Provenance of the Middle Permian, Delaware Mountain Group

PROVENANCE OF THE MIDDLE PERMIAN, DELAWARE MOUNTAIN GROUP:

DELAWARE BASIN, SOUTHEAST NEW MEXICO AND WEST TEXAS

JOHN MARTIN ANTHONY

Bachelor of Science, 2013 Louisiana State University Baton Rouge, Louisiana

Submitted to the Graduate Faculty of The College of Science and Engineering Texas Christian University In partial fulfillment of the requirements for the degree

MASTER OF SCIENCE IN GEOLOGY

May 2015

John Martin Anthony

2015

Acknowledgements

I would like to gratefully acknowledge the help and extreme generosity of all individuals

and universities while working on this project.

Firstly, I would like to thank my graduate advisor, Dr. Xianyang Xie. Without his support,

knowledge, and enthusiasm, this project would have would not have been nearly as enjoyable.

Dr. Xie was as dedicated of an advisor that I could have asked for. I would also like to thank the

following faculty members that served as my committee members: Dr. Helge Alsleben and Dr.

John Holbrook. Their support and input during my research was much appreciated.

Secondly, Ira Bradford deserves much recognition for serving as a mentor during my two

summer internships with Concho Resources. His guidance has been paramount in my pursuit

for becoming a better geologist. I would also like to thank Concho Resources for providing the

thin sections used for the petrographic work in this study.

Several geology departments were welcoming and provided their facilities for sample

processing and analyses. These universities include: University of Texas at Dallas, University

of Texas at Arlington, and the University of Arizona.

Lastly, I would like to thank specific family and friends. I want to thank my amazing

fiancée, Caroline, for her encouragement and support during my pursuit of a Master’s Degree.

Also, I would like to thank my parents who have always provided words of encouragement and

instilling me with a strong work ethic. I would not be where I am today without them. Finally, I

have to thank friends here in the geology department: Patrick, Justin, Garrett, and Robert.

Thesis work can be grueling and I’m glad I had a great group of friends to take my mind off

school when the time called for it.

Table of Contents

ACKNOWLEDGEMENTS ...... ii

LIST OF FIGURES ...... vi

LIST OF TABLES ...... viii

1. INTRODUCTION ...... 1

Purpose of Study ...... 1 Tectonic Setting ...... 2 Stratigraphy and Depositional Setting ...... 6 Previous Views on Provenance of the Delaware Mountain Group ...... 10

2. SANDSTONE MODAL MINERALOGY ...... 12

Point Counting Methods ...... 12 Framework Grain Types ...... 15 Monocrystalline Quartz ...... 16 Polycrystalline Quartz ...... 16 Potassium Feldspar ...... 16 Plagioclase Feldspar ...... 16 Volcanic Lithic Grains ...... 21 Siliciclastic Sedimentary and Metamorphic Lithic Grains ...... 21 Additional Categories ...... 24 Phyllosilicates ...... 24 Heavy Minerals ...... 24 Cement/Matrix ...... 24 Porosity ...... 25 Others ...... 25 Classification and Provenance Results ...... 31

iii

Brushy Canyon Formation ...... 31 Cherry Canyon Formation ...... 32 Bell Canyon Formation ...... 33 Comparisons to Previous Studies ...... 33

3. U-PB DETRITAL ZIRCON GEOCHRONOLOGY ...... 40

Sampling and Geochronology Methods ...... 40 Results ...... 44 JCT- 6446 ...... 45 JCT- 6068 ...... 47 JCT- 5872 ...... 49 JCT- 4946 ...... 51

4. POTENTIAL SOURCE TERRANES ...... 55

Archean/Paleoproterozoic (>1825 Ma) ...... 56 Late Paleoproterozoic (1600-1825 Ma) ...... 56 Early Mesoproterozoic (1300-1600 Ma) ...... 57 Mid-late Mesoproterozoic (920-1300 Ma) ...... 57 Neoproterozoic/Early Paleozoic (510-790 Ma) ...... 58 Mid-Paleozoic (285-490 Ma) ...... 60 Late Paleozoic (<285 Ma) ...... 60

5. DISCUSSION ...... 61

Ancestral Rocky Mountain Argument ...... 61 Appalachian Orogen Argument ...... 64 Ouachita Orogen Argument ...... 67 Paleogeography and Sediment Dispersal Pathways ...... 71 Brushy Canyon Formation ...... 72

Cherry Canyon Formation and Bell Canyon Formation ...... 72

6. CONCLUSIONS ...... 75

REFERENCES ...... 77

APPENDICES ...... 88

Appendix I – Raw Point Count Data ...... 88 Appendix II – U-PB Detrital Zircon Geochronology Results ...... 90 Appendix III – K-S Statistical Results ...... 108

VITA

ABSTRACT

List of Figures

1. Middle Permian Basin Setting of Permian Basin ...... 4

2. Paleogeography of Northwestern Pangea ...... 5

3. Shelf-Basin Transect from the Northwest Shelf to the Delaware Basin ...... 7

4. Block Diagram of Interpreted Delaware Mountain Group Deposition ...... 9

5. Major Transport Directions for Bell Canyon Sandstones ...... 11

6. Stratigraphic Cross Section of Sampled Wells ...... 13

7. Monocrystalline Quartz Grains ...... 17

8. Polycrystalline Quartz Grains ...... 18

9. Potassium Feldspar Grains ...... 19

10. Plagioclase Feldspar Grains ...... 20

11. Volcanic Lithic Grains ...... 22

12. Siliciclastic Sedimentary and Metamorphic Lithic Grains ...... 23

13. Phyllosilicates ...... 26

14. Zircon Grains ...... 27

15. Calcite Cement/Matrix ...... 28

16. Pore Space ...... 29

17. Other Grains ...... 30

18. QtFL Ternary Plot using Folk Classification Scheme ...... 37

19. QtFL Ternary Plot Showing Potential Compositional Fields ...... 38

20. QmFLt Ternary Plot Showing Potential Compositional Fields ...... 39

21. Backscattered Electron Images of Processed Zircons ...... 42

22. Sample JCT- 6446; Normal Concordia Plot ...... 46

23. Sample JCT- 6446; Tera-Wasserburg Concordia Diagram ...... 46

24. Sample JCT- 6446; Relative Probability Plot ...... 47

25. Sample JCT- 6068; Normal Concordia Plot ...... 48

26. Sample JCT- 6068; Tera-Wasserburg Concordia Diagram ...... 48

27. Sample JCT- 6068; Relative Probability Plot ...... 49

28. Sample JCT- 5872; Normal Concordia Plot ...... 50

29. Sample JCT- 5872; Tera-Wasserburg Concordia Diagram ...... 50

30. Sample JCT- 5872; Relative Probability Plot ...... 51

31. Sample JCT- 4946; Normal Concordia Plot ...... 52

32. Sample JCT- 4946; Tera-Wasserburg Concordia Diagram ...... 52

33. Sample JCT- 4946; Relative Probability Plot ...... 53

34. Map of Main Age Provinces Capable of Supplying Zircons ...... 55

35. Normalized Probability Plots of Delaware Mountain Group Samples and Main Age Provinces ...... 62

36. Comparison of Detrital Zircon Ages from the Delaware Mountain Group with Devonian-Permian Appalachian Foreland Strata ...... 65

37. Comparison of Detrital Zircon Ages from the Cherry Canyon Formation and Bell Canyon Formation with Ouachita Derived Strata ...... 68

38. Interpreted Paleogeography and Sediment Dispersal Pathways during Deposition of the Siliciclastic Strata of the Brushy Canyon Formation ...... 73

39. Interpreted Paleogeography and Sediment Dispersal Pathways during Deposition of the Cherry Canyon Formation and Bell Canyon Formation ...... 74

vii

List of Tables

1. List of Thin Sections used for Sandstone Point-Counting and Geochronology ...... 14

2. Categories used for Sandstone Point-counts ...... 15

3a. Normalized Point-count Data from the Brushy Canyon Formation Samples ...... 35

3b. Normalized Point-count Data from the Cherry Canyon Formation Samples ...... 35

3c. Normalized Point-count Data from the Bell Canyon Formation Samples ...... 36

4. Ages and Percentages of Analyzed Detrital Zircons ...... 45

5. Probability (P) values from Kolmogorov-Smirnoff Analysis ...... 54

viii

1. INTRODUCTION

1.1 Purpose of Study

Detailed sandstone point counting can be used to assist in determining provenance by identifying mineralogy, tectonic setting, transport history, and diagenesis. Furthermore, U-Pb detrital zircon geochronology using Laser Ablation,

Multicollector, Inductively Coupled Plasma Mass Spectrometry (LA-MC-ICPMS) is a proven analytical method capable of rapidly producing abundant age data on individual zircon crystals or detrital grains (Gehrels et al., 2006, 2008). The combination of these two techniques enhances the capability of defining potential source terranes, ancient sediment dispersal pathways, and paleogeography.

The purpose of this study is to further document the provenance of the siliciclastic strata of the middle Permian (Guadalupian), Delaware Mountain Group of the Delaware Basin, located in west Texas and southeast New Mexico (Figure 1). In this study, 54 thin sections made from whole core and sidewall core that were sampled from the three formations that comprise the Delaware Mountain Group (Bell Canyon,

Cherry Canyon, and Brushy Canyon), were chosen for detailed sandstone point counting. Additionally, four whole core samples, selected from the J.C.Trees Well in the southern Delaware Basin, were processed for U-Pb detrital zircon geochronology analyses. Providing additional geochronological data from another area of the basin

(southern Delaware Basin) was a major priority of this study, as was presenting undocumented age data from the Cherry Canyon Formation. The combination of sandstone point counting and geochronological data documented in this study provides additional constraints regarding the potential source terrane(s) and sediment dispersal pathways for the siliciclastic strata of the middle Permian, Delaware Mountain Group.

1.2 Tectonic Setting

Prior to development of the Permian Basin and its sub-basins, deposition of approximately 7,000 ft. (2,133 m) of late Precambrian-Mississippian strata accumulated in a larger, ancestral basin known as the Tobosa Basin (Adams 1965). The collision of

Laurentia and Gondwana and the final assembly of Pangea during Carboniferous time fragmented the Tobosa Basin, resulting in significant loading that caused uplift of shelfal areas along high-angle reverse faults and subsidence in depressed areas (Beaubouef et al. 1999). This collisional event created the structural features that are commonly associated with the Permian Basin: the Delaware Basin, Central Basin Platform, and

Midland Basin (Figure 1; Hills 1984; Yang and Dorobek 1992). The Permian Basin developed in a foreland basin setting during late Mississippian to early Pennsylvanian time, near the southwestern boundary of the Appalachian-Ouachita-Marathon orogenic belt (Figure 2; Hills 1984; Yang and Dorobek 1992). It is bordered to the south by the

Marathon orogenic belt and the basins and uplifts associated with the Ancestral Rocky

Mountains to the north. Termination of the Appalachian-Ouachita-Marathon orogenic belt was located in Mexico along a transform boundary that extended northwest toward the Cordilleran margin of western North America (Stewart 1988; Dickinson and Lawton

2001). The Permian Basin was located approximately ≈ 5-10° north of the equator during the late Carboniferous to Permian (Ziegler et al. 1997) and is believed to have possessed an arid climate due to the plethora of evaporite and eolian siliciclastic strata preserved across the region (King 1948; Oriel et al. 1967; Fischer and Sarnthein 1988).

The Delaware Basin, located in southeast New Mexico and west Texas, is one several basins that comprise the Permian Basin. It covers an area of approximately

13,000 mi 2 (33,669 km 2) and is filled with Phanerozoic sedimentary rocks with a maximum depth of 24,000 ft. (7,315 m) (Hills 1984). The Delaware Basin is one of the deepest intracratonic basins in North America. During the middle Permian

(Guadalupian), the Delaware Basin was a pear shaped deep water (400-600m) basin bordered by broad, commonly submerged platform areas such as, the Diablo Platform to the west, the Central Basin Platform to the east, and the Northwest Shelf to the north

(King 1948; Harms 1974). The basin joined with the Marfa Basin via the Hovey

Channel to the south, ultimately connecting the basin with the Marathon foreland and the open ocean. Additionally, the Delaware Basin and the Midland Basin were connected via the Sheffield Channel and San Simon Channel; however, these areas were filled by middle to late Guadalupian time, effectively merging the Eastern Shelf,

Midland Basin, and Central Basin Platform (Bozanich 1979; Ward et al. 1986).

Figure 1: Middle Permian (early Guadalupian) basin setting of the Permian Basin, highlighting the major sub-basins and platforms of the region and sample localities used for point counting and geochronology in this study (Modified from Silver and Todd 1969; Hills 1984).

Figure 2: Reconstructed paleogeography of northwestern Pangea during the middle Permian (Modified from Soreghan et al. 2008). Depicted here are the remnant Antler belt, Central Pangaean Mountains, and the Ancestral Rocky Mountains. The Permian Basin is highlighted by the black box at the southwestern edge of the Appalachia- Ouachita-Marathon orogenic belt. Inset in the bottom right depicts global geography during the middle Permian.

1.3 Stratigraphy and Depositional Setting

The Delaware Mountain Group was deposited and accumulated in the Delaware

Basin during middle Permian (Guadalupian) time. It unconformably overlies the Bone

Spring Limestone and is overlain by the Castille Formation. In ascending order, the

Delaware Mountain Group is composed of the Brushy Canyon Formation, Cherry

Canyon Formation, and Bell Canyon Formation (Figure 3; King 1942; Harms 1974).

These three strata of the Delaware Mountain Group range in thickness from 3,200-

5,300 ft. (975-1,615 m) of stratigraphically cyclic, mixed siliciclastic/carbonate slope, and basin floor strata (Dutton et al. 2003). Lithologically, the basinal strata are composed of fine-grained sandstones and interbedded organic-rich siltstones

(Williamson 1980). Furthermore, these strata interfinger with and onlap ramp-to shelf- carbonate that rim the Delaware Basin (Figure 3). The Brushy Canyon basinal siliciclastic strata, which are the oldest lithostratigraphic unit of the Delaware Mountain

Group, onlap the Cutoff Formation, carbonate strata of the Victorio Peak Dolomite, and

San Andres ramp margins. The Cherry Canyon Formation interfingers and passes into shelf-edge carbonate strata of the Goat Seep and Capitan Formation. Similarly, the Bell

Canyon Formation interfingers and passes into shelf-edge carbonate strata of the

Capitan Formation and the mixed carbonate-siliciclastic strata of the Artesia group. The

Brushy Canyon lacks the prominent carbonate members that are present in the Cherry

Canyon and Bell Canyon formations (King 1942). The Helgler Member is used as the marker to divide the Bell Canyon Formation from the underlying Cherry Canyon

Formation. Other carbonate members used to subdivide the Cherry Canyon and Bell

Canyon include the South Wells, Getaway, Manzanita, Pinery, Rader, McCombs, and

Lamar (Hull 1957).

To the south, in the Marathon foreland, the Word and Altuda formations are correlatable to the Cherry Canyon and Bell Canyon formations. Rudine et al. (2000) determined that the Word Formation accumulated in a predominately shallow marine setting with occasional emergence. In contrast, the Altuda Formation includes slope to basinal turbidites as well as shallow-marine facies (Haneef et al. 2000). Both siliciclastic facies chiefly consist of quartzose siltstone and are considered to be sourced from the Marathon orogenic belt to the south (Haneef et al. 2000; Rudine et al. 2000).

Figure 3: Schematic cross section of the shelf-basin transect from the Northwest Shelf to the Delaware Basin showing the major Guadalupian aged lithostratigraphic units. Also displayed are the three formations that comprise the Delaware Mountain Group (modified from King 1948; Newell et al. 1953; Silver and Todd 1969).

The Delaware Mountain Group represents marine deposition, potentially formed by shallow marine currents (King 1948; Newell et al. 1953), density currents (Harms

1974; Williamson 1979; Harms et al. 1984), and/or submarine-fan turbidity currents

(Passega 1954; Hull 1957; Hayes 1964; Jacka 1968; Rossen and Sarg 1987). Despite the disagreement of ultimate marine sediment transportation, the siliciclastic strata of the Delaware Mountain Group are interpreted as being formed within a 2nd order cycle composed of Lowstand, Transgressive, and Highstand sequence sets (Beaubouef et al.

1999), that were pre-sorted by eolian processes before delivery into the basin (Newell et al. 1953; Hull 1957; Harms 1974). Newell et al. (1953) were the first to suggest eolian origin due to the fine-grained and well-sorted character of the strata, a conclusion reinforced by the rounding of grains and lack of clay observed by Fischer and Sarnthein

(1988). The intermingling of carbonate and clastic strata at the shelf-basin margin in the

Delaware Mountain Group was first described as exhibiting a “cyclic and reciprocal sedimentation model” (Wilson 1967; Kendall 1969; Silver and Todd 1969; Meissner

1972). This model was eventually redefined to relate shelf and basin transportation cycles to a time of alternating eustatic sea-level rise and fall (Jacka et al. 1979;

Mazzullo et al. 1991; Osleger 1998; Tinker 1998). High-magnitude and high-frequency glacioeustatic changes were common due to icehouse conditions present during the

Carboniferous-Permian which heavily influenced the changes in eustatic sea-level

(Fielding et al. 2008). This model is further supported by the occurrence of interbedded very-fine grained sandstone and organic-rich siltstone, whose cyclic interbedding has been interpreted to record eustatic sea-level rise and fall (Meissner 1969; Fischer and

Sarnthein 1988; Gardner 1992). During times of eustatic sea level lows, the shelf and

back-barrier systems were exposed, and a lack of accommodation space allowed high rates of sediment supply to carve large incised valleys within the slope and sediment was deposited in a channel levee system that terminated in broad lobes. The slow relative rise in sea level caused a decrease of sediment transport to the basin floor and deposition was concentrated in slope channels. Subsequently, during times of increased relative sea level, the shelf was flooded allowing for accommodation on the surrounding shelves and prevented sands from being delivered to the basin. Thin, regionally extensive, organic-rich siltstones accumulated in the basin floor by slow undisturbed settling of marine algal material and airborne silt (Figure 4) (Beaubouef et al. 1999).

Figure 4: Slope to basin block diagrams of the interpreted depositional environment and the relationship with alternating sea-levels for the Delaware Mountain Group (Modified from Beaubouef et al. 1999).

1.4 Previous Views on Provenance of the Delaware Mountain Group

Previous interpretations for the main source region/regions that supplied the siliciclastic material for the Delaware Mountain Group concentrate on the basement- cored uplifts of the Ancestral Rocky Mountains located northwest of the Delaware

Basin. Most influential for this interpretation is the generally arkosic/subarkosic composition documented in the Delaware Mountain Group and several Guadalupian aged units within the Northwest Shelf (Hull 1957; Berg 1979; Watson 1979; Williamson

1979). This has led most authors to suggest a plutonic-metamorphic source from the north associated with the Ancestral Rocky Mountains in New Mexico and Colorado, and/or the midcontinent region to the north-northwest (Figure 2; King 1948; Hull 1957;

Mazzullo et al. 1991). An additional interpretation is potential sourcing from the

Arbuckle and Wichita uplifts to the northeast (Figure 2; Hull et al. 1957; Watson 1979).

Newell et al. (1953) present the possibility of a source to the east and northeast

(Oklahoma and Colorado) that was recycled from Pennsylvanian-aged sandstone.

Other studies suggest that the sediment that comprises the Cherry Canyon and Bell

Canyon formations originated on the Northwest shelf and the Central Basin Platform

(Newell et al., 1953; Bozanich, 1979), while King (1948) suggests sediment was potentially shed from a southern to southwestern source. Kocurek and Kirkland (1998) postulated that the siliciclastic strata of the Delaware Mountain Group were delivered via an eolian system represented by the Permian Whitehorse Group of the midcontinent

(Kansas and Oklahoma). This interpretation is further based on the evidence of measured southwestward sediment transport for the Whitehorse. Additionally, northeast-southwest trending submarine channels throughout the Delaware Mountain

Group that suggest the major source of sediment delivery into the basin was from the north/northeast (Figure 5; Payne 1976); They did not determine an exact source terrane however.

Figure 5: Major transport directions for the Bell Canyon sandstones in the Delaware basin during the late Guadalupian (Modified from Payne 1976). A more recent study, conducted in the northern Delaware Basin by Soreghan and Soreghan (2013), exploited outcrop samples from the Bell Canyon Formation and

Brushy Canyon Formation for U-Pb detrital zircon geochronology and reported age results that contradict an Ancestral Rocky Mountain source. The minor occurrence of a

Late Paleoproterozoic age population lead the authors to suggest the source of the

Delaware Mountain Group strata were not derived from the uplifts associated with the

Ancestral Rocky Mountains, but from the Ouachita orogen, recycled Appalachian detritus, and key sources within terranes uplifted south of the Ouachita Orogen such as the Yucatan-Maya terrane. Additionally, they mentioned the possibility of a provenance shift between Brushy Canyon and Cherry Canyon time due to filling of the Midland basin.

2. Sandstone Modal Mineralogy

2.1 Point Counting Methods

A total of 54 samples from the Delaware Mountain Group were collected via the subsurface and were cut from whole core and sidewall core that were taken from six wells across the Delaware Basin (Figure 1). Thin section samples range in subsea depths from 4,699-7,469 ft. (1,432-2,276m) and include the three formations that comprise the Delaware Mountain Group: Bell Canyon, Cherry Canyon, and Brushy

Canyon formations (Figure 6; Table 1).

All thin sections were mounted on a glass slide, cut to a standard thickness of 30, microns, treated with blue epoxy, and stained for potassium feldspar. Point counts were conducted using the Gazzi-Dickinson method in order to minimize compositional dependence on grain size (Dickinson 1970; Gazzi et al. 1973; Ingersoll et al. 1979).

