 adul. vein 4 4.5 211.7 0 0 Qtz.-chal.- EVBV-1 1-1 adul. vein 6 3.5 135.6 0 0 Qtz.-chal.- EVBV-2 1-2 adul. vein 4.5 3 155.7 0 0 Qtz.-chal.- EVBV-2 1-3 adul. vein 12.5 6.25 147.9 0 0 Qtz.-chal.- EVBV-2 1-4 adul. vein 5.25 3.25 158.7 0 0 Qtz.-chal.- EVBV-2 1-5 adul. vein 9.5 7.5 144.6 0 0 Qtz.-chal.- WCBV-1 1-1 adul. vein 5.25 4.25 163.7 0 0 Qtz.-chal.- WCBV-1 1-1 adul. vein 4.25 2 187.3 −0.1 0.18 Qtz.-chal.- WCBV-1 1-2 adul. vein 5 4 192.5 −0.1 0.18 Qtz.-chal.- WCBV-1 1-3 adul. vein 10.25 10.25 167.3 0 0 Qtz.-chal.- WCBV-1 2-1 adul. vein 6.5 5.5 126.0 −0.1 0.18 Qtz.-chal.- WCBV-2 2-2 adul. vein 4.5 2.5 158.3 −0.1 0.18 Qtz.-chal.- WCBV-2 2-3 adul. vein 7.5 5.25 186.3 −0.1 0.18 Qtz.-chal.- WCBV-2 2-4 adul. vein 5.25 4.5 197.8 0 0 Qtz.-chal.- WCBV-2 2-5 adul. vein 9 3.75 138.7 −0.5 0.90 Qtz.-chal.- WCBV-2 2-6 adul. vein 9 3.5 109.3 −0.2 0.36 Qtz.-chal.- WCBV-2 2-7 adul. vein 6.75 3.25 162.1 0 0 Qtz.-chal.- WCBV-2 2-8 adul. vein 8.75 2.5 140.6 −0.1 0.18

Sample ID Inclusion ID Sample Dimensions Th (°C) Tm (°C) Eq. Wt.% NaCl Type (µm) Qtz.-chal.- WCBV-2 2-9 adul. vein 4.5 3 123.5 0 0 Qtz.-chal.- WCBV-2 2-10 adul. vein 6 3 167.9 0 0 Qtz.-chal.- WCBV-2 3-1 adul. vein 8 3 166.2 −0.3 0.54 Qtz.-chal.- WCBV-2 3-2 adul. vein 5 2 148.8 −0.4 0.72 Qtz.-chal.- WCBV-2 4-1 adul. vein 5.5 5.5 130.5 −0.2 0.36 Qtz.-chal.- WCBV-2 4-2 adul. vein 5.75 3.5 118.2 −0.6 0.36 Qtz.-chal.- WCBV-2 1-1 adul. vein 9 6 146.8 −0.2 0.36 Qtz.-chal.- WCBV-2 1-1 adul. vein 7 3.5 185.6 0 0 Opaline BEO-ST-2 1-2 sinter 22.5 19.5 183.2 −0.2 0.36 Opaline BEO-ST-2 1-3 sinter 11 4.25 143.4 0 0 Opaline BEO-ST-2 1-4 sinter 22 12.5 162.8 −0.1 0.18 Opaline BEO-ST-2 1-5 sinter 17 12.75 228.6 −0.2 0.36 Opaline BEO-ST-7 2-1 sinter 7 5.25 178.2 −0.1 0.18 Opaline BEO-ST-7 2-2 sinter 9.5 6 181.7 −0.1 0.18 Opaline BEO-ST-7 2-3 sinter 7.75 2.25 190.0 0 0 Opaline BEO-ST-7 1-1 sinter 9.75 4.25 169.3 0 0 Opaline BEO-ST-7 2-1 sinter 5 3.75 171.1 −0.2 0.36 Opaline BEO-ST-7 2-2 sinter 110 61 218.6 0 0 Opaline BEO-ST-7 2-3 sinter 8.5 8.5 188.5 0 0 Opaline BEO-ST-7 2-4 sinter 14 12.25 249.3 −0.3 0.54 Opaline BEO-ST-11 3-1 sinter 12 8.5 134.6 −0.8 1.45 BEO-ST-11 Opaline 3-2 sinter 6 4.25 229.6 −0.3 0.54 BEO-ST-11 Opaline 3-3 sinter 7.75 4.5 294.9 0 0 BEO-ST-11 Opaline 3-4 sinter 6.5 6.5 250.1 −0.4 0.72

Sample ID Inclusion ID Sample Dimensions Th (°C) Tm (°C) Eq. Wt.% NaCl Type (µm) BEO-ST-11 Opaline 3-5 sinter 5 5 313.1 0 0 BEO-ST-11 Opaline 3-6 sinter 8.5 5 194.4 −0.2 0.36 BEO-ST-11 Opaline 3-7 sinter 7.5 5 174.1 0 0 BEO-ST-11 Opaline 1-1 sinter 13.5 2 200.7 0 0 BEO-ST-11 Opaline 1-2 sinter 6.5 4.75 201.5 −0.1 0.18 BEO-ST-11 Opaline 1-3 sinter 7.5 7.5 219.8 −0.3 0.54 BEO-ST-11 Opaline 2-1 sinter 9.5 4.75 233.6 0 0 BEO-ST-11 Opaline 2-2 sinter 11 5 213.1 −0.2 0.36 Opaline BEO-ST-12 1-1 sinter 6 6 160.2 0 0 Opaline BEO-ST-12 1-2 sinter 10.25 5 188.9 0 0 Opaline BEO-ST-12 1-3 sinter 5.75 2.75 263.7 −0.1 0.18 Opaline BEO-ST-12 2-1 sinter 11.25 9.75 165.8 0 0 Opaline BEO-ST-12 2-2 sinter 32 20.5 159.0 0 0 Opaline BEO-ST-12 3-1 sinter 16.75 6.75 209.1 0 0

* “Qtz.-chal.-adul. Vein” corresponds to Quartz-chalcedony-adularia vein.

Figure 9: Microthermometry histograms displaying homogenization (Th) temperatures (a), and melting-point depression (Tm) temperatures (b) of White Canyon vein quartz and Beowawe siliceous sinter.

Most of the microthermometry data are from isolated fluid inclusions, though some are from fluid inclusion arrays that appear to correlate with growth bands (Figure 8a). Homogenization temperatures (Th) for liquid-vapor fluid inclusions have a wide range of values from 100 to

313°C, with a standard deviation of ±1°C, indicative of heterogeneous liquid-vapor entrapment typical of geyser environments (Figure 9a). Fluid inclusions hosted by unconsolidated sinter have a higher average Th of 205°C compared to fluid inclusions hosted by White Canyon quartz veins, whose Th averages about 159°C. Last-ice-melting temperatures (Tm) for fluid inclusions hosted

by both sinter and quartz veins are consistently at 0°C with a minimum of −0.8°C, with a

standard deviation of ±0.1°C (Figure 9b). These temperatures indicate low total dissolved solids

contents corresponding to 0 to 1.4 equivalent weight % NaCl.

GEOCHEMICAL REACTION PATH MODELING

Geochemical reaction path modeling was carried out to investigate the behavior of hydrothermal fluid as it ascended along the Malpais Fault from a deep carbonate reservoir underlying the Roberts Mountains thrust fault. Three scenarios were modeled. The first model simulated a fluid that cooled as it ascended according to the present-day thermal gradient reported by Cole & Ravinsky (1984) for the Ginn 1-13 well. The second model simulated a fluid that cooled much less as it ascended, following the thermal gradient during peak heat transport predicted by the hydrologic modeling of Person et al. (2008). In this second scenario, fluid discharges at the ground surface at a temperature of 96° C in contrast to a temperature of 25° C in the first scenario. The third model simulated the effects of elevated sulfur concentration on precious metal transport and precipitation under the present-day thermal gradient.

Cole-Ravinsky profile (CR) model

The first model tracks the evolution of a hydrothermal fluid as it rises along the present- day geothermal gradient in the Ginn 1-13 well, and thus provides insights into the reaction products formed during waning hydrothermal activity. The initial composition of the model fluid

is shown in Table 3. Concentrations of K, Na, Cl, F, SO , HCO , and SiO2 were obtained from analyses of water from the Ginn 1-13 well, drilled by Standard Oil of California and American

Thermal Resources in 1974-1975, which at a total depth of 2,915 m is the deepest well in the

Beowawe area (Zoback, 1979; Cole & Ravinsky, 1984). The temperature at the base of the Ginn

1-13 well at the time of drilling was about 210° C, which was assigned to be the initial temperature of the model fluid. Although the Ginn 1-13 well does not quite penetrate 3 km into

Paleozoic carbonates, the initial fluid composition is a satisfactory starting point for reaction-path modeling. Based on the abundance of carbonate species in Beowawe hydrothermal fluids and their heavy carbon isotope composition, the hydrothermal fluids are thought to have equilibrated

Table 3: Initial composition of the carbonate reservoir fluid.

Ionic Species Carbonate reservoir Shallow aquifer fluid Saturated mineral governing fluid (ppm) (ppm) concentration Mg2+ 0.0257 23.9 Dolomite Al3+ 8.87 10-6 2.99 Saponite-Ca SiO2(aq) 334.0 125.0 Quartz Ca2+ 1.75 59.3 Calcite Fe2+ 0.000401 1.25 10-10 Magnetite Ag+ 0.00496 ------Acanthite Ba2+ 0.019 ------Witherite Au+ 0.000148 ------Native gold Cl- 58.8 75.7 ------F- 7.88 ------Na+ 202.0 57.7 ------K+ 29.9 8.59 ------SO2- 11.1 138.0 Pyrite 4 Log ƒO 40 0.7 ------pH 6.5 6.5 ------

25 with the carbonate reservoir (Day, 1987). Thus, model concentrations of calcium, magnesium, and barium were specified by saturation with respect to calcite, dolomite, and witherite

respectively. Iron concentration was governed by magnetite saturation and the log fOwas set equal to −40, a value slightly more reducing than the magnetite- hematite buffer and chosen because of the absence of hematite in carbonates. The pH of the model fluid was assigned a value of 6.5. This is higher than the pH value of 8.4 reported for the Ginn 1-13 well by Cole &

Ravinsky (1984) and for most of the hydrothermal discharge sites at Beowawe (White, 1992).

The lower pH value was justified by the probability of significant CO2 exsolution along the

ascent path due to pressure decrease and that it coincided approximately with K-feldspar

saturation. Model calculations that employed the higher pH value of 8.4 caused very high levels

of supersaturation for numerous Fe-Mg-silicates that are not reported in the well logs.

Concentration of Al was governed by equilibrium with respect to the clay mineral saponite-Ca, a

common sedimentary clay mineral that could plausibly be expected in carbonates. This Al

concentration also prevented other Al-bearing minerals from being initially supersaturated.

Model sulfur concentration was specified by equilibrium with respect to pyrite, and Au and Ag

concentrations were specified by equilibrium with respect to native gold and silver.

Having established a plausible composition for a hydrothermal fluid that had resided in

the Paleozoic carbonate rocks, this fluid was then allowed to react successively with the overlying

rocks to simulate its chemical evolution along its ascent to the surface. Figure 10 shows the

model stratigraphy, lithology, and temperature profiles used in the reaction path calculations,

performed using the “React” program in the Geochemist’s Workbench software with the

“thermo.com.v8.r6+” thermodynamic database (Bethke, 2004). This database was modified

slightly to include data for the aqueous species, AgHS , AgHS , AgOH , AuCl , AuCl ,

AuCl , AuCl , AuHS , AuHS , and AuOH , calculated using the SUPCRT92 software

Figure 10: Schematic cross section of Beowawe with corresponding reaction path model segments, highlighting the hydrothermal fluid flow path up the Malpais Fault from the carbonate reservoir, the intermediate aquifer in which fluid mixing takes place, and discharge at the surface.

(Johnson et al., 1992) and the “slop07” database (Shock & Helgeson, 1988). The “slop07” database also had first to be modified to include equation of state parameters for AuHS,

AuOH, and AgHS obtained from Bessinger & Apps (2005). Modal mineral assemblages

for each stratigraphic segment were obtained from Struhsacker (1980) and Winter (2009).

All of the reaction path calculations assumed a water-rock ratio of 100, where in each

segment, 1 kg of hydrothermal solution was allowed to react with 10 g of wall rock with relative

mineral proportions shown in Figure 10. A model water-rock ratio of 100 would translate into a

1% increase in wall rock porosity due to dissolution by the hydrothermal fluid. The reaction path

calculations were carried out in a batch format: A separate reaction path calculation was carried

out for each stratigraphic segment, where the starting composition of the hydrothermal fluid for a

segment was obtained from the modeling results of the preceding segment. A further assumption,

based in part on the geophysical data of Zoback (1979) cited previously and the alteration

assemblages shown in Figure 5, is that the upper one kilometer of the subsurface is saturated with

a resident dilute, oxidizing, neutral pH meteoric fluid that has infiltrated from the ground surface.

Segment 1

Table 4 shows a list of minerals, calculated from the SpecE8 program, to be within at

least 0.5 log unit of saturation. A full listing of the speciation output is provided in Appendix I.

Talc and the Fe-Mg silicate hydroxide, minnesotaite, are two of the most super-saturated minerals

and their presence is consistent with the low-grade metamorphic conditions expected from the

initial model temperature of 210⁰C. Tremolite is very close to saturation, also consistent with a

low-grade metamorphic environment. Several silica phases are predicted to be near saturation in

the hydrothermal fluid, with quartz slightly super-saturated and chalcedony, cristobalite, coesite,

Table 4: Abbreviated list of minerals with the highest saturation indices for the carbonate source hydrothermal fluid, as calculated by SpecE8.

Mineral Saturation Index (log Q/K) Talc 0.8451 Acanthite 0.4203 Minnesotaite 0.2050

Quartz 0.1412 Dolomite 0.0018

Chalcedony 0.0262 Saponite-Mg 0.0599 Tremolite 0.0909 Hematite 0.1031 Aragonite 0.1535 Cristobalite-α 0.1555 Cristobalite-ß 0.3554 SiO2(am) 0.4573 Saponite-Na 0.4586

29 and amorphous silica all slightly undersaturated, which is consistent with the high degree of sinter deposition and silicification at Beowawe and White Canyon.

The concentration of gold predicted to be in solution is very low at 0.15 ppb, but is the

maximum for the prescribed pH and logfO, given the assumption of gold, magnetite, and pyrite

saturation. Gold concentration could be higher in a fluid essentially free of iron, which would

allow greater concentrations of reduced sulfur, the main complexing agent and solubility

enhancer of gold. However, the assumption that Fe concentration is governed by saturation with

respect to magnetite rather than the more soluble siderite is probably already generous in terms of

promoting gold solubility, given the carbonate host rock. Thus, sub-ppb gold concentrations

appear likely for the hydrothermal fluid at this stage. The concentration of silver predicted to be

in solution is 5 ppb, which is also very low. Silver solubility is enhanced most by the formation

of complexes with chloride, which is only 59 ppm, based on measurements of bore hole fluids.

Thus, the gold and silver carrying capacity of the hydrothermal fluid as it leaves the Paleozoic

carbonate reservoir is expected to be low, which means that the fluid would not be very effective

at causing gold and silver mineralization, unless the fluid were able to act over very long periods

of time.

Segment 2

Segment 2 represents the first reaction-path batch model carried out using “React”.

This segment represents an interval along the Malpais fault where considerable offset has been

created between the Paleozoic carbonates and the shaley siltstones of the Ordovician Valmy

Formation (Figure 10). Miocene diabase dikes also cross-cut portions of the shaley siltstone.

The overall model reactant lithology, thus, was a composite of these three component lithologies

in the following proportions: 50% carbonates, 40% shaley siltstone, and 10% diabase dikes. The

30 proportions of reactant minerals in this segment are shown in Figure 10. In addition, Ag and Au were assumed to exist in the model in concentrations of 44 and 0.4 ppb, respectively, which are weighted averages of the global averages for basalt, shale, and carbonate rocks as reported in

Faure (1998). The fluid was simulated to cool from 210.0 to 193.0⁰C (Figure 10). A full listing of the React outputs is in Appendix II.

Results of the reaction path models are shown in Figures 11-14. The hydrothermal fluid

overall undergoes only minor changes in composition as a result of its reactions with the minerals

in segment 2. The pH decreased from 6.5 to 6.39, the log fO decreased from −40 to −42.4, and the TDS content decreased from 2905 to 2770 ppm (Figure 11). The slight drop in pH may be the result of the net precipitation of 0.049 g of calcite from the fluid, which results from the

+ 2+ production of H from the reaction of Ca and HCO , though the latter is not strongly affected.

The drop in oxygen fugacity probably reflects the effects of contact with reduced Fe in minerals

like fayalite and magnetite in the diabase dikes. The decrease in TDS content indicates that

mineral precipitation is outpacing mineral dissolution, probably largely due to the effects of

cooling, and largely driven by the precipitation of quartz, the most abundant mineral precipitated,

and whose solubility is strongly temperature dependent. The appearance of quartz and calcite at

this depth (Figure 12a) is consistent with the observations shown in Figure 5b. Besides HCO ,

the concentrations of F, Na, Cl, P, and Ba are not strongly affected by the reactions in segment 2.

Magnesium, S, and SiO2 show slight decreases in concentration whereas K, Ca, and Fe show increases (Figure 13 a,b).

Some phyllic and zeolite alteration is already predicted to develop in segment 2 through the precipitation of saponite, nontronite, minnesotaite, and mesolite (Figure 12b), though in the field, most of the clay and zeolite mineral precipitation occurs at shallower depths. However, two important Fe minerals, pyrite (Figure 12c) and chlorite (daphnite) are predicted to be saturated or nearly saturated, respectively, consistent with field observations. The model also predicts the

Figure 11: (a) pH, (b) log , and (c) total dissolved solids (TDS) trends as a function of depth corresponding to lithologic segments encountered by hydrothermal fluid rising along the Malpais Fault.

Figure 12: (a) Quartz and carbonate mineral, (b) clay and zeolite mineral, and (c) miscellaneous mineral precipitation trends as a function of depth for the CR model.

Figure 13: Aqueous concentration trends of (a) Mg, K, Ca, Na, and HCO , (b) Fe, SiO2, total S, and Cl, and (c) precious metals as a function of depth for ascending hydrothermal fluid for the CR model.

Figure 14: (a) Mass of precious metal precipitation, (b) host rock porosity change, and (c) relative hydraulic conductivity (K) change as a function of depth depth. (No data are shown for segments 5 and 6 for n=0.1, as porosity was completely occluded there and hydraulic conductivity would go to zero.)

35 precipitation of 0.13 g diaspore, which is probably serving as a sink for the aluminum released by the dissolution of feldspars and muscovite (Figure 12c). The field reports do not show any Al- bearing alteration minerals over the depth interval of segment 2, suggesting that either they were not recognized or that Al was transported in solution metastably to shallower depths before precipitating.

About 0.1 µg of gold is predicted to precipitate as a result of reaction with the 10 g of rock, equating to a gold concentration of about 10 ppb (Figure 14a). This represents a substantial enrichment over the initial gold concentration of 0.4 ppb in the model rock of segment 2, and corresponds to a decrease in the gold concentration of the hydrothermal fluid from 0.15 ppb in segment 1 to 0.04 ppb in segment 2. About 2.9 µg of silver are predicted to precipitate in the form of acanthite, equating to a silver concentration of 290 ppb (Figure 14a). As for gold, this represents a substantial enrichment over the initial silver concentration of 44 ppb in the model rock of segment 2, and corresponds to a decrease in the silver concentration of the hydrothermal fluid from about 3 ppb in segment 1, to about 2 ppb in segment 2. Thus, the hydrothermal fluid has precipitated much of its gold and silver in segment 2, leading to modest precious metal mineralization there.

The reaction path modeling results have hydrologic as well as geochemical and mineralogical implications. The modeling predicts a net increase in mineral volume of 0.107 cm3

by the end of the reaction path. With knowledge of the initial porosity or volume of voids, it is

possible to calculate the change in host rock porosity caused by the reaction path by

differentiating

(1) to get

(2)

36 where Vv is the volume of voids, Vs is the volume of solids, and n is porosity. With the

3 knowledge or an assumption of initial porosity, and knowledge of Vs (3.642 cm for 10 g of reactants), Vv can be found from equation 1, allowing dn to be computed from equation 2. For common initial porosity values between 10 and 25%, porosity would decrease between 2.6 and

2.2%, respectively. From these equations it can also be determined that the initial porosity of the host rock must be at least about 2.9% to avoid its pore space becoming completely occluded by mineral precipitation (Figure 14b).

Changes in host rock hydraulic conductivity can also be determined from changes in host rock porosity through the Kozeny-Carman equation (Bear, 1972),

(3)

where ρw is the density of water, g is gravitational acceleration, µ is the viscosity of water, and dm

is the mean grain size of the porous medium. For an initial porosity of 10%, the predicted amount

of mineral precipitation would lead to a hydraulic conductivity decrease by a factor of about 2.6,

whereas for an initial porosity of 25%, the hydraulic conductivity decrease would only be a factor

of 1.4 (Figure 14c). Thus, the amount of mineral precipitation predicted by the reaction path

could have enough impact on porosity and permeability to alter the flow rate of the hydrothermal

fluid significantly, provided the initial porosity of the host rock was low.

Segment 3

Segment three represents an interval where both the footwall and the hanging wall of the

Malpais Fault are composed of shaley siltstones of the Ordovician Valmy Formation cross-cut by

Miocene diabase dikes (Figure 10). Model lithologic proportions consist of 80% shaley siltstone

and 20% diabase. The proportions of reactant minerals in each lithology are the same as in

segment 2 and sum to a total of 10 g. A weighted average of global mean Ag and Au

37 concentrations for shaley siltstone and diabase resulted in model concentrations for segment three of 78 and 0.8 ppb. The amount of reactant fluid was 1 kg, which was allowed to cool from

193.0to 178.0° C.

Figure 11 shows the acidity, redox state, and salinity of the younger hydrothermal fluid to have undergone relatively minor changes as it reacted with the segment three host rock. The pH

decreased from an initial value of 6.39 to 6.32, log fO decreased from −42.1 to −44.1, and TDS content decreased from 2770 to 2743 ppm. Other chemical constituents in the hydrothermal fluid also underwent only minor changes. The concentrations of Ba, Cl, F, and Na remained effectively constant (Figure 13a,b). The concentrations of Fe, Mg, and K increased slightly, most likely as a result of reaction with enstatite, fayalite, ferrosilite, fluorapatite, forsterite, K-feldspar,

− and magnetite in the model host rock (Figure 13a,b). The concentrations of Al, Ca, HCO3 , SiO2, and S decreased slightly, most likely as a result of precipitation of diaspore, dolomite, muscovite, pyrite, quartz, nontronite, and saponite (Figures 12 & 13a,b). In addition, minnesotaite was predicted to precipitate, though not in sufficient quantity to prevent a net increase of Fe in the fluid.

Segment 3 lies largely within alteration zone IV (Figure 5a), which is characterized by the presence of chlorite and epidote. Chlorite (daphnite) is predicted to be slightly undersaturated with a saturation index (SI) of −0.06, which within the uncertainty of the thermodynamic data could mean that it is actually saturated. Epidote is even more undersaturated in segment 3 than in segment 2 (SI is −2.8 versus −1.8), probably as a result of the lower temperature of segment 3.

This may indicate that the hydrothermal fluid was hotter over the segments 2 and 3 depth intervals in the past than it is now to allow epidote to precipitate. As in segment 2, phyllic and zeolite alteration is again predicted to develop, which is still somewhat deeper than observed in the field, where it occurs in alteration zones II and III (Figure 5a). Another discrepancy is that calcite is not predicted to precipitate, though it is close to saturation with a SI of −0.21. Instead,

38 dolomite is predicted to precipitate. However, the model prediction of quartz and pyrite precipitation agrees with field observations.

The precious metal concentration of the hydrothermal fluid decreases from segment 2 to

3 (Figure 13c). Gold decreases from 0.041 to 0.015 ppb and silver decreases from 2.2 to 1.5 ppb.

The solubility of both metals is probably decreased by the decreasing temperature as well as sulfur content, as both metals exist in solution primarily as bisulfide complexes. Bisulfide is commonly an important if not the principal complexing agent for gold, but in this case it is also for silver because of the low chloride content of the fluid. The decreased aqueous concentrations of precious metals lead to the deposition of about 3.4 µg Au and 1.5 µg Ag relative to 10 g of reactant rock, corresponding to concentrations of 3.4 and 150 ppb, respectively (Figure 14a).

These precious metal concentrations are higher than the initial values of 0.8 ppb Au and 78 ppb

Ag in the reactant rock, indicating that segment 3 would have become slightly enriched in

precious metals by the hydrothermal fluid.

The model predicts a net increase in mineral volume of 0.0115 cm3 by the end of the reaction path in segment 3. This represents a small amount of mineral precipitation, and would only decrease the host rock porosity by about 0.3% for an initial porosity in the range of 10 to

25%. The porosity threshold for total pore space occlusion by this amount of mineral precipitation is about 0.36%, which is probably much lower than the actual porosity of the rock

(Figure 14b). A porosity decrease of only 0.3% has a negligible effect on hydraulic conductivity, changing its value by 4 to 11% for initial porosity values of 10 to 25% (Figure 14c). Thus, the amount of mineral precipitation predicted by the modeling is unlikely to have changed the hydrology of segment 3 significantly, unless the initial porosity of the rock was very low.

Segment 4

Model segment 4 consists of the upper part of the Valmy Formation and contains

predominantly quartzite with minor barite nodules (Figure 10). The initial reactant mineral

assemblage was assumed to be composed of 95% quartz and 5% barite, as no published reports of

the precise modal mineral proportions of the upper Valmy were found. The Au and Ag content of

segment 4 reactant rock was assumed to be zero and 10 ppb, respectively, based on the data of

Faure (1998) for sandstone. The temperature of the hydrothermal fluid was assumed to decrease

from 178.0 to 158.0°C (Figure 10).

The base modeling predicts the hydrothermal fluid to undergo only minor changes in

composition as a result of reaction with the simple mineralogy of segment 4 host rock. The pH

decreased from 6.3 to 6.0 due to the precipitation of witherite (Figures 11a & 12a). Log fO stayed nearly constant increasing from −44.1 to −44.0, and the TDS content decreased from 2743 to 2689 ppm (Figure 11b,c). The concentrations of most aqueous components remain effectively unchanged in segment 4, including Ca, Cl, F, K, Mg, and Na, (Figure 13a,b). Aqueous

components that decrease include Al, HCO , Fe, and SiO2, which results from the precipitation of

diaspore, witherite, pyrite, and quartz (Figures 12 a,c & 13a,b). Aqueous components that

increase include Ba and S, which is a direct result of the net dissolution of barite (Figure 13a,b).

Segment 4 coincides largely with the lower half of alteration zone III (Figure 5a), which

is characterized by smectite and chlorite alteration. No phyllic mineral of any type or chlorite

was predicted to precipitate by the modeling. Kaolinite and montmorillonite have the two highest

SI values of any clay minerals at −0.78 and −0.98, respectively, but are still well undersaturated.