Thin sections were point counted using PETROG™, an automated modal analysis system, and a polarizing microscope. 350 framework grains were counted per section to ensure compositional reproducibility of +/- 5% for all grain types with a 2-σ confidence range of 94-95% (Van der Plas and Tobi 1965).

Framework grains include monocrystalline quartz, polycrystalline quartz, potassium feldspar, plagioclase feldspar, volcanic lithic grains, siliciclastic sedimentary lithic grains and metamorphic lithic grains. Additional categories tabulated but not included as framework grains on ternary diagrams are mica grains, heavy minerals, cement/matrix, pore space and an others category (i.e. opaque minerals and fossils).

All raw point-counting data were normalized to represent framework percentage and plotted on sandstone classification ternary plots (Folk 1980) and provenance discrimination ternary plots (Dickinson et al. 1983).

Figure 6: Cross section of wells used in this study. Location of thin sections denoted by “X” and location of samples used for detrital zircon geochronology denoted by “Star”.

Table 1. Sample list of thin sections used for point-counting with their associated subsurface depth (feet) and formation. (N denotes total number of thin sections analyzed per formation)

Sample Localities Bell Canyon (N=16) Cherry Canyon (N=29) Brushy Canyon (N=10) J.C. Trees JCT-4946 JCT-5872 JCT-6068 JCT-6348 JCT-6446 Big Chief BC-5260 BC-6111 BC-7163 BC-5359 BC-6379 BC-7469 BC-5517 BC-6772 BC-5779 BC-6917 Austin Hayter AH-5291 AH-5765 AH-6859 AH-5463 AH-5833 AH-7276 AH-5518 AH-5987 AH-5574 AH-6088 AH-6190 AH-6295 AH-6394 Sandhills St. SH-4699 SH-5322 SH-6243 SH-4770 SH-5516 SH-6546 SH-4930 SH-5671 SH-5013 SH-5748 SH-5852 SH-6006 SH-6194 Espada St. ES-5064 ES-5601 ES-6707 ES-5204 ES-5816 ES-7024 ES-5331 ES-5949 ES-6087 ES-6223 ES-6470 ES-6546 Cottonmouth CM-6144 CM-6277

2.2 Framework Grain Types

Classification of framework grains types in this study followed criteria set forth by

Dickinson (1970), Ingersoll and Suczek (1979), Folk (1980), and Critelli and Ingersoll

(1995). Grain type categories and their assignment to ternary plot parameters are listed below.

Table 2. Categories used for sandstone point counts (note framework grains in bold) and grain parameters in recalculated plots

Symbol Counted Categories Qm Monocrystalline Quartz Qp Polycrystalline Quartz Fk Potassium Feldspar Fp Plagioclase Feldspar Lv Volcanic Lithic Grains Lss+m Siliciclastic Sedimentary Lithic Grains and Metamorphic Lithic Grains Phyllo Phyllosilicates H Heavy Minerals C/M Cement/Matrix Φ Pore Space O Other not in categories above

Recalculated Parameters QtFL Plot Qt = Total Quatrzose Grains (Qm+Qp) F = Total Feldspars (Fk+Fp) L = Total unstable Lithic Grains (Lv+Lss+m)

QmFLt Plot Qm = Total Monocrystalline Quartz (Qm) F = Total Feldspars (Fk+Fp) Lt = Total Lithic Grains (Qp+Lv+Lss+m)

Monocrystalline Quartz (Qm)

Monocrystalline quartz grains are defined as single domains of quartz with straight or undulatory extinction (Figure 7). Grains commonly display thin layers of inclusions on their surfaces and authigenic overgrowths.

Polycrystalline Quartz (Qp)

Polycrystalline quartz consists of multiple less than silt sized (0.0625 mm) crystal domains of quartz (Figure 8). Grains possess both equant and elongate crystal domains. Chert is included in this framework grain category and consists of polycrystalline quartz with microscopic crystal domains.

Potassium Feldspar (Fk)

Monocrystalline potassium feldspar is distinguished through the yellow potassium feldspar stain that was applied to half of each thin section (Figure 9). When unstained, grains can be distinguished by features such as alteration, cleavage, and relief.

Microcline grains fall under this category and are most readily identified by plaid or tartan twinning.

Plagioclase (Fp)

Plagioclase feldspar grains are recognizable by the presence of simple, albite, and polysynthetic twinning (Figure 10). Grains can be readily distinguished from quartz because of the darker appearance of the feldspars caused by sericitization and secondary vacuolization. Calcite replacement is a common diagenetic alteration observed as well. Perthite grains, intergrowths of plagioclase and potassium feldspar, were tabulated under the plagioclase feldspar category.

Figure 7: Photomicrograph of monocrystalline quartz grains, Delaware Mountain Group. A.) Sample AH-5291 from the Bell Canyon Formation. B.) Sample CM-6144 from the Brushy Canyon Formation.

Figure 8: Photomicrograph of polycrystalline quartz grains, Delaware Mountain Group. A.) Sample JCT-3 from the Cherry Canyon Formation. B.) Sample CM-6277 from the Brushy Canyon Formation.

Figure 9: Photomicrograph of potassium feldspar grains in plain light, Delaware Mountain Group. A.) Sample JCT-2 from the Cherry Canyon Formation. B.) Sample SH-5748 from the Cherry Canyon Formation. Note the yellow dye in the potassium feldspar grains.

Figure 10: Photomicrograph of plagioclase feldspar grains in cross polarized light, Delaware Mountain Group. A.) Sample AHS-5574 from the Bell Canyon Formation. B.) Sample AHS-6088 from the Cherry Canyon Formation. Note albite twinning.

Volcanic Lithic Grains (Lv)

Volcanic lithic grains (Figure 11) are identified on the basis of their texture. This framework grain type is rare in the Delaware Mountain Group. Volcanic lithic grain texture identification includes:

Lathwork grains – elongate, blade-like, plagioclase laths that are either intergrown to form one solitary grain or set in a dark, vitric or altered vitric groundmass.

Felsite grains – microcrystalline aggregates of quartz and feldspar that resemble chert grains. In contrast to chert, they have a strong internal relief when viewed with oblique illumination, have little to no argillaceous material, and commonly contain stained potassium feldspar microcrysts.

Microlitic grains – plagioclase crystals that are short, blocky, and typically set in a dark vitric or altered vitric groundmass.

Siliciclastic Sedimentary and Metamorphic Lithic Grains (Lss+m)

Siliciclastic sedimentary and metavolcanic lithic grains are tabulated under one category and identified by several attributes. Siliciclastic sedimentary lithic grains include mostly argillaceous siltstone or mudstone (Figure 12). The grains are often black, gray, and brown/red. Metamorphic lithic grains are characterized by the observance of equant polygonal domains of silt-sized quartz with aligned mica as well as any volcanic lithic grains that show signs of secondary alteration due to metamorphic processes (Figure 11).

Figure 11: Photomicrograph of volcanic lithic grains in cross polarized light, Delaware Mountain Group. A.) Sample AHS-6190 from the Cherry Canyon Formation. Note the felsitic texture. B.) Sample JCT-3 from the Cherry Canyon Formation. Note the lathwork texture

Figure 12: Photomicrograph of siliciclastic sedimentary and metamorphic lithic grains, Delaware Mountain Group. A.) Sample JCT-5, argillaceous mudstone from the Cherry Canyon Formation. B.) Sample JCT-1, metamorphic lithic grain from the Bell Canyon Formation.

2.3 Additional Categories

Grains in the following categories were tabulated during the point counts, but are not included in the grain populations plotted on sandstone classification ternary diagrams and provenance discrimination ternary diagrams.

Phyllosilicates (Phyllo)

Phyllosilicate grains include biotite and muscovite. Biotite grains appear green to brown in color and possess well developed cleavage. Muscovite has no color, bright interference colors, and cleavage. Phyllosilicates constitute a minor percentage in most of the Delaware Mountain Group samples, with the exception of some Brushy Canyon

Formation samples (Figure 13).

Heavy Minerals (H)

Heavy minerals include amphibole, pyroxene, sphene, tourmaline, and zircon grains (Figure 14).

Cement/Matrix (C/M)

Cement/Matrix is common and occurs in various forms throughout the Delaware

Mountain Group (Figure 15). Early to advanced stage of quartz overgrowth cementation can be seen, as well as authigenic dolomite cementation. More common however, is the presence of calcite cement that possesses poikilotopic texture. In general, the size of calcite rhombs closely resembles the size of the detrital grains. In the case of the Delaware Mountain Group, they are silt-sized.

Pore Space ( Φ)

Pore space in the Brushy Canyon Formation samples has been completely cemented. However, the Bell Canyon Formation and Cherry Canyon Formation have preserved pore space. Pore space can be distinguished by the blue staining of thin section samples (Figure 16). Porosity types present include primary interparticle porosity, secondary porosity caused by partial dissolution of detrital grains, and fracture porosity.

Others not in categories above (O)

Grains in the others category include carbonate detrital grains, identifiable bioclastic fragments, such as ooids and brachiopods, organic matter, and minerals that appear opaque (Figure 17).

Figure 13: Photomicrograph of phyllosilicates, Delaware Mountain Group. A.) Sample CM-6144 from the Brushy Canyon Formation showing muscovite in plain polarized light. B.) Sample CM-6277 from the Brushy Canyon Formation showing muscovite in cross polarized light.

Figure 14: Photomicrograph of zircon grain from the Delaware Mountain Group. A.) Sample JCT-5 from the Cherry Canyon Formation in plain light. B.) Same image as A but in cross polarized light.

Figure 15: Photomicrograph of calcite cement in the Delaware Mountain Group. A.) Sample JCT-5 from the Cherry Canyon Formation. B.) Sample CM-6277 from the Brushy Canyon Formation. Note that the calcareous cement can be distinguished by high-order interference colors.

Figure 16: Photomicrograph of preserved porosity in the Delaware Mountain Group. A.) Sample SH-5617 from the Cherry Canyon Formation. B.) Sample ES-6223 from the Cherry Canyon Formation.

Figure 17: Photomicrograph of other grains in the Delaware Mountain Group. A.) Sample BC-6111, opaque mineral from the Cherry Canyon Formation. B.) Sample BC- 6772, preserved ooid with displaced nucleus from the Cherry Canyon Formation.

2.4 Classification Results

Mineralogical data compiled from point counting provide a baseline check on detrital modes and confirms that the Delaware Mountain Group sandstones samples are predominately arkosic to subarkosic (Figure 18). Additionally, the data indicates a predominately transitional continental provenance field (Figure 19 and Figure 20).

Provenance and classification results for the individual formations of the Delaware

Mountain Group are detailed in the following sections. Tabulated summaries for normalized point count data for sandstone samples of the Brushy Canyon, Cherry

Canyon, and Bell Canyon formations (Table 3 a-c) and raw point count data are also available (Appendix I).

Brushy Canyon Formation

Sandstone samples of the Brushy Canyon Formation exhibit arkosic-subarkosic mineralogy (average Q79, F18, L3) (Figure 18; Folk 1980). There are two samples that exhibit a quartzarenite mineralogy. The two samples are from the Cottonmouth sample location in the northern Delaware Basin and possess the largest percentage of total quartz for all the samples point-counted. The other Brushy Canyon samples contained a larger amount of silt and clay-sized particles compared to all other samples throughout the Delaware Mountain Group. Observed porosity in the samples is practically non-existent. The sandstones primarily plot in the transitional continental provenance field on both the QtFL and QmFLt ternary diagrams (Figure 19 and Figure

20; Dickinson et al. 1983). The sample total from the Brushy Canyon in this study is small therefore samples plotting in other provenance fields carry more weight. The two samples from the Cottonmouth locality plot in the craton interior provenance field in both

the QtFL and QmFLt ternary diagrams. There is one sample that plots in the recycled orogenic provenance field on the QtFL ternary diagram and two additional samples that plot in the craton interior provenance field on the QmFLt ternary diagram.

Cherry Canyon Formation

Sandstone samples of the Cherry Canyon Formation exhibit arkosic-subarkosic mineralogy (average Q72, F24, L4) (Figure 18; Folk 1980). There is a larger percentage of plagioclase in the Cherry Canyon samples in comparison to the Bell

Canyon samples; however, potassium feldspar still constitutes a larger percentage of the total feldspars. Similarly, there is a more common occurrence of volcanic lithic grains in comparison to the Bell Canyon; however, lithic grain percentages are dominated by siliciclastic sedimentary and metamorphic lithic grains. The average porosity counted in the samples is ~17%. Continuing the similarities with the Bell

Canyon, the more porosity preserved in a sample means less cement in the sample, and vice versa. Sandstone samples are texturally submature and moderately- to well- sorted. The Cherry Canyon sandstone samples plot primarily in the transitional continental provenance field on both the QtFL and QmFLt ternary diagrams (Figure 19 and Figure 20; Dickinson et al. 1983). There are several outlying data points on the

QtFL ternary diagram that plot in the recycled orogenic provenance field. These samples have a higher percentage of total lithic grains. The QmFLt ternary diagram has one data point in the mixed provenance field and several data points in the craton interior provenance field.

Bell Canyon Formation

Sandstone samples of the Bell Canyon Formation exhibit arkosic-subarkosic mineralogy (average Q74, F23, L3) (Figure 18; Folk 1980). Compared to plagioclase, potassium feldspar represents a larger percentage of the total feldspars. In addition, lithic fragments are dominated by siliciclastic sedimentary and metamorphic lithic grains.

Most of the sandstone samples are texturally submature and moderately to well-sorted.

A notable observation for additional grains counted is the relationship of porosity and cement in each sample. As expected the more porosity preserved in a sample the less cement is present, and vice versa. The sandstones primarily plot in the transitional continental provenance field on both the QtFL and QmFLt ternary diagrams (Figure 19 and Figure 20; Dickinson et al. 1983). There are two outlying data points on the QtFL ternary diagram in two different provenance fields: one plotting on the craton interior, and the other plotting on recycled orogenic. The QmFLt ternary diagram has one outlier that plots in the craton interior provenance field.

Comparisons to Previous Studies

There is a substantial amount of petrographic data collected by previous workers that exists for the Delaware Mountain Group. All three formations of the Delaware

Mountain Group have undergone some sort of petrographical analysis. Comparison of the point-count data from this study with previous sandstone petrology studies from the

Delaware Mountain Group establishes consistency of the point-counts with multiple operators and creates a larger, more robust dataset for the purpose of provenance analysis.

Previous petrographic data reported for the Bell Canyon, Cherry Canyon, and

Brushy Canyon formations (Hull 1957; Berg 1978; Watson 1979; Williamson 1979;

Harms et al. 1988; Soreghan and Soreghan 2013) are in agreement with the composition of framework grains in this study. Most samples from the aforementioned studies and the samples from this study possess arkosic-subarkosic mineralogy (Folk

1980) and fall within the transitional continental provenance field defined by Dickinson et al. (1983). It is worth noting that the majority of these studies obtained their petrographical data from outcrops in the northern Delaware Basin, whereas petrographical data for this study are obtained from Delaware Mountain Group via subsurface core in the southern Delaware Basin. Comparisons with other point count studies (Harms et al. 1984; Soreghan and Soreghan 2013) reveal very similar results.

Normalized framework grain percentages from previous point count studies are within ±

2% of the normalized framework grains in this study, further confirming the accuracy of point-counts conducted in this study. Samples that plotted outside of the commonly seen provenance fields are most likely due to a difference in grain identification and classification between operators.

Table 3a. Recalculated point-count data for sandstone samples of the Brushy Canyon Formation ( N=10) %Qt-F-L %Qm-F-Lt Sample Qt F L Qm F Lt BC-7163 80 16 4 79 16 5 BC-7469 77 22 1 76 22 2 AH-6859 79 14 7 76 14 10 AH-7276 79 20 1 78 20 2 SH-6243 66 30 4 63 30 7 SH-6546 70 27 3 69 27 4 ES-6707 77 20 3 75 20 5 ES-7024 75 24 1 73 24 3 CM-6144 94 5 1 87 5 8 CM-6277 93 5 2 88 5 7 Mean 79 18 3 76 18 5

Table 3b. Recalculated point-count data for sandstone samples of the Cherry Canyon Formation ( N=29) %Qt-F-L %Qm-F-Lt Sample Qt F L Qm F Lt JCT-5872 72 18 10 70 18 12 JCT-6068 77 21 2 63 21 16 JCT-6348 75 22 3 67 22 11 JCT-6446 81 17 2 74 17 9 BC-6111 91 5 4 88 5 7 BC-6379 77 21 2 77 21 2 BC-6772 79 20 1 79 20 1 BC-6917 85 13 2 84 13 3 AH-5765 80 17 3 77 17 6 AH-5833 75 22 3 70 22 8 AH-5987 80 17 3 77 16 7 AH-6088 80 15 5 77 15 8 AH-6190 78 17 5 74 17 9 AH-6295 78 18 4 74 18 8 AH-6394 80 17 3 77 17 6 SH-5322 66 28 6 63 28 9 SH-5516 61 38 1 60 38 2 SH-5671 58 36 6 56 36 8

Table 3b.(Continued) %Qt-F-L %Qm-F-Lt Sample Qt F L Qm F Lt SH-5748 64 27 9 59 27 14 SH-5852 61 37 2 60 37 3 SH-6006 64 28 8 62 28 10 SH-6194 67 29 4 66 29 5 ES-5601 69 27 4 66 27 7 ES-5816 63 34 3 62 34 4 ES-5949 68 29 3 67 29 4 ES-6087 82 17 1 79 17 4 ES-6223 75 24 1 71 24 5 ES-6470 78 17 5 71 17 12 ES-6546 81 14 5 73 14 13 Mean 74 22 4 70 22 8

Table 3c. Recalculated point-count data for sandstone samples of the Bell Canyon Formation ( N=16) %Qt-F-L %Qm-F-Lt Sample Qt F L Qm F Lt JCT-4946 77 20 3 75 20 5 BC-5260 77 21 2 77 21 2 BC-5359 76 23 1 76 23 1 BC-5517 83 15 2 83 15 2 BC-5779 80 18 2 79 18 3 AH-5291 77 18 5 73 18 9 AH-5463 77 19 4 75 19 6 AH-5518 77 18 5 74 18 8 AH-5574 72 22 6 69 22 9 SH-4699 77 15 8 76 15 9 SH-4770 71 27 2 70 27 3 SH-4930 62 36 2 61 36 3 SH-5013 67 29 4 67 29 4 ES-5064 64 35 1 63 35 2 ES-5204 71 26 3 68 26 6 ES-5331 74 24 2 72 24 4 Mean 74 23 3 72 23 5

Figure 18: QtFL ternary plot showing the Folk (1980) sandstone classification scheme for the Bell Canyon, Cherry Canyon, and Brushy Canyon formations of the Delaware Mountain Group. (Inset ternary diagrams represent only the top half of the sandstone classification plot; n denotes number of thin sections per sample)

Figure 19: QtFL ternary plot showing the potential compositional fields indicative of sand derivation from various types of provenances for the Bell Canyon, Cherry Canyon, and Brushy Canyon formations of the Delaware Mountain Group (Dickinson et al. 1983). (Inset ternary diagrams represent only the top half of the provenance discrimination plot; n denotes number of thin sections per sample)

Figure 20: QmFLt ternary plot showing the potential compositional fields indicative of sand derivation from various types of provenances for the Bell Canyon, Cherry Canyon, and Brushy Canyon formations of the Delaware Mountain Group (Dickinson et al 1983). (Inset ternary diagrams represent only the top half of the provenance discrimination plot; n denotes number of thin sections per sample).

3. U-PB DETRITAL ZIRCON GEOCHRONOLOGY

3.1 Sampling and Geochronology Methods

Four samples were collected and analyzed from whole core taken from the J.C

Tree well in the southern Delaware Basin (Figure 1). Samples from the Delaware

Mountain Group that were prepared and underwent geochronology analysis include one

Bell Canyon Formation sample (JCT-4946) and three Cherry Canyon Formation samples (JCT-5872, JCT-6068, and JCT-6446)(Figure 6). Unfortunately, a Brushy

Canyon sample was unavailable for analyses. Sample preparation was completed at

Texas Christian University and University of Texas at Arlington under the guidance of

Dr. Xiangyang Xie and U-Pb geochronology analysis was conducted at the University of

Arizona.

Each sample was crushed into small chips using a jaw crusher and then milled into sand-sized particles with a disc-mill. Iron filings from the disc grinder were removed from the sample using a hand magnet. Next, the sample was hand washed to separate the light minerals from the heavy minerals. Each sample underwent ten wash cycles in order to effectively eliminate light minerals. The remaining heavy minerals were washed with acetone and allowed to dry. After drying, the sample was sieved to remove grains greater than 350 µm thus leaving fine-sand sized and smaller grains.

Grains less than 350 µm were then subjected to two passes through a Frantz LB-1 separator. The magnetic separator had a set front slope of 10° and a side slope of 20°.

The slope setting remained the same for each pass, but the magnetic strength was increased from the first pass to the second. The magnetic strength for pass #1 was 1.0

Amps and 1.5 Amps for pass #2. The resulting magnetic fraction from each pass was

labeled and stored. The non-magnetic portion from pass #2 was processed using

Methylene Iodide (MI, ρ≥ 3.3 g/cm 3). Under a fume hood, heavy minerals were recovered using heavy liquid separation techniques that utilize a separatory funnel. MI was poured into the separatory funnel and then the sample was poured directly into the funnel containing MI. The sample was stirred with a stirring rod to allow the heavy minerals to separate and settle at the bottom of the flask. The stopper on the separatory flask was opened for 2-3 seconds to release the heavy minerals onto a filter paper/flask setup below. The sample was then washed with acetone and allowed to dry. The sample was then placed into a petri dish with alcohol and examined under a binocular microscope. A metal dental tool was used to remove any non-zircon grains.

The zircons were removed from the petri dish using a plastic pipette and sent to the

University of Arizona LaserChron lab where the zircon grains were further prepared for

U-Pb detrital zircon geochronology analyses.

Samples were analyzed at the University of Arizona LaserChron Center using the

Laser-Ablation Multicollector Inductively Coupled Plasma Mass Spectrometer (LA-MC-

ICPMS) (Gehrels et al. 2006, 2008). Zircon grains were mounted on a one-inch epoxy, sanded to ~ 20 microns, polished, imaged (Figure 21), and ready for laser ablation. The laser ablation process begins by ablating a 30 micron spot on a single zircon grain with a Photon Machines Analyte G2 excimer laser. The ablated matter is carried via a helium carrier airway transport to a plasma source of a Nu Plasma Multicollector

ICPMS. At this point simultaneous measuring of U, Th, and Pb isotopes takes place.

Faraday detectors containing 3x10 11 ohm resistors detect 238 U, 232 Th, and 208 Pb-206 Pb in static mode, and analyze 204 Pb and 202 Hg using discrete dynode ion counters.

Figure 21: Examples of backscattered electron images of zircons in processed samples. A) JCT-4946 (Bell Canyon sample). B) JCT-6446 (Cherry Canyon sample).

A range of individual zircon grains were analyzed depending on recovered zircons per sample. Each analysis consisted of 15 one-second fires with the laser off, followed by 15 one-second fires with the laser on. The machine was then purged for 30 seconds between each sample. The ablation pit is ~ 15 microns in depth. A Sri Lankan zircon crystal (known age of 563.5 ± 3.2 Ma (2σ error)) was used as a standard during ablation and was analyzed five times at the beginning of each sample set, after every fifth unknown zircon, and five more times at the conclusion of a sample set. The data from the known standards were used to correct for isotopic and elemental fractionation and calibrate the machine during operation. The errors in determining 206 PB/ 238 U and

206 Pb/ 204 Pb produce a ~1-2% (2σ error) measurement error in the 206 PB/ 238 U age. For grains that are >1.0 Ga, the errors in measurement of 206 Pb/ 207 Pb and 206 Pb/ 204 Pb also produce a ~1-2% (2σ error), but are significantly larger for younger grains due to the low intensity of the 207 Pb signal. For most analyses, including this study, the cross-over in precision of 206 Pb/238 U and 206 Pb/ 207 Pb ages occurs at ~1.0 Ga (Gehrels et al., 2006,

2008).

Similar to the methods used in Gehrels et al. (2008), the interpreted best age for grains < 1 Ga are taken from 206 Pb/ 238 U ages whereas grains > 1 Ga are taken from

206 Pb/ 207 Pb ages. For grains >1.0 Ga, ages were analyzed for discordance by comparing the 206 Pb/ 207 Pb ages to 206 Pb/ 238 U ages. Subsequently, grains <1.0 Ga were analyzed for discordance by comparing 206 Pb/ 238 U ages to 207 Pb/ 235 U ages. In both cases, discordance of >20% (<80% concordance) and a reverse discordance of >10%

(<110% concordance) was set as a cutoff to filter out poor data. Grains that are < 400

Ma were free of U/Pb age discordance discrimination and were always used. Age

certainties are reported at the 1-σ level and include only measurement errors.

Complete data from geochronology analyses can be found in the Appendix II. For complete details and further instruction of the heavy liquid separation technique, laser ablation, isotope dating, and data reduction process please visit the University of

Arizona LaserChron Center website.

3.2 Results

The detrital zircon geochronology results (Appendix II) are plotted on three types of diagrams that were constructed using Isoplot3 software: Normal concordia plots,

Tera-Wasserburg concordia plots and relative probability plots. Normal concordia plots display 206 Pb/ 238 U and 207 Pb/235 U isotope ratios, whereas, Tera-Wasserburg concordia plots display the inverse of 207 Pb/ 206 Pb and 238 U/206 Pb isotope ratios. Both plots are particularly useful to sort through poor data and can reveal potential lead loss in individual grains. Relative probability plots asses the reliability of the age data by comparing U/Pb ages and their errors. Therefore, if each grain in a group of similar age has a low error, that group will plot as a high peak on the probability chart, whereas groups of similar age grains with high error will have a low peak. Most importantly, the probability plot illustrates the modal age spectra of the areas that supplied zircons to the

Delaware Basin during the middle Permian.

Age data obtained from each sample were divided into seven age populations that can be further associated with potential source terranes. Zircon age populations for the various source regions originate from Hoffman (1989) and Dickinson and Gehrels

(2009). Detrital zircon age populations include: Paleoproterozoic/Archean (>1825 Ma),

Late Paleoproterozoic (1600-1825 Ma), Early Mesoproterozoic (1300-1600 Ma), Mid-

Late Mesoproterozoic (920-1300 Ma), Neoproterozoic/Early Paleozoic (510-790 Ma),

Mid-Paleozoic (275-490 Ma), Late Paleozoic (<275 Ma). Raw percentage of each age population are summarized in Table 4 and further discussed in the following sections.

Table 4: Ages and percentages of detrital zircons from analyzed samples in the Delaware Mountain Group (n= number of concordant detrital zircons per sample).

Bell Canyon Cherry Canyon Formation Formation JCT-4946 JCT-5872 JCT-6068 JCT-6446 Age (Ma) Source Terrane Age (n=75) (n=143) (n=77) (n=152) <275 Late Paleozoic 1 1% 0 0% 1 1% 0 0% 275-490 Mid-Paleozoic 28 37% 35 24% 24 31% 49 32%

510-790 Neoproterozoic/Early Paleozoic 16 21% 29 20% 14 18% 19 13% 920-1300 Mid-late Mesoproterozoic 9 12% 39 27% 18 23% 32 21% 1300-1600 Early Mesoproterozoic 8 11% 19 13% 9 12% 27 18% 1600-1825 Late Paleoproterozoic 7 9% 9 6% 4 5% 4 3% >1825 Paleoproterozic/Archean 6 8% 12 8% 7 9% 11 7%

JCT-6446

Sample JCT-6446, the oldest stratigraphic sample of the Cherry Canyon

Formation, has 152 individual zircon grains that have concordant detrital-zircon ages.

This sample has the largest number of zircons that were analyzed and their U/Pb isotope data are displayed on a normal concordia plot and Tera-Wasserburg plot

(Figure 22 and 23) and show the accuracy and error of individual grain analyses. A relative probability plot displaying the ages of each zircon grain from the sample illustrates modal ages of the primary source areas that supplied zircons to the Delaware

Basin during the middle Permian (Figure 24). The age data reveal a mixed distribution of age populations ranging as young as ~310 Ma to ~3533 Ma. Mid-Paleozoic (275-490

Ma) grains contribute the largest percentage (32%) to the age population. Mid-late

Mesoproterozoic (920-1300 Ma) and early Mesoproterozoic (1300-1600 Ma) grains contribute 21% and 18% to the total age population, respectively. Neoproterozoic/Early

Paleozoic (510-790 Ma) grains form a subordinate percentage (13%) of the total age spectra. Late Paleoproterozoic (1600-1825 Ma; 3%) age and Paleoproterozoic-Archean

(>1825 Ma; 7%) grains constitute only a minor fraction of the total age population. Of the four samples that underwent analyses, JCT-6446 had the largest population of early

Mesoproterozoic grains and the smallest population of Neoproterozoic/Early Paleozoic and late Paleoproterozoic grains.

Figure 22: Normal concordia diagram, sample JCT-6446, Cherry Canyon Formation.

Figure 23: Tera-Wasserburg concordia diagram, sample JCT-6446, Cherry Canyon Formation.

Figure 24: Relative probability plot, sample JCT-6446, Cherry Canyon Formation.

JCT-6068

Another Cherry Canyon sample, JCT-6068 has 77 has individual zircon grains that have concordant detrital-zircon ages. Zircon U/Pb isotope data are displayed on a normal concordia plot and Tera-Wasserburg plot (Figure 25 and 26) and show the accuracy and error of individual grain analyses. The age data reveal a mixed distribution of age populations ranging as young as ~295 Ma to ~2774 Ma., with a major population of Mid-Paleozoic (275-490 Ma) (31%) and mid-late Mesoproterozoic (920-

1300 Ma) (23%) grains (Figure 27). Neoproterozoic/Early Paleozoic (510-790 Ma) grains make up a modest 18% of the age population in the sample. Forming a relatively minor percentage of the age populations are early Mesoproterozoic (1300-1580 Ma;

12%), late Paleoproterozoic (1600-1825 Ma; 5%), and Paleoproterozoic-Archean

(>1825 Ma; 9%) grains.

Figure 25: Normal concordia diagram, sample JCT-6068, Cherry Canyon Formation.

Figure 26: Tera-Wasserburg concordia diagram, sample JCT-6068, Cherry Canyon Formation.

Figure 27: Relative probability plot, sample JCT-6068, Cherry Canyon Formation.

JCT-5872

Sample JCT-5872, the youngest stratigraphic sample of the Cherry Canyon

Formation, has 143 individual zircon grains that have concordant detrital-zircon ages.

Zircon U/Pb isotope data are displayed on a normal concordia plot and Tera-

Wasserburg plot (Figure 28 and 29) and show the accuracy and error of individual grain analyses. Similar to the other Cherry Canyon samples, the age data reveal a mixed distribution of age populations ranging as young as ~300 Ma to ~3233 Ma. Three age populations constitute a major percentage of the sample and include Mid-Paleozoic

(275-490 Ma) (24%), Neoproterozoic/Early Paleozoic (510-790 Ma) (20%), and mid-late

Mesoproterozoic (920-1300 Ma) (27%) grains (Figure 30). Forming a relatively minor percentage of the age populations are early Mesoproterozoic (1300-1580 Ma; 13%), late Paleoproterozoic (1600-1825 Ma; 6%), and Paleoproterozoic-Archean (>1825 Ma;

8%) grains. Of the four samples analyzed, JCT-5872 has the largest fraction of mid-late

Mesoproterozoic age grains.

Figure 28: Normal concordia diagram, sample JCT-5872, Cherry Canyon Formation.

Figure 29: Tera-Wasserburg concordia diagram, sample JCT-5872, Cherry Canyon Formation.

Figure 30: Relative probability plot, sample JCT-5872, Cherry Canyon Formation.

JCT-4946

Sample JCT-4946, the lone sample from the Bell Canyon Formation, has 75 individual zircon grains that have concordant detrital-zircon ages. Zircon U/Pb isotope data are displayed on a normal concordia plot and Tera-Wasserburg plot (Figure 31 and

32) and show the accuracy and error of individual grain analyses. The data reveal a mixed distribution of sources spanning as young as ~286 Ma to ~2864 Ma, with a major population of Mid-Paleozoic (275-490 Ma) (37%) and Neoproterozoic/Early Paleozoic

(510-790 Ma) (21%) grains (Figure 33). Subordinate age populations of the sample include mid-late Mesoproterozoic (950-1300 Ma; 12%) age, early Mesoproterozoic

(1300-1580 Ma; 11%) age, late Paleoproterozoic (1600-1825 Ma; 9%) age, and

Paleoproterozoic-Archean (>1825 Ma; 8%) age grains. One grain in the sample has an age of 286 Ma, which is the approximate time of early Permian deposition in the

Delaware Basin. Of the four samples that underwent analyses, JCT-4946 has the largest fraction of Paleozoic and Neoproterozoic grains and the smallest fraction of

Mesoproterozoic grains.

Figure 31: Normal concordia diagram, sample JCT-4946, Bell Canyon Formation.

Figure 32: Tera-Wasserburg concordia diagram, sample JCT-4946, Bell Canyon Formation.

Figure 33: Relative probability plot, sample JCT-4946, Bell Canyon Formation.

The Kolmogorov-Smirnoff statistical test (K-S test) (Press et al. 2007) has been used in previous studies to compare detrital zircon age distributions (Berry et al. 2001;

DeGraaf-Surpless et al. 2003; Dickinson et al. 2010). In addition to visually comparing age distributions with histograms and probability density plots, this test allows a mathematical comparison between age distributions of two samples and determines if there is a large statistical difference between the two. Following the methods set forth by Guynn and Gehrels (2010) a P value < 0.05 signifies that there is a >95% confidence level that the two age distributions are not the same. Note that the K-S test can only determine the probability that two populations are not the same and must be used in

conjunction with visual comparisons of age populations. The K-S statistical test was applied to the four samples in this study and pass the test for a 95% confidence level (P values > 0.05) and are not rejected (Table 5).

Table 5: Probability (P) values from Kolmogorov-Smirnoff analysis for detrital zircon populations of the Delaware Mountain Group samples.

JCT-4946 JCT-5872 JCT-6068 JCT-6446 JCT-4946 0.126 0.528 0.102 JCT-5872 0.126 0.925 0.726 JCT-6068 0.528 0.925 0.589 JCT-6446 0.102 0.726 0.589

4. Potential Source Terranes

Extensive studies have taken place to better understand the ages terranes that may have supplied sediment to basins across central and southern North America (e.g.

Bickford et al. 1986; Hoffman 1989; Anderson and Morrison 1992; Burchfiel et al. 1992;

Van Schmus et al. 1996; Dickinson and Lawton 2001; Dickinson and Gehrels 2009).

Potential source terranes for the zircons documented in this study are further discussed in relation to their associated age population and in a geographical perspective (Figure

34). Number of detrital zircon grains and raw percentages reported in this study and their associated age populations have been tabulated (Table 4).

Figure 34: Map of central North America displaying the location of the main age provinces that may have supplied sediment to Permian strata (Modified from Soreghan et al. 2002, and references therein, and Gehrels et al. 2011 and references therein).

Archean/Paleoproterozoic (>1825 Ma)

The Superior-Wyoming (2.5-2.7 and 3.0 Ga) and the Penokean-Trans-Hudson

(1.8-2.0 Ga) provinces of the Laurentian craton are potential sources for ages >1825 Ma

(Hoffman 1989; Van Schmus et al. 1996). Archean age grains have been documented in Pennsylvanian strata of the Marathon and Arkoma basins, located in Texas and

Oklahoma, respectively (Sharrah 2006; Gleason et al. 2007). Gehrels et al. (2011) documented grains of Archean age in Permian strata of the Grand Canyon. All results are traced to a Laurentian provenance. Grains of Paleoproterozoic age are relatively uncommon in Laurentia (Soreghan and Soreghan 2013). Grains that have documented

Paleoproterozoic ages exist in Pennsylvanian strata in the Appalachian Basin (Thomas et al. 2004) and middle Permian strata in the Delaware Basin (Soreghan and Soreghan

2013). These basins are associated with tectonic events along the Gondwanan margin

(Trompette 2000), which suggests potential recycling of various Appalachian terranes, such as the Avalon and Carolina terranes (Soreghan and Soreghan 2013). Additionally,

Paleoproterozoic grains have been documented from Suwanee terranes in the Florida subsurface (Mueller et al. 1994) and the Maya block in Mexico (Weber et al. 2006).

Late Paleoproterozoic (1600-1825 Ma)

The late Paleoproterozoic age population is associated with the Yavapai-

Mazatzal terrane, which are metasedimentary and metavolcanic assemblages that span across the central and southwestern United States. During Pennsylvanian-early

Permian time several denuded uplifts in the Ancestral Rocky Mountains exposed the

Yavapai-Mazatzal terrane (Gehrels et al. 2011). Furthermore, late Paleoproterozoic

age grains are documented throughout Paleozoic strata of the Grand Canyon (Gehrels et al. 2011) and more specifically in Pennsylvanian-early Permian strata. These results along with previous interpretations suggest that there was active denudation of the

Ancestral Rocky Mountains during the Pennsylvanian-early Permian (Soreghan et al.

2002; Soreghan et al. 2007; Dickinson and Gehrels 2003; Gehrels et al. 2011). This age population has been documented in Pennsylvanian strata of the Marathon/Ouachita orogenic system (Gleason et al. 2007; Sharrah 2006) and in Paleozoic strata of the

Appalachian foreland (Eriksson et al. 2004).

Early Mesoproterozoic (1300-1600 Ma)

The early Mesoproterozoic age population is related to the granite-rhyolite province located in central North America. These rocks formed during a period of anorogenic magmatism that is represented by plutons that are present across the region (Van Schmus et al. 1996). Additionally, these plutons were integrated in the uplifts associated with the Ancestral Rocky Mountains (Hoffman 1989; Van Schmus et al. 1996).

Middle-Late Mesoproterozoic (920-1300 Ma)

The middle-late Mesoproterozoic age population is linked to tectonic events associated with the Grenville orogeny in eastern and southern North America, as well as parts of present-day Mexico and the Gondwana continents. Zircons of this age have been well-documented and are predominant populations in a number of North American sandstones ranging in ages from Neoproterozoic to Mesozoic. (Rainbird et al. 1992,

1997; Dickinson and Gehrels 2003; Sharrah 2006; Gleason et al. 2007; Gehrels et al.

2011; Hietpas et al. 2011; Rainbird et al. 2012; Soreghan and Soreghan 2013). This is due to the recycling of this terrane that occurred during the Appalachian orogeny.

Neoproterozoic/Early Paleozoic (510-790)

Potential sources for Neoproterozoic age populations occur in several terranes located adjacent to Gondwana that were caught up in the suture created during the collision of Laurentia and Gondwana (Soreghan and Soreghan 2013). Within the

Appalachian orogen, “peri-Gondwanan” terranes include the Avalon terrane in the northern Appalachians, Carolina terrane in the southern Appalachians, and Suwanee terrane in the Florida subsurface. Ranging in ages of 760-515 Ma, these terranes were uplifted and denuded during the Appalachian orogeny in the late Paleozoic (Opdyke et al. 1987; Mueller et al. 1994; Dickinson and Gehrels et al. 2003; Murphy et al. 2004;

Sharrah 2006; Martens et al. 2010; Thompson et al. 2012).

Additional “peri-Gondwanan” terranes include terranes that were accreted to and are now present in Mexico and Central America. The Yucatan-Maya (a.k.a. Maya block, Maya terrane, and Yucatan-Chiapas) and the Coahuilla terranes had accreted and were uplifted by Permian time (Sacks and Secor 1990; Dickinson and Lawton 2001;

Poole et al. 2005) and include Permian-Pennsylvanian strata with documented detrital zircon ages of 650-500 Ma (Weber et al. 2006; Martens et al. 2010). The exact placement of these Mexican/Central American “peri-Gondwanan” terranes is not known and several interpretations exist (Dickinson and Lawton 2001; Murphy et al. 2004;

Vega-Granilo et al. 2008; Martens et al. 2010; Soreghan and Soreghan 2013).

However, all of these terranes were involved in the collisional event that formed

Pangea, and are thus capable of supplying detrital zircons to the Ouachita-Marathon system and beyond (Soreghan and Soreghan 2013).

This age population also includes Early Paleozoic ages (Cambrian-Ordovician).

Potential source terranes include Cambrian-Ordovician igneous rocks that are located across New Mexico and southern Colorado and record magmatic ages of 664-457 Ma and 574-427 Ma, respectively (McMillan and McLemore 2004). Furthermore, the igneous exposures are located in areas that underwent uplift associated with the

Ancestral Rocky Mountains in Pennsylvanian time. Whether these potential sources were exposed in later Permian time remains in question (Soreghan and Soreghan

2013). Additionally, the Amarillo-Wichita uplift is a potential source terrane with Early

Paleozoic ages. More specifically, North American strata ranging from Pennsylvanian-

Triassic age have documented Cambrian age populations that are linked to the denudation of the Wichita uplift in Oklahoma (Dickinson and Gehrels 2003; Sharrah

2006; Gleason et al. 2007; Dickinson et al. 2010; Gehrels et al. 2011). The Wichita uplift, a highland associated with the Ancestral Rocky Mountains was actively eroded in

Pennsylvanian time and includes Cambrian age granite units accurately dated to 530 ±

3 Ma and 533 ± 3 Ma (Wright et al. 1996; Hames et al. 1998; Hogan et al. 2000).

However by middle to late Permian time erosion of these uplifts remains in question

(Gehrels et al. 2011; Soreghan et al. 2012).

Mid-Paleozoic (285-490 Ma)

The Taconic (490-440 Ma), Acadian (420-350 Ma), and Alleghanian (320-260

Ma) orogenies of the overall Appalachian orogen are potential sources for Paleozoic age populations (Simonetti and Doig 1990; Miller et al 2000; Aleinikioff et al. 2002;

Hatcher et al. 2002). Additionally, accreted terranes in Mexico, such as the Mixteca terrane (480-440 Ma), Yucatan-Maya terrane (418 Ma), and Oaxaquia (416-386 Ma) possess Paleozoic age grains (Keppie et al. 2004, 2008; Weber et al. 2006, 2008).

Near middle Permian time, collision of the Mixteca terrane had occurred (Keppie et al.

2004), Oaxaquia and Yucatan-Maya terrane had begun to suture (Torres et al. 1999;

Weber et al. 2008) and Oaxaquia had begun to collide with the North American craton

(Torres et al. 1999). Denudation to these Mexican terranes was in full effect, thus making them capable of supplying zircons to the Delaware Basin during the middle

Permian (Soreghan and Soreghan 2013).

Late Paleozoic (< 285 Ma)

During the deposition of the Delaware Mountain Group, the East Mexico arc was an active arc system (284-232 Ma) that formed due to the final closure of the Ouachita suture (Torres et al. 1999; Dickinson and Lawton 2001). Volcanic tephra units have been reported in all three units of the Delaware Mountain Group and are interpreted to have been sourced from the Las Delicias arc, a part of the Eat Mexico arc (King 1948;

Nicklen et al. 2007).