Calcite, which is reported from throughout the length of segment 4 (Figure 5b), is also not predicted to precipitate with a SI value of −0.85. The only minerals predicted by the models to precipitate that are also reported from the field for the segment 4 interval are pyrite and quartz.

The overall discrepancy of model results and field observation with respect to mineral precipitation probably indicates that segment 4 has a more complex mineralogy than modeled,

40 and that cooling alone of the hydrothermal fluid is not enough to produce the mineral assemblages observed in the field.

Gold concentration in the hydrothermal fluid remains effectively constant in segment 4, and Ag shows a slight increase from 1.5 ppb to 1.6 ppb (Figure 13c). These concentration patterns result from the absence of any gold or silver phase precipitates in segment 4, and the dissolution of silver from the host rock. This contrasts with field observations that report alteration zone III (which encompasses model segment 4) to be enriched in Au and Ag (Cole &

Ravinsky, 1984).

The net volume of mineral precipitation in segment 4 is about 8.4×10−3 cm3 and consists

mainly of quartz. This volume is slightly less than the volume of minerals precipitated in

segment 3, and means that as for segment 3, the hydraulic properties of segment 4 would not

change significantly from the reaction path, unless the initial porosity was very low (Figure

14b,c).

Segment 5

This segment is the first of two in which the ascending hydrothermal fluid was allowed to

react with a dilute, oxidizing, neutral pH meteoric fluid as well as with the host rock. The

presence of oxidizing meteoric water over the depth interval represented by segments 5 and 6 is

inferred primarily from the presence of hematite in the alteration assemblage (Figure 5b).

Segment 5 consists of basaltic andesite with modal mineral proportions shown in Figure 10, assumed in the absence of any published mineralogical characterizations. The concentrations of

Ag and Au in the host rock were assumed to be 81 ppb and 4 ppb, respectively, which are the averages of values for basalt and high-Ca granite reported by Faure (1998). The hydrothermal- meteoric fluid mixture was allowed to cool from 158.0 to 58.0° C, the largest drop in temperature for any segment.

The model meteoric water was assumed to have initially the average composition of non- thermal Beowawe spring water, which is believed to be shallowly circulating (Olmsted & Rush,

1987). The concentrations of Fe and Al, which were not measured by Olmsted and Rush (1987) were prescribed by assuming saturation with respect to magnetite and albite. The meteoric fluid was also assumed to have a pH of 6.5 and to be in equilibrium with atmospheric oxygen (Table

3). One kg of this meteoric fluid was assumed to react with 1 kg of hydrothermal fluid and 10 grams of basaltic andesite host rock.

Base modeling results show an increase in the hydrothermal fluid’s pH from 6.0 to 6.5,

and decreases in its log fO from −44 to −59 and TDS content from 2689 to 1426 ppm (Figure

11). The pH trend is most likely caused by the sharp temperature decrease and more basic character of the meteoric fluid, which together overpower the production of H+ during the

precipitation of most of the minerals in the reaction path. The large decrease in log fO is noteworthy, given the high concentration of oxygen introduced by the meteoric fluid, but is probably caused by the large amount of hematite precipitated (Figure 12c). The large TDS

content decrease is mostly a result of the large decrease in HCO concentration, caused by the

precipitation of calcite, dolomite, and siderite (Figure 12a). Quartz also precipitates in

abundance, decreasing significantly the silica concentration. Other aqueous constituents that

decrease in concentration include Al, F, and SO . The decrease in Al results primarily from the abundant kaolinite precipitation (Figure 12b). The F decrease is slight, probably reflecting

primarily the effects of dilution. The decrease in SO results primarily from pyrite precipitation

(Figure 12c). Ca, Mg, and Fe, all increase significantly due to interaction with anorthite, enstatite, ferrosilite, and magnetite in the basaltic andesite host rock. Na and Cl concentrations

increase very slightly (Figure 13a,b).

Segment 5 coincides largely with alteration zone II (Figure 5a), which is characterized by

clay mineral alteration (chlorite and illite at greater depths and montmorillonite and kaolinite at

42 shallower depths), zeolite alteration, and Au enrichment. The reaction path modeling predicts abundant kaolinite precipitation, but no other clay minerals or zeolites, though the zeolite minerals, mesolite and stilbite, are predicted to be relatively close to saturation with SI values of

−0.36 and −0.31, respectively. The precipitation of quartz, calcite, pyrite, and hematite predicted by the modeling coincides well with field observations. However, the modeling also predicts the precipitation of significant muscovite, dolomite, and siderite, which are not reported from the field.

The concentrations of both Au and Ag decrease sharply by several orders of magnitude from 1.5×10−5 to 4.3×10−10 ppm for Au and from 1.6 × 10−3 to 4.2 × 10−6 for Ag. Thus, the

hydrothermal fluid is effectively stripped of its remaining precious metal content in segment 5

(Figure 13c). This results in the precipitation of about 5.5 ppb Au and 166 ppb Ag, which

equates to net increases of 1.5 and 85 ppb (Figure 14a). As for segment 3, gold and silver

precipitation is probably caused by a combination of cooling and decreasing sulfur content, which

would destabilize the bisulfide complexes.

Segment 5 experiences a net volume increase of 0.54 cm3, which is the largest for any of the segments, and is caused mainly by the precipitation of quartz and kaolinite. This quantity of mineral precipitation would reduce host rock porosity by 12% for an initial porosity of 25%, and based on the Kozeny-Carman equation, would reduce hydraulic conductivity by about an order of magnitude (Figure 14c). As the initial porosity decreases, the porosity reduction increases such that total porosity occlusion occurs at an initial porosity of about 14% (Figure 14b). Thus, the predicted quantity of mineral precipitation would have a significant impact on the flow of the hydrothermal fluid, perhaps blocking its flow entirely, leading to a buildup of fluid pressure that could eventually be relieved by hydrofracturing, or diverting flow to a more permeable section of the fault zone, as has happened previously with the shift of hydrothermal discharge from White

Canyon to Beowawe.

Segment 6

As for segment 5, in segment 6 the hydrothermal fluid reacted with meteoric fluid as well

as with the host rock, in this case, Miocene dacite. The model meteoric fluid had the same

composition as in segment 5, and the mineralogical composition of the dacite is shown in Figure

10. The precious metal content of the host rock in segment 6 was assumed to be the same as in

segment 5. Temperature during the reaction path decreased from 58.0 to 25.0⁰ C, which is the

temperature of fluid discharging at the surface.

Compared to the other segments, the hydrothermal fluid in segment 6 undergoes the

largest pH change (from 6.5 to 7.6) and the largest log fO change (from −59 to −0.9; Figure

11a,b). The TDS content continues to drop from 1426 to 941 ppm (Figure 11c). Some of the pH

increase may be a result of cooling. However, some of it is probably also a result of the

dissolution of feldspar and pyroxene, which consumes H+, and the disproportionate

reprecipitation of their silica as quartz, which has no direct effect on H+ concentration and thus

results in a net depletion of H+ in solution. In contrast to segment 5, the redox state of the hydrothermal fluid in segment 6 is much more affected by the strongly oxidizing character of the meteoric fluid and becomes quite oxidizing, despite the abundance of hematite precipitated, which would remove oxygen from solution. The TDS content decline is caused primarily by a

strong decline in HCO concentration, which corresponds to a significant amount of calcite and

dolomite precipitation (Figure 12a). Most other aqueous components also decreased in

concentration. Al concentration decreased sharply in response to the precipitation of diaspore,

mesolite, and muscovite (Figure 12b,c). Ca and Mg were diminished by the precipitation of

calcite, dolomite, and mesolite (Figure 12a,b & 13a). K was diminished by muscovite

precipitation (Figures 12c, 13a). Fe concentration decreased sharply due to hematite precipitation

(Figures 12c, 13b). Na and F decreased slightly, probably due to dilution (Figure 13a). Silica

decreased primarily due to the precipitation of quartz, and to a lesser extent mesolite and

44 muscovite (Figures 12, 13b). Cl concentration remained about the same. S concentration increased slightly, due to its introduction by the meteoric fluid and the absence of a sulfur sink that had existed in the previous segments with the precipitation of pyrite (Figure 13b).

Segment 6 encompasses all of alteration zone I and the uppermost part of zone II (Figure

5a). Zone I is characterized by zeolite, montmorillonite, and kaolinite, and zone II by smectite, zeolite, and enrichment in Au. The modeling predicts significant zeolite (mesolite), kaolinite, and hematite precipitation without pyrite, in agreement with field observations. The modeling predicts abundant quartz precipitation, though in the field, quartz corresponds only to the deepest portion of segment 6 and gives way to chalcedony and cristobalite at shallower depths. In the modeling, chalcedony and cristobalite are predicted to be slightly undersaturated with SI values of −0.27 and −0.55, respectively. A significant amount of calcite and dolomite is predicted to precipitate throughout the reaction path, though in the field, calcite is only reported from the bottom of segment 6 and dolomite is not reported at all. This precipitation is probably a function of the high concentrations of Ca and Mg in the fluid at this stage, which are about 21 and 1 ppm, respectively, but are an order of magnitude or more lower in discharged fluids in the field. This suggests that Ca and Mg are removed more efficiently from the hydrothermal fluid or less Ca and

Mg are introduced into the fluid from the host rocks than was modeled.

In order to get hematite to precipitate, nontronite (montmorillonite) was suppressed.

However, when it is included in the simulation and instead diaspore is suppressed, then both nontronite and kaolinite are predicted to precipitate. This shows that kinetics probably played an important role in the observed alteration assemblage, in that although it was not possible for all of the observed alteration minerals to precipitate at the same time, temporary kinetic inhibition of some minerals may have allowed others to precipitate, which over time would have created the entire observed mineral assemblage.

Aqueous concentrations of Au and Ag increase sharply in segment 6 from 4.3 10−7 and

4.2 10−3 ppb at the start of the segment to 0.02 and 0.042 ppb at discharge, respectively (Figure

13c). The oxidizing and more basic character of the hydrothermal fluid prevents Au from being transported as a bisulfide complex, despite an overall increase in the sulfur content of the fluid from 17 to 43 ppm, but allows Au to be transported as the hydroxide complex, Au(OH). Silver is no longer transported primarily via bisulfide complexes but via chloride complexes. Thus, the hydrothermal fluid has the potential to become replenished in Au and Ag at shallow depths, which could ultimately lead to Au and Ag mineralization. Significant but subeconomic Au and

Ag mineralization has been reported at depths of less than about 100 m at White Canyon by

Struhsacker (1986), but was not predicted in the modeling for segment 6.

The modeling predicts a net mineral volume increase of 0.4 cm3 over segment 6. This is the second largest mineral volume increase of the six segments of the flow path, and results in a porosity drop of about 9 to 11%, assuming an initial porosity range of 10 to 25%. For an initial porosity of 25%, this amount of mineral precipitation would lower permeability by nearly an order of magnitude (Figure 14c). For an initial porosity of 11% or less, this amount of mineral precipitation would totally occlude porosity, leading to zero permeability (Figure 14b). Thus, the amount of mineral precipitation predicted during the segment 6 reaction path would lead to a significant decrease in the rate of flow of the hydrothermal fluid over time.

Person et al. profile (P) model

The purpose of the second model was to determine if hotter hydrothermal fluid ascending during the time of peak heat transport, as modeled by Person et al. (2008), before the current state of thermal collapse could produce a better match of the alteration mineral assemblage seen in the field. The model calculations were carried out with the same initial fluid composition as used in the CR model shown in Table 3. The calculations in the P model were carried out batchwise for the same six lithologic segments used in the CR model. The results of the calculations are shown in Figs. 11-17. React outputs for this model type are listed in Appendix III.

Figure 15: Aqueous concentration trends of (a) Mg, K, Ca, Na, and HCO , (b) Fe, SiO2, total S, and Cl, and (c) precious metals for ascending hydrothermal fluid for the thermal profile of Person et al. (2008; P model).

Figure 16: (a) Quartz and carbonate mineral, (b) clay and zeolite mineral, and (c) miscellaneous mineral precipitation trends as a function of depth for the P model.

Figure 17: a) Mass of precious metal precipitation, (b) host rock porosity change, and (c) relative hydraulic conductivity (K) change as a function of depth depth. (As for Figure 14, no data are shown for segments 5 and 6 for n=0.1, as porosity was completely occluded there and hydraulic conductivity would go to zero.)

Overall, the predicted compositions of the hydrothermal fluid for the Cole & Ravinsky

(1984) and Person et al. (2008) temperature profiles were quite similar at greater depths where the

temperature profiles were most similar, but diverged at shallower depths where the temperature

profiles also diverged. The pH of the model hydrothermal fluids remained within about 0.3 units

of one another for the two temperature profiles until segment 6. There, the pH of the CR model

fluid increased rapidly to a final value of about 7.6 whereas the pH of the P model fluid increased

more slowly to a final value of about 6.7. Log fO of the two model hydrothermal fluids was also

very similar along most of the ascent until segment 6. There, the log of the CR model fluid increased sharply to atmospheric values (−0.9), whereas that of the P model fluid continued to decrease slightly to about −55 due to the higher temperatures at this point which would promote pyrite precipitation. The TDS content versus depth profiles for the CR and P models were nearly superimposed upon one another. Both model fluids had nearly constant TDS content with depth until segment 4, after which TDS content decreased sharply.

Elemental concentrations of the CR and P model fluids can be compared in Figures 13

and 15. The concentrations of Mg, Ca, K, Na, and HCO as a function of depth are very similar for the two models. Larger differences between the two models exist for S and Fe at shallow depths. The S concentration is much lower but the Fe concentration is much higher in the P model than in the CR model. The lower S concentration in the P model at shallow depth is caused by continued pyrite precipitation, which is absent in segment 6 in the CR model (cf. Figs.

12 and 16). The higher Fe concentration in the P model is allowed by the cessation of hematite precipitation, large masses of which continue to be precipitated in segment 6 in the CR model.

Silica is also maintained at somewhat higher concentrations in the P model than in the CR model because the lower thermal gradient in the P model causes less precipitation of quartz.

Aqueous Au and Ag concentrations differ significantly from one another in the two models at shallow depths. The CR model shows a sharp decline in both Au and Ag concentration

50 in segment 5. However, the concentrations of both metals increase sharply in segment 6 in the strongly oxidizing conditions encountered there. The P model predicts a continuous gradual decline in Au and Ag concentrations throughout segments 5 and 6. Final Ag concentration for the two models at discharge is about the same, but Au concentration at discharge is lower in the P model than in the CR model by more than three orders of magnitude. These concentrations of Au and Ag precipitated mirror the aqueous concentrations, though the absolute differences between the two models are not large. The mass of Au and Ag precipitated decreases with decreasing depth in the P model from about 11 ppb to 4 ppb, and 735 to 13 ppb, respectively. The mass of

Au precipitated in the CR model is within 1-2 ppb of the mass precipitated in the P model.

However, the mass of Ag precipitated at the top of the CR model is about 536 ppb higher than in the P model.

The P model predicted relatively small overall changes compared to the CR model in the precipitated amounts of dolomite, witherite, and diaspore, significant overall increases in pyrite, calcite, mesolite, nontronite, minnesotaite, and stilbite, and significant overall decreases in quartz, muscovite, hematite, kaolinite, and siderite. On the whole, the P model did not produce a significantly improved match to the observed alteration assemblage in the Ginn 1-13 well.

Calculated porosity changes and hydraulic conductivities for P model premixing segments are relatively similar with the exception that segment 4 appears to increase slightly in porosity (by 0.1%) rather than decrease like every other segment in the two models. The first mixing segment of the P model predicts a lower porosity change and hydraulic conductivity of

−9.1% and 34,280 m/yr, respectively assuming a 25% initial porosity. However, the last segment predicts a greater porosity change of −12.4% and hydraulic conductivity increasing to 40,750 m/yr.

High S model

A third model scenario considered the effects of increased sulfur content on Au and Ag transport and precipitation in the Beowawe hydrothermal system. Sulfur concentration could potentially be increased by emissions from a cooling magma body, and may explain why the nearby Mule Canyon, which has a documented magmatic genetic association, contained economic concentrations of gold and silver, whereas Beowawe, which is amagmatic, does not appear to contain economic concentrations of gold and silver. In this third model scenario, total sulfur concentration (specified as sulfate) at the beginning of the reaction path was increased from

11 ppm to 1000 ppm and initial Fe concentration was assumed to be governed by pyrite saturation. SpecE8 output results are listed in Appendix I. The temperature-depth profile was the same as in the CR model. In addition, this model assumed that diabase dikes do not cut through segments 2 and 3, and that the shallow oxidizing aquifer contained negligible Fe. The results of this simulation are shown in Figure 18 with React outputs for each segment shown in Appendix

IV.

The two order of magnitude increase in initial sulfur concentration of the hydrothermal fluid results in about a three order of magnitude increase in the fluid’s Au concentration and 2.5 order of magnitude increase in the fluid’s Ag concentration compared to the CR and P models

(Figure 18). Aqueous Au and Ag concentrations decrease by about an order of magnitude through segment 2, corresponding to substantial precipitation of gold and silver on the order of about 101 and 102 ppm, respectively. These precipitated concentrations are about three orders of

magnitude greater than predicted by the CR and P models at this stage. As in the CR and P

models, aqueous Au and Ag concentrations in the high sulfur model remain relatively constant

through segments 3 and 4. Gold and silver precipitation decrease sharply during segment 3 to

about 500 ppb and 2 ppm, respectively. Gold precipitation ceases in segment 4, while silver

precipitation continues at about the same concentration. Aqueous Au and Ag concentrations

Figure 18: (a) Aqueous concentration trends of Fe, S, and Cl (b) aqueous precious metal trends, and (c) precious metal precipitation as a function of depth for the high sulfur model.

53 decrease sharply in segment 5 as in the CR model. In contrast to the CR model, aqueous Au and

Ag concentrations continue to decrease in segment 6 instead of increasing again. Gold and silver both precipitate in concentrations of about 1 ppm at the end of segment 5, decreasing to about 5 and 20 ppb by the end of segment 6, which is about the same as predicted by the CR and P models for gold, but significantly lower than the hundreds of ppb predicted by the CR and P models for silver. Thus, the high sulfur model predicts significantly higher gold-silver mineralization along most of the flow path compared to the CR and P models, except for gold at shallow depths, which is about the same as in the other models.

Figure 18 also shows that aqueous Au and Ag concentrations mirror aqueous sulfur concentration, indicating the strong control that sulfur concentration has on Au and Ag solubility in this fluid. The large decrease in sulfur concentration beginning in segment 5 corresponds to a large increase in Fe concentration caused by reaction with mafic volcanic rocks. This increase in

Fe concentration causes pyrite precipitation, which greatly diminishes the sulfur concentration and therefore the Au and Ag concentration in the fluid.

DISCUSSION

The results presented in the preceding section provide useful insights into the questions of whether hydrothermal fluid flow at Beowawe was episodic and how this fluid would have interacted with the rocks along its flow path, including to what extent the fluid would have precipitated gold and silver. The sinter stratigraphy compositional profiles generated by ICP-

AES provide permissive evidence that the Beowawe hydrothermal flow system is episodic in nature. The non-monotonic co-variations in concentration for detectable elements support a scenario in which multiple pulses of fluid with differing compositions flowed through the system.

This support would be strengthened if the pattern persisted at higher spatial resolution.

Additional, if equivocal, support for episodic fluid flow comes from the microthermometry data.

The majority of last-ice melting temperatures of fluid inclusions hosted both by White Canyon quartz veins and siliceous sinter are between zero and −0.1° C, which equates to about 0.18 eq. wt.% (1800 ppm) NaCl, similar to the salinity of fluids discharging at the surface today, and indicating that hydrothermal fluids have for the most part remained dilute over the lifespan of the system. However, some last-ice melting temperatures are significantly lower than zero, with a minimum of −0.8° C, which equals about 1.4 eq. wt.% NaCl or 14,000 ppm, which is about a factor of five higher than the maximum predicted in the models. Thus, hydrothermal fluid circulating through the Beowawe-White Canyon area has not always been as dilute as it is now, though it is not possible to say from the microthermometry data with what frequency salinity increases have occurred. It is also possible that the elemental composition of the hydrothermal fluid may have varied without concomitant variation in bulk salinity. These elemental composition variations in the fluid would be reflected in the sinter compositions, but would not be discernible in the microthermometry data. It is possible that higher salinity would correlate to higher fluid temperature, as the solubility of most minerals increases with increasing temperature.

This hypothesis however could not be tested, as the inclusions appear to have trapped a

55 heterogeneous (liquid-vapor) fluid consistent with the hot spring and geyser environment at

Beowawe.

The reaction path modeling results of this study are broadly congruent with the hypothesis that a fluid sourced from a deep-seated carbonate aquifer below the Roberts Mountain thrust fault was capable of producing the mineral alteration assemblages, including gold-silver mineralization, observed in the Ginn 1-13 well and other drill holes in the Beowawe area. This fluid was probably saturated with respect to calcite and/or dolomite, perhaps pyrite, near neutral

in pH, and was assumed to have a log fO that was slightly more reducing than prescribed by

magnetite-hematite equilibrium in order to enhance gold solubility (Figure 19). This fluid

probably also mixed with a cooler, more oxidizing fluid as it approached the ground surface.

Moving upward from alteration zone IV to I (Figure 5a), modeled zone IV minerals that

are congruent with Figure 5b are quartz, calcite, pyrite, and possibly chlorite (daphnite), which

was calculated to be only slightly undersaturated with a saturation index of −0.07.

Incongruencies between the model results and field reports include the predicted absence of epidote, but the precipitation of minor clay and zeolite (mesolite) minerals, which in the field are observed to occur at much shallower depths. Pyrite, quartz, and arguably chlorite (daphnite, with saturation index of −0.06) are predicted to continue to precipitate through the model segments coinciding with alteration zone III, in accordance with field observations. The clay minerals, nontronite, saponite, and minnesotaite are also predicted to continue to precipitate. The first clay alteration is also reported in the field from zone III, though this consists principally of illite and montmorillonite. The reaction path models for the segments corresponding to alteration zone II correctly predict the continued precipitation of quartz, calcite, and pyrite, and the beginning of kaolinite and hematite precipitation. None of the zeolites, chabazite, thomsonite, wairakite, heulandites, laumontite, reported from the field was predicted by the models to precipitate.

However, two other zeolite minerals, stilbite and mesolite, were predicted to be only slightly

57 undersaturated, with saturation indices of about −0.3. The models also predict the precipitation of minor muscovite, dolomite, and siderite, which are not reported from the field. Model segments 5 and 6 overlap alteration zone I and are in agreement with respect to the precipitation of kaolinite and hematite without pyrite. Mesolite is not reported from the field, but its predicted precipitation in the models may be regarded as representing the zeolite mineral class, which is abundant at shallow depths at Beowawe. In the models, quartz is predicted to precipitate instead of chalcedony and cristobalite, which are observed in the field, though the saturation indices of chalcedony and cristobalite are within about −0.5. The models also predict the precipitation of calcite and dolomite, though neither of these minerals is reported in the field in alteration zone I.

Thus, the reaction path modeling results are broadly congruent with observed alteration assemblages in the field, though uncertainty in the initial composition of the hydrothermal fluid and mineralogy of the rocks along the ascent path make a precise match between model and field observations difficult to achieve. The models also affirm the importance of quartz (and by proxy, possibly other silica phases also) as an alteration phase, which is consistent with the intense silicification at Beowawe.

The reaction path models can also be used to predict porosity and permeability change along the flow path. Table 5 shows the predicted porosity change resulting from one reaction path for each model segment where 10 g of rock reacted with 1 kg of water, as well as how many similar reaction path events would be required to occlude porosity completely in each segment and the associated change in hydraulic conductivity. This number of reaction path events can be regarded as a proxy for the number of flow events, and in Table 5, they are assumed to correspond in a 1:1 fashion. This approach is a bit simplistic, because the rock would become less reactive with respect to the fluid over time as the rock became altered, and also as porosity decreased, rock permeability and thus fluid flow and solute flux would all decrease, changing the number of required events. Nonetheless, from Table 5 it is clear that porosity would be occluded

Table 5: Table showing maximum concentration of gold and silver achievable before 100% porosity occlusion due to mineral precipitation.

Segment Vs (cm3) Vv (cm3) dn No. Fluid Pulses Total Au (ppm) Total Ag (ppm) 2 (CR) 3.642 0.106 0.028 44 16.1 0.47 3 (CR) 3.15 0.010 0.003 359 60.8 1.2 4 (CR) 3.707 0.008 0.002 553 0 0 5 (CR) 3.809 0.535 0.123 10 2.8 0.06 6 (CR) 3.278 0.401 0.109 12 0 0 2 (P) 3.642 0.108 0.028 42 15.5 0.47 3 (P) 3.15 0.014 0.004 28 6.1 0.13 4 (P) 3.707 -0.003 -0.001 ------0 0 5 (P) 3.809 0.383 0.091 12 1.1 0.05 6 (P) 3.82 0.542 0.124 9 0.1 0.04

*Vs = volume of solids in reactant rock, Vv = volume of void space in reactant rock, dn = predicted change in porosity (fraction) as a result of reaction of the hydrothermal fluid with its host rock.

**No. Fluid Pulses represents the number of reaction paths needed to occlude host rock porosity fully, assuming an initial porosity of 25%.

59 sooner in the upper part of the flow path (segments 5 and 6) than in the lower part of the flow path. This is because the temperature gradient is higher at shallower depths, leading to greater mineral precipitation, particularly of quartz, which is the most abundant mineral precipitated throughout the flow path.

If permeability along the current flow path in the Malpais fault decreased below the permeability of adjacent rocks, then flow would shift toward these adjacent higher permeability zones. However, if the permeability of the surrounding rock was also very low, then the hydrothermal fluid would have no avenue of escape to the surface and fluid pressure would build until it ruptured rock to form a new flow path or reopen the preexisting path. Based on the absence of hydrothermal brecciation along the Malpais fault, Struhsacker (1986) suggested that the locus of hydrothermal fluid flow has shifted progressively along the fault as porosity and permeability were diminished by mineral precipitation, notably, westward from White Canyon to

Beowawe. If this pattern continues, then the calculated number of flow episodes for each model segment shown in Table 5 represents a Au-Ag enrichment factor that could be reached before porosity was completed occluded and flow through the path was shut down. This means that no more than a few hundred ppb Au and several ppm Ag would be expected to accumulate in the lower part of the flow path, and several ppb Au and several ppm Ag in the upper part of the flow path. This conclusion is consistent with Struhsacker’s (1986) explanation for why the Beowawe-

White Canyon area is only weakly mineralized with respect to precious metals, which is that without repetitive cycles of fluid overpressuring and hydrofracturing, fluid flux through any part of the flow path never lasted long enough to allow high concentrations of precious metals to accumulate. A further implication of the results in Table 5 is that if high grade precious metal mineralization exists in the Beowawe-White Canyon area, it is likely to be too deep to be extracted economically, unless an older deposit has been brought to the surface through uplift and erosion.

The concentrations of precipitated gold and silver could be increased above those shown in Table 5 if the concentration of sulfur in the hydrothermal fluid were higher. In the CR and P models, the initial sulfur concentration was governed by saturation with respect to pyrite where iron concentration was governed by saturation with respect to magnetite as part of the magnetite- hematite buffer to specify the redox state of the fluid. These assumptions effectively place the fluid at the triple point of magnetite-hematite-pyrite equilibrium shown in Figure 19b which corresponds to a total sulfur concentration of about 3.7 ppm, which is equivalent to about 11 ppm sulfate, and leads to low gold solubility. However, if the hydrothermal fluid’s iron content was too low to allow either hematite or magnetite to be stable, then the fluid could have a higher H2S

activity that would place it further to the right in the pyrite field and allow much higher dissolved

gold concentrations, which ultimately could lead to higher concentrations of gold precipitated.

Most likely the concentration of sulfur in the hydrothermal fluid was not as high as the

1000 ppm of sulfate assumed in the “high-sulfur” reaction path model. Cole & Ravinsky report a sulfate concentration of 47 ppm from the Ginn 1-13 well, and sulfate concentrations from 27.7 to

76 ppm from two other deep wells in the Beowawe area. These measured values are higher than the CR and P model value but of the same order of magnitude, suggesting that the hydrothermal fluid did not have radically higher gold transport and mineralization capacity than indicated by the CR and P models. In all three models, aqueous gold and silver concentration decrease steadily along the flow path, despite the fact that additional gold and silver at average crustal concentrations are introduced into the fluid as it reacts with the host rock. Thus, if the hydrothermal fluid did not encounter any anomalously gold-silver-rich sources along its ascent and concomitantly undergo an increase in sulfide and chloride concentration, then the predicted changes in the fluid’s temperature, pH, and redox state would have prevented the fluid from ever becoming more enriched in gold and silver than it was when it left the carbonate reservoir.

CONCLUSIONS

The non-monotonic co-variation in concentration of trace elements in sinter as a function of stratigraphic position provides permissive evidence for episodic hydrothermal fluid flow at Beowawe. The presence of a population of fluid inclusions with salinities higher than those of most fluid inclusions and higher than present day discharge fluid supports the possibility that fluid composition has varied over time and that flow may have been episodic. However, even the most saline fluid inclusions represent a relatively dilute fluid at a maximum concentration of about 14,000 equivalent ppm NaCl. Most of the fluid inclusions have salinities corresponding to less than about 1800 ppm NaCl, similar to the TDS content of present-day discharging fluids. Hydrothermal fluids discharging at Beowawe must have been consistently poor in gold and silver over time, as neither metal was detected in any of the sinter samples.

Most of the fluid inclusions observed in the veins from White Canyon and sinter from Beowawe consisted of a single liquid phase, indicating relatively cool discharge temperatures less than about 50° C. A minority of fluid inclusions have two phases, which exist in highly variable proportions leading to highly variable homogenization temperatures, probably resulting from heterogeneous phase entrapment at higher temperatures associated with geyser or fumarole activity.

Reaction-path models simulating hydrothermal fluid rising along the Malpais Fault, cooling as it reacts with rocks along its path, and mixing at shallow depths with a dilute, oxidizing fluid at nearly neutral pH are in broad agreement with mineral alteration patterns reported by Cole & Ravinsky (1984) for the Ginn 1-13 well. Discrepancies between model results and field observations probably reflect uncertainties in the mineralogy of the host rock and starting composition of the hydrothermal fluid. The net volume of mineral precipitation predicted by the models is sufficient to alter host rock porosity significantly, particularly at shallow depths where the temperature gradient is greatest. If the modeled reaction paths were repeated through

62 separate flow episodes, then porosity along the flow path could eventually be occluded, perhaps in as few as two reaction paths or flow episodes in the upper model segments. In contrast, for the

CR model, between 10 and over 100 flow episodes could perhaps have traversed the lower model segments before complete porosity occlusion. This means that a greater amount of precious metal enrichment could be achieved in the deeper parts of the flow paths than in the shallower parts, with concentrations reached in segment 2 of about 250 ppb Au and 11 ppm Ag. If more permeable alternate flow paths were available to the hydrothermal fluid as porosity and permeability diminished along the current flow path, then flow would shift to these new alternate pathways and gold and silver would never become concentrated to ore grades, unless the sulfide and chloride concentrations of the hydrothermal fluid were much higher than indicated by the presently available evidence. A previous shift in flow due to porosity-permeability decrease appears to have occurred from White Canyon to Beowawe. This shift in flow was probably allowed by the high permeability of the Malpais fault, which prevents repeated cycles of overpressuring, hydrothermal fracturing, and flow that seem to be a characteristic of higher grade epithermal gold-silver deposits.

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APPENDIX I

SpecE8 output results for the initial carbonate reservoir fluid (segment 1)

Figure 1A: CR and P models

Temperature = 210.0 C Pressure = 19.013 bars pH = 6.500 log fO2 = -40.000 Eh = -0.3678 volts pe = -3.8373 Ionic strength = 0.009656 Activity of water = 0.999942 Solvent mass = 1.000000 kg Solution mass = 1.002906 kg Solution density = 0.833 g/cm3 Chlorinity = 0.001664 molal Dissolved solids = 2897 mg/kg sol'n Rock mass = 0.009000 kg Carbonate alkalinity= 373.77 mg/kg as CaCO3

Minerals in system moles log moles grams volume (cm3) ------Ag 0.009271 -2.033 1.000 0.09523 Au 0.005077 -2.294 1.000 0.05186 Calcite 0.009991 -2.000 1.000 0.3690 Dolomite 0.005423 -2.266 1.000 0.3490 Fluorapatite 0.001983 -2.703 1.000 Magnetite 0.004319 -2.365 1.000 0.1923 Pyrite 0.008335 -2.079 1.000 0.1995 Saponite-Ca 0.002594 -2.586 1.000 0.3519 Witherite 0.005067 -2.295 1.000 0.2321 ______(total) 9.000 1.841*

Aqueous species molality mg/kg sol'n act. coef. log act. ------CO2(aq) 0.04090 1795. 1.0000 -1.3882 Na+ 0.008809 201.9 0.8503 -2.1255 HCO3- 0.007484 455.3 0.8503 -2.1963 SiO2(aq) 0.005544 332.1 1.0000 -2.2562 Cl- 0.001648 58.27 0.8458 -2.8557 K+ 0.0007666 29.89 0.8458 -3.1882 F- 0.0004020 7.615 0.8481 -3.4674 H2S(aq) 6.848e-005 2.327 1.0000 -4.1644 HS- 4.641e-005 1.531 0.8481 -4.4049 HSiO3- 2.882e-005 2.215 0.8503 -4.6108 CaHCO3+ 2.338e-005 2.357 0.8503 -4.7015 OH- 2.120e-005 0.3594 0.8481 -4.7453 Ca++ 1.732e-005 0.6922 0.5417 -5.0276 NaCl(aq) 1.515e-005 0.8830 1.0000 -4.8195 HF(aq) 1.002e-005 0.1999 1.0000 -4.9992 H2(aq) 4.772e-006 0.009592 1.0000 -5.3213 NaF(aq) 2.941e-006 0.1231 1.0000 -5.5315 NaHSiO3(aq) 2.895e-006 0.2889 1.0000 -5.5384 CaCO3(aq) 2.211e-006 0.2206 1.0000 -5.6555 Formate 1.823e-006 0.08185 0.8481 -5.8107 CO3-- 1.113e-006 0.06657 0.5265 -6.2323 SO4-- 8.547e-007 0.08187 0.5212 -6.3512 CaF+ 8.234e-007 0.04850 0.8503 -6.1548 KCl(aq) 6.537e-007 0.04860 1.0000 -6.1846 Methane(aq) 6.245e-007 0.009989 1.0000 -6.2045 MgHCO3+ 5.835e-007 0.04964 0.8503 -6.3044 Mg++ 4.055e-007 0.009827 0.5606 -6.6433 H+ 3.637e-007 0.0003656 0.8694 -6.5000 NaOH(aq) 1.937e-007 0.007723 1.0000 -6.7130 S-- 1.906e-007 0.006095 0.5317 -6.9942 Ba++ 1.315e-007 0.01801 0.5317 -7.1554

CaCl+ 6.786e-008 0.005110 0.8503 -7.2388 MgF+ 5.833e-008 0.002518 0.8503 -7.3046 Ag(HS)(aq) 4.467e-008 0.006278 1.0000 -7.3500 KSO4- 3.474e-008 0.004681 0.8503 -7.5296 Na(For)(aq) 3.272e-008 0.002219 1.0000 -7.4852 Formic_acid(aq) 1.949e-008 0.0008945 1.0000 -7.7101 CaSO4(aq) 1.500e-008 0.002036 1.0000 -7.8240 (only species > 1e-8 molal listed)

Mineral saturation states log Q/K log Q/K ------Talc 0.8451s/sat Saponite-H -0.9123 Acanthite 0.4203s/sat Siderite -0.9341 Minnesotaite 0.2050s/sat Magnesite -0.9401 Quartz 0.1412s/sat Nontronite-Ca -0.9700 Dolomite-ord 0.0018s/sat Troilite -1.0032 Fluorapatite 0.0000 sat Nontronite-Mg -1.0176 Witherite 0.0000 sat Fluorite -1.0460 Dolomite 0.0000 sat Diopside -1.0514 Saponite-Ca 0.0000 sat Pyrrhotite -1.0687 Ag 0.0000 sat Cronstedtite-7A -1.1373 Pyrite 0.0000 sat Enstatite -1.1761 Au 0.0000 sat Fayalite -1.3351 Calcite 0.0000 sat Greenalite -1.3361 Magnetite 0.0000 sat Chrysotile -1.3757 Chalcedony -0.0262 Nontronite-Na -1.4286 Saponite-Mg -0.0599 Nontronite-K -1.7064 Tremolite -0.0909 FeO -1.7905 Hematite -0.1031 Sellaite -1.8050 Aragonite -0.1535 Nontronite-H -1.8532 Cristobalite(alp -0.1555 Hedenbergite -1.9452 Cristobalite(bet -0.3554 C -2.0860 Coesite -0.3824 Wustite -2.1015 SiO2(am) -0.4573 Wollastonite -2.2673 Saponite-Na -0.4586 Pseudowollastoni -2.3116 Ferrosilite -0.6015 Brucite -2.7289 Dolomite-dis -0.7216 Andradite -2.7589 Saponite-K -0.7373 (only minerals with log Q/K > -3 listed)

Gases fugacity log fug. ------H2O(g) 14.82 1.171 CO2(g) 4.117 0.615 H2(g) 0.002820 -2.550 H2S(g) 0.002629 -2.580 CH4(g) 0.0003368 -3.473 (only gases with fugacities > 1.e-5 listed)

In fluid Sorbed Kd Original basis total moles moles mg/kg moles mg/kg L/kg ------Ag+ 0.00927 4.61e-008 0.00496 Al+++ 0.000856 3.30e-010 8.87e-006 Au+ 0.00508 7.53e-010 0.000148 Ba++ 0.00507 1.38e-007 0.0190 Ca++ 0.0258 4.38e-005 1.75 Cl- 0.00166 0.00166 58.8 F- 0.00240 0.000416 7.88 Fe++ 0.0213 7.21e-009 0.000401 H+ -0.0334 0.0410 41.2 H2O 55.5 55.5 9.96e+005

HCO3- 0.0743 0.0484 2.95e+003 HPO4-- 0.00595 6.28e-009 0.000601 K+ 0.000767 0.000767 29.9 Mg++ 0.0132 1.06e-006 0.0257 Na+ 0.00883 0.00883 202. O2(aq) -0.0308 -0.000235 -7.49 SO4-- 0.0168 0.000116 11.1 SiO2(aq) 0.0151 0.00558 334.

Elemental composition In fluid Sorbed total moles moles mg/kg moles mg/kg ------Aluminum 0.0008560 3.295e-010 8.865e-006 Barium 0.005068 1.385e-007 0.01896 Calcium 0.02580 4.383e-005 1.751 Carbon 0.07432 0.04842 579.9 Chlorine 0.001664 0.001664 58.83 Fluorine 0.002399 0.0004158 7.877 Gold 0.005077 7.530e-010 0.0001479 Hydrogen 111.0 111.0 1.116e+005 Iron 0.02129 7.208e-009 0.0004014 Magnesium 0.01321 1.061e-006 0.02572 Oxygen 55.77 55.62 8.874e+005 Phosphorus 0.005949 6.276e-009 0.0001938 Potassium 0.0007673 0.0007673 29.91 Silicon 0.01510 0.005575 156.1 Silver 0.009271 4.609e-008 0.004957 Sodium 0.008830 0.008830 202.4 Sulfur 0.01679 0.0001160 3.710

Figure 2A: High S model

Temperature = 210.0 C Pressure = 19.013 bars pH = 6.500 log fO2 = -40.000 Eh = -0.3678 volts pe = -3.8373 Ionic strength = 0.009819 Activity of water = 0.999942 Solvent mass = 1.000000 kg Solution mass = 1.001974 kg Solution density = 0.833 g/cm3 Chlorinity = 0.001664 molal Dissolved solids = 1970 mg/kg sol'n Rock mass = 0.008000 kg Carbonate alkalinity= 161.19 mg/kg as CaCO3

Minerals in system moles log moles grams volume (cm3) ------Ag 0.009271 -2.033 1.000 0.09523 Au 0.005077 -2.294 1.000 0.05186 Calcite 0.009991 -2.000 1.000 0.3690 Dolomite 0.005423 -2.266 1.000 0.3490 Fluorapatite 0.001983 -2.703 1.000 Pyrite 0.008335 -2.079 1.000 0.1995 Saponite-Ca 0.002594 -2.586 1.000 0.3519 Witherite 0.005067 -2.295 1.000 0.2321 ______(total) 8.000 1.649*

Aqueous species molality mg/kg sol'n act. coef. log act. ------CO2(aq) 0.01759 772.6 1.0000 -1.7547 Na+ 0.008809 202.1 0.8493 -2.1260 H2S(aq) 0.006125 208.3 1.0000 -2.2129 SiO2(aq) 0.005544 332.4 1.0000 -2.2562 HS- 0.004156 137.2 0.8471 -2.4534 HCO3- 0.003222 196.2 0.8493 -2.5628 Cl- 0.001648 58.32 0.8448 -2.8562 K+ 0.0007636 29.79 0.8448 -3.1904 F- 0.0004009 7.601 0.8471 -3.4691 SO4-- 7.680e-005 7.364 0.5187 -4.3997 Ca++ 4.045e-005 1.618 0.5395 -4.6611 HSiO3- 2.885e-005 2.220 0.8493 -4.6108 CaHCO3+ 2.341e-005 2.362 0.8493 -4.7015 OH- 2.122e-005 0.3602 0.8471 -4.7453 S-- 1.713e-005 0.5481 0.5293 -5.0426 NaCl(aq) 1.512e-005 0.8817 1.0000 -4.8206 Ag(HS)2- 1.128e-005 1.959 0.8557 -5.0154 HF(aq) 9.980e-006 0.1993 1.0000 -5.0009 H2(aq) 4.772e-006 0.009601 1.0000 -5.3213 Ag(HS)(aq) 3.995e-006 0.5620 1.0000 -5.3984 CaSO4(aq) 3.119e-006 0.4237 1.0000 -5.5060 KSO4- 3.094e-006 0.4174 0.8493 -5.5804 NaF(aq) 2.926e-006 0.1226 1.0000 -5.5337 NaHSiO3(aq) 2.891e-006 0.2888 1.0000 -5.5389 CaCO3(aq) 2.211e-006 0.2208 1.0000 -5.6555 CaF+ 1.909e-006 0.1126 0.8493 -5.7900 Mg++ 9.464e-007 0.02296 0.5586 -6.2768 Formate 7.851e-007 0.03527 0.8471 -6.1772 Au(HS)2- 7.248e-007 0.1903 0.8557 -6.2075 KCl(aq) 6.495e-007 0.04832 1.0000 -6.1874 HSO4- 6.226e-007 0.06032 0.8493 -6.2767 MgHCO3+ 5.842e-007 0.04974 0.8493 -6.3044 CO3-- 4.806e-007 0.02879 0.5241 -6.5988 H+ 3.641e-007 0.0003662 0.8686 -6.5000 Ba++ 3.072e-007 0.04210 0.5293 -6.7889 Methane(aq) 2.685e-007 0.004300 1.0000 -6.5710 NaOH(aq) 1.934e-007 0.007721 1.0000 -6.7135 CaCl+ 1.578e-007 0.01189 0.8493 -6.8729 MgF+ 1.353e-007 0.005845 0.8493 -6.9398 Au(HS)(aq) 5.896e-008 0.01354 1.0000 -7.2294 MgCl+ 1.578e-008 0.0009411 0.8493 -7.8728 S2-- 1.485e-008 0.0009505 0.5187 -8.1133 Na(For)(aq) 1.405e-008 0.0009539 1.0000 -7.8522 (only species > 1e-8 molal listed)

Mineral saturation states log Q/K log Q/K ------Antigorite 4.9480s/sat SiO2(am) -0.4573 Tremolite 2.4746s/sat Saponite-Na -0.5192 Acanthite 2.3719s/sat Fluorite -0.6829 Talc 1.9446s/sat Dolomite-dis -0.7216 Quartz 0.1412s/sat Saponite-K -0.7986 Dolomite-ord 0.0018s/sat Enstatite -0.8097 Fluorapatite 0.0000 sat Barite -0.9044 Calcite 0.0000 sat Magnesite -0.9401 Ag 0.0000 sat Saponite-H -0.9727 Dolomite 0.0000 sat Anthophyllite -1.3887 Saponite-Ca 0.0000 sat Sellaite -1.4420 Au 0.0000 sat Anhydrite -1.5582 Pyrite 0.0000 sat Wollastonite -1.9009

Witherite 0.0000 sat Pseudowollastoni -1.9451 Chalcedony -0.0262 Bassanite -2.2538 Saponite-Mg -0.0599 CaSO4:0.5H2O(bet -2.2715 Aragonite -0.1535 Brucite -2.3624 Cristobalite(alp -0.1555 C -2.4525 Chrysotile -0.2763 Forsterite -2.4689 Diopside -0.3184 S -2.4880 Cristobalite(bet -0.3554 Gypsum -2.7717 Coesite -0.3825 Troilite -2.9547 (only minerals with log Q/K > -3 listed)

Gases fugacity log fug. ------H2O(g) 14.82 1.171 CO2(g) 1.770 0.248 H2S(g) 0.2352 -0.629 H2(g) 0.002820 -2.550 CH4(g) 0.0001448 -3.839 (only gases with fugacities > 1.e-5 listed)

In fluid Sorbed Kd Original basis total moles moles mg/kg moles mg/kg L/kg ------Ag+ 0.00929 1.53e-005 1.64 Al+++ 0.000856 1.01e-013 2.71e-009 Au+ 0.00508 7.84e-007 0.154 Ba++ 0.00507 3.18e-007 0.0436 Ca++ 0.0258 7.13e-005 2.85 Cl- 0.00166 0.00166 58.9 F- 0.00240 0.000416 7.88 Fe++ 0.00833 9.05e-013 5.04e-008 H+ -0.0145 0.0340 34.2 H2O 55.5 55.5 9.98e+005 HCO3- 0.0467 0.0208 1.27e+003 HPO4-- 0.00595 1.54e-009 0.000148 K+ 0.000767 0.000767 29.9 Mg++ 0.0132 1.69e-006 0.0410 Na+ 0.00883 0.00883 203. O2(aq) -0.0534 -0.0207 -660. SO4-- 0.0271 0.0104 998. SiO2(aq) 0.0151 0.00558 334.

Elemental composition In fluid Sorbed total moles moles mg/kg moles mg/kg ------Aluminum 0.0008560 1.008e-013 2.714e-009 Barium 0.005068 3.182e-007 0.04361 Calcium 0.02583 7.126e-005 2.850 Carbon 0.04674 0.02084 249.8 Chlorine 0.001664 0.001664 58.88 Fluorine 0.002399 0.0004158 7.884 Gold 0.005078 7.837e-007 0.1541 Hydrogen 111.0 111.0 1.117e+005 Iron 0.008335 9.047e-013 5.043e-008 Magnesium 0.01321 1.689e-006 0.04097 Oxygen 55.70 55.57 8.873e+005 Phosphorus 0.005949 1.542e-009 4.766e-005 Potassium 0.0007673 0.0007673 29.94 Silicon 0.01510 0.005575 156.3 Silver 0.009286 1.528e-005 1.645 Sodium 0.008830 0.008830 202.6 Sulfur 0.02708 0.01041 333.1

APPENDIX II

Reaction path output results for segments in the CR model

Figure 3A: Segment 2

Step # 100 Xi = 1.0000 Temperature = 192.8 C Pressure = 13.230 bars pH = 6.386 log fO2 = -42.414 Eh = -0.3561 volts pe = -3.8523 Ionic strength = 0.010518 Activity of water = 0.999942 Solvent mass = 0.999916 kg Solution mass = 1.002686 kg Solution density = 0.855 g/cm3 Chlorinity = 0.001659 molal Dissolved solids = 2763 mg/kg sol'n Rock mass = 0.010106 kg Carbonate alkalinity= 418.29 mg/kg as CaCO3

moles moles grams cm3 Reactants remaining reacted reacted reacted ------Ag 7.341e-024 4.079e-009 4.400e-007 4.190e-008 Albite 4.286e-019 0.001144 0.3000 0.1147 Anorthite -7.657e-019 0.001078 0.3000 0.1087 Au -2.019e-028 2.031e-011 4.000e-009 2.074e-010 Calcite 3.253e-019 0.04996 5.000 1.845 Enstatite 8.132e-020 0.001494 0.1500 0.04673 Fayalite -1.739e-019 0.0001227 0.02500 0.005691 Ferrosilite 1.296e-018 0.001137 0.1500 0.03747 Fluorapatite 3.160e-020 3.966e-005 0.02000 Forsterite -1.885e-020 0.0001777 0.02500 0.007781 Magnetite 6.861e-020 0.0001296 0.03000 0.005769 Muscovite -3.833e-019 0.0002511 0.1000 0.03533 Quartz -4.315e-017 0.06324 3.800 1.435

Minerals in system moles log moles grams volume (cm3) ------Acanthite 1.485e-008 -7.828 3.680e-006 5.078e-007 Au 5.601e-010 -9.252 1.103e-007 5.722e-009 Calcite 0.05044 -1.297 5.049 1.863 Diaspore 0.002171 -2.663 0.1302 0.03855 Fluorapatite 3.966e-005 -4.402 0.02000 Mesolite 0.0008215 -3.085 0.3186 0.1406 Minnesotaite 0.0004812 -3.318 0.2280 0.07115 Nontronite-Ca 0.0001510 -3.821 0.06409 0.01980 Pyrite 2.536e-005 -4.596 0.003043 0.0006071 Quartz 0.06774 -1.169 4.070 1.537 Saponite-Mg 0.0005842 -3.233 0.2237 0.07808 ______(total) 10.11 3.749*

Aqueous species molality mg/kg sol'n act. coef. log act. ------CO2(aq) 0.03927 1724. 1.0000 -1.4059 Na+ 0.009360 214.6 0.8530 -2.0978 HCO3- 0.008370 509.3 0.8530 -2.1463 SiO2(aq) 0.003230 193.6 1.0000 -2.4908 Cl- 0.001646 58.18 0.8484 -2.8551 K+ 0.001015 39.58 0.8484 -3.0648 F- 0.0004028 7.632 0.8507 -3.4651 H2S(aq) 3.949e-005 1.342 1.0000 -4.4035 Ca++ 3.458e-005 1.382 0.5485 -4.7219

CaHCO3+ 3.319e-005 3.346 0.8530 -4.5481 HS- 2.524e-005 0.8324 0.8507 -4.6681 HSiO3- 1.400e-005 1.076 0.8530 -4.9230 OH- 1.356e-005 0.2300 0.8507 -4.9380 NaCl(aq) 1.237e-005 0.7209 1.0000 -4.9076 Methane(aq) 1.114e-005 0.1782 1.0000 -4.9531 HF(aq) 8.518e-006 0.1699 1.0000 -5.0696 AlO2- 5.224e-006 0.3072 0.8530 -5.3511 H2(aq) 5.008e-006 0.01007 1.0000 -5.3003 Formate 2.805e-006 0.1259 0.8507 -5.6222 CaCO3(aq) 2.688e-006 0.2683 1.0000 -5.5706 NaF(aq) 2.375e-006 0.09944 1.0000 -5.6244 NaHSiO3(aq) 1.423e-006 0.1420 1.0000 -5.8468 CO3-- 1.233e-006 0.07379 0.5330 -6.1823 CaF+ 1.030e-006 0.06066 0.8530 -6.0563 MgHCO3+ 8.318e-007 0.07077 0.8530 -6.1491 Mg++ 8.043e-007 0.01949 0.5677 -6.3404 KCl(aq) 6.444e-007 0.04791 1.0000 -6.1908 H+ 4.710e-007 0.0004735 0.8722 -6.3863 HAlO2(aq) 2.013e-007 0.01204 1.0000 -6.6963 Ba++ 1.339e-007 0.01834 0.5383 -7.1421 NaAlO2(aq) 1.128e-007 0.009220 1.0000 -6.9477 NaOH(aq) 9.178e-008 0.003661 1.0000 -7.0373 CaCl+ 8.919e-008 0.006718 0.8530 -7.1187 MgF+ 7.510e-008 0.003243 0.8530 -7.1934 Na(For)(aq) 4.662e-008 0.003162 1.0000 -7.3315 S-- 4.068e-008 0.001301 0.5383 -7.6596 Fe++ 3.300e-008 0.001838 0.5485 -7.7422 Formic_acid(aq) 2.924e-008 0.001342 1.0000 -7.5340 SO4-- 2.853e-008 0.002734 0.5276 -7.8223 Ag(HS)(aq) 2.003e-008 0.002815 1.0000 -7.6984 (only species > 1e-8 molal listed)

Mineral saturation states log Q/K log Q/K ------Corundum 0.6319s/sat Troilite -0.9024 Saponite-Ca 0.0688s/sat Albite_low -0.9380 Magnetite 0.0153s/sat Albite -0.9383 Mesolite 0.0000 sat Fluorite -0.9537 Calcite 0.0000 sat Pyrrhotite -0.9691 Quartz 0.0000 sat Celadonite -0.9700 Nontronite-Ca 0.0000 sat Smectite-low-Fe- -0.9727 Pyrite 0.0000 sat Sanidine_high -0.9813 Acanthite 0.0000 sat Magnesite -0.9994 Minnesotaite 0.0000 sat Beidellite-Na -1.0294 Au 0.0000 sat Cronstedtite-7A -1.0563 Diaspore 0.0000 sat Smectite-high-Fe -1.0806 Fluorapatite 0.0000 sat Greenalite -1.2156 Saponite-Mg 0.0000 sat Paragonite -1.2408 Dolomite-ord -0.0164 Analcime -1.2434 Dolomite -0.0182 C -1.2477 Nontronite-Mg -0.0572 Beidellite-K -1.2662 Ag -0.0606 Phlogopite -1.2675 Daphnite-14A -0.0663 Pyrophyllite -1.2868 Montmor-Ca -0.1045 Fayalite -1.3561 Muscovite -0.1185 Chamosite-7A -1.4222 Montmor-Mg -0.1290 Ripidolite-14A -1.4454 Witherite -0.1315 Beidellite-H -1.4584 Aragonite -0.1513 Hercynite -1.5006 Hematite -0.1672 Albite_high -1.5629 Chalcedony -0.1736 Laumontite -1.5981 Boehmite -0.1958 Clinoptilolite-C -1.6273

Stilbite -0.2460 Enstatite -1.7022 Cristobalite(alp -0.3118 FeO -1.7870 Annite -0.3228 Mordenite -1.7927 Saponite-Na -0.3914 Sellaite -1.7956 Scolecite -0.4583 Epidote -1.8479 Nontronite-Na -0.4602 Epidote-ord -1.8673 Maximum_Microcli -0.4809 Diopside -1.9914 K-Feldspar -0.5026 Wustite -2.1285 Montmor-Na -0.5210 Clinoptilolite-h -2.2390 Cristobalite(bet -0.5239 Lawsonite -2.2934 Coesite -0.5405 Wairakite -2.4057 Beidellite-Ca -0.5699 Kalsilite -2.4624 Talc -0.5856 Andalusite -2.4889 Siderite -0.5890 Prehnite -2.4893 Beidellite-Mg -0.6257 Kyanite -2.4906 Saponite-K -0.6276 Hedenbergite -2.4974 SiO2(am) -0.6374 Chrysotile -2.5177 Ferrosilite -0.6770 Daphnite-7A -2.5780 Gibbsite -0.6920 Jadeite -2.5829 Nontronite-K -0.6955 Sillimanite -2.6539 Montmor-K -0.6980 Clinochlore-14A -2.6701 Dolomite-dis -0.7889 Anorthite -2.6990 Saponite-H -0.8188 Wollastonite -2.7850 Kaolinite -0.8431 Pseudowollastoni -2.8401 Illite -0.8557 Nepheline -2.8526 Nontronite-H -0.8664 Fe(OH)2 -2.9504 (only minerals with log Q/K > -3 listed)

Gases fugacity log fug. ------H2O(g) 10.51 1.022 CO2(g) 4.136 0.617 CH4(g) 0.007116 -2.148 H2(g) 0.003415 -2.467 H2S(g) 0.001540 -2.813 (only gases with fugacities > 1.e-5 listed)

In fluid Sorbed Kd Original basis total moles moles mg/kg moles mg/kg L/kg ------Ag+ 5.00e-008 2.03e-008 0.00219 Al+++ 0.00405 5.54e-006 0.149 Au+ 7.71e-010 2.11e-010 4.15e-005 Ba++ 1.38e-007 1.38e-007 0.0189 Ca++ 0.0513 7.16e-005 2.86 Cl- 0.00166 0.00166 58.6 F- 0.000454 0.000415 7.86 Fe++ 0.00177 3.33e-008 0.00186 H+ -0.0322 0.0393 39.5 H2O 55.5 55.5 9.97e+005 HCO3- 0.0981 0.0477 2.90e+003 HPO4-- 0.000119 7.56e-009 0.000723 K+ 0.00102 0.00102 39.6 Mg++ 0.00185 1.73e-006 0.0419 Na+ 0.00993 0.00938 215. O2(aq) -0.000169 -0.000156 -4.97 SO4-- 0.000116 6.48e-005 6.21 SiO2(aq) 0.0781 0.00325 194.