5. DISCUSSION

Based on the reported detrital zircon age populations and sandstone point counts from the samples in this study, three potential source terranes have been identified for the siliciclastic strata of the Delaware Mountain Group. The potential source areas include, the Ancestral Rocky Mountains, the Appalachian orogen, and the Ouachita orogen, and each will be discussed in detail below.

5.1 Ancestral Rocky Mountain Argument

Previous interpretations for the main source region/regions that supplied the siliciclastic material for the Delaware Mountain Group are concentrated on the basement-cored uplifts of the Ancestral Rocky Mountains. Similar to previous studies, results from sandstone point counting in this study suggest a granitic/plutonic- metamorphic provenance for the siliciclastic strata of the middle Permian, Delaware

Mountain Group, such as the uplifts associated with the Ancestral Rocky Mountains

(Kluth and Coney 1981; Dickinson et al. 1983); however, U-Pb detrital zircon geochronologic data from this study contradict this interpretation. Similar to Soreghan and Soreghan (2013), the geochronologic data indicate that the ages (late

Paleoproterozoic; 1600-1825 Ma), which would be associated with the Yavapai-

Mazatzal source terrane exposed in the Ancestral Rocky Mountains, make up only a minor percentage (3-9%) of the total age spectra in each of the four samples in this study and display a low probability (Figure 35). Instead, the largest age populations present in the four samples from the Delaware Mountain Group are Mid-Paleozoic (24-

37%), middle-late Mesoproterozoic (12-27%), and Neoproterozoic/Early Paleozoic (13-

21%) grains (Table 4); all of which display a significant probability (Figure 35).

Figure 35: Normalized probability plots of detrital zircon ages from the Delaware Mountain Group samples of this study and main ages of zircons that may have originated from various source regions, as indicated by shaded vertical bars (Modified from Gehrels et al. 2011). N denotes number of detrital zircons with concordant ages in each sample. (Note the minor influence from Yavapai-Mazatzal terrane often associated with the Ancestral Rocky Mountains).

Kluth and Coney (1981) suggested that by mid-Pennsylvanian time, uplift of the

Ancestral Rocky Mountains had reached its maximum and erosion of Pre-

Pennsylvanian strata resulted in exposure of Precambrian crystalline basement rock. If the Delaware Mountain Group was in fact sourced from the Ancestral Rocky Mountain uplifts there should be an abundance of Precambrian ages reported from the samples.

Additional terranes that are associated with the Ancestral Rocky Mountains and possess Paleozoic and Neoproterozoic age populations include: the Wichita uplift of

Oklahoma, which was actively eroded in Pennsylvanian time and includes granite units dated to 530 ± 3 Ma and 533 ± 3 Ma (Wright et al. 1996; Hogan et al. 2000; Hames et al. 1998) and Cambrian-Ordovician igneous intrusions that were uplifted in parts of the

Ancestral Rocky Mountain (i.e., Uncompahgre Plateau) (McMillan and McLemore

2004). Cambrian age grains documented elsewhere in North America have been attributed to these uplifts (Dickinson and Gehrels 2003; Gleason et al. 2007; Dickinson et al. 2010; Gehrels et al. 2011). However, only 13 grains (2%) and 26 grains (6%) of the four samples possess Cambrian and Ordovician age grains, respectively. Soreghan et al. (2012) compiled field and subsurface data from the core Ancestral Rocky

Mountain system, including the Wichita uplift and the Uncompahgre Plateau in

Colorado, and suggested that these uplifts had ceased to erode during the middle

Permian due to observed onlap in early Permian strata. Additionally, detrital zircon ages reported from the Colorado Plateau and Grand Canyon further suggest that the

Ancestral Rocky Mountains became a much less significant source of sediment by middle Permian time (Dickinson and Gehrels 2003; Gehrels et al. 2011). While the arkosic/subarkosic mineralogy commonly associated with an Ancestral Rocky Mountain

source is present in our Delaware Mountain Group samples, U-Pb detrital zircon geochronology results from this study suggest that these uplifts were not a major source of sediment for the Delaware Mountain Group. This result is in agreement with detrital zircon ages reported in the northern Delaware Basin (Soreghan and Soreghan 2013).

5.2 Appalachian Orogen Argument Paleozoic, middle-late Mesoproterozoic, and Neoproterozoic age grains make up a significant percentage of the total age spectra reported in our four samples and calls for further examination into the source terranes associated with these age populations.

Similar to this study, Gehrels et al. (2011) conducted a study on Paleozoic sandstones from the Grand Canyon and reported ages from Permian samples that possess a lesser percentage of grains originating from the Ancestral Rocky Mountains (late-

Paleoproterozoic) and a larger percentage of grains originating from the Appalachian orogen (Paleozoic) and “peri-Gondwanan” terranes (Neoproterozoic). Furthermore, there was a major change in provenance beginning in Mississippian time and extending into early Permian time that is represented by the dominance of grain ages (270-380

Ma, 415-475 Ma and 1030-1190 Ma) interpreted to have originated from the

Appalachian orogen (Gehrels et al. 2011). In this situation, a transcontinental river system that originated in the Appalachian region transported sediment southwestward during times of lowstand and then this sediment was further transported by eolian processes into western Pangea (Gehrels 2003, 2009; Gehrels et al. 2011). Based on the abundance of Paleozoic and Neoproterozoic zircon ages reported in this study it is conceivable to consider this same transcontinental transport model was delivering sediment to the Delaware Basin during deposition of the Delaware Mountain Group.

For a more comprehensive comparison, detrital zircon ages previously reported in the Delaware Mountain Group (Soreghan and Soreghan 2013) and Devonian-

Permian strata associated with the Appalachian orogen (Gray and Zeitler 1997;

McLennan et al. 2001; Eriksson et al. 2004; Thomas et al. 2004; Becker et al. 2005,

2006; Park et al. 2010) have been compiled for comparison with detrital zircon ages from this study (Figure 36).

Figure 36: Comparison of detrital zircon ages the Middle Permian Delaware Mountain Group (this study and Soreghan and Soreghan 2013), with zircon age distributions from Gray and Zeitler (1997), McLennan et al. (2001) Eriksson et al. (2004), Thomas et al. (2004), Becker et al. (2005, 2006) and Park et al. (2010).

The Devonian-Permian Appalachian strata record well defined age peaks at

1040 Ma, 1080 Ma, and 1175 Ma indicating a strong Grenville orogeny influence and subordinate age peaks associated with the Taconic orogeny (490-440 Ma) and the

Acadian orogeny (420-350 Ma). Preliminary visual comparison reveals the Brushy

Canyon detrital zircon age distributions have some similarities to age distributions reported throughout strata in the Appalachian foreland basin. In contrast to the Cherry

Canyon Formation and Bell Canyon Formation samples, the two Brushy Canyon

Formation samples have “Appalachian-like” age signatures, such as a solitary and well developed Paleozoic age peaks (420 Ma and 412 Ma, respectively), and significant input of Grenville age grains (50% and 41% of the total age spectra, respectively).

Ages reported from the Cherry Canyon and Bell Canyon formation samples, on the other hand, have a lesser influence from Grenville age grains (32%-12%) and a much more significant influence from Neoproterozoic ages.

Because it is difficult to gauge the degree of similarity and dissimilarity between the age populations the K-S test was applied to the Delaware Mountain Group ages reported in this study and Soreghan and Soreghan (2013), as well as Devonian-

Permian Appalachian foreland strata (Appendix III). Statistical results reveal all but one

Delaware Mountain Group sample, Brushy Canyon Formation (n=87), have a P value

<0.05 when compared with the Appalachian foreland strata signifying that there is at least a >95% confidence level that they are from a different parent population.

Additionally, sandstones that are interpreted to have been sourced from the

Appalachian orogen are considerably richer in quartz and possess minor percentages of feldspars. The predominately arkosic/subarkosic mineralogy seen in the Delaware

Mountain Group samples simply cannot be reconciled with an Appalachian orogen source. Based on these reasons it is highly unlikely that the siliciclastic strata of the

Delaware Mountain Group were derived from the Appalachian orogen.

5.3 Ouachita Orogen Argument

Dickinson and Lawton (2003) place the timing of suturing of Gondwana to

Laurentia to form the Ouachita orogen around 290-310 Ma, and by the middle-late

Permian, Ouachita sediments were being thrust onto the North American craton

(Stewart et al. 1999). Often included in Ouachita sediments are recycled Appalachian detritus and sediment from “peri-Gondwanan” terranes, which results in a mixed

Paleozoic and Neoproterozoic ages. There is limited detrital zircon age data directly from the Ouachita orogeny. Detrital zircon data obtained from Pennsylvanian strata of the Haymond Formation in the Marathon Basin (Gleason et al. 2007) and Triassic strata from the Chinle-Dockum Group and Auld Lang Syne Group (Dickinson et al. 2010) are the only data that further support an Ouachita derived source for the Delaware Mountain

Group. The Haymond Formation is considered to represent Carboniferous flysch that is related to the Ouachita thrust system. Furthermore, Gleason et al. (2007) attributed the

Laurentian-dominated distribution of age populations seen in detrital zircon data to possible recycling of Appalachian detritus along the Ouachita-Marathon suture zone.

Dickinson et al. (2010) noticed similar age spectra for the Chinle-Dockum Group and the Auld Lang Syne Group as in the Haymond Formation and suggested that these strata were sourced predominately from the Ouachita orogen.

Following similar comparative measures, detrital zircon ages previously reported in the Delaware Mountain Group (Soreghan and Soreghan 2013), and Ouachita derived strata (Pennsylvanian Haymond Formation, and detrital zircon grains older than 290 Ma from the Triassic Chinle-Dockum and Auld Lang Syne Groups) have been compiled for comparison with detrital zircon ages from this study (Figure 37).

Figure 37: Comparison of detrital zircon ages the Middle Permian Delaware Mountain Group (this study and Soreghan and Soreghan 2013) with zircon ages from “Ouachita- derived” strata (Dickinson et al. 2010; Gleason et al. 2007).

In contrast to comparisons made with the Appalachian foreland strata, preliminary visual comparison reveals the detrital zircon age distributions of the

Delaware Mountain Group samples are more similar to the Ouachita derived sediment of the Haymond Formation and the Chinle-Dockum and Auld Lang Syne Group. A more distributed pattern of Neoproterozoic/Early Paleozoic age (510-790) and Mid-Paleozoic

(490-285 Ma) populations is commonly observed in Ouachita derived sediments, and is also seen in the Delaware Mountain Group samples, especially the Cherry Canyon and

Bell Canyon formations. Despite the similarities, a major mismatch is the abundance of

Grenville age grains in both the Haymond Formation and the Chinle-Dockum and Auld

Lang Syne Group. The Haymond Formation is Pennsylvanian in age and was likely more influenced by recycled Appalachian detritus instead of “Peri-Gondwanan” terranes due to the initial stages of unroofing within the Ouachita system. The Chinle-Dockum and Auld Lang Syne Group display “Peri-Gondwanan” age signatures but the influence from Grenville age grains may suggest influence from recycled Appalachian detritus.

However, Grenville derived sediments do occur in “Peri-Gondwanan” terranes south of the Ouachita-Marathon suture (Keppie 2008; Weber et al. 2008; Martens et al. 2010).

The K-S test was applied to the Delaware Mountain Group ages reported in this study and Soreghan and Soreghan (2013), as well as ages reported from the Ouachita derived strata (Appendix III). Statistical results reveal several ideas: It is very unlikely the Haymond Formation and the Delaware Mountain Group originated from the same parent population. However, the Delaware Mountain Group samples from the northern

Delaware Basin (Soreghan and Soreghan 2013) were potentially derived from the same parent population as the Chinle-Dockum and Auld Lang Syne Group. Furthermore,

results suggest that the Cherry Canyon and Bell Canyon samples from this study

(southern Delaware Basin) were likely influenced and derived from a different parent population than samples from the northern Delaware Basin. The K-S test provides only one piece to the provenance puzzle for the siliciclastic strata of the Delaware Mountain

Group and conclusions cannot solely be made on a statistical test.

Despite the differences presented from the K-S test there are similarities between the Delaware Mountain Group samples from this study and Delaware

Mountain Group samples from other studies. The major similarity is the consistent arkosic-subarkosic mineralogy observed throughout the Delaware Mountain Group in all parts of the basin. This is suggestive of one dominant and consistent granitic/rhyolitic source terrane supplying sediment to the Delaware basin during deposition of the

Delaware Mountain Group. Additionally, key Paleozoic and Neoproterozoic ages reported in the northern Delaware basin can be correlated with ages reported in this study. As first suggested by Soreghan and Soreghan (2013), Paleozoic and

Neoproterozoic age populations seen in the Delaware Mountain Group samples of this study can be linked to detrital zircon ages from the Macal Formation and the Santa

Rosa Group within the Yucatan-Maya terrane (415-425; 540-645 Ma) (Weber et al.

2006; Martens et al. 2010). Additionally, these two formations exhibit a predominantly feldspathic mineralogy, similar to that of the Delaware Mountain Group samples, as a result of local granitic and rhyolitic sources (Weber et al. 2006; Martens et al. 2010).

Furthermore, Devonian detrital zircon grains reported in the Mixteca, Oaxaquia and the

Yucatan-Maya terranes suggest that there was uplift and denudation of Paleozoic terranes (Keppie et al. 2008; Martens et al. 2010). Grains younger than <415 Ma and

seen in the Cherry Canyon and Bell Canyon samples can be attributed to the Oaxaquia terrane (Keppie et al. 2004, 2008). Finally, the Grenville age grains seen in the

Delaware Mountain Group samples can be linked to these Mexican terranes where there is Grenville-age basement present (Keppie 2008; Weber et al. 2008; Martens et al. 2010). Despite inconclusive results from the K-S test, age dates and mineralogy reported in this study can be reconciled with the Ouachita orogen, including key terranes accreted and uplifted south of the Ouachita suture zone, as the primary source terranes for the siliciclastic strata of the Delaware Mountain Group.

5.4 Paleogeography and Sediment Dispersal Pathways As originally suggested by Soreghan and Soreghan (2013), sediment delivery to the Delaware Basin during deposition of the Delaware Mountain Group likely included fluvial transport from the foreland of the Ouachita orogenic belt as well as key terranes docked south of the Ouachita fold thrust belt such as the Yucatan-Maya and Oaxaquia terranes. Once a remnant ocean basin, this region was subaerially exposed by

Permian time (Ingersoll et al. 1995; Soreghan and Soreghan 2013). Within the

Ouachita region paleocurrent data indicate a northwest/westward flow (Hicks 1962;

Thompson 1982; Sharrah 2006). This sediment was further transported by easterly/northeasterly trade winds and delivered to the Delaware Basin (Parrish and

Peterson 1988). Although there are similarities between the four detrital zircon samples from this study and the four detrital zircon samples from Soreghan and Soreghan (2013) there are consistent differences that are likely a result of the location within the basin and more importantly a provenance evolution. Two sediment dispersal models are proposed for the Delaware Mountain Group and presented in the following sections.

Brushy Canyon Formation Deposition

As river systems carried sediment from the Ouachita orogen, northeasterly trade winds transported and reworked the sediment (Figure 38). The arkosic mineralogy (36-

47% feldspar) documented in the Permian Whitehorse Group of Oklahoma and Kansas and other feldspathic units in the region links the source (Ouachita orogen) to the sink

(Delaware basin) during deposition of the Brushy Canyon Formation (Kocurek and

Kirkland 1998; Soreghan and Soreghan 2013). The eolian units of the Whitehorse

Group indicate a southwestern transport direction towards the Delaware basin further supporting this sediment dispersal model (Harlin 1982; Kocurek and Kirkland 1998).

Continuing with the depositional model: eolian sands from the Whitehorse Group would prograde across the emergent shelf during glacial times of lowstand and increased eolian activity, cross a mudflat zone that has been designated as an eolian transport corridor within the equivalent Artesia Group, and finally deposited into the Delaware basin (Kocurek and Kirkland 1998).

Cherry Canyon Formation and Bell Canyon Formation

A similar fluvial transport system was likely operating during deposition of the

Cherry Canyon and Bell Canyon formations; however a major difference is a direct influx of sediment from terranes directly to the east and southeast (Figure 39). This timing coincides with continued accretion of terranes along the Ouachita-Marathon suture zone and the disappearance of inland seas that resulted in the filling of the

Midland Basin (Soreghan and Soreghan 2013). Additionally, this explains the greater amount of Paleozoic and Neoproterozoic ages seen in these samples.

Figure 38: Interpreted paleogeography and sediment dispersal pathways during deposition of the siliciclastic strata of the Brushy Canyon Formation (Modified from Kocurek and Kirkland 1998; Soreghan and Soreghan 2013). Inset at upper right depicts central North American paleogeography for the middle Permian (Modified from Blakey 2011). 73

Figure 39: Interpreted paleogeography and sediment dispersal pathways during deposition of the Cherry Canyon and Bell Canyon formations (Modified from Kocurek and Kirkland 1998; Soreghan and Soreghan 2013). Note the filling of the Midland Basin has commenced by this time and has resulted in direct sourcing from terranes to the east/southeast. Inset 74 at upper right depicts central North American paleogeography for the middle Permian (Modified from Blakey 2011).

6. CONCLUSIONS

Utilizing sandstone modal mineralogy and U-Pb detrital zircon geochronology, this study was able to shed further light on the provenance for the siliciclastic strata of the middle Permian Delaware Mountain Group of the Delaware basin.

1. Despite the long held interpretation of the proximal Ancestral Rocky Mountains

as the primary source for these strata, detrital zircon geochronology results from

this study suggest the Ancestral Rocky Mountains were not a primary source of

sediment for the siliciclastic strata of the Delaware Mountain Group and were not

actively eroding during this time.

2. The abundance of Paleozoic and Neoproterozoic age grains coupled with the

predominately subarkosic mineralogy seen in the Delaware Mountain Group

samples can be reconciled with an Ouachita orogen source, including key Peri-

Gondwanan terranes to the south such as the Yucatan-Maya and Oaxaquia

terranes.

3. Comparison of detrital zircon age data from this study with previously reported

ages from the Delaware Mountain Group reveals a provenance evolution

between deposition of the Brushy Canyon Formation and the Cherry and Bell

Canyon formations during middle Permian time. This coincides with the

disappearance of inland seas and the filling of the Midland Basin, which resulted

in more direct sourcing from terranes to the east and southeast.

4. Sediment dispersal pathways were likely similar and included fluvial transport

from the Ouachita foreland region. During deposition of the Brushy Canyon

Formation fluvial transport terminated in the arid mid-continent region where

these sediments were further transported by eolian processes characterized by winds from the east/northeast. During deposition of the Cherry Canyon and Bell

Canyon formation there was likely similar fluvial transport. However, there was more direct sourcing from terranes to the east and southeast due to the aforementioned filling of the Midland Basin.