Elemental composition In fluid Sorbed total moles moles mg/kg moles mg/kg ------Aluminum 0.004054 5.537e-006 0.1490

Barium 1.384e-007 1.384e-007 0.01895 Calcium 0.05128 7.158e-005 2.861 Carbon 0.09813 0.04769 571.3 Chlorine 0.001659 0.001659 58.64 Fluorine 0.0004544 0.0004148 7.859 Gold 7.712e-010 2.111e-010 4.146e-005 Hydrogen 111.0 111.0 1.116e+005 Iron 0.001771 3.332e-008 0.001856 Magnesium 0.001851 1.729e-006 0.04191 Oxygen 55.93 55.61 8.874e+005 Phosphorus 0.0001190 7.558e-009 0.0002335 Potassium 0.001016 0.001016 39.61 Silicon 0.07808 0.003245 90.91 Silver 5.003e-008 2.034e-008 0.002188 Sodium 0.009931 0.009375 215.0 Sulfur 0.0001155 6.481e-005 2.073

Figure 4A: Segment 3

Step # 100 Xi = 1.0000 Temperature = 178.4 C Pressure = 9.531 bars pH = 6.322 log fO2 = -44.079 Eh = -0.3387 volts pe = -3.7800 Ionic strength = 0.011627 Activity of water = 0.999942 Solvent mass = 0.999966 kg Solution mass = 1.002716 kg Solution density = 0.873 g/cm3 Chlorinity = 0.001653 molal Dissolved solids = 2743 mg/kg sol'n Rock mass = 0.008447 kg Carbonate alkalinity= 474.92 mg/kg as CaCO3 Sediment porosity = 0.997

moles moles grams cm3 Reactants remaining reacted reacted reacted ------Ag -7.044e-024 7.231e-009 7.800e-007 7.428e-008 Albite 8.335e-019 0.0004576 0.1200 0.04588 Anorthite -5.480e-019 0.0004313 0.1200 0.04347 Au -4.039e-028 4.062e-011 8.000e-009 4.149e-010 Enstatite -9.580e-019 0.0005977 0.06000 0.01869 Fayalite -5.802e-020 4.907e-005 0.01000 0.002277 Ferrosilite -5.921e-019 0.0004548 0.06000 0.01499 Fluorapatite -2.835e-020 1.586e-005 0.008000 Forsterite 4.161e-020 7.108e-005 0.01000 0.003112 K-Feldspar 1.519e-018 0.0007186 0.2000 0.07823 Magnetite -7.708e-020 5.183e-005 0.01200 0.002308 Muscovite -7.666e-019 0.0005021 0.2000 0.07065 Quartz -8.630e-017 0.1265 7.600 2.870

Minerals in system moles log moles grams volume (cm3) ------Acanthite 6.827e-009 -8.166 1.692e-006 2.335e-007 Au 1.741e-010 -9.759 3.430e-008 1.779e-009 Diaspore 0.001890 -2.723 0.1134 0.03357 Dolomite-ord 0.0004236 -3.373 0.07812 0.02726 Fluorapatite 1.586e-005 -4.800 0.007998 Minnesotaite 0.0001976 -3.704 0.09365 0.02922

Muscovite 0.0005357 -3.271 0.2134 0.07538 Nontronite-Mg 5.011e-005 -4.300 0.02113 0.006502 Pyrite 1.529e-005 -4.816 0.001834 0.0003660 Quartz 0.1311 -0.882 7.879 2.975 Saponite-Ca 0.0001018 -3.992 0.03924 0.01381 ______(total) 8.447 3.161*

Aqueous species molality mg/kg sol'n act. coef. log act. ------CO2(aq) 0.03720 1632. 1.0000 -1.4295 Na+ 0.009790 224.5 0.8531 -2.0782 HCO3- 0.009502 578.2 0.8531 -2.0912 SiO2(aq) 0.002695 161.5 1.0000 -2.5694 K+ 0.001697 66.17 0.8484 -2.8417 Cl- 0.001642 58.04 0.8484 -2.8561 F- 0.0004039 7.653 0.8508 -3.4639 Ca++ 3.400e-005 1.359 0.5494 -4.7286 CaHCO3+ 2.561e-005 2.582 0.8531 -4.6605 H2S(aq) 2.078e-005 0.7064 1.0000 -4.6823 Methane(aq) 1.511e-005 0.2417 1.0000 -4.8209 HS- 1.324e-005 0.4366 0.8508 -4.9484 NaCl(aq) 1.047e-005 0.6100 1.0000 -4.9802 HSiO3- 1.031e-005 0.7930 0.8531 -5.0555 OH- 9.606e-006 0.1629 0.8508 -5.0876 HF(aq) 6.983e-006 0.1393 1.0000 -5.1560 NaHCO3(aq) 6.349e-006 0.5319 1.0000 -5.1973 H2(aq) 3.011e-006 0.006054 1.0000 -5.5212 AlO2- 2.950e-006 0.1735 0.8531 -5.5991 Formate 2.426e-006 0.1089 0.8508 -5.6853 Mg++ 2.267e-006 0.05495 0.5692 -5.8893 NaF(aq) 1.995e-006 0.08352 1.0000 -5.7001 CaCO3(aq) 1.931e-006 0.1927 1.0000 -5.7143 MgHCO3+ 1.854e-006 0.1577 0.8531 -5.8009 CO3-- 1.464e-006 0.08762 0.5333 -6.1074 NaHSiO3(aq) 1.072e-006 0.1070 1.0000 -5.9699 KCl(aq) 8.448e-007 0.06281 1.0000 -6.0733 CaF+ 6.917e-007 0.04075 0.8531 -6.2291 H+ 5.454e-007 0.0005482 0.8730 -6.3223 MgF+ 1.491e-007 0.006439 0.8531 -6.8955 HAlO2(aq) 1.360e-007 0.008133 1.0000 -6.8666 Ba++ 1.345e-007 0.01842 0.5388 -7.1399 Fe++ 8.554e-008 0.004764 0.5494 -7.3279 CaCl+ 6.244e-008 0.004703 0.8531 -7.2735 NaOH(aq) 5.142e-008 0.002051 1.0000 -7.2889 NaAlO2(aq) 5.009e-008 0.004095 1.0000 -7.3003 Na(For)(aq) 3.783e-008 0.002566 1.0000 -7.4222 Formic_acid(aq) 2.339e-008 0.001074 1.0000 -7.6310 MgCO3(aq) 2.095e-008 0.001761 1.0000 -7.6789 H2PO4- 1.938e-008 0.001874 0.8531 -7.7817 MgCl+ 1.682e-008 0.001002 0.8531 -7.8432 Ag(HS)(aq) 1.378e-008 0.001936 1.0000 -7.8608 SO4-- 1.241e-008 0.001189 0.5278 -8.1837 S-- 1.046e-008 0.0003344 0.5388 -8.2492 (only species > 1e-8 molal listed)

Mineral saturation states log Q/K log Q/K ------Corundum 0.2006s/sat Kaolinite -0.8162 Quartz 0.0000 sat Dolomite-dis -0.8163 Muscovite 0.0000 sat Nontronite-H -0.8268 Diaspore 0.0000 sat Saponite-H -0.8329

Dolomite-ord 0.0000 sat Ice -0.8358 Au 0.0000 sat Scolecite -0.8792 Saponite-Ca 0.0000 sat Sanidine_high -0.9053 Nontronite-Mg 0.0000 sat Troilite -0.9850 Acanthite 0.0000 sat Smectite-low-Fe- -0.9949 Minnesotaite 0.0000 sat C -1.0005 Fluorapatite 0.0000 sat Cronstedtite-7A -1.0397 Pyrite 0.0000 sat Pyrrhotite -1.0530 Saponite-Mg -0.0010 Albite_low -1.1066 Dolomite -0.0017 Albite -1.1067 Nontronite-Ca -0.0099 Beidellite-Na -1.1104 Ag -0.0164 Goethite -1.1139 Magnetite -0.0458 Fluorite -1.1193 Daphnite-14A -0.0612 Smectite-high-Fe -1.1213 Montmor-Mg -0.1489 Phlogopite -1.1725 Chalcedony -0.1792 Greenalite -1.1778 Witherite -0.1929 Beidellite-K -1.2697 Hematite -0.1931 Pyrophyllite -1.3352 Montmor-Ca -0.1937 Analcime -1.3840 Annite -0.2043 Paragonite -1.4181 Boehmite -0.2091 Fayalite -1.4618 Calcite -0.2132 Ripidolite-14A -1.4793 Mesolite -0.2625 Chamosite-7A -1.4863 Tridymite -0.2982 Beidellite-H -1.5263 Cristobalite(alp -0.3254 Sellaite -1.5759 Aragonite -0.3629 Hercynite -1.6807 Maximum_Microcli -0.3654 Albite_high -1.7707 K-Feldspar -0.3873 Enstatite -1.7867 Siderite -0.4007 FeO -1.8902 Saponite-Na -0.4185 Mordenite -1.9781 Nontronite-Na -0.4284 Monohydrocalcite -1.9913 Cristobalite(bet -0.5483 Laumontite -2.0393 Coesite -0.5555 Wustite -2.2403 Stilbite -0.5669 Kalsilite -2.4152 Montmor-Na -0.5673 Chrysotile -2.5107 Saponite-K -0.5771 Clinoptilolite-C -2.5186 Talc -0.5835 Diopside -2.5192 Nontronite-K -0.5863 Daphnite-7A -2.6183 SiO2(am) -0.6708 Kyanite -2.6654 Montmor-K -0.6740 Andalusite -2.6789 Beidellite-Mg -0.6815 Clinochlore-14A -2.7405 Beidellite-Ca -0.6927 Lawsonite -2.7436 Gibbsite -0.7173 Jadeite -2.7512 Ferrosilite -0.7247 Sillimanite -2.8547 Celadonite -0.7769 Epidote -2.8735 Illite -0.8046 Epidote-ord -2.8901 Magnesite -0.8063 (only minerals with log Q/K > -3 listed)

Gases fugacity log fug. ------H2O(g) 7.699 0.886 CO2(g) 4.029 0.605 CH4(g) 0.01101 -1.958 H2(g) 0.002304 -2.638 H2S(g) 0.0008122 -3.090 (only gases with fugacities > 1.e-5 listed)

In fluid Sorbed Kd Original basis total moles moles mg/kg moles mg/kg L/kg ------Ag+ 2.75e-008 1.39e-008 0.00149 Al+++ 0.00355 3.14e-006 0.0844

Au+ 2.51e-010 7.72e-011 1.52e-005 Ba++ 1.38e-007 1.38e-007 0.0188 Ca++ 0.000582 6.23e-005 2.49 Cl- 0.00165 0.00165 58.4 F- 0.000430 0.000414 7.84 Fe++ 0.000708 8.61e-008 0.00480 H+ 0.0231 0.0372 37.4 H2O 55.5 55.5 9.97e+005 HCO3- 0.0476 0.0468 2.84e+003 HPO4-- 4.76e-005 2.07e-008 0.00198 K+ 0.00223 0.00170 66.2 Mg++ 0.000742 4.31e-006 0.104 Na+ 0.00981 0.00981 225. O2(aq) -0.000130 -0.000101 -3.22 SO4-- 6.46e-005 3.41e-005 3.26 SiO2(aq) 0.137 0.00271 162.

Elemental composition In fluid Sorbed total moles moles mg/kg moles mg/kg ------Aluminum 0.003551 3.136e-006 0.08439 Barium 1.376e-007 1.376e-007 0.01885 Calcium 0.0005820 6.230e-005 2.490 Carbon 0.04760 0.04675 560.0 Chlorine 0.001653 0.001653 58.44 Fluorine 0.0004296 0.0004137 7.839 Gold 2.513e-010 7.717e-011 1.516e-005 Hydrogen 111.0 111.0 1.116e+005 Iron 0.0007084 8.612e-008 0.004796 Magnesium 0.0007416 4.308e-006 0.1044 Oxygen 55.89 55.62 8.874e+005 Phosphorus 4.760e-005 2.067e-008 0.0006384 Potassium 0.002234 0.001698 66.20 Silicon 0.1368 0.002706 75.80 Silver 2.753e-008 1.388e-008 0.001493 Sodium 0.009810 0.009810 224.9 Sulfur 6.464e-005 3.406e-005 1.089

5A: Segment 4

Step # 100 Xi = 1.0000 Temperature = 157.6 C Pressure = 5.694 bars pH = 6.024 log fO2 = -44.048 Eh = -0.2402 volts pe = -2.8107 Ionic strength = 0.012558 Activity of water = 0.999942 Solvent mass = 1.000019 kg Solution mass = 1.002708 kg Solution density = 0.897 g/cm3 Chlorinity = 0.001647 molal Dissolved solids = 2682 mg/kg sol'n Rock mass = 0.009999 kg Carbonate alkalinity= 370.74 mg/kg as CaCO3 Sediment porosity = 0.997

moles moles grams cm3 Reactants remaining reacted reacted reacted ------Ag -6.107e-025 9.271e-010 1.000e-007 9.523e-009 Barite -2.880e-018 0.002142 0.5000 0.1116 Quartz -1.832e-016 0.1581 9.500 3.587

Minerals in system moles log moles grams volume (cm3) ------Barite 0.001077 -2.968 0.2512 0.05609 Diaspore 2.311e-006 -5.636 0.0001386 4.104e-005 Pyrite 8.390e-008 -7.076 1.007e-005 2.008e-006 Quartz 0.1587 -0.799 9.538 3.601 Witherite 0.001065 -2.973 0.2102 0.04880 ______(total) 9.999 3.706

Aqueous species molality mg/kg sol'n act. coef. log act. ------CO2(aq) 0.03732 1638. 1.0000 -1.4281 Na+ 0.009770 224.0 0.8567 -2.0773 HCO3- 0.007423 451.7 0.8567 -2.1966 SiO2(aq) 0.002066 123.8 1.0000 -2.6849 K+ 0.001659 64.69 0.8520 -2.8497 Cl- 0.001639 57.94 0.8520 -2.8551 SO4-- 0.0009981 95.63 0.5366 -3.2712 F- 0.0004022 7.621 0.8544 -3.4639 Ca++ 3.707e-005 1.482 0.5585 -4.6840 H2S(aq) 3.624e-005 1.232 1.0000 -4.4408 KSO4- 3.354e-005 4.521 0.8567 -4.5416 HS- 1.358e-005 0.4480 0.8544 -4.9353 CaHCO3+ 1.335e-005 1.346 0.8567 -4.9415 CaSO4(aq) 1.066e-005 1.447 1.0000 -4.9723 HF(aq) 8.487e-006 0.1693 1.0000 -5.0712 NaCl(aq) 7.913e-006 0.4612 1.0000 -5.1016 NaHCO3(aq) 7.431e-006 0.6226 1.0000 -5.1290 HSO4- 4.080e-006 0.3950 0.8567 -5.4565 HSiO3- 3.794e-006 0.2917 0.8567 -5.4881 OH- 3.355e-006 0.05691 0.8544 -5.5426 MgSO4(aq) 3.296e-006 0.3956 1.0000 -5.4821 NaF(aq) 1.475e-006 0.06178 1.0000 -5.8311 H+ 1.080e-006 0.001085 0.8765 -6.0239 AlO2- 7.339e-007 0.04317 0.8567 -6.2015 CO3-- 7.204e-007 0.04312 0.5422 -6.4082 Mg++ 6.823e-007 0.01654 0.5784 -6.4038 Ba++ 5.981e-007 0.08192 0.5478 -6.4846 KCl(aq) 5.937e-007 0.04414 1.0000 -6.2265 CaCO3(aq) 5.526e-007 0.05516 1.0000 -6.2576 CaF+ 4.491e-007 0.02646 0.8567 -6.4148 NaHSiO3(aq) 3.965e-007 0.03958 1.0000 -6.4017 MgHCO3+ 2.680e-007 0.02280 0.8567 -6.6390 HAlO2(aq) 7.465e-008 0.004466 1.0000 -7.1270 H2(aq) 6.755e-008 0.0001358 1.0000 -7.1704 Formate 6.088e-008 0.002733 0.8544 -7.2839 CaCl+ 4.361e-008 0.003285 0.8567 -7.4275 MgF+ 2.789e-008 0.001204 0.8567 -7.6217 H2PO4- 1.973e-008 0.001908 0.8567 -7.7721 Ag(HS)(aq) 1.464e-008 0.002058 1.0000 -7.8344 NaOH(aq) 1.252e-008 0.0004994 1.0000 -7.9024 (only species > 1e-8 molal listed)

Mineral saturation states log Q/K log Q/K ------Quartz 0.0000 sat Beidellite-Na -1.3118 Witherite 0.0000 sat Sanidine_high -1.3405 Diaspore 0.0000 sat Montmor-K -1.3476 Pyrite 0.0000 sat Pyrophyllite -1.4100 Barite 0.0000 sat Stilbite -1.4537 Acanthite -0.0937 Illite -1.4566 Chalcedony -0.1878 Beidellite-K -1.4567 Boehmite -0.2296 Anhydrite -1.5313 Tridymite -0.2544 Albite_low -1.5997 Cristobalite(alp -0.3466 Albite -1.5997 Muscovite -0.3676 Beidellite-H -1.6312 Corundum -0.4187 Analcime -1.8270 Coesite -0.5790 Dolomite-ord -1.8651 Cristobalite(bet -0.5865 Dolomite -1.8665 Au -0.6718 Scolecite -1.8712 SiO2(am) -0.7211 Paragonite -1.9237 Ice -0.7377 Magnesite -2.0882 Maximum_Microcli -0.7389 Bassanite -2.2047 Gibbsite -0.7467 CaSO4:0.5H2O(bet -2.2572 K-Feldspar -0.7599 Albite_high -2.3251 Kaolinite -0.7752 Sellaite -2.4078 Calcite -0.8534 Gypsum -2.4262 Montmor-Ca -0.9175 Mordenite -2.4531 Beidellite-Ca -0.9379 Monohydrocalcite -2.4718 Montmor-Mg -0.9751 Celadonite -2.6488 Ag -0.9883 Siderite -2.7312 Aragonite -1.0009 Dolomite-dis -2.7495 Beidellite-Mg -1.0327 Fluorapatite -2.7912 Mesolite -1.0612 Kalsilite -2.8950 Montmor-Na -1.2451 Kyanite -2.9334 Fluorite -1.2770 Andalusite -2.9709 (only minerals with log Q/K > -3 listed)

Gases fugacity log fug. ------H2O(g) 4.699 0.672 CO2(g) 4.123 0.615 H2S(g) 0.001391 -2.857 H2(g) 6.044e-005 -4.219 (only gases with fugacities > 1.e-5 listed)

In fluid Sorbed Kd Original basis total moles moles mg/kg moles mg/kg L/kg ------Ag+ 1.47e-008 1.47e-008 0.00159 Al+++ 3.13e-006 8.17e-007 0.0220 Au+ 7.72e-011 7.72e-011 1.52e-005 Ba++ 0.00214 6.04e-007 0.0827 Ca++ 6.21e-005 6.21e-005 2.48 Cl- 0.00165 0.00165 58.2 F- 0.000413 0.000413 7.82 Fe++ 8.59e-008 2.05e-009 0.000114 H+ 0.0363 0.0374 37.6 H2O 55.5 55.5 9.97e+005 HCO3- 0.0458 0.0448 2.72e+003 HPO4-- 2.06e-008 2.06e-008 0.00197 K+ 0.00169 0.00169 66.0 Mg++ 4.28e-006 4.28e-006 0.104 Na+ 0.00979 0.00979 224. O2(aq) -0.000100 -9.97e-005 -3.18

SO4-- 0.00218 0.00110 105. SiO2(aq) 0.161 0.00207 124.

Elemental composition In fluid Sorbed total moles moles mg/kg moles mg/kg ------Aluminum 3.128e-006 8.172e-007 0.02199 Barium 0.002142 6.038e-007 0.08270 Calcium 6.213e-005 6.213e-005 2.483 Carbon 0.04583 0.04476 536.2 Chlorine 0.001647 0.001647 58.24 Fluorine 0.0004127 0.0004127 7.819 Gold 7.717e-011 7.717e-011 1.516e-005 Hydrogen 111.0 111.0 1.116e+005 Iron 8.595e-008 2.052e-009 0.0001143 Magnesium 4.279e-006 4.279e-006 0.1037 Oxygen 55.94 55.62 8.874e+005 Phosphorus 2.063e-008 2.063e-008 0.0006372 Potassium 0.001693 0.001693 66.02 Silicon 0.1608 0.002070 57.99 Silver 1.474e-008 1.474e-008 0.001586 Sodium 0.009787 0.009787 224.4 Sulfur 0.002176 0.001100 35.16

6A: Segment 5

Step # 100 Xi = 1.0000 Temperature = 57.6 C Pressure = 1.013 bars pH = 6.483 log fO2 = -59.218 Eh = -0.1730 volts pe = -2.6361 Ionic strength = 0.016068 Activity of water = 0.999933 Solvent mass = 1.999487 kg Solution mass = 2.002341 kg Solution density = 0.989 g/cm3 Chlorinity = 0.001894 molal Dissolved solids = 1426 mg/kg sol'n Rock mass = 0.010868 kg Carbonate alkalinity= 562.24 mg/kg as CaCO3 Sediment porosity = 0.998

moles moles grams cm3 Reactants remaining reacted reacted reacted ------Ag 6.721e-024 7.463e-009 8.050e-007 7.666e-008 Al+++ 2.617e-019 0.0001110 0.002995 Albite -9.487e-018 0.009534 2.500 0.9558 Anorthite 8.335e-018 0.008986 2.500 0.9057 Au 1.212e-026 2.031e-010 4.000e-008 2.074e-009 Ca++ 1.950e-018 0.001480 0.05932 Cl- 2.650e-018 0.002140 0.07587 Enstatite 8.470e-019 0.001245 0.1250 0.03894 Fe++ 1.904e-030 2.230e-015 1.245e-013 Ferrosilite 5.475e-018 0.01800 2.375 0.5932 H+ 3.388e-018 0.003520 0.003548 H2O -6.117e-014 55.51 1000. HCO3- 1.199e-017 0.006490 0.3960 K+ 2.118e-019 0.0002200 0.008602 Magnetite 1.499e-019 0.0005399 0.1250 0.02404

Mg++ 6.268e-019 0.0009840 0.02392 Na+ -5.363e-018 0.002510 0.05770 O2(aq) 2.181e-019 0.0001940 0.006208 Quartz 4.499e-017 0.03329 2.000 0.7552 SO4-- 2.500e-018 0.001440 0.1383 SiO2(aq) -3.673e-018 0.002080 0.1250

Minerals in system moles log moles grams volume (cm3) ------Acanthite 1.106e-008 -7.956 2.741e-006 3.783e-007 Au 2.802e-010 -9.552 5.520e-008 2.863e-009 Calcite 0.005477 -2.261 0.5482 0.2023 Dolomite-ord 0.002087 -2.680 0.3849 0.1343 Hematite 0.005851 -2.233 0.9343 0.1771 Kaolinite 0.01233 -1.909 3.184 1.227 Muscovite 0.0009846 -3.007 0.3922 0.1385 Pyrite 0.0007319 -3.136 0.08781 0.01752 Quartz 0.07499 -1.125 4.506 1.701 Siderite 0.007170 -2.144 0.8307 0.2106 ______(total) 10.87 3.809

Aqueous species molality mg/kg sol'n act. coef. log act. ------HCO3- 0.01111 676.7 0.8746 -2.0126 Na+ 0.01084 248.9 0.8746 -2.0231 CO2(aq) 0.005872 258.1 1.0000 -2.2312 Cl- 0.001890 66.92 0.8702 -2.7839 Ca++ 0.001310 52.44 0.6040 -3.1016 SO4-- 0.0004917 47.16 0.5823 -3.5432 K+ 0.0004631 18.08 0.8702 -3.3947 SiO2(aq) 0.0003195 19.17 1.0000 -3.4956 F- 0.0002046 3.882 0.8724 -3.7483 CaHCO3+ 0.0001226 12.38 0.8746 -3.9697 NaHCO3(aq) 7.390e-005 6.199 1.0000 -4.1313 Mg++ 5.995e-005 1.455 0.6236 -4.4272 CaSO4(aq) 4.021e-005 5.467 1.0000 -4.3956 Fe++ 9.146e-006 0.5100 0.6040 -5.2577 CaCO3(aq) 7.650e-006 0.7645 1.0000 -5.1164 MgSO4(aq) 6.812e-006 0.8187 1.0000 -5.1668 MgHCO3+ 5.831e-006 0.4968 0.8746 -5.2924 CO3-- 3.674e-006 0.2202 0.5879 -5.6655 NaCl(aq) 3.394e-006 0.1981 1.0000 -5.4693 KSO4- 1.254e-006 0.1692 0.8746 -5.9600 CaF+ 1.129e-006 0.06658 0.8746 -6.0057 CaCl+ 3.727e-007 0.02811 0.8746 -6.4868 H+ 3.680e-007 0.0003704 0.8930 -6.4833 HSiO3- 3.497e-007 0.02692 0.8746 -6.5145 OH- 2.891e-007 0.004910 0.8724 -6.5982 NaF(aq) 2.409e-007 0.01010 1.0000 -6.6182 MgF+ 2.213e-007 0.009571 0.8746 -6.7131 HF(aq) 1.655e-007 0.003306 1.0000 -6.7812 MgCO3(aq) 1.233e-007 0.01038 1.0000 -6.9091 NaHSiO3(aq) 7.734e-008 0.007730 1.0000 -7.1116 MgCl+ 6.013e-008 0.003588 0.8746 -7.2791 KCl(aq) 3.855e-008 0.002870 1.0000 -7.4140 NaCO3- 2.818e-008 0.002335 0.8746 -7.6083 HSO4- 2.711e-008 0.002628 0.8746 -7.6250 AlO2- 1.949e-008 0.001148 0.8746 -7.7684 (only species > 1e-8 molal listed)

Mineral saturation states log Q/K log Q/K ------Nontronite-Ca 0.9744s/sat Monohydrocalcite -0.9630 Nontronite-Mg 0.8449s/sat Beidellite-Mg -0.9859 Nontronite-Na 0.6452s/sat Maximum_Microcli -0.9861 Nontronite-K 0.4484s/sat K-Feldspar -0.9899 Diaspore 0.2781s/sat Montmor-Na -1.0741 Nontronite-H 0.1703s/sat SiO2(am) -1.0789 Pyrite 0.0000 sat Magnetite -1.1505 Dolomite-ord 0.0000 sat Beidellite-Na -1.1857 Acanthite 0.0000 sat Montmor-K -1.2647 Calcite 0.0000 sat Dolomite-dis -1.3329 Siderite 0.0000 sat Pyrophyllite -1.3349 Hematite 0.0000 sat Illite -1.3556 Quartz 0.0000 sat Beidellite-K -1.3829 Muscovite 0.0000 sat Magnesite -1.4518 Au 0.0000 sat Dawsonite -1.5534 Kaolinite 0.0000 sat Beidellite-H -1.6615 Dolomite -0.0002 Scolecite -1.7159 Boehmite -0.0744 Anhydrite -1.9246 Aragonite -0.1432 Sanidine_high -1.9938 Tridymite -0.1581 Paragonite -2.0196 Chalcedony -0.2445 Gypsum -2.0527 Ice -0.2749 Ferrosilite -2.1726 Stilbite -0.3128 Albite_low -2.1785 Ag -0.3487 Albite -2.1785 Mesolite -0.3611 Cronstedtite-7A -2.1924 Gibbsite -0.4288 Analcime -2.2497 Cristobalite(alp -0.4856 Sellaite -2.2521 Goethite -0.5525 Bassanite -2.5680 Fluorite -0.6926 Corundum -2.6579 Coesite -0.7354 CaSO4:0.5H2O(bet -2.7001 Montmor-Ca -0.8052 Celadonite -2.7619 Cristobalite(bet -0.8554 Minnesotaite -2.7645 Beidellite-Ca -0.8566 Mordenite -2.7967 Montmor-Mg -0.8752 (only minerals with log Q/K > -3 listed)

Gases fugacity log fug. ------CO2(g) 0.3453 -0.462 H2O(g) 0.1464 -0.835 (only gases with fugacities > 1.e-5 listed)

In fluid Sorbed Kd Original basis total moles moles mg/kg moles mg/kg L/kg ------Ag+ 2.22e-008 7.80e-011 4.20e-006 Al+++ 0.0276 4.79e-008 0.000645 Au+ 2.80e-010 4.36e-015 4.29e-010 Ca++ 0.0105 0.00296 59.3 Cl- 0.00379 0.00379 67.1 F- 0.000413 0.000413 3.92 Fe++ 0.0196 1.83e-005 0.511 H+ -0.111 0.0117 5.90 H2O 111. 111. 9.98e+005 HCO3- 0.0512 0.0344 1.05e+003 K+ 0.00191 0.000929 18.1 Mg++ 0.00223 0.000146 1.77 Na+ 0.0218 0.0218 251. O2(aq) 0.000364 -2.61e-008 -0.000417 SO4-- 0.00254 0.00108 51.8

SiO2(aq) 0.103 0.000640 19.2

Elemental composition In fluid Sorbed total moles moles mg/kg moles mg/kg ------Aluminum 0.02762 4.786e-008 0.0006449 Calcium 0.01053 0.002964 59.32 Carbon 0.05120 0.03437 206.2 Chlorine 0.003787 0.003787 67.06 Fluorine 0.0004127 0.0004127 3.915 Gold 2.803e-010 4.359e-015 4.288e-010 Hydrogen 222.1 222.0 1.117e+005 Iron 0.01962 1.831e-005 0.5106 Magnesium 0.002233 0.0001460 1.772 Oxygen 111.4 111.1 8.876e+005 Potassium 0.001913 0.0009286 18.13 Silicon 0.1033 0.0006396 8.972 Silver 2.220e-008 7.800e-011 4.202e-006 Sodium 0.02183 0.02183 250.6 Sulfur 0.002543 0.001080 17.29

7A: Segment 6

Step # 100 Xi = 1.0000 Temperature = 25.0 C Pressure = 1.013 bars pH = 7.593 log fO2 = -0.918 Eh = 0.7667 volts pe = 12.9606 Ionic strength = 0.013535 Activity of water = 0.999929 Solvent mass = 1.999862 kg Solution mass = 2.001746 kg Solution density = 1.013 g/cm3 Chlorinity = 0.002015 molal Dissolved solids = 941 mg/kg sol'n Rock mass = 0.011244 kg Carbonate alkalinity= 353.58 mg/kg as CaCO3 Sediment porosity = 0.998

moles moles grams cm3 Reactants remaining reacted reacted reacted ------Ag -1.082e-024 7.463e-010 8.050e-008 7.666e-009 Al+++ 2.617e-019 0.0001110 0.002995 Albite 1.092e-017 0.007627 2.000 0.7646 Anorthite -1.775e-018 0.007189 2.000 0.7246 Au 1.212e-026 2.031e-010 4.000e-008 2.074e-009 Ca++ 1.950e-018 0.001480 0.05932 Cl- 2.650e-018 0.002140 0.07587 Enstatite 1.694e-018 0.002490 0.2500 0.07789 Fe++ 1.904e-030 2.230e-015 1.245e-013 Ferrosilite -7.589e-018 0.02842 3.750 0.9366 H+ 3.388e-018 0.003520 0.003548 H2O -6.117e-014 55.51 1000. HCO3- 1.199e-017 0.006490 0.3960 K+ 2.118e-019 0.0002200 0.008602 Magnetite -5.413e-019 0.0004319 0.1000 0.01923 Mg++ 6.268e-019 0.0009840 0.02392 Na+ -5.363e-018 0.002510 0.05770 O2(aq) 2.181e-019 0.0001940 0.006208

Quartz 4.499e-017 0.03329 2.000 0.7552 SO4-- 2.500e-018 0.001440 0.1383 SiO2(aq) -3.673e-018 0.002080 0.1250

Minerals in system moles log moles grams volume (cm3) ------Calcite 0.006334 -2.198 0.6339 0.2339 Diaspore 0.02096 -1.679 1.257 0.3722 Dolomite-ord 0.003530 -2.452 0.6510 0.2271 Hematite 0.01486 -1.828 2.373 0.4499 Mesolite 0.0002430 -3.614 0.09424 0.04160 Muscovite 0.0002255 -3.647 0.08983 0.03173 Quartz 0.1023 -0.990 6.144 2.320 ______(total) 11.24 3.677

Aqueous species molality mg/kg sol'n act. coef. log act. ------Na+ 0.01036 238.0 0.8894 -2.0355 HCO3- 0.006928 422.4 0.8894 -2.2103 Cl- 0.002012 71.27 0.8858 -2.7490 SO4-- 0.001318 126.4 0.6232 -3.0856 Ca++ 0.0004538 18.17 0.6419 -3.5357 K+ 0.0003658 14.29 0.8858 -3.4894 CO2(aq) 0.0003561 15.66 1.0000 -3.4485 O2(aq) 0.0001550 4.956 1.0000 -3.8096 F- 0.0001026 1.948 0.8876 -4.0405 SiO2(aq) 9.367e-005 5.623 1.0000 -4.0284 NaHCO3(aq) 8.147e-005 6.837 1.0000 -4.0890 CaSO4(aq) 3.120e-005 4.244 1.0000 -4.5058 Mg++ 2.890e-005 0.7018 0.6588 -4.7203 CaHCO3+ 2.298e-005 2.321 0.8894 -4.6896 CO3-- 1.768e-005 1.060 0.6281 -4.9544 CaCO3(aq) 6.925e-006 0.6924 1.0000 -5.1596 MgSO4(aq) 4.060e-006 0.4882 1.0000 -5.3915 NaCl(aq) 2.762e-006 0.1613 1.0000 -5.5587 KSO4- 2.306e-006 0.3114 0.8894 -5.6881 MgHCO3+ 1.473e-006 0.1255 0.8894 -5.8828 HSiO3- 4.808e-007 0.03703 0.8894 -6.3689 OH- 4.365e-007 0.007417 0.8876 -6.4118 NaCO3- 3.768e-007 0.03124 0.8894 -6.4749 MgCO3(aq) 2.041e-007 0.01719 1.0000 -6.6902 NaHSiO3(aq) 1.777e-007 0.01776 1.0000 -6.7504 CaF+ 1.459e-007 0.008612 0.8894 -6.8868 CaCl+ 1.193e-007 0.008999 0.8894 -6.9744 NaF(aq) 8.514e-008 0.003572 1.0000 -7.0699 MgF+ 4.497e-008 0.001946 0.8894 -7.3980 MgCl+ 2.866e-008 0.001711 0.8894 -7.5936 H+ 2.821e-008 2.840e-005 0.9045 -7.5932 KCl(aq) 1.844e-008 0.001373 1.0000 -7.7343 (only species > 1e-8 molal listed)

Mineral saturation states log Q/K log Q/K ------Nontronite-Ca 1.2988s/sat Montmor-Ca -1.1613 Nontronite-Na 1.1550s/sat Montmor-Na -1.2383 Nontronite-Mg 1.1411s/sat Montmor-Mg -1.2493 Nontronite-K 1.0141s/sat SiO2(am) -1.2891 Nontronite-H 0.3347s/sat Montmor-K -1.3754 Dolomite 0.0000 sat Dawsonite -1.4273 Dolomite-ord 0.0000 sat Illite -1.4778 Muscovite 0.0000 sat Dolomite-dis -1.5452

Quartz 0.0000 sat Fluorite -1.5697 Calcite 0.0000 sat Magnesite -1.6294 Diaspore 0.0000 sat Sanidine_high -1.6590 Mesolite 0.0000 sat Beidellite-Ca -1.6649 Hematite 0.0000 sat Celadonite -1.7299 Stilbite -0.0747 Beidellite-Na -1.8087 Ice -0.1388 Beidellite-Mg -1.8226 Aragonite -0.1443 Scolecite -1.9098 Tridymite -0.1941 Beidellite-K -1.9496 Chalcedony -0.2713 Albite_low -2.0467 Boehmite -0.4039 Albite -2.0468 Maximum_Microcli -0.4591 Analcime -2.0909 K-Feldspar -0.4601 Pyrophyllite -2.1175 Goethite -0.4835 Gypsum -2.1293 Kaolinite -0.4896 Anhydrite -2.3049 Cristobalite(alp -0.5508 Paragonite -2.4846 Gibbsite -0.5951 Beidellite-H -2.6291 Coesite -0.8103 Mordenite -2.9336 Monohydrocalcite -0.8344 Bassanite -2.9502 Cristobalite(bet -0.9952 (only minerals with log Q/K > -3 listed)

Gases fugacity log fug. ------O2(g) 0.1208 -0.918 H2O(g) 0.02577 -1.589 CO2(g) 0.01028 -1.988 (only gases with fugacities > 1.e-5 listed)

In fluid Sorbed Kd

Original basis total moles moles mg/kg moles mg/kg L/kg ------Ag+ 7.85e-010 7.85e-010 4.23e-005 Al+++ 0.0221 1.75e-008 0.000236 Au+ 2.03e-010 2.03e-010 2.00e-005 Ca++ 0.0111 0.00103 20.6 Cl- 0.00403 0.00403 71.4 F- 0.000206 0.000206 1.95 Fe++ 0.0297 2.53e-018 7.07e-014 H+ -0.139 0.000659 0.332 H2O 111. 111. 9.99e+005 HCO3- 0.0282 0.0148 452. K+ 0.000962 0.000736 14.4 Mg++ 0.00360 6.94e-005 0.843 Na+ 0.0211 0.0209 240. O2(aq) 0.00774 0.000310 4.96 SO4-- 0.00271 0.00271 130. SiO2(aq) 0.104 0.000189 5.66

Elemental composition In fluid Sorbed total moles moles mg/kg moles mg/kg ------Aluminum 0.02212 1.751e-008 0.0002360 Calcium 0.01105 0.001030 20.63 Carbon 0.02822 0.01483 88.99 Chlorine 0.004030 0.004030 71.37 Fluorine 0.0002058 0.0002058 1.953 Gold 2.031e-010 2.031e-010 1.998e-005 Hydrogen 222.1 222.0 1.118e+005

Iron 0.02972 2.532e-018 7.065e-014 Magnesium 0.003600 6.942e-005 0.8429 Oxygen 111.4 111.1 8.877e+005 Potassium 0.0009617 0.0007362 14.38 Silicon 0.1039 0.0001886 2.647 Silver 7.852e-010 7.852e-010 4.231e-005 Sodium 0.02105 0.02089 239.9 Sulfur 0.002710 0.002710 43.41

APPENDIX III

Reaction path output results for segments in the P model

8A: Segment 2

Step # 100 Xi = 1.0000 Temperature = 192.9 C Pressure = 13.259 bars pH = 6.386 log fO2 = -42.402 Eh = -0.3562 volts pe = -3.8522 Ionic strength = 0.010503 Activity of water = 0.999942 Solvent mass = 0.999915 kg Solution mass = 1.002686 kg Solution density = 0.855 g/cm3 Chlorinity = 0.001659 molal Dissolved solids = 2763 mg/kg sol'n Rock mass = 0.010106 kg Carbonate alkalinity= 417.54 mg/kg as CaCO3

Minerals in system moles log moles grams volume (cm3) ------Acanthite 1.484e-008 -7.829 3.677e-006 5.075e-007 Au 5.592e-010 -9.252 1.101e-007 5.712e-009 Calcite 0.05043 -1.297 5.047 1.863 Diaspore 0.002127 -2.672 0.1276 0.03778 Fluorapatite 3.966e-005 -4.402 0.02000 Mesolite 0.0008435 -3.074 0.3271 0.1444 Minnesotaite 0.0004812 -3.318 0.2281 0.07116 Nontronite-Ca 0.0001510 -3.821 0.06408 0.01980 Pyrite 2.524e-005 -4.598 0.003029 0.0006043 Quartz 0.06767 -1.170 4.066 1.535 Saponite-Mg 0.0005842 -3.233 0.2237 0.07808 ______(total) 10.11 3.750*

Aqueous species molality mg/kg sol'n act. coef. log act. ------CO2(aq) 0.03930 1725. 1.0000 -1.4056 Na+ 0.009345 214.2 0.8530 -2.0985 HCO3- 0.008355 508.4 0.8530 -2.1471 SiO2(aq) 0.003234 193.8 1.0000 -2.4902 Cl- 0.001646 58.18 0.8485 -2.8550 K+ 0.001015 39.58 0.8485 -3.0648 F- 0.0004028 7.631 0.8508 -3.4651 H2S(aq) 3.965e-005 1.348 1.0000 -4.4017 Ca++ 3.453e-005 1.380 0.5486 -4.7225 CaHCO3+ 3.317e-005 3.344 0.8530 -4.5483

HS- 2.531e-005 0.8348 0.8508 -4.6669 HSiO3- 1.401e-005 1.077 0.8530 -4.9226 OH- 1.357e-005 0.2302 0.8508 -4.9375 NaCl(aq) 1.237e-005 0.7210 1.0000 -4.9076 Methane(aq) 1.110e-005 0.1776 1.0000 -4.9546 HF(aq) 8.540e-006 0.1704 1.0000 -5.0685 AlO2- 5.237e-006 0.3080 0.8530 -5.3499 H2(aq) 5.023e-006 0.01010 1.0000 -5.2990 Formate 2.804e-006 0.1259 0.8508 -5.6223 CaCO3(aq) 2.685e-006 0.2680 1.0000 -5.5711 NaF(aq) 2.375e-006 0.09944 1.0000 -5.6244 NaHSiO3(aq) 1.422e-006 0.1420 1.0000 -5.8470 CO3-- 1.229e-006 0.07353 0.5331 -6.1837 CaF+ 1.031e-006 0.06075 0.8530 -6.0557 MgHCO3+ 8.285e-007 0.07049 0.8530 -6.1507 Mg++ 8.004e-007 0.01940 0.5678 -6.3425 KCl(aq) 6.456e-007 0.04800 1.0000 -6.1900 H+ 4.711e-007 0.0004735 0.8722 -6.3863 HAlO2(aq) 2.018e-007 0.01207 1.0000 -6.6951 Ba++ 1.339e-007 0.01834 0.5384 -7.1420 NaAlO2(aq) 1.131e-007 0.009249 1.0000 -6.9464 NaOH(aq) 9.192e-008 0.003666 1.0000 -7.0366 CaCl+ 8.929e-008 0.006726 0.8530 -7.1182 MgF+ 7.493e-008 0.003236 0.8530 -7.1944 Na(For)(aq) 4.657e-008 0.003158 1.0000 -7.3319 S-- 4.094e-008 0.001309 0.5384 -7.6568 Fe++ 3.286e-008 0.001830 0.5486 -7.7440 Formic_acid(aq) 2.928e-008 0.001344 1.0000 -7.5334 SO4-- 2.866e-008 0.002746 0.5277 -7.8203 Ag(HS)(aq) 2.008e-008 0.002822 1.0000 -7.6973 (only species > 1e-8 molal listed)

Mineral saturation states log Q/K log Q/K ------Corundum 0.6349s/sat Troilite -0.9020 Saponite-Ca 0.0690s/sat Albite_low -0.9379 Magnetite 0.0159s/sat Albite -0.9382 Au 0.0000 sat Fluorite -0.9531 Calcite 0.0000 sat Pyrrhotite -0.9686 Quartz 0.0000 sat Celadonite -0.9703 Minnesotaite 0.0000 sat Smectite-low-Fe- -0.9725 Pyrite 0.0000 sat Sanidine_high -0.9808 Fluorapatite 0.0000 sat Magnesite -1.0005 Saponite-Mg 0.0000 sat Beidellite-Na -1.0292 Mesolite 0.0000 sat Cronstedtite-7A -1.0562 Nontronite-Ca 0.0000 sat Smectite-high-Fe -1.0803 Acanthite 0.0000 sat Greenalite -1.2158 Diaspore 0.0000 sat Paragonite -1.2407 Dolomite-ord -0.0178 Analcime -1.2434 Dolomite -0.0196 C -1.2496 Nontronite-Mg -0.0574 Beidellite-K -1.2659 Ag -0.0609 Phlogopite -1.2671 Daphnite-14A -0.0664 Pyrophyllite -1.2864 Montmor-Ca -0.1041 Fayalite -1.3554 Muscovite -0.1182 Chamosite-7A -1.4217 Montmor-Mg -0.1288 Ripidolite-14A -1.4451 Witherite -0.1319 Beidellite-H -1.4579 Aragonite -0.1513 Hercynite -1.4993 Hematite -0.1668 Albite_high -1.5625 Chalcedony -0.1736 Laumontite -1.5967 Boehmite -0.1957 Clinoptilolite-C -1.6240 Stilbite -0.2456 Enstatite -1.7016

Cristobalite(alp -0.3117 FeO -1.7863 Annite -0.3225 Mordenite -1.7923 Saponite-Na -0.3916 Sellaite -1.7960 Scolecite -0.4570 Epidote -1.8441 Nontronite-Na -0.4606 Epidote-ord -1.8635 Maximum_Microcli -0.4807 Diopside -1.9894 K-Feldspar -0.5023 Wustite -2.1277 Montmor-Na -0.5210 Clinoptilolite-h -2.2359 Cristobalite(bet -0.5237 Lawsonite -2.2920 Coesite -0.5404 Wairakite -2.4028 Beidellite-Ca -0.5694 Kalsilite -2.4617 Talc -0.5856 Prehnite -2.4859 Siderite -0.5901 Andalusite -2.4876 Beidellite-Mg -0.6253 Kyanite -2.4894 Saponite-K -0.6276 Hedenbergite -2.4953 SiO2(am) -0.6372 Chrysotile -2.5177 Ferrosilite -0.6767 Daphnite-7A -2.5778 Gibbsite -0.6918 Jadeite -2.5828 Nontronite-K -0.6957 Sillimanite -2.6525 Montmor-K -0.6978 Clinochlore-14A -2.6696 Dolomite-dis -0.7900 Anorthite -2.6959 Saponite-H -0.8187 Wollastonite -2.7830 Kaolinite -0.8433 Pseudowollastoni -2.8380 Illite -0.8554 Nepheline -2.8520 Nontronite-H -0.8664 Fe(OH)2 -2.9501 (only minerals with log Q/K > -3 listed)

Gases fugacity log fug. ------H2O(g) 10.53 1.023 CO2(g) 4.138 0.617 CH4(g) 0.007085 -2.150 H2(g) 0.003423 -2.466 H2S(g) 0.001546 -2.811 (only gases with fugacities > 1.e-5 listed)

In fluid Sorbed Kd Original basis total moles moles mg/kg moles mg/kg L/kg ------Ag+ 5.01e-008 2.04e-008 0.00219 Al+++ 0.00405 5.55e-006 0.149 Au+ 7.72e-010 2.13e-010 4.17e-005 Ba++ 1.38e-007 1.38e-007 0.0189 Ca++ 0.0513 7.15e-005 2.86 Cl- 0.00166 0.00166 58.6 F- 0.000454 0.000415 7.86 Fe++ 0.00177 3.32e-008 0.00185 H+ -0.0322 0.0394 39.6 H2O 55.5 55.5 9.97e+005 HCO3- 0.0981 0.0477 2.90e+003 HPO4-- 0.000119 7.54e-009 0.000722 K+ 0.00102 0.00102 39.6 Mg++ 0.00185 1.72e-006 0.0417 Na+ 0.00993 0.00936 215. O2(aq) -0.000169 -0.000156 -4.98 SO4-- 0.000116 6.50e-005 6.23 SiO2(aq) 0.0781 0.00325 195.