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APPENDICES

Appendix I: Raw Point Count Data

Table 1a. Raw point-count data for sandstone samples of the Brushy Canyon Formation ( N=10) Sample Qm Qp Fk Fp Lv Lss+m Mi H C/M Φ O n BC-7163 238 5 34 12 6 5 2 0 116 0 10 429 BC-7469 227 2 60 7 2 2 1 9 28 8 9 356 AH-6859 228 7 29 13 11 12 14 3 41 0 11 368 AH-7276 234 3 47 12 1 3 6 4 35 0 11 356 SH-6243 190 7 38 52 1 11 4 2 113 0 7 427 SH-6546 206 5 56 26 1 7 3 5 74 2 14 398 ES-6707 225 8 43 17 0 8 1 2 81 0 10 395 ES-7024 218 6 61 12 0 3 3 9 74 0 8 394 CM-6144 259 20 1 15 0 4 0 1 168 0 4 473 CM-6277 266 17 1 9 0 7 1 0 113 0 1 415

Table 1b. Raw point-count data for sandstone samples of the Cherry Canyon Formation ( N=29) Sample Qm Qp Fk Fp Lv Lss+m Mi H C/M Φ O n JCT-5872 210 6 44 9 2 29 4 8 38 42 15 407 JCT-6068 190 40 46 17 2 4 1 3 64 11 13 393 JCT-6348 200 23 55 11 2 8 1 3 64 19 8 396 JCT-6446 222 21 43 7 3 4 1 8 162 6 11 488 BC-6111 263 10 7 7 5 8 1 1 32 10 7 351 BC-6379 241 1 55 11 1 4 2 6 18 7 4 350 BC-6772 237 0 47 13 1 1 4 0 193 0 7 504 BC-6917 266 4 29 10 3 4 13 0 18 0 3 350 AH-5765 230 9 43 8 6 3 1 1 37 23 3 365 AH-5833 209 14 54 13 2 8 4 1 25 21 2 353 AH-5987 232 11 38 11 5 5 5 3 26 12 2 350 AH-6088 236 9 35 12 11 5 7 0 22 11 2 350 AH-6190 233 13 43 9 7 9 0 1 10 23 2 350 AH-6295 239 7 50 9 5 7 1 0 16 13 3 350 AH-6394 246 10 45 9 4 5 2 1 19 6 3 350 SH-5322 193 5 45 41 6 10 4 11 104 23 3 445 SH-5516 179 2 55 61 0 2 1 2 90 27 6 427 SH-5671 168 7 58 49 3 15 1 7 41 46 5 399

Table 1b. Sample Qm Qp Fk Fp Lv Lss+m Mi H C/M Φ O n SH-5748 178 12 38 43 4 24 0 1 169 0 3 473 SH-5852 179 3 46 65 0 7 9 3 50 12 8 382 SH-6006 185 7 46 38 5 19 4 9 110 2 9 434 SH-6194 202 2 48 41 3 8 1 7 60 13 14 399 ES-5601 199 6 59 22 3 10 0 4 18 37 4 363 ES-5816 187 2 57 44 3 7 0 3 26 30 4 363 ES-5949 203 2 51 35 1 8 1 2 49 9 4 366 ES-6087 237 9 41 9 0 3 1 1 6 48 2 358 ES-6223 214 11 52 19 0 4 2 0 11 36 6 355 ES-6470 214 21 44 6 4 11 5 4 101 0 7 417 ES-6546 220 21 35 7 4 12 3 2 47 8 11 371

Table 1c. Raw point-count data for sandstone samples of the Bell Canyon Formation ( N=16). N denotes number of thin sections analyzed. Sample Qm Qp Fk Fp Lv Lss+m Mi H C/M Φ O n JCT-4946 224 8 49 10 2 7 2 4 16 27 5 354 BC-5260 229 1 54 10 2 4 1 6 13 21 9 350 BC-5359 227 0 57 12 1 3 3 2 14 36 2 357 BC-5517 254 0 42 4 2 4 2 9 4 43 7 372 BC-5779 250 3 46 9 0 5 2 3 5 24 3 350 AH-5291 219 11 47 8 0 15 6 4 29 9 2 350 AH-5463 237 8 54 5 0 12 3 0 21 8 2 350 AH-5518 223 8 50 4 3 12 0 2 34 17 0 353 AH-5574 210 9 52 15 5 13 3 1 11 26 5 350 SH-4699 228 2 41 5 4 20 3 6 48 26 10 394 SH-4770 210 3 47 34 0 6 6 10 40 27 8 390 SH-4930 184 3 65 41 0 6 8 8 215 0 3 533 SH-5013 198 3 43 46 4 7 7 8 121 29 8 473 ES-5064 190 1 68 39 0 2 3 8 34 24 13 382 ES-5204 206 7 71 6 0 10 1 4 94 13 10 422 ES-5331 217 6 56 15 0 7 0 3 92 2 1 399

Appendix II: U-PB Detrital Zircon Geochronology Data

Table 2. U-Pb geochronographic analyses for JCT-4946 (Bell Canyon Formation). Analysis Isotope ratios Apparent ages (Ma) 207Pb* ± 206Pb* ± error 206Pb* ± 207Pb* ± 206Pb* ± Best age ± 235U* (%) 238U (%) corr. 238U* (Ma) 235U (Ma) 207Pb* (Ma) (Ma) (Ma) JCT 4946 #1 0.3396 6.4 0.0455 1.6 0.25 286.8 4.4 296.9 16.5 377.1 140.2 286.8 4.4 JCT 4946 #2 0.4653 20.0 0.0495 6.0 0.30 311.7 18.2 387.9 64.5 872.3 398.0 311.7 18.2 JCT 4946 #3 0.3586 6.3 0.0526 1.3 0.20 330.3 4.1 311.2 17.0 170.4 144.9 330.3 4.1 JCT 4946 #4 0.4081 1.4 0.0526 1.4 0.95 330.6 4.4 347.5 4.2 462.3 10.2 330.6 4.4 JCT 4946 #5 0.4095 1.3 0.0533 0.7 0.55 335.0 2.3 348.5 3.7 439.4 23.5 335.0 2.3 JCT 4946 #6 0.4032 6.3 0.0544 1.3 0.21 341.7 4.3 344.0 18.3 359.4 138.9 341.7 4.3 JCT 4946 #7 0.4197 2.1 0.0559 0.6 0.29 350.8 2.1 355.8 6.3 389.1 45.3 350.8 2.1 JCT 4946 #8 0.4621 1.1 0.0593 0.9 0.80 371.4 3.2 385.8 3.6 472.8 14.9 371.4 3.2 JCT 4946 #9 0.4406 3.7 0.0602 0.7 0.19 377.1 2.6 370.6 11.6 330.8 82.8 377.1 2.6 JCT 4946 #10 0.4795 1.3 0.0616 0.7 0.54 385.4 2.6 397.8 4.3 470.0 24.3 385.4 2.6 JCT 4946 #11 0.4514 4.7 0.0666 0.7 0.16 415.3 3.0 378.2 14.7 156.9 107.8 415.3 3.0 JCT 4946 #12 0.5351 1.4 0.0680 0.6 0.44 424.1 2.5 435.2 4.9 494.1 27.6 424.1 2.5 JCT 4946 #13 0.5400 1.6 0.0689 0.6 0.39 429.6 2.6 438.4 5.6 485.0 31.9 429.6 2.6 JCT 4946 #14 0.4719 7.6 0.0692 1.1 0.15 431.2 4.7 392.5 24.7 170.7 175.3 431.2 4.7 JCT 4946 #15 0.5472 2.2 0.0698 0.8 0.34 435.2 3.2 443.2 7.9 485.0 45.7 435.2 3.2 JCT 4946 #16 0.5469 2.3 0.0699 0.7 0.31 435.6 3.0 443.0 8.2 481.7 47.7 435.6 3.0 JCT 4946 #17 0.5096 7.0 0.0703 1.3 0.18 438.0 5.3 418.2 24.1 310.5 157.7 438.0 5.3 JCT 4946 #18 0.5502 2.3 0.0706 0.9 0.38 439.9 3.7 445.2 8.3 472.2 47.4 439.9 3.7 JCT 4946 #19 0.5605 1.1 0.0710 0.3 0.25 442.2 1.2 451.8 4.0 501.0 23.5 442.2 1.2 JCT 4946 #20 0.5674 0.9 0.0720 0.6 0.60 448.4 2.5 456.3 3.5 496.2 16.7 448.4 2.5 JCT 4946 #21 0.5521 3.2 0.0722 0.9 0.29 449.2 4.1 446.4 11.6 431.7 68.6 449.2 4.1 JCT 4946 #22 0.5984 7.8 0.0741 1.7 0.21 460.8 7.5 476.2 29.7 551.5 167.0 460.8 7.5 JCT 4946 #23 0.5876 2.8 0.0758 0.7 0.24 470.7 3.1 469.3 10.6 462.5 60.4 470.7 3.1

90 JCT 4946 #24 0.6033 2.0 0.0759 0.6 0.30 471.4 2.7 479.3 7.6 517.3 41.6 471.4 2.7

JCT 4946 #25 0.6257 1.2 0.0763 0.6 0.48 473.8 2.7 493.4 4.8 585.6 23.2 473.8 2.7 JCT 4946 #26 0.6177 1.1 0.0773 0.6 0.55 479.8 2.8 488.4 4.2 529.2 19.9 479.8 2.8 JCT 4946 #27 0.5958 4.4 0.0776 1.0 0.22 481.5 4.4 474.6 16.8 440.9 96.0 481.5 4.4 JCT 4946 #28 0.6760 1.4 0.0780 1.0 0.67 484.4 4.5 524.4 5.9 702.6 22.8 484.4 4.5 JCT 4946 #29 0.6312 1.7 0.0784 0.6 0.36 486.6 2.9 496.8 6.6 544.2 34.4 486.6 2.9 JCT 4946 #30 0.6433 3.2 0.0825 0.8 0.24 510.9 3.8 504.3 12.9 474.7 69.7 510.9 3.8 JCT 4946 #31 0.6754 6.0 0.0838 1.8 0.30 518.8 8.9 524.0 24.6 546.8 125.4 518.8 8.9 JCT 4946 #32 0.6866 7.4 0.0905 1.6 0.21 558.5 8.5 530.8 30.7 413.2 162.2 558.5 8.5 JCT 4946 #33 0.7104 4.9 0.0905 1.0 0.20 558.8 5.2 545.0 20.9 487.5 107.1 558.8 5.2 JCT 4946 #34 0.7819 2.2 0.0916 1.2 0.53 565.1 6.3 586.6 9.7 670.7 39.3 565.1 6.3 JCT 4946 #35 0.6977 4.1 0.0921 0.9 0.22 568.1 4.9 537.4 17.2 409.2 89.8 568.1 4.9 JCT 4946 #36 0.7384 3.9 0.0934 1.1 0.28 575.6 6.0 561.5 17.0 504.7 83.3 575.6 6.0 JCT 4946 #37 0.7198 7.1 0.0972 1.8 0.26 597.7 10.4 550.6 30.2 359.9 154.9 597.7 10.4 JCT 4946 #38 0.8344 3.8 0.1005 0.9 0.25 617.3 5.5 616.1 17.4 611.5 78.7 617.3 5.5 JCT 4946 #39 0.8449 2.5 0.1011 1.0 0.41 621.0 6.1 621.8 11.8 625.0 49.8 621.0 6.1 JCT 4946 #40 0.8552 5.8 0.1024 0.8 0.15 628.4 5.1 627.5 27.3 624.3 124.5 628.4 5.1 JCT 4946 #41 0.8919 4.2 0.1039 1.1 0.25 637.3 6.5 647.4 20.2 682.5 87.3 637.3 6.5 JCT 4946 #42 0.8982 1.9 0.1046 1.2 0.64 641.1 7.5 650.7 9.2 684.4 31.4 641.1 7.5 JCT 4946 #43 0.9059 4.2 0.1069 0.9 0.22 654.6 5.8 654.9 20.1 656.0 87.3 654.6 5.8 JCT 4946 #44 0.9889 2.7 0.1137 1.2 0.44 694.0 7.8 698.2 13.5 711.7 51.0 694.0 7.8 JCT 4946 #45 1.1361 2.6 0.1282 0.8 0.30 777.8 5.7 770.7 13.9 750.1 52.0 777.8 5.7 JCT 4946 #46 1.2766 4.1 0.1389 1.2 0.30 838.6 9.7 835.3 23.5 826.6 82.1 838.6 9.7 JCT 4946 #47 1.3362 5.0 0.1446 4.5 0.91 870.9 36.8 861.6 29.0 837.7 43.9 870.9 36.8 JCT 4946 #48 1.9149 1.1 0.1809 1.0 0.91 1072.1 10.0 1086.3 7.4 1114.9 9.1 1114.9 9.1 JCT 4946 #49 1.6359 1.1 0.1532 1.1 0.93 919.0 9.1 984.1 7.2 1132.5 8.3 1132.5 8.3 JCT 4946 #50 1.9215 1.9 0.1786 0.7 0.39 1059.1 7.1 1088.6 12.4 1148.1 33.9 1148.1 33.9 JCT 4946 #51 2.1638 2.3 0.2006 1.1 0.49 1178.5 12.2 1169.5 16.1 1152.8 40.3 1152.8 40.3 JCT 4946 #52 2.3019 1.3 0.2078 1.1 0.90 1217.0 12.7 1212.9 9.0 1205.5 10.9 1205.5 10.9 JCT 4946 #53 2.3182 1.9 0.2075 0.7 0.36 1215.4 7.4 1217.9 13.2 1222.2 34.0 1222.2 34.0 91 JCT 4946 #54 2.5109 2.0 0.2182 1.8 0.90 1272.5 21.2 1275.2 14.8 1279.8 17.3 1279.8 17.3

JCT 4946 #55 2.7646 1.0 0.2337 0.4 0.42 1353.7 4.9 1346.0 7.2 1333.9 17.1 1333.9 17.1 JCT 4946 #56 2.8603 1.3 0.2382 1.1 0.82 1377.2 13.5 1371.5 10.0 1362.7 14.6 1362.7 14.6 JCT 4946 #57 2.7152 1.1 0.2243 0.7 0.64 1304.6 8.5 1332.6 8.4 1378.0 16.7 1378.0 16.7 JCT 4946 #58 2.8773 2.5 0.2375 1.0 0.38 1373.7 11.9 1376.0 18.9 1379.6 44.6 1379.6 44.6 JCT 4946 #59 3.1893 1.4 0.2493 0.6 0.44 1435.0 8.0 1454.6 11.1 1483.3 24.4 1483.3 24.4 JCT 4946 #60 3.3415 1.0 0.2576 0.5 0.52 1477.4 6.8 1490.8 7.8 1509.9 16.1 1509.9 16.1 JCT 4946 #61 3.3712 1.5 0.2595 1.0 0.67 1487.4 13.1 1497.7 11.6 1512.3 20.9 1512.3 20.9 JCT 4946 #62 3.6077 1.2 0.2682 0.8 0.71 1531.5 11.2 1551.2 9.2 1578.2 15.3 1578.2 15.3 JCT 4946 #63 3.8076 1.5 0.2752 0.8 0.52 1567.2 10.8 1594.4 12.0 1630.4 23.8 1630.4 23.8 JCT 4946 #64 4.0365 1.7 0.2878 0.9 0.55 1630.8 13.4 1641.6 13.9 1655.4 26.6 1655.4 26.6 JCT 4946 #65 4.2068 1.3 0.2959 0.7 0.58 1671.1 10.6 1675.4 10.3 1680.6 18.9 1680.6 18.9 JCT 4946 #66 4.2737 1.9 0.2965 0.9 0.46 1673.8 12.6 1688.3 15.3 1706.3 30.3 1706.3 30.3 JCT 4946 #67 4.5071 0.9 0.3092 0.6 0.67 1736.7 8.9 1732.3 7.3 1726.9 12.0 1726.9 12.0 JCT 4946 #68 4.8081 1.0 0.3186 0.9 0.85 1783.1 13.5 1786.3 8.6 1790.1 10.0 1790.1 10.0 JCT 4946 #69 5.1708 1.1 0.3364 0.7 0.61 1869.4 11.1 1847.8 9.5 1823.6 16.0 1823.6 16.0 JCT 4946 #70 5.7647 1.1 0.3513 0.8 0.75 1940.7 14.0 1941.1 9.7 1941.5 13.3 1941.5 13.3 JCT 4946 #71 6.2709 1.5 0.3662 1.3 0.84 2011.7 21.7 2014.4 13.0 2017.1 14.1 2017.1 14.1 JCT 4946 #72 5.6919 1.2 0.3194 1.2 0.99 1786.9 19.3 1930.1 10.8 2087.6 3.1 2087.6 3.1 JCT 4946 #73 11.2279 1.9 0.4673 1.6 0.82 2471.8 32.1 2542.2 17.7 2598.9 18.0 2598.9 18.0 JCT 4946 #74 13.7238 0.7 0.5262 0.6 0.93 2725.4 14.0 2730.8 6.4 2734.8 3.9 2734.8 3.9 JCT 4946 #75 15.4494 0.4 0.5472 0.4 0.93 2813.4 8.7 2843.4 3.9 2864.6 2.5 2864.6 2.5 Rejected Grain(s) JCT 4946 #76 0.4999 10.5 0.0754 2.5 0.24 468.4 11.3 411.7 35.4 104.8 240.6 468.4 11.3

Table 3. U-Pb geochronographic analyses for JCT-5872 (Cherry Canyon Formation). Analysis Isotope ratios Apparent ages (Ma) 207Pb* ± 206Pb* ± error 206Pb* ± 207Pb* ± 206Pb* ± Best age ± 235U* (%) 238U (%) corr. 238U* (Ma) 235U (Ma) 207Pb* (Ma) (Ma) (Ma) JCT 5872 #1 0.3323 3.2 0.0477 0.7 0.23 300.5 2.1 291.3 8.0 218.2 71.6 300.5 2.1 JCT 5872 #2 0.3675 10.4 0.0480 2.6 0.25 302.1 7.6 317.8 28.3 434.5 223.8 302.1 7.6 JCT 5872 #3 0.3479 1.7 0.0481 0.5 0.31 302.7 1.6 303.2 4.4 307.0 36.6 302.7 1.6 JCT 5872 #4 0.3154 5.6 0.0483 1.1 0.19 304.1 3.2 278.3 13.6 67.2 130.5 304.1 3.2 JCT 5872 #5 0.3541 4.6 0.0499 1.5 0.33 313.7 4.6 307.8 12.2 263.1 99.9 313.7 4.6 JCT 5872 #6 0.3561 3.9 0.0508 0.8 0.20 319.7 2.4 309.3 10.4 231.4 87.9 319.7 2.4 JCT 5872 #7 0.3766 4.4 0.0544 1.3 0.29 341.5 4.2 324.6 12.1 204.7 96.8 341.5 4.2 JCT 5872 #8 0.3858 3.8 0.0545 0.9 0.24 342.1 3.0 331.3 10.8 256.2 85.0 342.1 3.0 JCT 5872 #9 0.3998 1.8 0.0546 0.6 0.35 342.8 2.1 341.5 5.2 332.5 38.3 342.8 2.1 JCT 5872 #10 0.3937 3.0 0.0549 0.9 0.30 344.7 3.0 337.1 8.5 284.5 64.7 344.7 3.0 JCT 5872 #11 0.4034 1.3 0.0551 0.8 0.65 345.9 2.8 344.1 3.7 332.3 22.1 345.9 2.8 JCT 5872 #12 0.3748 13.0 0.0558 3.0 0.23 350.1 10.1 323.2 36.0 133.5 298.3 350.1 10.1 JCT 5872 #13 0.4433 2.0 0.0593 1.3 0.64 371.2 4.6 372.6 6.1 381.2 33.8 371.2 4.6 JCT 5872 #14 0.4448 2.0 0.0598 1.3 0.66 374.1 4.8 373.6 6.3 370.5 33.9 374.1 4.8 JCT 5872 #15 0.4017 5.7 0.0598 1.6 0.27 374.6 5.7 342.8 16.6 132.8 129.3 374.6 5.7 JCT 5872 #16 0.4707 5.2 0.0630 3.9 0.75 394.0 14.9 391.7 16.9 378.1 77.6 394.0 14.9 JCT 5872 #17 0.4464 3.9 0.0631 0.9 0.24 394.5 3.6 374.7 12.3 254.4 87.6 394.5 3.6 JCT 5872 #18 0.4838 1.7 0.0647 0.6 0.33 404.4 2.2 400.7 5.5 379.5 35.4 404.4 2.2 JCT 5872 #19 0.4787 4.2 0.0658 1.0 0.23 410.8 3.9 397.1 13.9 318.3 93.4 410.8 3.9 JCT 5872 #20 0.4710 9.0 0.0660 1.9 0.21 412.0 7.5 391.9 29.3 274.8 202.5 412.0 7.5 JCT 5872 #21 0.4722 5.8 0.0662 1.0 0.18 413.5 4.1 392.7 18.9 271.8 131.3 413.5 4.1 JCT 5872 #22 0.5117 2.8 0.0670 0.6 0.20 417.8 2.3 419.6 9.8 429.6 62.1 417.8 2.3 JCT 5872 #23 0.5028 5.0 0.0676 0.7 0.15 421.6 3.0 413.6 17.1 369.1 112.3 421.6 3.0 JCT 5872 #24 0.5028 5.0 0.0676 0.7 0.15 421.6 3.0 413.6 17.1 369.1 112.3 421.6 3.0 JCT 5872 #25 0.5166 1.4 0.0679 0.7 0.52 423.4 3.0 422.9 4.9 420.4 27.4 423.4 3.0 93 JCT 5872 #26 0.5347 1.9 0.0696 0.6 0.30 433.5 2.3 434.9 6.7 442.1 40.2 433.5 2.3

JCT 5872 #27 0.5512 2.6 0.0698 0.9 0.34 434.9 3.7 445.8 9.3 502.4 53.3 434.9 3.7 JCT 5872 #28 0.4831 6.5 0.0698 1.2 0.19 435.0 5.2 400.2 21.6 203.8 149.1 435.0 5.2 JCT 5872 #29 0.5357 2.6 0.0701 0.7 0.26 436.6 2.8 435.6 9.1 430.4 55.3 436.6 2.8 JCT 5872 #30 0.5109 4.3 0.0707 1.0 0.24 440.6 4.4 419.1 14.9 302.1 96.2 440.6 4.4 JCT 5872 #31 0.5340 4.4 0.0714 0.9 0.21 444.5 3.9 434.5 15.5 381.7 96.7 444.5 3.9 JCT 5872 #32 0.6143 18.5 0.0737 6.9 0.37 458.5 30.5 486.3 71.5 619.5 372.6 458.5 30.5 JCT 5872 #33 0.5645 3.6 0.0767 1.2 0.32 476.2 5.3 454.5 13.4 345.8 78.3 476.2 5.3 JCT 5872 #34 0.5966 3.9 0.0783 1.5 0.37 486.2 6.8 475.1 14.8 422.0 80.9 486.2 6.8 JCT 5872 #35 0.6364 1.2 0.0790 0.8 0.72 490.3 3.9 500.1 4.6 545.0 17.5 490.3 3.9 JCT 5872 #36 0.6628 2.7 0.0815 2.1 0.77 504.9 10.3 516.3 11.1 567.4 37.7 504.9 10.3 JCT 5872 #37 0.6719 3.3 0.0828 2.8 0.85 512.9 13.9 521.9 13.4 561.3 37.3 512.9 13.9 JCT 5872 #38 0.6860 1.0 0.0832 0.6 0.60 514.9 2.9 530.4 4.0 597.4 16.9 514.9 2.9 JCT 5872 #39 0.6379 4.8 0.0833 0.9 0.19 515.8 4.4 501.0 18.8 433.8 104.3 515.8 4.4 JCT 5872 #40 0.6438 8.5 0.0862 2.0 0.23 532.9 10.1 504.7 33.7 378.9 185.6 532.9 10.1 JCT 5872 #41 0.6822 4.2 0.0900 0.8 0.19 555.3 4.3 528.1 17.1 412.1 91.3 555.3 4.3 JCT 5872 #42 0.6947 3.8 0.0902 1.0 0.26 556.5 5.2 535.6 15.6 447.6 80.5 556.5 5.2 JCT 5872 #43 0.6602 8.1 0.0915 1.7 0.20 564.1 8.9 514.7 32.7 300.9 181.2 564.1 8.9 JCT 5872 #44 0.7125 5.3 0.0923 1.3 0.25 569.2 7.1 546.2 22.2 451.5 113.2 569.2 7.1 JCT 5872 #45 0.7640 3.1 0.0941 1.1 0.34 579.6 5.8 576.3 13.6 563.1 63.5 579.6 5.8 JCT 5872 #46 0.7338 3.3 0.0947 1.5 0.46 583.0 8.4 558.8 14.2 461.1 65.0 583.0 8.4 JCT 5872 #47 0.7960 1.7 0.0955 1.2 0.72 588.0 6.8 594.6 7.5 619.8 24.9 588.0 6.8 JCT 5872 #48 0.7332 9.9 0.0969 3.1 0.31 596.3 17.5 558.4 42.5 406.8 210.9 596.3 17.5 JCT 5872 #49 0.8362 3.8 0.0997 1.2 0.31 612.8 7.0 617.1 17.7 632.9 78.3 612.8 7.0 JCT 5872 #50 0.8220 1.7 0.0999 0.6 0.34 614.0 3.4 609.2 7.9 591.4 34.9 614.0 3.4 JCT 5872 #51 0.8406 2.7 0.1003 1.8 0.65 616.0 10.4 619.5 12.7 632.2 44.9 616.0 10.4 JCT 5872 #52 0.8339 2.6 0.1006 0.8 0.30 617.6 4.6 615.8 12.2 608.8 54.5 617.6 4.6 JCT 5872 #53 0.8311 2.1 0.1007 1.0 0.46 618.7 5.8 614.2 9.9 597.9 41.2 618.7 5.8 JCT 5872 #54 0.8726 5.9 0.1010 4.7 0.80 620.2 27.6 637.0 27.8 696.9 75.8 620.2 27.6 JCT 5872 #55 0.7498 5.7 0.1012 1.1 0.19 621.7 6.5 568.1 24.8 358.9 126.4 621.7 6.5 94 JCT 5872 #56 0.8391 3.0 0.1021 1.0 0.33 626.9 6.0 618.7 14.0 588.5 61.9 626.9 6.0