Elemental composition In fluid Sorbed total moles moles mg/kg moles mg/kg ------Aluminum 0.004054 5.552e-006 0.1494 Barium 1.384e-007 1.384e-007 0.01895

Calcium 0.05128 7.151e-005 2.858 Carbon 0.09813 0.04771 571.5 Chlorine 0.001659 0.001659 58.64 Fluorine 0.0004544 0.0004148 7.859 Gold 7.717e-010 2.125e-010 4.174e-005 Hydrogen 111.0 111.0 1.116e+005 Iron 0.001771 3.317e-008 0.001848 Magnesium 0.001851 1.722e-006 0.04173 Oxygen 55.93 55.61 8.874e+005 Phosphorus 0.0001190 7.539e-009 0.0002329 Potassium 0.001016 0.001016 39.61 Silicon 0.07808 0.003250 91.02 Silver 5.006e-008 2.038e-008 0.002193 Sodium 0.009931 0.009360 214.6 Sulfur 0.0001155 6.505e-005 2.080

9A: Segment 3

Step # 100 Xi = 1.0000 Temperature = 160.6 C Pressure = 6.152 bars pH = 6.191 log fO2 = -46.435 Eh = -0.3162 volts pe = -3.6745 Ionic strength = 0.012190 Activity of water = 0.999942 Solvent mass = 0.999955 kg Solution mass = 1.002703 kg Solution density = 0.893 g/cm3 Chlorinity = 0.001653 molal Dissolved solids = 2740 mg/kg sol'n Rock mass = 0.008466 kg Carbonate alkalinity= 503.69 mg/kg as CaCO3 Sediment porosity = 0.997

Minerals in system moles log moles grams volume (cm3) ------Ag 1.997e-008 -7.700 2.155e-006 2.052e-007 Au 2.317e-010 -9.635 4.564e-008 2.367e-009 Diaspore 0.003467 -2.460 0.2080 0.06158 Dolomite-ord 0.0004476 -3.349 0.08254 0.02880 Fluorapatite 1.584e-005 -4.800 0.007988 Minnesotaite 0.0001142 -3.943 0.05410 0.01688 Nontronite-Mg 0.0001704 -3.769 0.07184 0.02211 Pyrite 2.488e-005 -4.604 0.002985 0.0005957

Quartz 0.1333 -0.875 8.008 3.024 Saponite-Mg 7.839e-005 -4.106 0.03002 0.01048 ______(total) 8.466 3.164*

Aqueous species molality mg/kg sol'n act. coef. log act. ------CO2(aq) 0.03664 1608. 1.0000 -1.4361 HCO3- 0.01007 612.8 0.8573 -2.0638 Na+ 0.009790 224.5 0.8573 -2.0761 K+ 0.002233 87.06 0.8527 -2.7204 SiO2(aq) 0.002148 128.7 1.0000 -2.6680 Cl- 0.001644 58.12 0.8527 -2.8534 F- 0.0004050 7.674 0.8550 -3.4605 Methane(aq) 4.788e-005 0.7660 1.0000 -4.3198 Ca++ 3.510e-005 1.403 0.5597 -4.7067 CaHCO3+ 1.846e-005 1.861 0.8573 -4.8006 Mg++ 1.087e-005 0.2635 0.5794 -5.2008 H2S(aq) 9.793e-006 0.3328 1.0000 -5.0091 NaHCO3(aq) 9.560e-006 0.8009 1.0000 -5.0195 NaCl(aq) 8.289e-006 0.4831 1.0000 -5.0815 HF(aq) 6.242e-006 0.1245 1.0000 -5.2047 MgHCO3+ 6.228e-006 0.5299 0.8573 -5.2725 HSiO3- 5.863e-006 0.4508 0.8573 -5.2987 HS- 5.286e-006 0.1744 0.8550 -5.3449 OH- 5.221e-006 0.08856 0.8550 -5.3502 Formate 2.148e-006 0.09644 0.8550 -5.7360 H2(aq) 1.853e-006 0.003725 1.0000 -5.7322 NaF(aq) 1.556e-006 0.06515 1.0000 -5.8081 CO3-- 1.390e-006 0.08318 0.5436 -6.1217 AlO2- 1.201e-006 0.07062 0.8573 -5.9875 CaCO3(aq) 1.113e-006 0.1111 1.0000 -5.9536 KCl(aq) 8.422e-007 0.06261 1.0000 -6.0746 H+ 7.343e-007 0.0007381 0.8768 -6.1912 NaHSiO3(aq) 6.136e-007 0.06124 1.0000 -6.2121 MgF+ 4.799e-007 0.02073 0.8573 -6.3857 CaF+ 4.625e-007 0.02725 0.8573 -6.4018 Fe++ 3.643e-007 0.02029 0.5597 -6.6906 Ba++ 1.357e-007 0.01859 0.5491 -7.1277 HAlO2(aq) 8.160e-008 0.004881 1.0000 -7.0883 H2PO4- 7.374e-008 0.007132 0.8573 -7.1992 MgCO3(aq) 6.176e-008 0.005193 1.0000 -7.2093 MgCl+ 5.356e-008 0.003192 0.8573 -7.3380 CaCl+ 4.427e-008 0.003335 0.8573 -7.4207 Na(For)(aq) 2.990e-008 0.002028 1.0000 -7.5244 Formic_acid(aq) 2.170e-008 0.0009961 1.0000 -7.6635 NaOH(aq) 2.056e-008 0.0008202 1.0000 -7.6869 NaAlO2(aq) 1.465e-008 0.001197 1.0000 -7.8343 (only species > 1e-8 molal listed)

Mineral saturation states log Q/K log Q/K ------Quartz 0.0000 sat Ice -0.7519 Ag 0.0000 sat Beidellite-Mg -0.7539 Saponite-Mg 0.0000 sat Kaolinite -0.7812 Au 0.0000 sat Ferrosilite -0.7869 Nontronite-Mg 0.0000 sat Nontronite-H -0.8490 Diaspore 0.0000 sat Saponite-H -0.8498 Fluorapatite 0.0000 sat Beidellite-Ca -0.8635 Minnesotaite 0.0000 sat Illite -0.8659 Dolomite-ord 0.0000 sat Dolomite-dis -0.8742 Pyrite 0.0000 sat Sanidine_high -1.0246

Dolomite -0.0015 Troilite -1.0523 Daphnite-14A -0.0533 Stilbite -1.0686 Muscovite -0.0619 Smectite-low-Fe- -1.0856 Saponite-Ca -0.0985 Goethite -1.0880 Nontronite-Ca -0.1086 Cronstedtite-7A -1.0908 Acanthite -0.1180 Pyrrhotite -1.1222 Siderite -0.1340 Greenalite -1.1290 Montmor-Mg -0.1728 Sellaite -1.1537 Chalcedony -0.1865 Smectite-high-Fe -1.2341 Magnetite -0.1995 Beidellite-Na -1.2407 Boehmite -0.2266 Phlogopite -1.2647 Tridymite -0.2615 Fluorite -1.2661 Annite -0.2667 Beidellite-K -1.3461 Hematite -0.3012 Pyrophyllite -1.3988 Montmor-Ca -0.3191 Albite_low -1.4017 Corundum -0.3298 Albite -1.4017 Witherite -0.3360 Scolecite -1.4937 Cristobalite(alp -0.3434 Ripidolite-14A -1.5219 Maximum_Microcli -0.4322 Chamosite-7A -1.5701 K-Feldspar -0.4535 Fayalite -1.6003 Saponite-Na -0.4764 Beidellite-H -1.6155 Nontronite-Na -0.4864 Analcime -1.6412 C -0.5045 Paragonite -1.7238 Magnesite -0.5323 Enstatite -1.8971 Calcite -0.5357 Hercynite -1.9177 Coesite -0.5755 FeO -2.0258 Talc -0.5794 Albite_high -2.1179 Cristobalite(bet -0.5808 Monohydrocalcite -2.1769 Saponite-K -0.5811 Mordenite -2.2705 Nontronite-K -0.5905 Wustite -2.3913 Montmor-Na -0.6503 Chrysotile -2.5011 Aragonite -0.6835 Kalsilite -2.5724 Mesolite -0.7064 Daphnite-7A -2.6708 Montmor-K -0.7118 Laumontite -2.6864 SiO2(am) -0.7136 Clinochlore-14A -2.8303 Gibbsite -0.7430 Kyanite -2.8936 Celadonite -0.7461 Andalusite -2.9274 (only minerals with log Q/K > -3 listed)

Gases fugacity log fug. ------H2O(g) 5.064 0.704 CO2(g) 4.043 0.607 CH4(g) 0.04050 -1.393 H2(g) 0.001622 -2.790 H2S(g) 0.0003776 -3.423 (only gases with fugacities > 1.e-5 listed)

In fluid Sorbed Kd Original basis total moles moles mg/kg moles mg/kg L/kg ------Ag+ 2.75e-008 7.56e-009 0.000813 Al+++ 0.00355 1.30e-006 0.0349 Au+ 2.52e-010 2.06e-011 4.05e-006 Ba++ 1.38e-007 1.38e-007 0.0188 Ca++ 0.000582 5.52e-005 2.21 Cl- 0.00165 0.00165 58.4 F- 0.000430 0.000414 7.84 Fe++ 0.000708 3.66e-007 0.0204 H+ 0.0232 0.0367 36.9 H2O 55.5 55.5 9.97e+005 HCO3- 0.0477 0.0468 2.85e+003 HPO4-- 4.76e-005 7.84e-008 0.00751

K+ 0.00223 0.00223 87.1 Mg++ 0.000742 1.77e-005 0.429 Na+ 0.00981 0.00981 225. O2(aq) -0.000130 -0.000128 -4.08 SO4-- 6.49e-005 1.51e-005 1.45 SiO2(aq) 0.137 0.00215 129.

Elemental composition In fluid Sorbed total moles moles mg/kg moles mg/kg ------Aluminum 0.003551 1.297e-006 0.03490 Barium 1.376e-007 1.376e-007 0.01885 Calcium 0.0005820 5.518e-005 2.206 Carbon 0.04769 0.04679 560.5 Chlorine 0.001653 0.001653 58.44 Fluorine 0.0004296 0.0004137 7.839 Gold 2.523e-010 2.061e-011 4.049e-006 Hydrogen 111.0 111.0 1.116e+005 Iron 0.0007084 3.660e-007 0.02038 Magnesium 0.0007415 1.769e-005 0.4289 Oxygen 55.89 55.61 8.874e+005 Phosphorus 4.760e-005 7.843e-008 0.002423 Potassium 0.002234 0.002234 87.09 Silicon 0.1368 0.002154 60.34 Silver 2.753e-008 7.559e-009 0.0008132 Sodium 0.009810 0.009810 224.9 Sulfur 6.485e-005 1.509e-005 0.4825

10A: Segment 4

Step # 100 Xi = 1.0000 Temperature = 141.0 C Pressure = 3.655 bars pH = 5.914 log fO2 = -46.235 Eh = -0.2194 volts pe = -2.6702 Ionic strength = 0.013093 Activity of water = 0.999942 Solvent mass = 1.000020 kg Solution mass = 1.002753 kg Solution density = 0.915 g/cm3 Chlorinity = 0.001647 molal Dissolved solids = 2725 mg/kg sol'n Rock mass = 0.009990 kg Carbonate alkalinity= 398.13 mg/kg as CaCO3 Sediment porosity = 0.997

moles moles grams cm3 Reactants remaining reacted reacted reacted ------Ag -6.107e-025 9.271e-010 1.000e-007 9.523e-009 Barite -2.880e-018 0.002142 0.5000 0.1116 Quartz -1.832e-016 0.1581 9.500 3.587

Minerals in system moles log moles grams volume (cm3) ------Barite 0.001044 -2.981 0.2438 0.05442 Diaspore 9.462e-007 -6.024 5.676e-005 1.680e-005 Pyrite 3.645e-007 -6.438 4.373e-005 8.726e-006 Quartz 0.1586 -0.800 9.529 3.598 Witherite 0.001097 -2.960 0.2165 0.05027

______(total) 9.990 3.703

Aqueous species molality mg/kg sol'n act. coef. log act. ------CO2(aq) 0.03762 1651. 1.0000 -1.4246 Na+ 0.009768 224.0 0.8603 -2.0755 HCO3- 0.007971 485.1 0.8603 -2.1638 K+ 0.002193 85.51 0.8557 -2.7266 SiO2(aq) 0.001656 99.24 1.0000 -2.7809 Cl- 0.001640 57.99 0.8557 -2.8528 SO4-- 0.0009925 95.09 0.5455 -3.2665 F- 0.0004036 7.646 0.8580 -3.4606 H2S(aq) 4.799e-005 1.631 1.0000 -4.3188 Ca++ 3.687e-005 1.473 0.5673 -4.6795 KSO4- 3.394e-005 4.575 0.8603 -4.5346 HS- 1.516e-005 0.5002 0.8580 -4.8857 MgSO4(aq) 1.187e-005 1.425 1.0000 -4.9255 NaHCO3(aq) 1.094e-005 0.9165 1.0000 -4.9610 CaHCO3+ 9.902e-006 0.9983 0.8603 -5.0696 CaSO4(aq) 7.707e-006 1.046 1.0000 -5.1131 HF(aq) 7.490e-006 0.1494 1.0000 -5.1255 NaCl(aq) 6.447e-006 0.3758 1.0000 -5.1906 Mg++ 4.356e-006 0.1056 0.5873 -5.5920 HSO4- 3.010e-006 0.2914 0.8603 -5.5867 HSiO3- 2.125e-006 0.1634 0.8603 -5.7380 OH- 1.814e-006 0.03077 0.8580 -5.8078 H+ 1.384e-006 0.001392 0.8798 -5.9143 MgHCO3+ 1.275e-006 0.1085 0.8603 -5.9600 NaF(aq) 1.184e-006 0.04959 1.0000 -5.9266 Ba++ 7.517e-007 0.1030 0.5567 -6.3783 CO3-- 6.917e-007 0.04139 0.5511 -6.4188 KCl(aq) 6.082e-007 0.04522 1.0000 -6.2159 CaCO3(aq) 3.311e-007 0.03304 1.0000 -6.4801 CaF+ 3.045e-007 0.01794 0.8603 -6.5817 AlO2- 2.996e-007 0.01762 0.8603 -6.5889 NaHSiO3(aq) 2.300e-007 0.02296 1.0000 -6.6382 MgF+ 1.256e-007 0.005422 0.8603 -6.9665 H2PO4- 7.495e-008 0.007249 0.8603 -7.1906 HAlO2(aq) 4.494e-008 0.002688 1.0000 -7.3474 Formate 4.251e-008 0.001908 0.8580 -7.4380 H2(aq) 3.244e-008 6.521e-005 1.0000 -7.4890 CaCl+ 3.132e-008 0.002359 0.8603 -7.5696 MgCl+ 1.395e-008 0.0008314 0.8603 -7.9207 (only species > 1e-8 molal listed)

Mineral saturation states log Q/K log Q/K ------Diaspore 0.0000 sat Beidellite-Na -1.4372 Barite 0.0000 sat Sanidine_high -1.4385 Pyrite 0.0000 sat Ag -1.4436 Witherite 0.0000 sat Illite -1.4627 Quartz 0.0000 sat Pyrophyllite -1.4743 Chalcedony -0.1953 Mesolite -1.4900 Tridymite -0.2145 Beidellite-K -1.5259 Boehmite -0.2471 Magnesite -1.6501 Cristobalite(alp -0.3650 Dolomite-ord -1.6724 Muscovite -0.4058 Dolomite -1.6737 Acanthite -0.5935 Beidellite-H -1.7217 Coesite -0.5995 Sellaite -1.8281 Cristobalite(bet -0.6201 Anhydrite -1.8368 Ice -0.6595 Albite -1.8801

Kaolinite -0.7407 Albite_low -1.8802 Gibbsite -0.7630 Stilbite -1.9376 SiO2(am) -0.7642 Analcime -2.0722 Maximum_Microcli -0.7834 Paragonite -2.2141 K-Feldspar -0.8026 Celadonite -2.4431 Corundum -0.9081 Scolecite -2.4650 Montmor-Mg -0.9192 Bassanite -2.5033 Montmor-Ca -0.9857 CaSO4:0.5H2O(bet -2.5671 Beidellite-Mg -1.0792 Dolomite-dis -2.6160 Beidellite-Ca -1.1055 Gypsum -2.6197 Calcite -1.1484 Monohydrocalcite -2.6424 Au -1.1903 Albite_high -2.6587 Montmor-Na -1.2693 Fluorapatite -2.6629 Aragonite -1.2944 Mordenite -2.7395 Montmor-K -1.3233 C -2.9263 Fluorite -1.4024 (only minerals with log Q/K > -3 listed)

Gases fugacity log fug. ------CO2(g) 4.128 0.616 H2O(g) 3.036 0.482 H2S(g) 0.001777 -2.750 H2(g) 3.257e-005 -4.487 (only gases with fugacities > 1.e-5 listed)

In fluid Sorbed Kd Original basis total moles moles mg/kg moles mg/kg L/kg ------Ag+ 8.46e-009 8.46e-009 0.000910 Al+++ 1.29e-006 3.47e-007 0.00934 Au+ 2.06e-011 2.06e-011 4.04e-006 Ba++ 0.00214 7.56e-007 0.104 Ca++ 5.51e-005 5.51e-005 2.20 Cl- 0.00165 0.00165 58.2 F- 0.000413 0.000413 7.82 Fe++ 3.65e-007 7.82e-010 4.36e-005 H+ 0.0366 0.0377 37.9 H2O 55.5 55.5 9.97e+005 HCO3- 0.0467 0.0456 2.78e+003 HPO4-- 7.82e-008 7.82e-008 0.00749 K+ 0.00223 0.00223 86.9 Mg++ 1.77e-005 1.77e-005 0.428 Na+ 0.00979 0.00979 224. O2(aq) -0.000128 -0.000126 -4.03 SO4-- 0.00216 0.00111 107. SiO2(aq) 0.160 0.00166 99.4

Elemental composition In fluid Sorbed total moles moles mg/kg moles mg/kg ------Aluminum 1.293e-006 3.473e-007 0.009344 Barium 0.002142 7.565e-007 0.1036 Calcium 5.514e-005 5.514e-005 2.204 Carbon 0.04671 0.04562 546.4 Chlorine 0.001647 0.001647 58.24 Fluorine 0.0004127 0.0004127 7.818 Gold 2.056e-011 2.056e-011 4.039e-006 Hydrogen 111.0 111.0 1.116e+005 Iron 3.653e-007 7.822e-010 4.356e-005 Magnesium 1.765e-005 1.765e-005 0.4278 Oxygen 55.94 55.62 8.874e+005 Phosphorus 7.825e-008 7.825e-008 0.002417

Potassium 0.002228 0.002228 86.86 Silicon 0.1603 0.001659 46.46 Silver 8.464e-009 8.464e-009 0.0009105 Sodium 0.009787 0.009787 224.4 Sulfur 0.002157 0.001112 35.57

11A: Segment 5

Step # 100 Xi = 1.0000 Temperature = 119.1 C Pressure = 2.003 bars pH = 6.204 log fO2 = -49.296 Eh = -0.2245 volts pe = -2.8845 Ionic strength = 0.011428 Activity of water = 0.999933 Solvent mass = 1.999085 kg Solution mass = 2.002302 kg Solution density = 0.937 g/cm3 Chlorinity = 0.001892 molal Dissolved solids = 1607 mg/kg sol'n Rock mass = 0.010940 kg Carbonate alkalinity= 438.90 mg/kg as CaCO3 Sediment porosity = 0.998

moles moles grams cm3 Reactants remaining reacted reacted reacted ------Ag -1.082e-024 7.463e-010 8.050e-008 7.666e-009 Al+++ 2.617e-019 0.0001110 0.002995 Albite -9.487e-018 0.009534 2.500 0.9558 Anorthite 8.335e-018 0.008986 2.500 0.9057 Au 1.212e-026 2.031e-010 4.000e-008 2.074e-009 Ca++ 1.950e-018 0.001480 0.05932 Cl- 2.650e-018 0.002140 0.07587 Enstatite 8.470e-019 0.001245 0.1250 0.03894 Fe++ 1.904e-030 2.230e-015 1.245e-013 Ferrosilite 5.475e-018 0.01800 2.375 0.5932 H+ 3.388e-018 0.003520 0.003548 H2O -6.117e-014 55.51 1000. HCO3- 1.199e-017 0.006490 0.3960 K+ 2.118e-019 0.0002200 0.008602 Magnetite 1.499e-019 0.0005399 0.1250 0.02404 Mg++ 6.268e-019 0.0009840 0.02392 Na+ -5.363e-018 0.002510 0.05770 O2(aq) 2.181e-019 0.0001940 0.006208 Quartz 4.499e-017 0.03329 2.000 0.7552 SO4-- 2.500e-018 0.001440 0.1383 SiO2(aq) -3.673e-018 0.002080 0.1250

Minerals in system moles log moles grams volume (cm3) ------Acanthite 3.421e-009 -8.466 8.477e-007 1.170e-007 Au 2.211e-010 -9.655 4.355e-008 2.259e-009 Boehmite 0.006041 -2.219 0.3624 0.1180 Dolomite-ord 0.002208 -2.656 0.4072 0.1421 Hematite 0.009201 -2.036 1.469 0.2786 Mesolite 0.003024 -2.519 1.173 0.5177 Muscovite 0.001390 -2.857 0.5536 0.1956 Pyrite 0.001217 -2.915 0.1461 0.02915

100

Quartz 0.05153 -1.288 3.096 1.169 Stilbite 0.005224 -2.282 3.733 1.742 ______(total) 10.94 4.192

Aqueous species molality mg/kg sol'n act. coef. log act. ------CO2(aq) 0.01489 654.4 1.0000 -1.8270 Na+ 0.009496 218.0 0.8745 -2.0807 HCO3- 0.008741 532.5 0.8745 -2.1167 Cl- 0.001886 66.74 0.8706 -2.7848 SiO2(aq) 0.001204 72.22 1.0000 -2.9194 K+ 0.0005105 19.93 0.8706 -3.3522 Ca++ 0.0004109 16.44 0.6022 -3.6065 F- 0.0002030 3.851 0.8726 -3.7517 CaHCO3+ 8.061e-005 8.136 0.8745 -4.1519 SO4-- 5.386e-005 5.166 0.5827 -4.5033 NaHCO3(aq) 1.782e-005 1.495 1.0000 -4.7491 Mg++ 1.480e-005 0.3591 0.6199 -5.0375 NaCl(aq) 5.704e-006 0.3328 1.0000 -5.2438 CaCO3(aq) 5.257e-006 0.5253 1.0000 -5.2792 CaSO4(aq) 3.488e-006 0.4741 1.0000 -5.4574 MgHCO3+ 3.128e-006 0.2664 0.8745 -5.5630 HSiO3- 2.356e-006 0.1813 0.8745 -5.6861 OH- 1.940e-006 0.03295 0.8726 -5.7713 CO3-- 1.628e-006 0.09756 0.5878 -6.0191 HF(aq) 1.194e-006 0.02384 1.0000 -5.9231 MgSO4(aq) 1.181e-006 0.1419 1.0000 -5.9278 CaF+ 1.100e-006 0.06487 0.8745 -6.0169 Fe++ 8.444e-007 0.04708 0.6022 -6.2938 H+ 7.015e-007 0.0007059 0.8911 -6.2040 NaF(aq) 4.465e-007 0.01872 1.0000 -6.3502 AlO2- 4.078e-007 0.02401 0.8745 -6.4478 H2S(aq) 3.640e-007 0.01239 1.0000 -6.4388 KSO4- 3.254e-007 0.04391 0.8745 -6.5458 CaCl+ 2.810e-007 0.02119 0.8745 -6.6095 NaHSiO3(aq) 2.758e-007 0.02756 1.0000 -6.5594 HS- 2.306e-007 0.007615 0.8726 -6.6963 MgF+ 1.440e-007 0.006225 0.8745 -6.8999 KCl(aq) 1.189e-007 0.008848 1.0000 -6.9249 MgCO3(aq) 4.315e-008 0.003632 1.0000 -7.3650 HSO4- 4.208e-008 0.004079 0.8745 -7.4341 HAlO2(aq) 4.123e-008 0.002469 1.0000 -7.3848 MgCl+ 3.662e-008 0.002185 0.8745 -7.4945 Formate 2.215e-008 0.0009957 0.8726 -7.7137 H2(aq) 1.011e-008 2.034e-005 1.0000 -7.9954 (only species > 1e-8 molal listed)

Mineral saturation states log Q/K log Q/K ------Nontronite-Ca 0.5912s/sat Maximum_Microcli -0.9313 Nontronite-Mg 0.5131s/sat K-Feldspar -0.9471 Diaspore 0.2717s/sat Illite -0.9884 Nontronite-Na 0.1389s/sat Corundum -0.9998 Dolomite-ord 0.0000 sat Pyrophyllite -1.0234 Stilbite 0.0000 sat Dolomite-dis -1.0293 Acanthite 0.0000 sat Fluorite -1.0566 Boehmite 0.0000 sat Beidellite-K -1.1092 Muscovite 0.0000 sat Magnesite -1.1647 Mesolite 0.0000 sat Beidellite-H -1.2189 Quartz 0.0000 sat Monohydrocalcite -1.3696 Pyrite 0.0000 sat Paragonite -1.3831

101

Au 0.0000 sat Ferrosilite -1.5215 Hematite 0.0000 sat Albite -1.5787 Dolomite -0.0010 Albite_low -1.5789 Calcite -0.0331 Sanidine_high -1.6642 Nontronite-K -0.1284 Minnesotaite -1.7177 Kaolinite -0.1499 Analcime -1.7520 Tridymite -0.1701 Cronstedtite-7A -1.7808 Aragonite -0.1777 Celadonite -1.9651 Chalcedony -0.2061 Smectite-low-Fe- -1.9970 Montmor-Ca -0.2138 Laumontite -2.1226 Nontronite-H -0.2343 Sellaite -2.1527 Montmor-Mg -0.2468 Mordenite -2.1800 Ag -0.3218 Daphnite-14A -2.3496 Beidellite-Ca -0.3890 Troilite -2.3627 Cristobalite(alp -0.3916 Chamosite-7A -2.3928 Siderite -0.4084 Anhydrite -2.3988 Beidellite-Mg -0.4666 Albite_high -2.4345 Gibbsite -0.5013 Pyrrhotite -2.4387 Ice -0.5564 Annite -2.4693 Magnetite -0.5876 Smectite-high-Fe -2.5571 Montmor-Na -0.6149 Hercynite -2.5727 Coesite -0.6292 Dawsonite -2.6970 Cristobalite(bet -0.6697 Greenalite -2.7235 Goethite -0.7595 Lawsonite -2.8323 Scolecite -0.8179 Saponite-Ca -2.8357 SiO2(am) -0.8274 Saponite-Mg -2.9216 Beidellite-Na -0.8409 Kyanite -2.9454 Montmor-K -0.8578 FeO -2.9570 (only minerals with log Q/K > -3 listed)

Gases fugacity log fug. ------H2O(g) 1.591 0.202 CO2(g) 1.551 0.191 H2S(g) 1.237e-005 -4.908 H2(g) 1.160e-005 -4.936 (only gases with fugacities > 1.e-5 listed)

In fluid Sorbed Kd Original basis total moles moles mg/kg moles mg/kg L/kg ------Ag+ 9.18e-009 2.34e-009 0.000126 Al+++ 0.0276 9.03e-007 0.0122 Au+ 2.24e-010 2.46e-012 2.42e-007 Ca++ 0.0105 0.00100 20.1 Cl- 0.00378 0.00378 67.0 F- 0.000412 0.000412 3.91 Fe++ 0.0196 1.69e-006 0.0472 H+ -0.111 0.0298 15.0 H2O 111. 111. 9.98e+005 HCO3- 0.0519 0.0475 1.45e+003 K+ 0.00244 0.00102 19.9 Mg++ 0.00225 3.86e-005 0.469 Na+ 0.0218 0.0190 219. O2(aq) 0.000337 -2.42e-006 -0.0386 SO4-- 0.00255 0.000119 5.71 SiO2(aq) 0.103 0.00241 72.4

Elemental composition In fluid Sorbed total moles moles mg/kg moles mg/kg ------Aluminum 0.02762 9.028e-007 0.01217 Calcium 0.01052 0.001003 20.07

102

Carbon 0.05188 0.04746 284.7 Chlorine 0.003782 0.003782 66.96 Fluorine 0.0004116 0.0004116 3.906 Gold 2.236e-010 2.463e-012 2.423e-007 Hydrogen 222.1 222.0 1.117e+005 Iron 0.01962 1.692e-006 0.04720 Magnesium 0.002247 3.865e-005 0.4691 Oxygen 111.4 111.1 8.876e+005 Potassium 0.002443 0.001021 19.94 Silicon 0.1028 0.002412 33.83 Silver 9.183e-009 2.341e-009 0.0001261 Sodium 0.02179 0.01903 218.5 Sulfur 0.002554 0.0001189 1.905

12A: Segment 6

Step # 100 Xi = 1.0000 Temperature = 96.0 C Pressure = 1.013 bars pH = 6.737 log fO2 = -55.374 Eh = -0.2882 volts pe = -3.9342 Ionic strength = 0.009903 Activity of water = 0.999929 Solvent mass = 1.999621 kg Solution mass = 2.001493 kg Solution density = 0.958 g/cm3 Chlorinity = 0.002015 molal Dissolved solids = 935 mg/kg sol'n Rock mass = 0.011115 kg Carbonate alkalinity= 375.98 mg/kg as CaCO3 Sediment porosity = 0.998

Minerals in system moles log moles grams volume (cm3) ------Ag 1.163e-009 -8.934 1.255e-007 1.195e-008

103

Au 2.042e-010 -9.690 4.022e-008 2.086e-009 Calcite 0.002659 -2.575 0.2661 0.09820 Diaspore 0.01492 -1.826 0.8953 0.2651 Dolomite-ord 0.003470 -2.460 0.6399 0.2233 Hematite 0.006071 -2.217 0.9694 0.1838 Mesolite 0.003614 -2.442 1.401 0.6187 Minnesotaite 0.005609 -2.251 2.658 0.8294 Pyrite 0.0007492 -3.125 0.08989 0.01794 Quartz 0.06981 -1.156 4.194 1.584 ______(total) 11.11 3.820