JCT 5872 #57 0.7832 5.3 0.1023 1.0 0.19 627.9 6.0 587.3 23.7 433.4 116.5 627.9 6.0 JCT 5872 #58 0.8419 9.0 0.1033 2.4 0.26 633.8 14.3 620.2 41.9 570.8 189.8 633.8 14.3 JCT 5872 #59 0.8508 5.2 0.1048 1.3 0.25 642.5 8.1 625.1 24.3 562.6 110.0 642.5 8.1 JCT 5872 #60 0.8769 4.5 0.1073 1.0 0.22 657.1 6.1 639.3 21.4 577.2 95.7 657.1 6.1 JCT 5872 #61 0.9074 2.2 0.1080 0.7 0.33 661.3 4.5 655.7 10.5 636.5 44.1 661.3 4.5 JCT 5872 #62 0.9656 5.3 0.1175 1.3 0.24 716.0 8.5 686.2 26.6 589.6 112.3 716.0 8.5 JCT 5872 #63 1.1414 2.6 0.1244 1.8 0.69 756.0 12.7 773.2 14.0 823.1 39.2 756.0 12.7 JCT 5872 #64 1.1147 1.5 0.1256 0.8 0.57 763.0 5.9 760.4 7.8 752.9 25.3 763.0 5.9 JCT 5872 #65 1.3617 2.7 0.1442 1.2 0.46 868.6 10.0 872.6 15.6 882.8 48.9 868.6 10.0 JCT 5872 #66 1.3963 2.8 0.1481 1.3 0.47 890.3 10.8 887.4 16.3 880.0 50.2 890.3 10.8 JCT 5872 #67 1.4816 1.2 0.1545 0.7 0.55 926.0 5.8 922.9 7.5 915.5 21.4 915.5 21.4 JCT 5872 #68 1.4663 3.4 0.1523 0.7 0.20 913.6 5.8 916.6 20.7 923.8 69.2 923.8 69.2 JCT 5872 #69 1.7152 2.5 0.1718 0.8 0.31 1022.0 7.2 1014.2 15.9 997.6 47.9 997.6 47.9 JCT 5872 #70 1.6710 1.2 0.1672 0.6 0.45 996.7 5.1 997.5 7.7 999.4 22.0 999.4 22.0 JCT 5872 #71 1.7497 3.4 0.1747 1.3 0.40 1038.0 12.9 1027.0 21.8 1003.8 62.9 1003.8 62.9 JCT 5872 #72 1.7746 2.0 0.1753 0.6 0.32 1041.0 6.2 1036.2 13.3 1026.1 39.2 1026.1 39.2 JCT 5872 #73 1.8114 2.1 0.1788 0.7 0.35 1060.4 7.1 1049.6 13.7 1027.0 39.8 1027.0 39.8 JCT 5872 #74 1.7598 1.7 0.1710 0.7 0.41 1017.6 6.7 1030.8 11.2 1059.0 31.7 1059.0 31.7 JCT 5872 #75 1.6323 3.6 0.1581 2.8 0.79 946.3 25.0 982.8 22.7 1065.2 44.8 1065.2 44.8 JCT 5872 #76 1.7624 2.3 0.1705 0.7 0.30 1014.6 6.4 1031.7 14.7 1068.1 43.4 1068.1 43.4 JCT 5872 #77 1.8291 1.6 0.1769 1.0 0.67 1049.8 10.1 1055.9 10.3 1068.7 23.6 1068.7 23.6 JCT 5872 #78 1.6976 2.5 0.1635 1.9 0.76 976.1 17.2 1007.6 16.1 1076.8 33.1 1076.8 33.1 JCT 5872 #79 1.8758 0.7 0.1805 0.6 0.83 1069.6 6.1 1072.6 4.9 1078.7 8.2 1078.7 8.2 JCT 5872 #80 1.8758 0.7 0.1805 0.6 0.83 1069.6 6.1 1072.6 4.9 1078.7 8.2 1078.7 8.2 JCT 5872 #81 1.8629 0.8 0.1788 0.5 0.64 1060.5 5.1 1068.0 5.3 1083.4 12.4 1083.4 12.4 JCT 5872 #82 1.9972 3.9 0.1916 1.6 0.40 1130.1 16.1 1114.6 26.4 1084.3 71.8 1084.3 71.8 JCT 5872 #83 1.8824 1.0 0.1805 0.6 0.61 1069.4 6.0 1074.9 6.6 1086.0 15.8 1086.0 15.8 JCT 5872 #84 1.8945 2.1 0.1816 0.8 0.38 1075.7 8.0 1079.1 13.9 1086.1 38.8 1086.1 38.8 JCT 5872 #85 1.8413 0.8 0.1764 0.7 0.95 1047.4 7.0 1060.3 5.0 1087.1 4.8 1087.1 4.8 95 JCT 5872 #86 1.7526 1.5 0.1679 0.8 0.57 1000.4 7.8 1028.1 9.5 1087.4 24.3 1087.4 24.3

JCT 5872 #87 1.9239 1.1 0.1833 0.5 0.46 1084.9 5.2 1089.4 7.6 1098.5 20.2 1098.5 20.2 JCT 5872 #88 1.9117 0.8 0.1807 0.8 0.91 1070.6 7.4 1085.2 5.5 1114.6 6.8 1114.6 6.8 JCT 5872 #89 2.0132 1.7 0.1898 1.0 0.62 1120.1 10.8 1120.0 11.4 1119.8 26.2 1119.8 26.2 JCT 5872 #90 2.1058 4.0 0.1978 1.5 0.38 1163.4 16.1 1150.7 27.3 1126.9 73.0 1126.9 73.0 JCT 5872 #91 1.9157 2.5 0.1799 1.5 0.60 1066.3 14.7 1086.6 16.6 1127.4 39.8 1127.4 39.8 JCT 5872 #92 1.9972 1.4 0.1860 0.8 0.55 1099.9 7.7 1114.6 9.4 1143.3 23.1 1143.3 23.1 JCT 5872 #93 2.1991 3.0 0.2046 0.9 0.30 1199.8 10.0 1180.8 20.9 1146.1 56.6 1146.1 56.6 JCT 5872 #94 2.1718 2.9 0.2013 0.7 0.25 1182.2 7.8 1172.0 20.3 1153.3 56.1 1153.3 56.1 JCT 5872 #95 2.0081 1.7 0.1861 1.7 0.97 1100.1 16.9 1118.2 11.7 1153.6 8.6 1153.6 8.6 JCT 5872 #96 2.1493 1.5 0.1984 1.4 0.91 1166.8 14.6 1164.8 10.4 1161.2 12.5 1161.2 12.5 JCT 5872 #97 1.9943 0.7 0.1838 0.6 0.85 1087.6 6.3 1113.6 5.0 1164.5 7.9 1164.5 7.9 JCT 5872 #98 2.1334 2.0 0.1958 1.5 0.73 1152.6 15.6 1159.7 14.0 1172.9 27.4 1172.9 27.4 JCT 5872 #99 2.3903 2.0 0.2131 0.6 0.33 1245.2 7.3 1239.7 14.0 1230.1 36.2 1230.1 36.2 JCT 5872 #100 2.2636 0.8 0.2014 0.7 0.82 1183.0 7.5 1201.0 6.0 1233.6 9.5 1233.6 9.5 JCT 5872 #101 2.4080 1.8 0.2123 0.6 0.33 1240.9 6.5 1245.0 12.7 1252.1 32.7 1252.1 32.7 JCT 5872 #102 2.5059 1.6 0.2195 1.5 0.96 1279.2 17.5 1273.8 11.4 1264.6 9.0 1264.6 9.0 JCT 5872 #103 2.5897 3.7 0.2258 1.1 0.30 1312.3 12.9 1297.7 26.9 1273.8 68.4 1273.8 68.4 JCT 5872 #104 2.6650 1.4 0.2274 0.9 0.62 1320.8 10.3 1318.8 10.3 1315.6 21.3 1315.6 21.3 JCT 5872 #105 2.7220 0.9 0.2313 0.4 0.49 1341.6 5.3 1334.5 6.6 1323.1 14.9 1323.1 14.9 JCT 5872 #106 2.6267 3.3 0.2217 1.3 0.39 1290.8 14.8 1308.1 24.0 1336.7 58.2 1336.7 58.2 JCT 5872 #107 2.7837 2.6 0.2319 1.0 0.40 1344.4 12.6 1351.2 19.5 1361.9 46.2 1361.9 46.2 JCT 5872 #108 2.9769 2.1 0.2423 0.8 0.39 1398.6 10.3 1401.7 15.9 1406.5 36.7 1406.5 36.7 JCT 5872 #109 3.1833 3.6 0.2581 1.2 0.33 1480.1 16.1 1453.1 28.2 1413.8 65.7 1413.8 65.7 JCT 5872 #110 3.2116 1.6 0.2548 0.9 0.58 1463.4 12.4 1460.0 12.6 1454.9 25.2 1454.9 25.2 JCT 5872 #111 3.2067 1.9 0.2539 0.7 0.38 1458.8 9.2 1458.8 14.5 1458.8 32.9 1458.8 32.9 JCT 5872 #112 3.2996 1.5 0.2607 1.0 0.68 1493.2 13.9 1481.0 12.0 1463.4 21.4 1463.4 21.4 JCT 5872 #113 3.0723 0.9 0.2421 0.8 0.93 1397.8 10.0 1425.8 6.5 1467.9 5.8 1467.9 5.8 JCT 5872 #114 3.4438 2.5 0.2699 0.9 0.35 1540.1 12.1 1514.5 19.7 1478.8 44.3 1478.8 44.3 JCT 5872 #115 3.1936 1.3 0.2502 0.8 0.65 1439.3 10.7 1455.6 9.9 1479.5 18.4 1479.5 18.4 96 JCT 5872 #116 3.2350 1.5 0.2529 1.3 0.81 1453.5 16.3 1465.6 12.0 1483.1 17.1 1483.1 17.1

JCT 5872 #117 3.3732 1.4 0.2627 0.8 0.55 1503.8 10.6 1498.2 11.3 1490.3 22.9 1490.3 22.9 JCT 5872 #118 3.3904 2.1 0.2640 0.7 0.33 1510.3 9.6 1502.2 16.9 1490.8 38.4 1490.8 38.4 JCT 5872 #119 3.4335 0.7 0.2636 0.6 0.84 1508.0 8.4 1512.1 5.9 1517.7 7.7 1517.7 7.7 JCT 5872 #120 3.5429 0.8 0.2692 0.7 0.84 1536.7 9.7 1536.9 6.7 1537.1 8.7 1537.1 8.7 JCT 5872 #121 3.6331 1.3 0.2723 0.8 0.62 1552.6 10.9 1556.8 10.1 1562.6 18.7 1562.6 18.7 JCT 5872 #122 3.4776 1.2 0.2575 0.9 0.74 1477.1 11.3 1522.1 9.1 1585.4 14.5 1585.4 14.5 JCT 5872 #123 3.8560 1.1 0.2799 0.6 0.52 1590.8 8.2 1604.5 9.1 1622.5 17.9 1622.5 17.9 JCT 5872 #124 3.8866 1.0 0.2792 0.5 0.54 1587.4 7.6 1610.9 8.1 1641.7 15.7 1641.7 15.7 JCT 5872 #125 3.8071 0.9 0.2718 0.9 0.99 1549.7 12.1 1594.2 7.2 1653.6 2.3 1653.6 2.3 JCT 5872 #126 4.1644 3.0 0.2972 2.9 0.98 1677.6 43.5 1667.0 24.7 1653.8 12.1 1653.8 12.1 JCT 5872 #127 3.9611 1.4 0.2824 1.1 0.82 1603.5 16.1 1626.3 11.3 1655.8 14.8 1655.8 14.8 JCT 5872 #128 4.2690 0.7 0.2947 0.5 0.74 1664.9 7.3 1687.4 5.5 1715.5 8.3 1715.5 8.3 JCT 5872 #129 4.7886 1.0 0.3166 0.9 0.83 1773.3 13.2 1782.9 8.6 1794.2 10.5 1794.2 10.5 JCT 5872 #130 3.8630 0.8 0.2547 0.7 0.89 1462.6 9.3 1606.0 6.5 1799.5 6.8 1799.5 6.8 JCT 5872 #131 4.7039 1.1 0.3100 1.1 0.96 1740.7 16.3 1767.9 9.3 1800.3 5.3 1800.3 5.3 JCT 5872 #132 4.9227 0.4 0.3231 0.3 0.82 1804.9 5.3 1806.2 3.5 1807.5 4.4 1807.5 4.4 JCT 5872 #133 5.0247 1.1 0.3261 0.9 0.82 1819.4 14.4 1823.5 9.3 1828.2 11.3 1828.2 11.3 JCT 5872 #134 5.0571 1.6 0.3175 1.5 0.97 1777.3 23.8 1828.9 13.3 1888.2 6.5 1888.2 6.5 JCT 5872 #135 5.7112 0.8 0.3471 0.8 0.99 1920.7 13.2 1933.1 6.9 1946.3 2.1 1946.3 2.1 JCT 5872 #136 5.9272 1.6 0.3527 1.6 0.96 1947.7 26.2 1965.2 14.1 1983.8 8.1 1983.8 8.1 JCT 5872 #137 6.0200 0.6 0.3572 0.5 0.87 1968.9 9.0 1978.7 5.3 1989.0 5.4 1989.0 5.4 JCT 5872 #138 6.0872 0.6 0.3480 0.5 0.87 1924.8 8.9 1988.4 5.4 2055.2 5.2 2055.2 5.2 JCT 5872 #139 6.4446 0.5 0.3541 0.5 0.88 1954.2 7.7 2038.4 4.6 2124.7 4.4 2124.7 4.4 JCT 5872 #140 9.5648 0.8 0.4474 0.7 0.86 2383.7 14.5 2393.8 7.8 2402.4 7.3 2402.4 7.3 JCT 5872 #141 10.6272 0.8 0.4464 0.7 0.90 2379.3 14.7 2491.1 7.6 2583.6 6.0 2583.6 6.0 JCT 5872 #142 11.4338 0.8 0.4735 0.8 0.92 2499.1 15.8 2559.2 7.7 2607.2 5.4 2607.2 5.4 JCT 5872 #143 18.4071 0.8 0.5177 0.7 0.98 2689.6 16.1 3011.3 7.2 3233.6 2.5 3233.6 2.5 Rejected Grain(s) JCT 5872 #144 0.4067 7.9 0.0654 1.7 0.22 408.3 6.9 346.5 23.1 -49.8 186.6 408.3 6.9 97 JCT 5872 #145 0.3457 35.0 0.0705 3.9 0.11 439.3 16.5 301.4 91.6 -665.8 983.9 439.3 16.5

JCT 5872 #146 0.7730 9.3 0.0759 5.1 0.54 471.9 23.1 581.5 41.4 1036.6 158.6 471.9 23.1 JCT 5872 #147 0.5050 9.7 0.0768 1.8 0.18 476.8 8.1 415.1 33.0 84.6 226.3 476.8 8.1 JCT 5872 #148 0.5193 6.8 0.0773 1.2 0.18 480.2 5.5 424.7 23.7 133.4 158.3 480.2 5.5 JCT 5872 #149 0.7428 2.6 0.0782 2.2 0.86 485.3 10.4 564.1 11.1 896.1 27.0 485.3 10.4 JCT 5872 #150 1.2302 2.1 0.1194 1.9 0.91 726.9 13.0 814.4 11.6 1061.9 16.8 726.9 13.0

Table 4. U-Pb geochronographic analyses for JCT-6068 (Cherry Canyon Formation). Analysis Isotope ratios Apparent ages (Ma) 207Pb* ± 206Pb* ± error 206Pb* ± 207Pb* ± 206Pb* ± Best age ± 235U* (%) 238U (%) corr. 238U* (Ma) 235U (Ma) 207Pb* (Ma) (Ma) (Ma) JCT 6068 #1 0.3004 11.8 0.0468 1.6 0.14 294.7 4.8 266.7 27.6 27.5 280.4 294.7 4.8 JCT 6068 #2 0.3641 2.8 0.0501 2.0 0.72 315.4 6.2 315.3 7.6 315.0 44.0 315.4 6.2 JCT 6068 #3 0.3718 1.9 0.0505 1.2 0.61 317.7 3.6 321.0 5.2 345.4 34.2 317.7 3.6 JCT 6068 #4 0.3932 0.9 0.0531 0.5 0.57 333.5 1.8 336.7 2.7 358.6 17.5 333.5 1.8 JCT 6068 #5 0.3808 5.7 0.0545 1.1 0.19 342.2 3.7 327.7 16.0 225.4 129.7 342.2 3.7 JCT 6068 #6 0.4038 2.3 0.0551 0.7 0.32 345.6 2.5 344.4 6.8 336.4 49.8 345.6 2.5 JCT 6068 #7 0.4250 1.7 0.0575 0.8 0.47 360.6 2.8 359.6 5.1 353.2 33.5 360.6 2.8 JCT 6068 #8 0.4794 4.0 0.0584 1.8 0.46 366.0 6.4 397.6 13.0 585.9 76.4 366.0 6.4 JCT 6068 #9 0.4318 1.8 0.0590 0.9 0.48 369.6 3.1 364.5 5.5 332.1 36.1 369.6 3.1 JCT 6068 #10 0.4011 3.6 0.0595 1.2 0.33 372.4 4.3 342.5 10.6 144.1 80.9 372.4 4.3 JCT 6068 #11 0.4843 2.1 0.0637 1.1 0.54 398.2 4.4 401.0 7.0 417.3 39.5 398.2 4.4 JCT 6068 #12 0.4944 1.4 0.0643 1.0 0.69 401.9 3.9 407.9 4.8 441.7 23.1 401.9 3.9 JCT 6068 #13 0.4850 4.2 0.0668 0.8 0.19 416.7 3.2 401.5 14.1 314.8 94.8 416.7 3.2 JCT 6068 #14 0.5265 5.0 0.0689 0.8 0.17 429.7 3.5 429.5 17.6 428.3 110.8 429.7 3.5 JCT 6068 #15 0.4788 5.0 0.0690 1.0 0.21 429.9 4.3 397.3 16.6 211.4 114.3 429.9 4.3

98 JCT 6068 #16 0.5237 2.1 0.0690 0.6 0.27 430.2 2.3 427.6 7.2 413.7 44.5 430.2 2.3

JCT 6068 #17 0.5090 3.8 0.0695 1.2 0.30 433.0 4.8 417.8 13.1 334.7 82.9 433.0 4.8 JCT 6068 #18 0.5469 1.5 0.0707 0.8 0.52 440.2 3.3 443.0 5.3 457.2 28.0 440.2 3.3 JCT 6068 #19 0.5896 6.0 0.0710 1.0 0.17 441.9 4.3 470.6 22.7 613.0 128.6 441.9 4.3 JCT 6068 #20 0.5349 5.9 0.0713 1.1 0.18 443.9 4.6 435.0 20.8 388.2 130.0 443.9 4.6 JCT 6068 #21 0.5692 1.3 0.0724 0.6 0.46 450.7 2.7 457.5 4.9 491.9 26.0 450.7 2.7 JCT 6068 #22 0.5890 2.4 0.0756 0.8 0.34 469.6 3.7 470.2 9.1 473.1 50.1 469.6 3.7 JCT 6068 #23 0.5613 5.1 0.0772 1.2 0.23 479.6 5.4 452.4 18.7 316.4 113.1 479.6 5.4 JCT 6068 #24 0.6219 1.6 0.0776 0.7 0.44 481.8 3.3 491.1 6.2 534.7 31.3 481.8 3.3 JCT 6068 #25 0.6350 2.0 0.0796 1.9 0.94 493.8 8.8 499.2 7.8 524.1 14.8 493.8 8.8 JCT 6068 #26 0.7506 3.6 0.0884 0.9 0.25 546.3 4.7 568.6 15.7 658.9 74.8 546.3 4.7 JCT 6068 #27 0.7606 2.8 0.0941 0.8 0.31 579.6 4.7 574.3 12.1 553.5 57.3 579.6 4.7 JCT 6068 #28 0.7729 3.1 0.0956 1.0 0.31 588.9 5.5 581.4 13.9 552.4 65.2 588.9 5.5 JCT 6068 #29 0.7344 5.3 0.0961 0.9 0.17 591.7 5.0 559.1 22.6 428.8 115.8 591.7 5.0 JCT 6068 #30 0.7482 4.7 0.1001 1.2 0.25 615.1 6.9 567.2 20.5 379.4 102.7 615.1 6.9 JCT 6068 #31 0.8055 2.1 0.1006 0.9 0.43 618.2 5.5 599.9 9.7 531.4 42.4 618.2 5.5 JCT 6068 #32 0.7523 6.8 0.1020 1.8 0.26 626.0 10.7 569.6 29.7 350.1 148.8 626.0 10.7 JCT 6068 #33 0.8649 1.3 0.1030 0.6 0.45 631.8 3.7 632.8 6.3 636.5 25.8 631.8 3.7 JCT 6068 #34 0.8781 2.4 0.1032 0.7 0.29 633.2 4.2 640.0 11.4 664.0 49.1 633.2 4.2 JCT 6068 #35 0.8066 5.9 0.1052 1.1 0.18 645.1 6.6 600.5 26.9 435.8 130.0 645.1 6.6 JCT 6068 #36 0.8151 6.9 0.1054 1.3 0.19 646.3 8.2 605.3 31.4 454.7 149.9 646.3 8.2 JCT 6068 #37 0.8727 2.0 0.1057 0.9 0.45 647.6 5.6 637.0 9.5 599.8 38.9 647.6 5.6 JCT 6068 #38 0.8937 7.0 0.1076 4.2 0.61 659.0 26.6 648.4 33.4 611.4 119.7 659.0 26.6 JCT 6068 #39 0.9901 2.2 0.1151 0.6 0.28 702.1 4.1 698.8 11.0 688.1 44.8 702.1 4.1 JCT 6068 #40 1.5379 2.9 0.1605 0.9 0.30 959.4 7.8 945.7 18.1 913.8 57.9 913.8 57.9 JCT 6068 #41 1.5431 3.9 0.1587 1.1 0.27 949.4 9.3 947.8 24.0 944.0 76.7 944.0 76.7 JCT 6068 #42 1.5721 1.0 0.1605 0.7 0.68 959.3 6.2 959.3 6.4 959.1 15.3 959.1 15.3 JCT 6068 #43 1.7362 2.5 0.1735 1.2 0.47 1031.2 11.1 1022.1 16.0 1002.5 44.5 1002.5 44.5 JCT 6068 #44 1.8937 1.7 0.1835 0.9 0.52 1086.2 8.7 1078.9 11.0 1064.1 28.5 1064.1 28.5 JCT 6068 #45 1.8633 1.0 0.1803 0.9 0.95 1068.7 9.2 1068.1 6.5 1067.1 6.0 1067.1 6.0 99 JCT 6068 #46 1.9170 2.4 0.1851 1.1 0.45 1094.6 11.1 1087.0 16.3 1071.9 43.7 1071.9 43.7

JCT 6068 #47 1.8089 2.1 0.1746 0.9 0.41 1037.5 8.3 1048.7 13.7 1072.1 38.3 1072.1 38.3 JCT 6068 #48 1.8784 0.8 0.1811 0.5 0.65 1073.1 5.0 1073.5 5.2 1074.3 12.1 1074.3 12.1 JCT 6068 #49 1.9162 1.6 0.1833 0.7 0.44 1084.8 6.9 1086.8 10.4 1090.6 28.1 1090.6 28.1 JCT 6068 #50 2.0728 2.0 0.1951 0.8 0.39 1148.8 8.0 1139.9 13.5 1123.0 36.1 1123.0 36.1 JCT 6068 #51 2.1121 0.9 0.1971 0.6 0.66 1159.5 6.7 1152.8 6.5 1140.0 14.2 1140.0 14.2 JCT 6068 #52 2.1216 1.9 0.1978 0.7 0.36 1163.7 7.4 1155.9 13.4 1141.2 36.0 1141.2 36.0 JCT 6068 #53 2.1201 1.9 0.1973 1.2 0.61 1161.0 12.3 1155.4 13.1 1144.8 30.0 1144.8 30.0 JCT 6068 #54 2.2003 1.6 0.2045 1.4 0.92 1199.6 15.6 1181.1 10.9 1147.5 12.3 1147.5 12.3 JCT 6068 #55 2.2416 1.6 0.2051 0.8 0.51 1202.8 8.8 1194.2 10.9 1178.5 26.4 1178.5 26.4 JCT 6068 #56 2.0490 1.8 0.1856 1.8 0.99 1097.7 18.3 1132.0 12.5 1198.4 5.7 1198.4 5.7 JCT 6068 #57 1.8137 1.2 0.1642 0.9 0.71 979.9 8.1 1050.4 8.2 1200.2 17.2 1200.2 17.2 JCT 6068 #58 2.8212 4.0 0.2388 1.3 0.34 1380.6 16.6 1361.2 29.8 1330.8 72.4 1330.8 72.4 JCT 6068 #59 2.8366 1.4 0.2378 0.7 0.48 1375.1 8.4 1365.3 10.7 1349.8 24.1 1349.8 24.1 JCT 6068 #60 2.4033 3.7 0.1986 3.4 0.90 1167.8 36.0 1243.6 26.8 1377.3 31.1 1377.3 31.1 JCT 6068 #61 2.9388 0.8 0.2393 0.6 0.76 1383.0 7.5 1392.0 6.0 1405.7 10.0 1405.7 10.0 JCT 6068 #62 2.8638 1.8 0.2296 1.4 0.76 1332.5 16.8 1372.5 13.9 1435.2 22.9 1435.2 22.9 JCT 6068 #63 3.1989 1.3 0.2530 0.7 0.57 1453.8 9.3 1456.9 9.8 1461.4 19.8 1461.4 19.8 JCT 6068 #64 3.1977 1.3 0.2523 1.0 0.80 1450.5 13.3 1456.6 9.9 1465.5 14.6 1465.5 14.6 JCT 6068 #65 3.3900 2.5 0.2657 1.1 0.43 1518.7 14.5 1502.1 19.5 1478.7 42.7 1478.7 42.7 JCT 6068 #66 3.6288 1.0 0.2786 0.9 0.93 1584.1 13.2 1555.9 8.0 1517.7 7.1 1517.7 7.1 JCT 6068 #67 3.7804 0.9 0.2773 0.7 0.81 1577.6 10.4 1588.6 7.4 1603.2 10.0 1603.2 10.0 JCT 6068 #68 3.9376 2.1 0.2825 2.0 0.97 1603.8 29.1 1621.5 17.2 1644.5 10.2 1644.5 10.2 JCT 6068 #69 3.9926 0.9 0.2860 0.8 0.86 1621.7 10.8 1632.7 7.2 1646.8 8.4 1646.8 8.4 JCT 6068 #70 4.6717 1.2 0.3220 0.6 0.49 1799.5 8.9 1762.2 9.6 1718.2 18.4 1718.2 18.4 JCT 6068 #71 5.2840 1.2 0.3386 1.0 0.83 1880.0 16.3 1866.3 10.3 1851.0 12.3 1851.0 12.3 JCT 6068 #72 5.4902 1.0 0.3411 0.7 0.67 1891.9 11.6 1899.1 9.0 1906.9 13.9 1906.9 13.9 JCT 6068 #73 5.9496 2.0 0.3651 1.2 0.62 2006.4 21.5 1968.5 17.3 1928.9 27.9 1928.9 27.9 JCT 6068 #74 6.3164 1.0 0.3654 0.8 0.83 2007.6 14.0 2020.7 8.6 2034.2 9.6 2034.2 9.6 JCT 6068 #75 6.8341 0.6 0.3812 0.6 0.96 2081.8 9.9 2090.2 5.1 2098.4 2.7 2098.4 2.7 100 JCT 6068 #76 13.7774 0.7 0.5236 0.6 0.86 2714.4 13.4 2734.5 6.7 2749.4 6.0 2749.4 6.0

JCT 6068 #77 14.5292 0.8 0.5439 0.7 0.85 2799.7 15.4 2784.9 7.6 2774.2 7.0 2774.2 7.0 Rejected Grain(s) JCT 6068 #78 0.4797 5.8 0.0709 1.3 0.23 441.3 5.6 397.9 18.9 152.6 131.3 441.3 5.6 JCT 6068 #79 0.4460 7.9 0.0710 1.7 0.22 442.0 7.4 374.5 24.9 -24.5 188.1 442.0 7.4 JCT 6068 #80 1.0486 3.3 0.1062 2.1 0.65 650.6 13.2 728.2 17.0 974.9 50.6 650.6 13.2

Table 8. U-Pb geochronographic analyses for JCT-6446 (Cherry Canyon Formation). Analysis Isotope ratios Apparent ages (Ma) 207Pb* ± 206Pb* ± error 206Pb* ± 207Pb* ± 206Pb* ± Best age ± 235U* (%) 238U (%) corr. 238U* (Ma) 235U (Ma) 207Pb* (Ma) (Ma) (Ma) JCT 6446 #1 0.3512 2.5 0.0492 0.7 0.28 309.6 2.1 305.6 6.5 275.7 54.3 309.6 2.1 JCT 6446 #2 0.3062 6.4 0.0492 1.2 0.20 309.9 3.8 271.2 15.2 -50.4 152.5 309.9 3.8 JCT 6446 #3 0.3574 2.2 0.0495 0.4 0.18 311.1 1.3 310.3 6.0 303.7 50.0 311.1 1.3 JCT 6446 #4 0.3713 7.9 0.0518 1.2 0.15 325.6 3.9 320.6 21.8 284.2 179.2 325.6 3.9 JCT 6446 #5 0.3681 3.6 0.0526 0.8 0.21 330.7 2.4 318.3 9.7 228.4 80.3 330.7 2.4 JCT 6446 #6 0.3961 2.5 0.0541 1.3 0.51 339.9 4.2 338.8 7.2 331.5 48.9 339.9 4.2 JCT 6446 #7 0.3626 12.4 0.0571 2.3 0.19 357.8 8.0 314.2 33.4 2.0 293.8 357.8 8.0 JCT 6446 #8 0.3757 6.9 0.0581 1.1 0.15 363.9 3.7 323.9 19.3 44.8 164.3 363.9 3.7 JCT 6446 #9 0.4358 1.6 0.0592 0.8 0.50 371.0 2.9 367.3 4.9 343.8 31.2 371.0 2.9 JCT 6446 #10 0.4314 1.9 0.0594 0.4 0.21 371.8 1.4 364.2 5.7 316.3 41.5 371.8 1.4 JCT 6446 #11 0.4259 3.8 0.0601 0.7 0.20 376.4 2.7 360.3 11.5 257.6 85.7 376.4 2.7 JCT 6446 #12 0.4253 4.4 0.0602 0.9 0.21 376.9 3.4 359.8 13.2 251.0 98.1 376.9 3.4 JCT 6446 #13 0.4279 4.8 0.0604 0.9 0.18 378.1 3.2 361.7 14.6 258.0 108.5 378.1 3.2 JCT 6446 #14 0.4277 5.6 0.0613 0.7 0.13 383.4 2.7 361.5 17.1 223.0 129.0 383.4 2.7 JCT 6446 #15 0.4324 3.1 0.0614 0.5 0.17 384.1 2.0 364.9 9.6 244.3 70.9 384.1 2.0

101 JCT 6446 #16 0.3578 9.7 0.0614 2.4 0.25 384.2 9.1 310.6 26.0 -211.1 236.7 384.2 9.1

JCT 6446 #17 0.4183 4.6 0.0618 1.3 0.28 386.4 4.8 354.9 13.7 153.6 103.2 386.4 4.8 JCT 6446 #18 0.4656 3.1 0.0628 0.6 0.20 392.5 2.3 388.1 9.9 361.9 68.1 392.5 2.3 JCT 6446 #19 0.4846 2.3 0.0637 0.5 0.24 398.3 2.1 401.2 7.5 417.9 49.4 398.3 2.1 JCT 6446 #20 0.5070 10.8 0.0638 4.1 0.38 398.7 16.0 416.4 36.9 515.9 219.5 398.7 16.0 JCT 6446 #21 0.4657 3.0 0.0641 0.6 0.21 400.8 2.5 388.2 9.6 314.3 66.4 400.8 2.5 JCT 6446 #22 0.4811 4.2 0.0642 0.7 0.17 401.1 2.7 398.8 13.8 385.7 92.7 401.1 2.7 JCT 6446 #23 0.4854 2.1 0.0650 0.6 0.31 406.2 2.5 401.8 7.0 376.4 45.0 406.2 2.5 JCT 6446 #24 0.4959 3.8 0.0665 0.7 0.18 414.9 2.7 408.9 12.8 375.0 84.0 414.9 2.7 JCT 6446 #25 0.4667 5.0 0.0670 0.8 0.16 418.1 3.2 388.9 16.1 219.0 114.2 418.1 3.2 JCT 6446 #26 0.4994 3.7 0.0676 0.7 0.19 421.9 2.9 411.3 12.4 352.6 81.2 421.9 2.9 JCT 6446 #27 0.5000 2.1 0.0682 0.6 0.29 425.6 2.5 411.7 7.2 334.6 46.2 425.6 2.5 JCT 6446 #28 0.5202 0.8 0.0683 0.5 0.54 426.2 1.9 425.3 2.9 420.3 15.6 426.2 1.9 JCT 6446 #29 0.5085 1.7 0.0684 0.4 0.23 426.2 1.6 417.4 5.9 369.2 37.7 426.2 1.6 JCT 6446 #30 0.4153 10.7 0.0687 1.3 0.12 428.1 5.5 352.7 31.8 -118.0 262.0 428.1 5.5 JCT 6446 #31 0.5032 3.1 0.0689 0.6 0.19 429.3 2.4 413.8 10.7 328.2 69.9 429.3 2.4 JCT 6446 #32 0.5280 1.4 0.0689 0.5 0.34 429.4 2.0 430.5 5.0 436.3 29.8 429.4 2.0 JCT 6446 #33 0.5205 5.6 0.0695 0.9 0.16 432.9 3.7 425.5 19.5 385.3 124.6 432.9 3.7 JCT 6446 #34 0.5008 5.8 0.0700 1.0 0.18 436.1 4.4 412.2 19.8 280.9 131.5 436.1 4.4 JCT 6446 #35 0.4988 5.8 0.0706 1.1 0.18 439.5 4.6 410.9 19.7 253.1 132.2 439.5 4.6 JCT 6446 #36 0.4983 7.7 0.0707 1.3 0.16 440.5 5.4 410.5 26.1 245.3 175.7 440.5 5.4 JCT 6446 #37 0.4907 6.0 0.0708 1.1 0.19 440.8 4.8 405.4 20.1 208.3 137.4 440.8 4.8 JCT 6446 #38 0.5254 5.4 0.0708 1.6 0.30 441.2 6.8 428.8 18.8 362.3 116.0 441.2 6.8 JCT 6446 #39 0.4916 14.5 0.0711 2.7 0.18 442.5 11.4 406.0 48.4 203.2 331.2 442.5 11.4 JCT 6446 #40 0.5454 2.1 0.0715 0.6 0.29 445.5 2.6 442.0 7.4 423.8 44.0 445.5 2.6 JCT 6446 #41 0.5267 7.5 0.0717 1.3 0.18 446.3 5.7 429.6 26.3 341.1 167.4 446.3 5.7 JCT 6446 #42 0.5444 3.2 0.0725 0.6 0.18 451.4 2.5 441.3 11.3 389.0 69.8 451.4 2.5 JCT 6446 #43 0.5426 10.1 0.0731 2.0 0.20 454.5 8.7 440.1 36.1 365.5 223.7 454.5 8.7 JCT 6446 #44 0.5668 5.8 0.0736 0.8 0.14 457.8 3.6 455.9 21.3 446.2 127.4 457.8 3.6 JCT 6446 #45 0.5654 4.6 0.0739 0.9 0.19 459.6 4.0 455.0 16.9 432.0 100.7 459.6 4.0 102 JCT 6446 #46 0.5692 5.3 0.0742 0.8 0.16 461.5 3.7 457.5 19.4 437.6 116.1 461.5 3.7

JCT 6446 #47 0.5802 5.3 0.0765 0.9 0.18 475.4 4.2 464.6 19.6 411.7 116.0 475.4 4.2 JCT 6446 #48 0.5983 2.4 0.0781 0.4 0.18 484.6 2.0 476.1 8.9 435.5 51.5 484.6 2.0 JCT 6446 #49 0.5966 3.8 0.0799 0.6 0.17 495.3 3.1 475.1 14.3 378.5 83.8 495.3 3.1 JCT 6446 #50 0.6669 3.1 0.0875 0.7 0.22 540.6 3.6 518.8 12.7 424.0 68.2 540.6 3.6 JCT 6446 #51 0.6745 3.5 0.0882 0.6 0.18 545.1 3.2 523.4 14.2 429.8 75.9 545.1 3.2 JCT 6446 #52 0.6584 5.3 0.0888 1.0 0.20 548.4 5.4 513.6 21.3 361.8 116.9 548.4 5.4 JCT 6446 #53 0.7689 3.3 0.0890 1.0 0.29 549.6 5.1 579.1 14.7 696.6 68.1 549.6 5.1 JCT 6446 #54 0.6568 6.0 0.0905 1.1 0.18 558.6 5.9 512.7 24.0 313.0 133.2 558.6 5.9 JCT 6446 #55 0.7623 3.7 0.0922 1.0 0.27 568.7 5.4 575.3 16.1 601.3 76.6 568.7 5.4 JCT 6446 #56 0.7268 8.2 0.0958 1.6 0.19 589.5 8.9 554.7 34.9 414.2 179.1 589.5 8.9 JCT 6446 #57 0.7497 4.6 0.0960 1.0 0.22 591.0 5.8 568.0 19.9 477.2 98.8 591.0 5.8 JCT 6446 #58 0.7352 6.3 0.0968 1.0 0.15 595.7 5.5 559.6 27.3 415.1 140.3 595.7 5.5 JCT 6446 #59 0.7294 8.0 0.0969 1.5 0.19 596.0 8.6 556.2 34.1 396.5 175.6 596.0 8.6 JCT 6446 #60 0.7550 4.4 0.0986 0.7 0.16 606.3 4.0 571.1 19.4 433.3 97.7 606.3 4.0 JCT 6446 #61 0.7562 5.8 0.1004 1.1 0.19 616.5 6.4 571.8 25.2 397.6 126.8 616.5 6.4 JCT 6446 #62 0.7948 5.1 0.1005 0.9 0.18 617.5 5.3 593.9 22.9 504.8 110.5 617.5 5.3 JCT 6446 #63 0.8379 1.9 0.1008 0.9 0.46 619.1 5.2 618.0 8.9 613.9 37.0 619.1 5.2 JCT 6446 #64 0.8256 2.2 0.1012 0.4 0.20 621.7 2.6 611.2 10.1 572.3 46.6 621.7 2.6 JCT 6446 #65 0.7837 5.2 0.1031 1.2 0.22 632.3 7.0 587.6 23.0 418.4 112.2 632.3 7.0 JCT 6446 #66 0.9283 1.2 0.1091 0.4 0.36 667.7 2.8 666.8 6.1 663.5 24.8 667.7 2.8 JCT 6446 #67 0.9273 3.9 0.1111 1.1 0.28 679.0 6.9 666.2 18.9 623.2 79.9 679.0 6.9 JCT 6446 #68 1.2166 1.7 0.1298 0.7 0.39 786.7 5.0 808.2 9.6 868.0 32.7 786.7 5.0 JCT 6446 #69 1.5439 2.2 0.1602 0.7 0.32 958.0 6.3 948.1 13.6 925.2 42.8 925.2 42.8 JCT 6446 #70 1.5142 2.4 0.1569 0.7 0.30 939.4 6.2 936.1 14.4 928.5 46.2 928.5 46.2 JCT 6446 #71 1.5535 1.7 0.1570 0.5 0.31 940.1 4.7 951.9 10.7 979.3 33.6 979.3 33.6 JCT 6446 #72 1.6443 1.5 0.1661 1.4 0.96 990.9 13.3 987.4 9.6 979.6 9.2 979.6 9.2 JCT 6446 #73 1.7166 1.4 0.1726 0.6 0.40 1026.2 5.3 1014.8 9.0 990.2 26.1 990.2 26.1 JCT 6446 #74 1.7834 3.2 0.1778 0.7 0.21 1054.7 6.7 1039.4 21.0 1007.5 64.1 1007.5 64.1 JCT 6446 #75 1.5932 1.8 0.1585 0.6 0.31 948.4 5.0 967.5 11.4 1011.2 35.3 1011.2 35.3 103 JCT 6446 #76 1.8148 3.3 0.1795 0.9 0.26 1064.4 8.4 1050.8 21.3 1022.7 63.5 1022.7 63.5