Aqueous species molality mg/kg sol'n act. coef. log act. ------Na+ 0.008586 197.2 0.8878 -2.1179 HCO3- 0.007464 455.0 0.8878 -2.1787 CO2(aq) 0.002794 122.9 1.0000 -2.5538 Cl- 0.002011 71.22 0.8846 -2.7499 SiO2(aq) 0.0008078 48.49 1.0000 -3.0927 K+ 0.0003645 14.24 0.8846 -3.4916 Ca++ 0.0002929 11.73 0.6364 -3.7296 F- 0.0001024 1.943 0.8862 -4.0423 CaHCO3+ 3.351e-005 3.385 0.8878 -4.5264 NaHCO3(aq) 2.112e-005 1.773 1.0000 -4.6752 Mg++ 1.027e-005 0.2494 0.6520 -5.1742 CaCO3(aq) 6.702e-006 0.6702 1.0000 -5.1738 CO3-- 4.867e-006 0.2918 0.6238 -5.5177 NaCl(aq) 4.355e-006 0.2543 1.0000 -5.3610 HSiO3- 3.713e-006 0.2860 0.8878 -5.4819 OH- 2.998e-006 0.05094 0.8862 -5.5757 MgHCO3+ 1.246e-006 0.1062 0.8878 -5.9561 Fe++ 1.147e-006 0.06398 0.6364 -6.1368 Methane(aq) 5.430e-007 0.008703 1.0000 -6.2652 NaHSiO3(aq) 4.618e-007 0.04618 1.0000 -6.3355 HS- 3.325e-007 0.01099 0.8862 -6.5307 CaF+ 2.579e-007 0.01522 0.8878 -6.6403 AlO2- 2.212e-007 0.01303 0.8878 -6.7070 H+ 2.031e-007 0.0002045 0.9018 -6.7372 H2S(aq) 1.649e-007 0.005615 1.0000 -6.7828 NaF(aq) 1.559e-007 0.006542 1.0000 -6.8070 CaCl+ 1.531e-007 0.01155 0.8878 -6.8666 Formate 1.315e-007 0.005912 0.8862 -6.9337 HF(aq) 1.069e-007 0.002136 1.0000 -6.9712 KCl(aq) 6.422e-008 0.004783 1.0000 -7.1923 MgCO3(aq) 6.199e-008 0.005222 1.0000 -7.2077 H2(aq) 4.376e-008 8.814e-005 1.0000 -7.3589 MgF+ 3.451e-008 0.001493 0.8878 -7.5138 MgCl+ 1.881e-008 0.001123 0.8878 -7.7773 (only species > 1e-8 molal listed)

Mineral saturation states log Q/K log Q/K ------Nontronite-Ca 0.7311s/sat Greenalite -0.9321 Nontronite-Mg 0.6285s/sat C -1.0230 Nontronite-Na 0.3528s/sat Ferrosilite -1.0521 Nontronite-K 0.0840s/sat Scolecite -1.0727 Hematite 0.0000 sat Beidellite-Ca -1.0887 Quartz 0.0000 sat Dolomite-dis -1.1311 Au 0.0000 sat Montmor-K -1.1709 Calcite 0.0000 sat Monohydrocalcite -1.1814 Pyrite 0.0000 sat Beidellite-Mg -1.1909 Dolomite-ord 0.0000 sat Magnesite -1.2830

104

Ag 0.0000 sat Illite -1.4186 Minnesotaite 0.0000 sat Beidellite-Na -1.4667 Diaspore 0.0000 sat Celadonite -1.6347 Mesolite 0.0000 sat Albite -1.6641 Dolomite -0.0007 Albite_low -1.6642 Daphnite-14A -0.0164 Pyrophyllite -1.6759 Stilbite -0.0272 Troilite -1.6867 Magnetite -0.0886 Sanidine_high -1.7338 Aragonite -0.1436 Beidellite-K -1.7361 Tridymite -0.1448 Pyrrhotite -1.7672 Siderite -0.1461 Analcime -1.8027 Nontronite-H -0.1837 Fluorite -1.8667 Chalcedony -0.2190 Chamosite-7A -1.9355 Boehmite -0.2999 Smectite-low-Fe- -1.9418 Acanthite -0.3733 Beidellite-H -2.0058 Cristobalite(alp -0.4232 Paragonite -2.0279 Ice -0.4486 Corundum -2.1947 Muscovite -0.5073 Fayalite -2.1984 Cronstedtite-7A -0.5367 Mordenite -2.3243 Montmor-Ca -0.5942 Saponite-Ca -2.3424 Kaolinite -0.6417 Smectite-high-Fe -2.3980 Montmor-Mg -0.6469 Saponite-Mg -2.4513 Coesite -0.6646 Laumontite -2.4640 Goethite -0.6716 Albite_high -2.6114 Annite -0.7186 FeO -2.6165 Cristobalite(bet -0.7300 Saponite-Na -2.7208 Gibbsite -0.7666 Dawsonite -2.7261 SiO2(am) -0.9059 Talc -2.8960 Maximum_Microcli -0.9088 Daphnite-7A -2.9109 Montmor-Na -0.9182 Hercynite -2.9471 K-Feldspar -0.9200 Saponite-K -2.9899 (only minerals with log Q/K > -3 listed)

Gases fugacity log fug. ------H2O(g) 0.7264 -0.139 CO2(g) 0.2566 -0.591 CH4(g) 0.0006324 -3.199 H2(g) 5.605e-005 -4.251 (only gases with fugacities > 1.e-5 listed)

In fluid Sorbed Kd Original basis total moles moles mg/kg moles mg/kg L/kg ------Ag+ 1.91e-009 7.51e-010 4.05e-005 Al+++ 0.0221 4.64e-007 0.00625 Au+ 2.04e-010 1.28e-013 1.26e-008 Ca++ 0.00917 0.000667 13.4 Cl- 0.00403 0.00403 71.4 F- 0.000206 0.000206 1.95 Fe++ 0.0297 2.30e-006 0.0641 H+ -0.134 0.00555 2.80 H2O 111. 111. 9.99e+005 HCO3- 0.0302 0.0206 629. K+ 0.000729 0.000729 14.2 Mg++ 0.00349 2.33e-005 0.282 Na+ 0.0197 0.0172 198. O2(aq) 0.000409 -4.34e-006 -0.0694 SO4-- 0.00150 1.01e-006 0.0484 SiO2(aq) 0.105 0.00162 48.7

105

Elemental composition In fluid Sorbed total moles moles mg/kg moles mg/kg ------Aluminum 0.02212 4.636e-007 0.006249 Calcium 0.009170 0.0006669 13.35 Carbon 0.03025 0.02065 123.9 Chlorine 0.004030 0.004030 71.38 Fluorine 0.0002058 0.0002058 1.954 Gold 2.043e-010 1.280e-013 1.260e-008 Hydrogen 222.1 222.0 1.118e+005 Iron 0.02972 2.297e-006 0.06410 Magnesium 0.003494 2.326e-005 0.2825 Oxygen 111.4 111.1 8.878e+005 Potassium 0.0007290 0.0007290 14.24 Silicon 0.1047 0.001624 22.78 Silver 1.914e-009 7.512e-010 4.048e-005 Sodium 0.01966 0.01722 197.8 Sulfur 0.001499 1.009e-006 0.01616

106

APPENDIX IV

Reaction path output results for segments in the high S model

107

13A: React output listing for the end of segment 2 (high S model)

Step # 100 Xi = 1.0000 Temperature = 192.8 C Pressure = 13.230 bars pH = 6.344 log fO2 = -41.768 Eh = -0.3373 volts pe = -3.6485 Ionic strength = 0.009885 Activity of water = 0.999942 Solvent mass = 0.999967 kg Solution mass = 1.002431 kg Solution density = 0.855 g/cm3 Chlorinity = 0.001661 molal Dissolved solids = 2458 mg/kg sol'n Rock mass = 0.010151 kg Carbonate alkalinity= 314.19 mg/kg as CaCO3

moles moles grams cm3 Reactants remaining reacted reacted reacted ------Ag -2.443e-024 3.708e-009 4.000e-007 3.809e-008 Albite 3.414e-019 0.0002383 0.06250 0.02389 Anorthite -5.548e-020 0.0002247 0.06250 0.02264 Calcite 3.253e-019 0.04996 5.000 1.845 Muscovite 1.097e-019 0.0003138 0.1250 0.04416 Quartz -9.162e-017 0.07906 4.750 1.794

Minerals in system moles log moles grams volume (cm3) ------Acanthite 7.461e-006 -5.127 0.001849 0.0002552 Au 6.818e-007 -6.166 0.0001343 6.965e-006 Calcite 0.04971 -1.304 4.975 1.836 Diaspore 0.0002481 -3.605 0.01489 0.004407 Mesolite 0.0006914 -3.160 0.2681 0.1184 Quartz 0.08139 -1.089 4.891 1.847 Witherite 4.944e-008 -7.306 9.756e-006 2.265e-006 ______(total) 10.15 3.806

Aqueous species molality mg/kg sol'n act. coef. log act. ------CO2(aq) 0.03265 1433. 1.0000 -1.4861 Na+ 0.008586 196.9 0.8566 -2.1334 HCO3- 0.006285 382.6 0.8566 -2.2689 SiO2(aq) 0.003230 193.6 1.0000 -2.4908 H2S(aq) 0.002384 81.05 1.0000 -2.6227 Cl- 0.001649 58.32 0.8523 -2.8522 HS- 0.001376 45.40 0.8545 -2.9297 K+ 0.001077 42.00 0.8523 -3.0373 F- 0.0004016 7.611 0.8545 -3.4645 Ca++ 4.980e-005 1.991 0.5568 -4.5570 CaHCO3+ 3.643e-005 3.674 0.8566 -4.5058 SO4-- 2.724e-005 2.611 0.5367 -4.8350 HSiO3- 1.265e-005 0.9725 0.8566 -4.9653 OH- 1.225e-005 0.2078 0.8545 -4.9803 NaCl(aq) 1.147e-005 0.6688 1.0000 -4.9404 HF(aq) 9.403e-006 0.1877 1.0000 -5.0267 AlO2- 4.718e-006 0.2776 0.8566 -5.3934 CaCO3(aq) 2.688e-006 0.2683 1.0000 -5.5706 H2(aq) 2.382e-006 0.004789 1.0000 -5.6231 NaF(aq) 2.191e-006 0.09176 1.0000 -5.6594 S-- 1.989e-006 0.06361 0.5470 -5.9635

108

CaF+ 1.501e-006 0.08846 0.8566 -5.8908 NaHSiO3(aq) 1.189e-006 0.1187 1.0000 -5.9248 KSO4- 1.132e-006 0.1526 0.8566 -6.0134 Formate 1.002e-006 0.04499 0.8545 -6.0675 CaSO4(aq) 9.023e-007 0.1225 1.0000 -6.0446 Mg++ 8.877e-007 0.02152 0.5754 -6.2918 CO3-- 8.297e-007 0.04966 0.5419 -6.3472 MgHCO3+ 6.986e-007 0.05946 0.8566 -6.2230 KCl(aq) 6.911e-007 0.05140 1.0000 -6.1604 H+ 5.177e-007 0.0005205 0.8749 -6.3440 Methane(aq) 4.737e-007 0.007581 1.0000 -6.3245 Ba++ 2.609e-007 0.03574 0.5470 -6.8456 HAlO2(aq) 2.013e-007 0.01204 1.0000 -6.6963 HSO4- 1.779e-007 0.01723 0.8566 -6.8170 Ag(HS)(aq) 1.556e-007 0.02188 1.0000 -6.8079 CaCl+ 1.307e-007 0.009848 0.8566 -6.9509 Ag(HS)2- 1.298e-007 0.02254 0.8626 -6.9508 NaAlO2(aq) 9.426e-008 0.007707 1.0000 -7.0257 MgF+ 8.376e-008 0.003618 0.8566 -7.1442 Au(HS)2- 8.317e-008 0.02183 0.8626 -7.1442 NaOH(aq) 7.670e-008 0.003060 1.0000 -7.1152 Au(HS)(aq) 1.687e-008 0.003871 1.0000 -7.7729 Na(For)(aq) 1.540e-008 0.001045 1.0000 -7.8124 Formic_acid(aq) 1.156e-008 0.0005308 1.0000 -7.9370 (only species > 1e-8 molal listed)

Mineral saturation states log Q/K log Q/K ------Corundum 0.6319s/sat Albite -1.0162 Diaspore 0.0000 sat Celadonite -1.0209 Calcite 0.0000 sat Beidellite-Na -1.0551 Au 0.0000 sat Ag -1.1124 Acanthite 0.0000 sat Magnesite -1.1156 Mesolite 0.0000 sat Beidellite-K -1.2711 Quartz 0.0000 sat Pyrophyllite -1.2868 Witherite 0.0000 sat Analcime -1.3182 Saponite-Ca -0.0261 Paragonite -1.3188 Montmor-Ca -0.1031 Phlogopite -1.3904 Saponite-Mg -0.1140 Beidellite-H -1.4584 Dolomite-ord -0.1327 Fluorapatite -1.4867 Muscovite -0.1333 Laumontite -1.5179 Dolomite -0.1344 Clinoptilolite-C -1.5645 Montmor-Mg -0.1468 Barite -1.6001 Aragonite -0.1513 Albite_high -1.6408 Chalcedony -0.1736 Enstatite -1.7382 Stilbite -0.1749 Sellaite -1.7457 Boehmite -0.1958 Mordenite -1.7976 Cristobalite(alp -0.3118 Diopside -1.9472 Scolecite -0.3780 C -1.9735 Maximum_Microcli -0.4957 Clinoptilolite-h -2.1761 K-Feldspar -0.5174 Lawsonite -2.2132 Cristobalite(bet -0.5239 Anhydrite -2.2605 Saponite-Na -0.5252 Wairakite -2.3255 Coesite -0.5405 Prehnite -2.3289 Beidellite-Ca -0.5567 Kalsilite -2.4772 Montmor-Na -0.5586 Andalusite -2.4889 Beidellite-Mg -0.6317 Kyanite -2.4906 SiO2(am) -0.6374 Anorthite -2.6187 Gibbsite -0.6920 Chrysotile -2.6258 Talc -0.6937 Sillimanite -2.6539 Montmor-K -0.7147 Jadeite -2.6609 Saponite-K -0.7406 Wollastonite -2.7048

109

Pyrite -0.7610 S -2.7444 Fluorite -0.7876 Pseudowollastoni -2.7598 Kaolinite -0.8431 Clinochlore-14A -2.8503 Illite -0.8736 Nepheline -2.9305 Dolomite-dis -0.9051 Margarite -2.9338 Saponite-H -0.9269 Bassanite -2.9489 Sanidine_high -0.9961 CaSO4:0.5H2O(bet -2.9780 Albite_low -1.0160 (only minerals with log Q/K > -3 listed)

Gases fugacity log fug. ------H2O(g) 10.51 1.022 CO2(g) 3.438 0.536 H2S(g) 0.09296 -1.032 H2(g) 0.001624 -2.789 CH4(g) 0.0003026 -3.519 (only gases with fugacities > 1.e-5 listed)

In fluid Sorbed Kd Original basis total moles moles mg/kg moles mg/kg L/kg ------Ag+ 1.52e-005 2.85e-007 0.0307 Al+++ 0.00163 5.01e-006 0.135 Au+ 7.82e-007 1.00e-007 0.0197 Ba++ 3.17e-007 2.68e-007 0.0367 Ca++ 0.0503 9.15e-005 3.66 Cl- 0.00166 0.00166 58.8 F- 0.000415 0.000415 7.86 Fe++ 9.02e-013 9.02e-013 5.03e-008 H+ -0.0172 0.0388 39.0 H2O 55.5 55.5 9.97e+005 HCO3- 0.0887 0.0390 2.37e+003 HPO4-- 1.54e-009 1.54e-009 0.000148 K+ 0.00108 0.00108 42.1 Mg++ 1.69e-006 1.69e-006 0.0409 Na+ 0.00907 0.00860 197. O2(aq) -0.00754 -0.00753 -240. SO4-- 0.00380 0.00379 363. SiO2(aq) 0.0867 0.00324 194.

Elemental composition In fluid Sorbed total moles moles mg/kg moles mg/kg ------Aluminum 0.001629 5.014e-006 0.1350 Barium 3.175e-007 2.681e-007 0.03672 Calcium 0.05025 9.146e-005 3.656 Carbon 0.08868 0.03898 467.0 Chlorine 0.001661 0.001661 58.76 Fluorine 0.0004148 0.0004148 7.861 Gold 7.819e-007 1.000e-007 0.01966 Hydrogen 111.0 111.0 1.116e+005 Iron 9.025e-013 9.025e-013 5.028e-008 Magnesium 1.687e-006 1.687e-006 0.04090 Oxygen 55.92 55.60 8.874e+005 Phosphorus 1.542e-009 1.542e-009 4.765e-005 Potassium 0.001079 0.001079 42.07 Silicon 0.08672 0.003244 90.89 Silver 1.521e-005 2.854e-007 0.03072 Sodium 0.009068 0.008601 197.3 Sulfur 0.003800 0.003792 121.3

110

14A: React output listing for the end of segment 3 (high S model)

Step # 100 Xi = 1.0000 Temperature = 160.6 C Pressure = 6.152 bars pH = 6.158 log fO2 = -45.495 Eh = -0.2931 volts pe = -3.4061 Ionic strength = 0.011331 Activity of water = 0.999942 Solvent mass = 0.999967 kg Solution mass = 1.002411 kg Solution density = 0.893 g/cm3 Chlorinity = 0.001659 molal Dissolved solids = 2438 mg/kg sol'n Rock mass = 0.010043 kg Carbonate alkalinity= 388.78 mg/kg as CaCO3 Sediment porosity = 0.997

moles moles grams cm3 Reactants remaining reacted reacted reacted ------Ag -6.107e-025 9.271e-010 1.000e-007 9.523e-009 Albite 6.827e-019 0.0004767 0.1250 0.04779 Anorthite -1.110e-019 0.0004493 0.1250 0.04529 Muscovite 2.194e-019 0.0006277 0.2500 0.08832 Quartz -1.832e-016 0.1581 9.500 3.587

Minerals in system moles log moles grams volume (cm3) ------Acanthite 3.028e-008 -7.519 7.504e-006 1.036e-006 Au 3.055e-008 -7.515 6.018e-006 3.121e-007 Calcite 0.0002998 -3.523 0.03001 0.01107 Diaspore 0.003262 -2.487 0.1957 0.05793 Quartz 0.1634 -0.787 9.818 3.707 ______(total) 10.04 3.776

Aqueous species molality mg/kg sol'n act. coef. log act. ------CO2(aq) 0.03066 1346. 1.0000 -1.5134 Na+ 0.009029 207.1 0.8614 -2.1091 HCO3- 0.007769 472.9 0.8614 -2.1744 H2S(aq) 0.002503 85.11 1.0000 -2.6015 SiO2(aq) 0.002148 128.7 1.0000 -2.6680 K+ 0.001703 66.42 0.8570 -2.8358 Cl- 0.001650 58.35 0.8570 -2.8495 HS- 0.001245 41.09 0.8592 -2.9706 F- 0.0004033 7.643 0.8592 -3.4603 Ca++ 0.0001651 6.600 0.5692 -4.0270 CaHCO3+ 6.812e-005 6.870 0.8614 -4.2315 SO4-- 2.660e-005 2.549 0.5485 -4.8360 NaCl(aq) 7.750e-006 0.4518 1.0000 -5.1107 NaHCO3(aq) 6.867e-006 0.5755 1.0000 -5.1632 HF(aq) 6.744e-006 0.1346 1.0000 -5.1711 HSiO3- 5.404e-006 0.4156 0.8614 -5.3321 OH- 4.812e-006 0.08164 0.8592 -5.3836 CaCO3(aq) 3.821e-006 0.3815 1.0000 -5.4178 CaF+ 2.203e-006 0.1298 0.8614 -5.7218 NaF(aq) 1.443e-006 0.06043 1.0000 -5.8408 CaSO4(aq) 1.407e-006 0.1911 1.0000 -5.8516

111

AlO2- 1.107e-006 0.06511 0.8614 -6.0208 Mg++ 1.019e-006 0.02469 0.5882 -6.2225 KSO4- 9.881e-007 0.1332 0.8614 -6.0700 CO3-- 9.794e-007 0.05863 0.5539 -6.2656 H+ 7.902e-007 0.0007945 0.8799 -6.1579 KCl(aq) 6.513e-007 0.04844 1.0000 -6.1862 H2(aq) 6.278e-007 0.001263 1.0000 -6.2022 Formate 5.614e-007 0.02521 0.8592 -6.3166 Methane(aq) 5.283e-007 0.008454 1.0000 -6.2772 NaHSiO3(aq) 5.266e-007 0.05257 1.0000 -6.2785 MgHCO3+ 4.570e-007 0.03890 0.8614 -6.4049 S-- 3.208e-007 0.01026 0.5591 -6.7463 Ba++ 2.640e-007 0.03617 0.5591 -6.8308 CaCl+ 2.126e-007 0.01602 0.8614 -6.7372 MgSO4(aq) 1.525e-007 0.01831 1.0000 -6.8167 Ag(HS)(aq) 1.381e-007 0.01941 1.0000 -6.8599 HSO4- 8.991e-008 0.008707 0.8614 -7.1110 Ag(HS)2- 8.691e-008 0.01509 0.8675 -7.1227 HAlO2(aq) 8.160e-008 0.004883 1.0000 -7.0883 Au(HS)2- 6.074e-008 0.01594 0.8675 -7.2783 MgF+ 4.546e-008 0.001964 0.8614 -7.4071 NaOH(aq) 1.765e-008 0.0007041 1.0000 -7.7533 NaAlO2(aq) 1.257e-008 0.001028 1.0000 -7.9007 (only species > 1e-8 molal listed)

Mineral saturation states log Q/K log Q/K ------Acanthite 0.0000 sat Montmor-Na -1.0314 Au 0.0000 sat Montmor-K -1.1200 Diaspore 0.0000 sat Sanidine_high -1.1734 Quartz 0.0000 sat Illite -1.2273 Calcite 0.0000 sat Beidellite-Na -1.2627 Aragonite -0.1478 Ag -1.3798 Witherite -0.1831 Beidellite-K -1.3952 Chalcedony -0.1865 Pyrophyllite -1.3988 Muscovite -0.2107 Albite_low -1.4680 Boehmite -0.2266 Albite -1.4681 Tridymite -0.2615 Dolomite-dis -1.5041 Corundum -0.3298 C -1.5218 Cristobalite(alp -0.3434 Beidellite-H -1.6155 Mesolite -0.3485 Monohydrocalcite -1.6412 Pyrite -0.3602 Magnesite -1.6980 Stilbite -0.4538 Analcime -1.7050 Coesite -0.5755 Paragonite -1.7902 Montmor-Ca -0.5771 Barite -1.8880 Cristobalite(bet -0.5808 Fluorapatite -1.9076 Maximum_Microcli -0.5810 Celadonite -1.9833 Fluorite -0.5859 Laumontite -2.0734 K-Feldspar -0.6023 Mordenite -2.1170 Dolomite-ord -0.6300 Sellaite -2.1749 Dolomite -0.6315 Albite_high -2.1842 Montmor-Mg -0.7116 Anhydrite -2.3811 SiO2(am) -0.7136 S -2.4483 Gibbsite -0.7430 Kalsilite -2.7212 Ice -0.7519 Lawsonite -2.7852 Beidellite-Ca -0.7624 Clinoptilolite-C -2.8117 Kaolinite -0.7812 Kyanite -2.8936 Scolecite -0.8807 Andalusite -2.9274 Beidellite-Mg -0.9335 Enstatite -2.9855 (only minerals with log Q/K > -3 listed)

112

Gases fugacity log fug. ------H2O(g) 5.064 0.704 CO2(g) 3.384 0.529 H2S(g) 0.09652 -1.015 H2(g) 0.0005497 -3.260 CH4(g) 0.0004468 -3.350 (only gases with fugacities > 1.e-5 listed)

In fluid Sorbed Kd Original basis total moles moles mg/kg moles mg/kg L/kg ------Ag+ 2.86e-007 2.25e-007 0.0242 Al+++ 0.00326 1.20e-006 0.0323 Au+ 1.00e-007 6.95e-008 0.0136 Ba++ 2.67e-007 2.67e-007 0.0366 Ca++ 0.000541 0.000241 9.63 Cl- 0.00166 0.00166 58.7 F- 0.000414 0.000414 7.84 Fe++ 9.49e-013 9.49e-013 5.29e-008 H+ 0.0268 0.0369 37.1 H2O 55.5 55.5 9.97e+005 HCO3- 0.0388 0.0385 2.34e+003 HPO4-- 1.54e-009 1.54e-009 0.000148 K+ 0.00170 0.00170 66.5 Mg++ 1.68e-006 1.68e-006 0.0408 Na+ 0.00905 0.00905 207. O2(aq) -0.00750 -0.00750 -239. SO4-- 0.00378 0.00378 362. SiO2(aq) 0.166 0.00215 129.