JCT 6446 #77 1.8574 1.8 0.1828 0.8 0.44 1082.1 7.9 1066.1 11.8 1033.5 32.5 1033.5 32.5 JCT 6446 #78 1.8376 1.4 0.1795 0.5 0.36 1064.3 5.0 1059.0 9.1 1048.2 26.1 1048.2 26.1 JCT 6446 #79 1.9335 2.6 0.1880 0.8 0.33 1110.3 8.7 1092.7 17.4 1058.0 49.4 1058.0 49.4 JCT 6446 #80 1.7920 1.3 0.1735 0.4 0.30 1031.6 3.9 1042.6 8.6 1065.6 25.4 1065.6 25.4 JCT 6446 #81 1.8423 1.4 0.1778 0.5 0.35 1055.1 4.9 1060.7 9.5 1072.1 27.1 1072.1 27.1 JCT 6446 #82 1.8650 1.1 0.1798 0.5 0.46 1066.0 4.9 1068.8 7.2 1074.5 19.5 1074.5 19.5 JCT 6446 #83 2.0306 0.9 0.1921 0.4 0.45 1132.7 4.3 1125.8 6.2 1112.5 16.4 1112.5 16.4 JCT 6446 #84 2.0140 1.0 0.1905 0.4 0.39 1123.9 4.2 1120.2 7.1 1113.1 19.3 1113.1 19.3 JCT 6446 #85 1.9435 1.4 0.1833 0.4 0.32 1085.2 4.4 1096.2 9.3 1118.2 26.2 1118.2 26.2 JCT 6446 #86 2.0555 5.0 0.1936 1.4 0.27 1141.1 14.2 1134.1 34.0 1120.9 95.4 1120.9 95.4 JCT 6446 #87 2.0681 2.5 0.1944 0.8 0.31 1145.2 8.1 1138.3 16.8 1125.1 46.6 1125.1 46.6 JCT 6446 #88 2.0377 2.0 0.1909 0.5 0.28 1126.5 5.6 1128.2 13.3 1131.4 37.4 1131.4 37.4 JCT 6446 #89 1.9490 1.9 0.1826 0.7 0.37 1081.3 7.0 1098.1 12.9 1131.6 35.5 1131.6 35.5 JCT 6446 #90 1.8743 1.7 0.1746 1.1 0.63 1037.4 10.2 1072.0 11.1 1143.1 25.8 1143.1 25.8 JCT 6446 #91 2.0124 3.6 0.1871 1.3 0.37 1105.4 13.4 1119.7 24.5 1147.5 66.8 1147.5 66.8 JCT 6446 #92 2.0321 0.6 0.1882 0.4 0.72 1111.6 4.4 1126.3 4.1 1154.8 8.2 1154.8 8.2 JCT 6446 #93 2.1071 0.6 0.1944 0.3 0.60 1145.4 3.5 1151.1 3.8 1161.9 8.9 1161.9 8.9 JCT 6446 #94 1.7424 1.9 0.1592 1.0 0.53 952.5 9.1 1024.3 12.6 1181.3 32.7 1181.3 32.7 JCT 6446 #95 2.1864 0.4 0.1995 0.3 0.79 1172.5 3.7 1176.7 3.1 1184.5 5.4 1184.5 5.4 JCT 6446 #96 2.2642 2.5 0.2030 0.5 0.19 1191.2 5.2 1201.2 17.8 1219.3 48.9 1219.3 48.9 JCT 6446 #97 1.9684 0.8 0.1763 0.7 0.77 1046.9 6.3 1104.8 5.7 1220.5 10.6 1220.5 10.6 JCT 6446 #98 2.4344 2.8 0.2157 2.2 0.78 1259.1 25.4 1252.8 20.4 1242.1 34.8 1242.1 34.8 JCT 6446 #99 2.5176 1.1 0.2197 0.5 0.45 1280.5 5.7 1277.1 7.9 1271.4 19.0 1271.4 19.0 JCT 6446 #100 2.5684 2.5 0.2233 0.6 0.26 1299.2 7.5 1291.7 18.1 1279.2 46.6 1279.2 46.6 JCT 6446 #101 2.6077 0.7 0.2243 0.3 0.45 1304.3 3.9 1302.8 5.3 1300.3 12.6 1300.3 12.6 JCT 6446 #102 2.5357 1.0 0.2168 0.4 0.38 1265.0 4.4 1282.3 7.3 1311.6 17.9 1311.6 17.9 JCT 6446 #103 2.8012 1.7 0.2372 0.9 0.49 1372.0 10.7 1355.9 13.1 1330.5 29.4 1330.5 29.4 JCT 6446 #104 2.6941 1.2 0.2265 0.4 0.33 1316.2 4.7 1326.8 8.8 1344.0 21.8 1344.0 21.8 JCT 6446 #105 2.7052 0.5 0.2272 0.4 0.79 1319.8 4.6 1329.9 3.6 1346.1 5.7 1346.1 5.7 104 JCT 6446 #106 2.8212 0.9 0.2364 0.4 0.45 1368.1 5.2 1361.2 7.0 1350.3 16.1 1350.3 16.1

JCT 6446 #107 2.8427 1.6 0.2375 0.4 0.27 1373.9 5.5 1366.9 12.2 1355.9 30.1 1355.9 30.1 JCT 6446 #108 2.7364 1.0 0.2286 0.5 0.51 1327.0 6.2 1338.4 7.5 1356.7 16.7 1356.7 16.7 JCT 6446 #109 2.7378 1.0 0.2277 0.5 0.48 1322.2 5.7 1338.8 7.4 1365.3 16.9 1365.3 16.9 JCT 6446 #110 2.9799 4.3 0.2448 1.3 0.30 1411.4 16.3 1402.5 32.8 1389.0 79.1 1389.0 79.1 JCT 6446 #111 2.8340 2.0 0.2299 1.3 0.68 1334.2 16.0 1364.6 14.7 1412.5 27.6 1412.5 27.6 JCT 6446 #112 2.8841 0.8 0.2337 0.6 0.68 1354.0 7.1 1377.8 6.4 1414.7 11.8 1414.7 11.8 JCT 6446 #113 2.8534 1.3 0.2312 0.5 0.40 1340.7 6.3 1369.7 9.9 1415.3 23.0 1415.3 23.0 JCT 6446 #114 2.9291 1.2 0.2370 0.5 0.42 1371.3 6.5 1389.5 9.4 1417.4 21.5 1417.4 21.5 JCT 6446 #115 3.0381 1.2 0.2427 0.7 0.62 1400.8 9.1 1417.3 8.9 1442.1 17.5 1442.1 17.5 JCT 6446 #116 3.2345 2.0 0.2565 0.5 0.27 1471.9 7.1 1465.5 15.4 1456.1 36.3 1456.1 36.3 JCT 6446 #117 3.1623 0.9 0.2489 0.4 0.44 1432.9 4.9 1448.0 6.7 1470.3 14.9 1470.3 14.9 JCT 6446 #118 3.4363 1.7 0.2685 0.8 0.46 1533.1 10.4 1512.7 13.0 1484.4 27.8 1484.4 27.8 JCT 6446 #119 3.3654 0.8 0.2615 0.3 0.40 1497.4 4.5 1496.4 6.6 1494.9 14.7 1494.9 14.7 JCT 6446 #120 3.3284 1.1 0.2581 0.4 0.35 1480.1 5.0 1487.7 8.5 1498.6 19.2 1498.6 19.2 JCT 6446 #121 3.4883 1.3 0.2685 0.5 0.41 1533.1 7.5 1524.6 10.6 1512.7 23.1 1512.7 23.1 JCT 6446 #122 3.5200 0.8 0.2683 0.4 0.46 1532.1 4.9 1531.7 6.2 1531.2 13.1 1531.2 13.1 JCT 6446 #123 3.7794 0.9 0.2842 0.5 0.53 1612.4 6.9 1588.4 7.3 1556.7 14.5 1556.7 14.5 JCT 6446 #124 3.5086 1.6 0.2620 0.8 0.49 1500.0 10.3 1529.2 12.3 1569.7 25.4 1569.7 25.4 JCT 6446 #125 3.4984 1.1 0.2604 0.7 0.66 1491.8 9.7 1526.9 8.8 1575.8 15.8 1575.8 15.8 JCT 6446 #126 3.6368 0.9 0.2703 0.6 0.65 1542.5 7.8 1557.6 7.0 1578.2 12.5 1578.2 12.5 JCT 6446 #127 3.6929 1.1 0.2724 0.9 0.87 1552.9 12.7 1569.8 8.4 1592.7 9.6 1592.7 9.6 JCT 6446 #128 3.9359 2.1 0.2877 0.8 0.37 1630.0 11.0 1621.1 16.8 1609.5 35.9 1609.5 35.9 JCT 6446 #129 3.9852 0.7 0.2892 0.3 0.53 1637.8 5.0 1631.2 5.3 1622.7 10.4 1622.7 10.4 JCT 6446 #130 4.0318 1.0 0.2918 0.5 0.50 1650.5 7.5 1640.6 8.4 1627.9 16.7 1627.9 16.7 JCT 6446 #131 4.1648 0.9 0.2989 0.5 0.50 1685.9 6.8 1667.1 7.6 1643.5 15.0 1643.5 15.0 JCT 6446 #132 4.3592 0.7 0.3045 0.4 0.61 1713.6 6.4 1704.6 5.8 1693.7 10.2 1693.7 10.2 JCT 6446 #133 4.3657 1.3 0.3010 0.6 0.47 1696.2 9.2 1705.9 10.7 1717.8 21.0 1717.8 21.0 JCT 6446 #134 3.8234 2.7 0.2616 1.9 0.70 1497.8 25.3 1597.7 21.8 1732.1 35.5 1732.1 35.5 JCT 6446 #135 4.5080 0.7 0.3068 0.4 0.65 1725.0 6.7 1732.4 5.7 1741.5 9.6 1741.5 9.6 105 JCT 6446 #136 4.6852 0.7 0.3160 0.5 0.70 1770.3 8.0 1764.6 6.2 1757.9 9.6 1757.9 9.6

JCT 6446 #137 4.6127 0.8 0.3105 0.6 0.78 1743.3 9.5 1751.6 6.7 1761.4 9.2 1761.4 9.2 JCT 6446 #138 4.6853 0.8 0.3130 0.4 0.52 1755.2 6.7 1764.6 6.9 1775.7 12.9 1775.7 12.9 JCT 6446 #139 4.8373 0.6 0.3206 0.4 0.61 1792.5 5.6 1791.4 4.9 1790.1 8.5 1790.1 8.5 JCT 6446 #140 4.8792 0.6 0.3231 0.4 0.67 1805.0 6.7 1798.7 5.4 1791.3 8.7 1791.3 8.7 JCT 6446 #141 4.9016 1.1 0.3228 0.7 0.60 1803.3 10.8 1802.5 9.7 1801.6 16.8 1801.6 16.8 JCT 6446 #142 5.6340 2.0 0.3529 0.7 0.37 1948.4 12.6 1921.3 17.3 1892.2 33.5 1892.2 33.5 JCT 6446 #143 4.6599 0.5 0.2865 0.5 0.95 1624.0 7.4 1760.1 4.5 1925.7 2.9 1925.7 2.9 JCT 6446 #144 5.8364 0.7 0.3481 0.6 0.90 1925.4 10.8 1951.8 6.3 1980.0 5.7 1980.0 5.7 JCT 6446 #145 6.1770 1.2 0.3655 0.5 0.47 2008.0 9.3 2001.2 10.1 1994.2 18.1 1994.2 18.1 JCT 6446 #146 6.2241 1.5 0.3570 0.9 0.55 1968.2 14.4 2007.8 13.5 2048.9 22.7 2048.9 22.7 JCT 6446 #147 6.8091 1.1 0.3873 0.8 0.74 2110.2 14.1 2086.9 9.3 2064.0 12.4 2064.0 12.4 JCT 6446 #148 5.6948 1.5 0.3216 0.6 0.38 1797.5 9.0 1930.6 13.0 2076.7 24.6 2076.7 24.6 JCT 6446 #149 7.6496 0.8 0.4077 0.4 0.54 2204.3 8.3 2190.7 7.4 2178.0 12.1 2178.0 12.1 JCT 6446 #150 7.3218 0.5 0.3850 0.4 0.70 2099.5 6.6 2151.5 4.7 2201.4 6.4 2201.4 6.4 JCT 6446 #151 7.5856 1.2 0.3854 0.8 0.72 2101.5 14.8 2183.2 10.4 2260.8 13.9 2260.8 13.9 JCT 6446 #152 26.3347 0.6 0.6114 0.5 0.95 3075.8 13.3 3359.0 5.6 3532.6 2.9 3532.6 2.9 Rejected Grain (s) JCT 6446 #153 0.6066 2.9 0.0684 1.4 0.47 426.4 5.7 481.4 11.1 752.6 53.9 426.4 5.7 JCT 6446 #154 0.4727 8.1 0.0701 1.3 0.16 436.7 5.4 393.1 26.3 143.5 187.3 436.7 5.4 JCT 6446 #155 0.4683 8.4 0.0709 1.3 0.16 441.8 5.6 390.0 27.3 93.1 197.6 441.8 5.6 JCT 6446 #156 0.5097 8.6 0.0755 1.4 0.16 469.2 6.2 418.3 29.6 146.1 200.4 469.2 6.2 JCT 6446 #157 0.5066 7.8 0.0767 1.3 0.17 476.5 6.1 416.1 26.6 94.0 182.0 476.5 6.1 JCT 6446 #158 0.5646 8.9 0.0836 1.4 0.16 517.5 7.1 454.5 32.7 147.3 206.7 517.5 7.1 JCT 6446 #159 0.5906 10.4 0.0908 0.9 0.09 560.4 5.0 471.3 39.2 57.8 247.2 560.4 5.0 JCT 6446 #160 0.6494 11.9 0.0928 3.2 0.27 572.1 17.4 508.1 47.4 229.4 264.5 572.1 17.4 JCT 6446 #161 1.0282 1.4 0.1045 1.1 0.79 640.8 6.9 718.0 7.4 967.5 18.1 640.8 6.9 JCT 6446 #162 0.8060 20.9 0.0759 6.5 0.31 471.8 29.5 600.2 95.0 1120.8 400.2 471.8 29.5

106

1. Analyses with >20% uncertainty (1-sigma) in 206Pb/238U age are not included. 2. Analyses with >20% uncertainty (1-sigma) in 206Pb/207Pb age are not included, unless 206Pb/238U age is <500 Ma. 3. Best age is determined from 206Pb/238U age for analyses with 206Pb/238U age <1000 Ma and from 206Pb/207Pb age for analyses with 206Pb/238Uage > 1000 Ma. 4. Concordance is based on 206Pb/238U age / 206Pb/207Pb age. Value is not reported for 206Pb/238U ages <400 Ma because of large uncertainty in 206Pb/207Pb age. 5. Analyses with 206Pb/238U age > 400 Ma and with >20% discordance (<80% concordance) are not included. 6. Analyses with 206Pb/238U age > 400 Ma and with >10% reverse discordance (<110% concordance) are not included. 7. All uncertainties are reported at the 1-sigma level, and include only measurement errors. 8. Systematic errors are as follows (at 2-sigma level): [sample 1: 2.5% (206Pb/238U) & 1.4% (206Pb/207Pb)] These values are reported on cells U1 and W1 of NUagecalc. 9. Analyses conducted by LA-MC-ICPMS, as described by Gehrels et al. (2008). 10. U concentration and U/Th are calibrated relative to Sri Lanka zircon standard and are accurate to ~20%. 11. Common Pb correction is from measured 204Pb with common Pb composition interpreted from Stacey and Kramers (1975). 12. Common Pb composition assigned uncertainties of 1.5 for 206Pb/204Pb, 0.3 for 207Pb/204Pb, and 2.0 for 208Pb/204Pb. 13. U/Pb and 206Pb/207Pb fractionation is calibrated relative to fragments of a large Sri Lanka zircon of 563.5 ± 3.2 Ma (2-sigma). 14. U decay constants and composition as follows: 238U = 9.8485 x 10-10, 235U = 1.55125 x 10-10, 238U/235U = 137.88. 15. Weighted mean and concordia plots determined with Isoplot (Ludwig, 2008).

107

Appendix III: K-S Statistical Results

Table 6: K-S Statistical Results from the Delaware Mountain Group samples of this study (JCT-4956, JCT-5872, JCT- 6068, JCT-6446), Soreghan and Soreghan (2013), and Devonian-Permian Appalachian foreland strata (Gray and Zeitler 1997; McLennan et al. 2001; Eriksson et al. 2004; Thomas et al. 2004; Becker et al. 2005, 2006; Park et al. 2010).

K-S P -values using error in

the CDF CYCN CYCN CYCN BLCN BLCN BLCN Appalachian BYCN (S&S) BYCN (S&S) (JCT-6446) (JCT-6068) (JCT-5872) (S&S) (S&S) (JCT-4946) Foreland Strata BYCN (S&S) 0.399 0.419 0.134 0.300 0.967 0.753 0.002 0.001 BYCN (S&S) 0.399 0.003 0.001 0.003 0.064 0.261 0.000 0.206 CYCN (JCT-6446) 0.419 0.003 0.592 0.728 0.936 0.601 0.102 0.000 CYCN (JCT-6068) 0.134 0.001 0.592 0.931 0.527 0.240 0.546 0.000 CYCN (JCT-5872) 0.300 0.003 0.728 0.931 0.808 0.577 0.125 0.000 BLCN (S&S) 0.967 0.064 0.936 0.527 0.808 0.737 0.046 0.000 BLCN (S&S) 0.753 0.261 0.601 0.240 0.577 0.737 0.007 0.000 BLCN (JCT-4946) 0.002 0.000 0.102 0.546 0.125 0.046 0.007 0.000 Appalachian 0.001 0.206 0.000 0.000 0.000 0.000 0.000 0.000 Foreland Strata

108

Table 7: K-S Statistical Results from the Delaware Mountain Group samples of this study (JCT-4956, JCT-5872, JCT- 6068, JCT-6446), Soreghan and Soreghan (2013), and “Ouachita-derived” strata (Dickinson et al. 2010; Gleason et al. 2007).

K-S P -values using error in

the CDF Chinle BYCN CYCN CYCN CYCN BLCN BLCN Haymond BYCN (S&S) BLCN (JCT-4946) Dockum-Auld (S&S) (JCT-6446) (JCT-6068) (JCT-5872) (S&S) (S&S) Formation Lang Syne BYCN (S&S) 0.389 0.002 0.001 0.002 0.254 0.061 0.000 0.266 0.000 BYCN (S&S) 0.389 0.386 0.135 0.275 0.746 0.966 0.002 0.061 0.001 CYCN (JCT-6446) 0.002 0.386 0.606 0.716 0.591 0.923 0.110 0.000 0.000 CYCN (JCT-6068) 0.001 0.135 0.606 0.944 0.241 0.529 0.516 0.001 0.000 CYCN (JCT-5872) 0.002 0.275 0.716 0.944 0.541 0.778 0.134 0.002 0.000 BLCN (S&S) 0.254 0.746 0.591 0.241 0.541 0.737 0.006 0.272 0.001 BLCN (S&S) 0.061 0.966 0.923 0.529 0.778 0.737 0.046 0.152 0.000 BLCN (JCT-4946) 0.000 0.002 0.110 0.516 0.134 0.006 0.046 0.000 0.000 Chinle Dockum- 0.266 0.061 0.000 0.001 0.002 0.272 0.152 0.000 0.000 Auld Lang Syne Haymond 0.000 0.001 0.000 0.000 0.000 0.001 0.000 0.000 0.000 Formation 109

VITA

Personal Background John Martin Anthony Born April 17, 1991, Shreveport, Louisiana Son of Martin and Karen Anthony

Education Bachelor of Science in Geology, 2013 Louisiana State University, Baton Rouge, LA

Master of Science in Geology, 2015 Texas Christian University, Fort Worth, TX

Experience Geoscience Intern, Summer 2013 Concho Resources, Midland, TX

Geoscience Intern, Summer 2014 Concho Resources, Midland, TX

Professional Societies American Association of Petroleum Geologists Geological Society of America

ABSTRACT

PROVENANCE OF THE MIDDLE PERMIAN, DELAWARE MOUNTAIN GROUP:

DELAWARE BASIN, SOUTHEAST NEW MEXICO AND WEST TEXAS

JOHN MARTIN ANTHONY, M.S., 2015 School of Geology, Energy, and the Environment Texas Christian University

Thesis Advisor: Dr. Xiangyang Xie, Assistant Professor of Geology Committee Members: Dr. Helge Alsleben and Dr. John Holbrook

The siliciclastic strata of the Middle Permian (Guadalupian), Delaware Mountain Group of the Delaware basin, located in southeast New Mexico and west Texas have long been interpreted to record deep marine deposition that were pre-sorted by eolian processes; however, the provenance of the Delaware Mountain Group is still debated. The majority of previous researchers have suggested the crystalline basement uplifts of the Ancestral Rocky Mountains as the primary source for the Delaware Mountain Group due to the observed arkosic-subarkosic mineralogy. This study combines point-count data of 54 thin sections from the three formations that comprise the Delaware Mountain Group (Bell Canyon, Cherry Canyon, and Brushy Canyon) and U-Pb detrital zircon geochronology analyses from four subsurface whole core samples of the Delaware Mountain Group to shed further light on the potential source terranes delivering siliciclastics to the Delaware basin during the Middle Permian. Samples exhibit the commonly observed arkosic-subarkosic mineralogy which has been associated with an Ancestral Rocky Mountain source; however, ages obtained via detrital zircon geochronology disagree with previous interpretations. Instead of an abundance of ages indicative of an Ancestral Rocky Mountain source (late Paleoproterozoic, 1600-1800 Ma), predominant age populations include, Mid-Paleozoic (275-490 Ma), Neoproterozoic/Early Paleozoic (510-790 Ma), and Mesoproterozoic (950-1200Ma) age grains. New data from this study further suggest that the Ancestral Rocky Mountains were not a major contributor of siliciclastic sediment to the Delaware basin during the Middle Permian. The predominately subarkosic mineralogy and detrital zircon ages reported in this study can best be reconciled with a Ouachita orogen source, including key “peri-Gondwanan” source terranes such as the Yucatan-Maya and Oaxaquia terrane. Additionally, this study provides missing Cherry Canyon Formation detrital zircon age dates. Comparison of reported ages in this study with ages previously reported in the Delaware Mountain Group reveal that there was a provenance evolution after deposition of the Brushy Canyon and the onset of deposition of the Cherry Canyon Formation. Furthermore, this timing coincides with the disappearance of inland seas, the filling of the Midland basin, and continued accretion of terranes along the Ouachita- Marathon suture zone.