Elemental composition In fluid Sorbed total moles moles mg/kg moles mg/kg ------Aluminum 0.003263 1.201e-006 0.03232 Barium 2.672e-007 2.672e-007 0.03661 Calcium 0.0005406 0.0002408 9.629 Carbon 0.03881 0.03851 461.5 Chlorine 0.001659 0.001659 58.66 Fluorine 0.0004137 0.0004137 7.841 Gold 1.000e-007 6.946e-008 0.01365 Hydrogen 111.0 111.0 1.116e+005 Iron 9.490e-013 9.490e-013 5.287e-008 Magnesium 1.683e-006 1.683e-006 0.04080 Oxygen 55.93 55.60 8.874e+005 Phosphorus 1.542e-009 1.542e-009 4.765e-005 Potassium 0.001704 0.001704 66.48 Silicon 0.1656 0.002154 60.34 Silver 2.855e-007 2.250e-007 0.02421 Sodium 0.009046 0.009046 207.5 Sulfur 0.003779 0.003779 120.9

15A: React output listing for the end of segment 4 (high S model)

Step # 100 Xi = 1.0000 Temperature = 141.0 C Pressure = 3.655 bars pH = 5.912 log fO2 = -47.164 Eh = -0.2383 volts pe = -2.9004 Ionic strength = 0.012016

113

Activity of water = 0.999942 Solvent mass = 1.000008 kg Solution mass = 1.002435 kg Solution density = 0.915 g/cm3 Chlorinity = 0.001647 molal Dissolved solids = 2421 mg/kg sol'n Rock mass = 0.010000 kg Carbonate alkalinity= 325.10 mg/kg as CaCO3 Sediment porosity = 0.997

moles moles grams cm3 Reactants remaining reacted reacted reacted ------Ag -6.107e-025 9.271e-010 1.000e-007 9.523e-009 Barite -2.880e-018 0.002142 0.5000 0.1116 Quartz -1.832e-016 0.1581 9.500 3.587

Minerals in system moles log moles grams volume (cm3) ------Acanthite 2.197e-008 -7.658 5.445e-006 7.515e-007 Barite 0.001324 -2.878 0.3089 0.06897 Diaspore 8.530e-007 -6.069 5.117e-005 1.515e-005 Pyrite 3.068e-013 -12.513 3.681e-011 7.345e-012 Quartz 0.1586 -0.800 9.529 3.598 Witherite 0.0008180 -3.087 0.1614 0.03747 ______(total) 10.00 3.705

Aqueous species molality mg/kg sol'n act. coef. log act. ------CO2(aq) 0.03099 1361. 1.0000 -1.5087 Na+ 0.008988 206.1 0.8650 -2.1093 HCO3- 0.006502 395.8 0.8650 -2.2499 H2S(aq) 0.002848 96.85 1.0000 -2.5454 K+ 0.001679 65.49 0.8606 -2.8401 SiO2(aq) 0.001656 99.27 1.0000 -2.7809 Cl- 0.001641 58.02 0.8606 -2.8502 HS- 0.0008910 29.40 0.8629 -3.1142 SO4-- 0.0007927 75.96 0.5576 -3.3546 F- 0.0004026 7.630 0.8629 -3.4592 Ca++ 0.0001699 6.793 0.5784 -4.0075 CaHCO3+ 3.795e-005 3.828 0.8650 -4.4837 CaSO4(aq) 2.956e-005 4.015 1.0000 -4.5292 KSO4- 2.122e-005 2.862 0.8650 -4.7362 NaHCO3(aq) 8.300e-006 0.6956 1.0000 -5.0809 HF(aq) 7.548e-006 0.1506 1.0000 -5.1222 NaCl(aq) 6.002e-006 0.3499 1.0000 -5.2217 HSO4- 2.456e-006 0.2378 0.8650 -5.6728 HSiO3- 2.104e-006 0.1618 0.8650 -5.7400 OH- 1.796e-006 0.03047 0.8629 -5.8098 CaF+ 1.428e-006 0.08414 0.8650 -5.9083 H+ 1.385e-006 0.001393 0.8833 -5.9124 CaCO3(aq) 1.270e-006 0.1268 1.0000 -5.8962 NaF(aq) 1.099e-006 0.04604 1.0000 -5.9589 MgSO4(aq) 1.073e-006 0.1289 1.0000 -5.9693 Ba++ 9.020e-007 0.1236 0.5683 -6.2902 CO3-- 5.528e-007 0.03309 0.5630 -6.5069 Mg++ 4.742e-007 0.01150 0.5974 -6.5478 KCl(aq) 4.713e-007 0.03505 1.0000 -6.3267 AlO2- 2.966e-007 0.01745 0.8650 -6.5908 NaHSiO3(aq) 2.119e-007 0.02115 1.0000 -6.6739 CaCl+ 1.473e-007 0.01110 0.8650 -6.8949 Ag(HS)(aq) 1.282e-007 0.01803 1.0000 -6.8920

114

MgHCO3+ 1.151e-007 0.009798 0.8650 -7.0019 Formate 1.010e-007 0.004535 0.8629 -7.0598 H2(aq) 9.450e-008 0.0001900 1.0000 -7.0246 Au(HS)2- 6.038e-008 0.01585 0.8710 -7.2791 S-- 5.689e-008 0.001820 0.5683 -7.4904 Ag(HS)2- 5.309e-008 0.009216 0.8710 -7.3349 HAlO2(aq) 4.494e-008 0.002689 1.0000 -7.3474 S2O3-- 2.999e-008 0.003355 0.5576 -7.7767 MgF+ 1.387e-008 0.0005992 0.8650 -7.9209 Methane(aq) 1.051e-008 0.0001682 1.0000 -7.9783 (only species > 1e-8 molal listed)

Mineral saturation states log Q/K log Q/K ------Acanthite 0.0000 sat Stilbite -1.2624 Witherite 0.0000 sat Montmor-Mg -1.3943 Quartz 0.0000 sat Beidellite-Na -1.4490 Pyrite 0.0000 sat Pyrophyllite -1.4743 Barite 0.0000 sat Sanidine_high -1.5539 Diaspore 0.0000 sat Beidellite-K -1.5640 Au -0.0577 Montmor-Na -1.5978 Chalcedony -0.1953 Montmor-K -1.6781 Tridymite -0.2145 Beidellite-H -1.7217 Boehmite -0.2471 Illite -1.7719 Cristobalite(alp -0.3650 S -1.7754 Muscovite -0.5212 Scolecite -1.7969 Calcite -0.5644 Ag -1.8014 Coesite -0.5995 Albite -1.9159 Cristobalite(bet -0.6201 Albite_low -1.9159 Ice -0.6595 Bassanite -1.9194 Aragonite -0.7105 CaSO4:0.5H2O(bet -1.9832 Fluorite -0.7276 Gypsum -2.0358 Kaolinite -0.7407 Monohydrocalcite -2.0585 Gibbsite -0.7630 C -2.0816 SiO2(am) -0.7642 Analcime -2.1065 Maximum_Microcli -0.8988 Dolomite-ord -2.1323 Corundum -0.9081 Dolomite -2.1336 K-Feldspar -0.9180 Paragonite -2.2499 Beidellite-Ca -0.9953 Mordenite -2.5590 Mesolite -1.0753 Magnesite -2.6940 Montmor-Ca -1.1922 Albite_high -2.6945 Beidellite-Mg -1.2376 Sellaite -2.7811 Anhydrite -1.2528 (only minerals with log Q/K > -3 listed)

Gases fugacity log fug. ------CO2(g) 3.400 0.532 H2O(g) 3.036 0.482 H2S(g) 0.1055 -0.977 H2(g) 9.489e-005 -4.023 CH4(g) 1.023e-005 -4.990 (only gases with fugacities > 1.e-5 listed)

In fluid Sorbed Kd Original basis total moles moles mg/kg moles mg/kg L/kg ------Ag+ 2.25e-007 1.81e-007 0.0195 Al+++ 1.20e-006 3.44e-007 0.00926 Au+ 6.90e-008 6.90e-008 0.0136 Ba++ 0.00214 9.07e-007 0.124 Ca++ 0.000240 0.000240 9.61

115

Cl- 0.00165 0.00165 58.3 F- 0.000413 0.000413 7.82 Fe++ 9.47e-013 6.40e-013 3.57e-008 H+ 0.0368 0.0376 37.8 H2O 55.5 55.5 9.97e+005 HCO3- 0.0384 0.0375 2.29e+003 HPO4-- 1.54e-009 1.54e-009 0.000148 K+ 0.00170 0.00170 66.3 Mg++ 1.68e-006 1.68e-006 0.0407 Na+ 0.00900 0.00900 206. O2(aq) -0.00748 -0.00748 -239. SO4-- 0.00591 0.00459 440. SiO2(aq) 0.160 0.00166 99.4

Elemental composition In fluid Sorbed total moles moles mg/kg moles mg/kg ------Aluminum 1.197e-006 3.441e-007 0.009262 Barium 0.002143 9.075e-007 0.1243 Calcium 0.0002403 0.0002403 9.607 Carbon 0.03836 0.03754 449.8 Chlorine 0.001647 0.001647 58.26 Fluorine 0.0004127 0.0004127 7.821 Gold 6.905e-008 6.905e-008 0.01357 Hydrogen 111.0 111.0 1.116e+005 Iron 9.472e-013 6.404e-013 3.568e-008 Magnesium 1.679e-006 1.679e-006 0.04070 Oxygen 55.92 55.60 8.874e+005 Phosphorus 1.542e-009 1.542e-009 4.765e-005 Potassium 0.001701 0.001701 66.34 Silicon 0.1603 0.001659 46.47 Silver 2.253e-007 1.813e-007 0.01951 Sodium 0.009004 0.009004 206.5 Sulfur 0.005911 0.004587 146.7

16A: React output listing for the end of segment 5 (high S model)

Step # 100 Xi = 1.0000 Temperature = 119.1 C Pressure = 2.003 bars pH = 6.250 log fO2 = -51.175 Eh = -0.2647 volts pe = -3.4006 Ionic strength = 0.010027 Activity of water = 0.999933 Solvent mass = 1.999102 kg Solution mass = 2.001823 kg Solution density = 0.937 g/cm3 Chlorinity = 0.001893 molal Dissolved solids = 1359 mg/kg sol'n Rock mass = 0.011021 kg Carbonate alkalinity= 380.62 mg/kg as CaCO3 Sediment porosity = 0.998

116

Ca++ 1.950e-018 0.001480 0.05932 Cl- 2.650e-018 0.002140 0.07587 Enstatite 8.470e-019 0.001245 0.1250 0.03894 Fe++ 8.417e-036 1.790e-020 9.997e-019 Ferrosilite 5.475e-018 0.01800 2.375 0.5932 H+ 3.859e-018 0.002610 0.002631 H2O -6.117e-014 55.51 1000. HCO3- 2.168e-019 0.004990 0.3045 K+ 2.118e-019 0.0002200 0.008602 Magnetite 1.499e-019 0.0005399 0.1250 0.02404 Mg++ -6.581e-019 0.0006930 0.01684 Na+ -5.363e-018 0.002510 0.05770 O2(aq) 2.181e-019 0.0001940 0.006208 Quartz 4.499e-017 0.03329 2.000 0.7552 SO4-- 2.500e-018 0.001440 0.1383 SiO2(aq) -3.673e-018 0.002080 0.1250

Minerals in system moles log moles grams volume (cm3) ------Ag 1.787e-007 -6.748 1.927e-005 1.835e-006 Au 6.925e-008 -7.160 1.364e-005 7.074e-007 Boehmite 0.003535 -2.452 0.2121 0.06906 Daphnite-14A 0.0005084 -3.294 0.3628 0.1085 Dolomite-ord 0.001894 -2.723 0.3493 0.1219 Hematite 0.007044 -2.152 1.125 0.2132 Mesolite 0.005012 -2.300 1.944 0.8580 Muscovite 0.0009772 -3.010 0.3892 0.1375 Pyrite 0.002988 -2.525 0.3585 0.07154 Quartz 0.04910 -1.309 2.950 1.114 Stilbite 0.004660 -2.332 3.330 1.554 ______(total) 11.02 4.248

Aqueous species molality mg/kg sol'n act. coef. log act. ------CO2(aq) 0.01170 514.2 1.0000 -1.9318 Na+ 0.008475 194.6 0.8810 -2.1269 HCO3- 0.007582 462.0 0.8810 -2.1753 Cl- 0.001888 66.83 0.8775 -2.7809 SiO2(aq) 0.001204 72.23 1.0000 -2.9194 K+ 0.0004554 17.78 0.8775 -3.3984 Ca++ 0.0003235 12.95 0.6183 -3.6989 F- 0.0002033 3.858 0.8792 -3.7477 CaHCO3+ 5.651e-005 5.705 0.8810 -4.3029 Mg++ 1.893e-005 0.4595 0.6347 -4.9202 NaHCO3(aq) 1.400e-005 1.174 1.0000 -4.8539 NaCl(aq) 5.174e-006 0.3020 1.0000 -5.2862 CaCO3(aq) 4.130e-006 0.4128 1.0000 -5.3840 MgHCO3+ 3.553e-006 0.3028 0.8810 -5.5044 HSiO3- 2.601e-006 0.2002 0.8810 -5.6399 OH- 2.142e-006 0.03638 0.8792 -5.7251 Fe++ 1.961e-006 0.1094 0.6183 -5.9163 CO3-- 1.537e-006 0.09212 0.6051 -6.0315 HF(aq) 1.083e-006 0.02164 1.0000 -5.9653 CaF+ 8.906e-007 0.05254 0.8810 -6.1054 H+ 6.273e-007 0.0006314 0.8960 -6.2502 H2S(aq) 6.253e-007 0.02128 1.0000 -6.2039 AlO2- 4.503e-007 0.02652 0.8810 -6.4016 HS- 4.373e-007 0.01444 0.8792 -6.4152 NaF(aq) 4.051e-007 0.01699 1.0000 -6.3924 NaHSiO3(aq) 2.758e-007 0.02757 1.0000 -6.5594 Methane(aq) 2.400e-007 0.003846 1.0000 -6.6197

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CaCl+ 2.275e-007 0.01716 0.8810 -6.6980 MgF+ 1.889e-007 0.008171 0.8810 -6.7787 Formate 1.673e-007 0.007519 0.8792 -6.8325 KCl(aq) 1.078e-007 0.008028 1.0000 -6.9673 H2(aq) 8.800e-008 0.0001772 1.0000 -7.0555 MgCO3(aq) 5.492e-008 0.004625 1.0000 -7.2602 MgCl+ 4.804e-008 0.002867 0.8810 -7.3734 HAlO2(aq) 4.123e-008 0.002470 1.0000 -7.3848 SO4-- 1.933e-008 0.001855 0.6004 -7.9352 (only species > 1e-8 molal listed)

Mineral saturation states log Q/K log Q/K ------Nontronite-Ca 0.5912s/sat Illite -0.9360 Nontronite-Mg 0.5477s/sat K-Feldspar -0.9471 Diaspore 0.2717s/sat Corundum -0.9998 Nontronite-Na 0.1389s/sat Pyrophyllite -1.0234 Hematite 0.0000 sat Dolomite-dis -1.0293 Boehmite 0.0000 sat Ferrosilite -1.0516 Ag 0.0000 sat Annite -1.0595 Quartz 0.0000 sat Magnesite -1.0599 Daphnite-14A 0.0000 sat Beidellite-K -1.1092 Dolomite-ord 0.0000 sat Fluorite -1.1411 Au 0.0000 sat Beidellite-H -1.2189 Mesolite 0.0000 sat C -1.2725 Stilbite 0.0000 sat Greenalite -1.3137 Pyrite 0.0000 sat Paragonite -1.3831 Muscovite 0.0000 sat Chamosite-7A -1.4530 Dolomite -0.0010 Monohydrocalcite -1.4744 Siderite -0.0433 Albite -1.5787 Acanthite -0.0613 Albite_low -1.5789 Magnetite -0.1177 Troilite -1.6578 Nontronite-K -0.1284 Sanidine_high -1.6642 Calcite -0.1379 Smectite-low-Fe- -1.6721 Montmor-Mg -0.1430 Pyrrhotite -1.7338 Montmor-Ca -0.1446 Analcime -1.7520 Kaolinite -0.1499 Celadonite -1.7555 Tridymite -0.1701 Sellaite -2.0275 Chalcedony -0.2061 Smectite-high-Fe -2.0811 Nontronite-H -0.2343 Hercynite -2.1028 Aragonite -0.2825 Laumontite -2.1226 Minnesotaite -0.3080 Fayalite -2.1695 Beidellite-Ca -0.3890 Mordenite -2.1800 Cristobalite(alp -0.3916 Saponite-Ca -2.2069 Beidellite-Mg -0.4320 Saponite-Mg -2.2582 Gibbsite -0.5013 Albite_high -2.4345 Montmor-Na -0.5457 FeO -2.4871 Ice -0.5564 Saponite-Na -2.6592 Coesite -0.6292 Daphnite-7A -2.7828 Cristobalite(bet -0.6697 Talc -2.7993 Goethite -0.7595 Dawsonite -2.8018 Montmor-K -0.7886 Lawsonite -2.8323 Scolecite -0.8179 Wustite -2.8463 SiO2(am) -0.8274 Saponite-K -2.9270 Beidellite-Na -0.8409 Enstatite -2.9322 Cronstedtite-7A -0.8410 Kyanite -2.9454 Maximum_Microcli -0.9313 (only minerals with log Q/K > -3 listed)

Gases fugacity log fug. ------H2O(g) 1.591 0.202

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CO2(g) 1.219 0.086 CH4(g) 0.0002629 -3.580 H2(g) 0.0001010 -3.996 H2S(g) 2.124e-005 -4.673 (only gases with fugacities > 1.e-5 listed)

In fluid Sorbed Kd Original basis total moles moles mg/kg moles mg/kg L/kg ------Ag+ 1.82e-007 2.86e-009 0.000154 Al+++ 0.0276 9.88e-007 0.0133 Au+ 6.93e-008 1.41e-012 1.39e-007 Ca++ 0.0107 0.000770 15.4 Cl- 0.00378 0.00378 67.0 F- 0.000412 0.000412 3.91 Fe++ 0.0196 3.93e-006 0.110 H+ -0.112 0.0234 11.8 H2O 111. 111. 9.98e+005 HCO3- 0.0425 0.0387 1.18e+003 K+ 0.00192 0.000911 17.8 Mg++ 0.00194 4.55e-005 0.553 Na+ 0.0210 0.0170 195. O2(aq) -0.00694 -5.47e-006 -0.0875 SO4-- 0.00598 2.17e-006 0.104 SiO2(aq) 0.103 0.00241 72.4

Elemental composition In fluid Sorbed total moles moles mg/kg moles mg/kg ------Aluminum 0.02762 9.876e-007 0.01331 Calcium 0.01071 0.0007702 15.42 Carbon 0.04249 0.03870 232.2 Chlorine 0.003784 0.003784 67.02 Fluorine 0.0004116 0.0004116 3.906 Gold 6.925e-008 1.414e-012 1.391e-007 Hydrogen 222.1 222.0 1.118e+005 Iron 0.01962 3.931e-006 0.1097 Magnesium 0.001940 4.553e-005 0.5529 Oxygen 111.4 111.1 8.877e+005 Potassium 0.001916 0.0009105 17.78 Silicon 0.1028 0.002412 33.85 Silver 1.815e-007 2.859e-009 0.0001541 Sodium 0.02100 0.01698 195.0 Sulfur 0.005979 2.169e-006 0.03475

17A: React output listing for the end of segment 6 (high S model)

Step # 100 Xi = 1.0000 Temperature = 96.0 C Pressure = 1.013 bars pH = 6.752 log fO2 = -55.374 Eh = -0.2892 volts pe = -3.9486 Ionic strength = 0.008987 Activity of water = 0.999929 Solvent mass = 1.999312 kg Solution mass = 2.000992 kg Solution density = 0.958 g/cm3 Chlorinity = 0.002016 molal Dissolved solids = 840 mg/kg sol'n Rock mass = 0.011266 kg

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Carbonate alkalinity= 329.96 mg/kg as CaCO3 Sediment porosity = 0.998

moles moles grams cm3 Reactants remaining reacted reacted reacted ------Ag -1.082e-024 7.463e-010 8.050e-008 7.666e-009 Al+++ 2.617e-019 0.0001110 0.002995 Albite 1.092e-017 0.007627 2.000 0.7646 Anorthite -1.775e-018 0.007189 2.000 0.7246 Au 1.212e-026 2.031e-010 4.000e-008 2.074e-009 Ca++ 1.950e-018 0.001480 0.05932 Cl- 2.650e-018 0.002140 0.07587 Enstatite 1.694e-018 0.002490 0.2500 0.07789 Fe++ 8.417e-036 1.790e-020 9.997e-019 Ferrosilite -7.589e-018 0.02842 3.750 0.9366 H+ 3.859e-018 0.002610 0.002631 H2O -6.117e-014 55.51 1000. HCO3- 2.168e-019 0.004990 0.3045 K+ 2.118e-019 0.0002200 0.008602 Magnetite -5.413e-019 0.0004319 0.1000 0.01923 Mg++ -6.581e-019 0.0006930 0.01684 Na+ -5.363e-018 0.002510 0.05770 O2(aq) 2.181e-019 0.0001940 0.006208 Quartz 4.499e-017 0.03329 2.000 0.7552 SO4-- 2.500e-018 0.001440 0.1383 SiO2(aq) -3.673e-018 0.002080 0.1250

Minerals in system moles log moles grams volume (cm3) ------Ag 1.423e-009 -8.847 1.535e-007 1.462e-008 Au 2.037e-010 -9.691 4.011e-008 2.080e-009 Diaspore 0.008499 -2.071 0.5099 0.1509 Dolomite-ord 0.003179 -2.498 0.5862 0.2045 Hematite 0.005863 -2.232 0.9362 0.1775 Mesolite 0.004176 -2.379 1.620 0.7150 Minnesotaite 0.005758 -2.240 2.729 0.8514 Pyrite 0.0007200 -3.143 0.08639 0.01724 Quartz 0.05092 -1.293 3.060 1.155 Stilbite 0.002434 -2.614 1.739 0.8116 ______(total) 11.27 4.084

Aqueous species molality mg/kg sol'n act. coef. log act. ------Na+ 0.007714 177.2 0.8922 -2.1623 HCO3- 0.006550 399.3 0.8922 -2.2333 CO2(aq) 0.002384 104.8 1.0000 -2.6227 Cl- 0.002011 71.25 0.8892 -2.7475 SiO2(aq) 0.0008078 48.50 1.0000 -3.0927 K+ 0.0003304 12.91 0.8892 -3.5320 Ca++ 0.0002891 11.58 0.6479 -3.7274 F- 0.0001024 1.944 0.8907 -4.0400 CaHCO3+ 2.956e-005 2.986 0.8922 -4.5788 NaHCO3(aq) 1.682e-005 1.412 1.0000 -4.7741 Mg++ 1.210e-005 0.2939 0.6625 -5.0959 CaCO3(aq) 6.140e-006 0.6140 1.0000 -5.2118 CO3-- 4.351e-006 0.2609 0.6360 -5.5579 NaCl(aq) 3.955e-006 0.2309 1.0000 -5.4029 HSiO3- 3.819e-006 0.2942 0.8922 -5.4676 OH- 3.083e-006 0.05239 0.8907 -5.5613 MgHCO3+ 1.310e-006 0.1117 0.8922 -5.9324 Fe++ 1.054e-006 0.05883 0.6479 -6.1655

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Methane(aq) 4.633e-007 0.007426 1.0000 -6.3341 NaHSiO3(aq) 4.310e-007 0.04310 1.0000 -6.3655 HS- 3.419e-007 0.01130 0.8907 -6.5164 CaF+ 2.593e-007 0.01530 0.8922 -6.6358 AlO2- 2.275e-007 0.01340 0.8922 -6.6926 H+ 1.957e-007 0.0001971 0.9052 -6.7516 H2S(aq) 1.649e-007 0.005616 1.0000 -6.7828 CaCl+ 1.540e-007 0.01162 0.8922 -6.8620 NaF(aq) 1.416e-007 0.005939 1.0000 -6.8491 Formate 1.153e-007 0.005188 0.8907 -6.9882 HF(aq) 1.039e-007 0.002078 1.0000 -6.9832 MgCO3(aq) 6.767e-008 0.005701 1.0000 -7.1696 KCl(aq) 5.885e-008 0.004384 1.0000 -7.2303 H2(aq) 4.376e-008 8.815e-005 1.0000 -7.3589 MgF+ 4.134e-008 0.001788 0.8922 -7.4332 MgCl+ 2.254e-008 0.001346 0.8922 -7.6966 (only species > 1e-8 molal listed)

Mineral saturation states log Q/K log Q/K ------Nontronite-Ca 0.7362s/sat Scolecite -1.0419 Nontronite-Mg 0.6461s/sat Ferrosilite -1.0521 Nontronite-Na 0.3428s/sat Beidellite-Ca -1.0836 Nontronite-K 0.0754s/sat C -1.0919 Au 0.0000 sat Dolomite-dis -1.1311 Stilbite 0.0000 sat Montmor-K -1.1442 Mesolite 0.0000 sat Beidellite-Mg -1.1732 Pyrite 0.0000 sat Monohydrocalcite -1.2195 Dolomite-ord 0.0000 sat Magnesite -1.2449 Hematite 0.0000 sat Illite -1.4075 Diaspore 0.0000 sat Beidellite-Na -1.4766 Ag 0.0000 sat Celadonite -1.5538 Quartz 0.0000 sat Pyrophyllite -1.6759 Minnesotaite 0.0000 sat Troilite -1.6867 Dolomite -0.0007 Albite -1.6941 Daphnite-14A -0.0164 Albite_low -1.6942 Calcite -0.0380 Beidellite-K -1.7447 Magnetite -0.0886 Sanidine_high -1.7598 Tridymite -0.1448 Pyrrhotite -1.7672 Aragonite -0.1816 Analcime -1.8315 Nontronite-H -0.1837 Smectite-low-Fe- -1.8546 Siderite -0.2150 Fluorite -1.8599 Chalcedony -0.2190 Chamosite-7A -1.9355 Boehmite -0.2999 Beidellite-H -2.0058 Acanthite -0.3733 Saponite-Ca -2.0164 Cristobalite(alp -0.4232 Paragonite -2.0579 Ice -0.4486 Saponite-Mg -2.1128 Muscovite -0.5333 Corundum -2.1947 Cronstedtite-7A -0.5367 Fayalite -2.1984 Montmor-Ca -0.5538 Smectite-high-Fe -2.2824 Montmor-Mg -0.5939 Mordenite -2.3262 Kaolinite -0.6417 Saponite-Na -2.4098 Coesite -0.6646 Laumontite -2.4331 Goethite -0.6716 Talc -2.5751 Cristobalite(bet -0.7300 FeO -2.6165 Annite -0.7446 Albite_high -2.6414 Gibbsite -0.7666 Saponite-K -2.6776 Montmor-Na -0.8928 Dawsonite -2.8250 SiO2(am) -0.9059 Daphnite-7A -2.9109 Greenalite -0.9321 Saponite-H -2.9382 Maximum_Microcli -0.9348 Hercynite -2.9471 K-Feldspar -0.9461

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(only minerals with log Q/K > -3 listed)

Gases fugacity log fug. ------H2O(g) 0.7264 -0.139 CO2(g) 0.2189 -0.660 CH4(g) 0.0005396 -3.268 H2(g) 5.605e-005 -4.251 (only gases with fugacities > 1.e-5 listed)

In fluid Sorbed Kd Original basis total moles moles mg/kg moles mg/kg L/kg ------Ag+ 2.17e-009 7.51e-010 4.05e-005 Al+++ 0.0221 4.76e-007 0.00642 Au+ 2.04e-010 1.28e-013 1.26e-008 Ca++ 0.00905 0.000650 13.0 Cl- 0.00403 0.00403 71.4 F- 0.000206 0.000206 1.95 Fe++ 0.0297 2.11e-006 0.0589 H+ -0.138 0.00473 2.38 H2O 111. 111. 9.99e+005 HCO3- 0.0243 0.0180 548. K+ 0.000675 0.000661 12.9 Mg++ 0.00321 2.71e-005 0.329 Na+ 0.0186 0.0155 178. O2(aq) 0.000407 -4.04e-006 -0.0646 SO4-- 0.00144 1.03e-006 0.0494 SiO2(aq) 0.105 0.00162 48.8

Elemental composition In fluid Sorbed total moles moles mg/kg moles mg/kg ------Aluminum 0.02212 4.760e-007 0.006419 Calcium 0.009053 0.0006503 13.02 Carbon 0.02434 0.01798 107.9 Chlorine 0.004030 0.004030 71.40 Fluorine 0.0002058 0.0002058 1.954 Gold 2.038e-010 1.280e-013 1.260e-008 Hydrogen 222.0 222.0 1.118e+005 Iron 0.02972 2.112e-006 0.05895 Magnesium 0.003206 2.708e-005 0.3289 Oxygen 111.4 111.0 8.878e+005 Potassium 0.0006753 0.0006607 12.91 Silicon 0.1047 0.001624 22.79 Silver 2.174e-009 7.511e-010 4.049e-005 Sodium 0.01862 0.01546 177.7 Sulfur 0.001441 1.028e-006 0.01648

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