Lower Permian Through Lower Trassic Paleontology, Stratigraphy, and Chemostratigraphy of the Bilk Creek Mountains of Humboldt County, Nevada

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LOWER PERMIAN THROUGH LOWER TRASSIC PALEONTOLOGY, STRATIGRAPHY, AND CHEMOSTRATIGRAPHY OF THE BILK CREEK MOUNTAINS OF HUMBOLDT COUNTY, NEVADA

Christopher Allen Klug

A Thesis

Submitted to the Graduate College of Bowling Green State University in partial fulfillment of the requirements for the degree of

MASTER OF SCIENCE

December 2007

Committee:

Margaret M. Yacobucci, Advisor

James E. Evans

John R. Farver

Christopher Klug

ABSTRACT

Margaret M. Yacobucci, Advisor

The primary goal of this study was to use paleontological, geochemical ( C), and sedimentological data to determine if a complete Permian-Triassic boundary section is present at the Bilk Creek Mountains of northwestern Nevada.

The Bilk Creek Mountains of northwestern Nevada contain a marine record deposited in a back-arc terrane environment, starting in the Lower Permian Bilk Creek

Limestone and extending to the Middle Triassic Quinn River Formation. Field work through these units reveals changes in the marine benthic fauna through this interval, including across the Permian-Triassic boundary.

Data collected from the Bilk Creek Limestone reveals a diverse benthic marine fauna, with brachiopods being the most abundant. Within the Bilk Creek Limestone, two different faunal signatures are apparent. The transition and separation of these groups are marked by the appearance and the abundance of Boreal brachiopods such as Spiriferella,

Neospirifer, Stenoscisma, Muirwoodia transversa, Neophricodothyris sp., and Derbyia, replacing mid-latitude to Tethyan-derived brachiopods such as Crurithyris, Dielasma,

Squamularia sp., and Rhynchopora. When the brachiopod faunas of the Bilk Creek were compared statistically with other known Early Permian rocks deposited along northwestern and western Pangea, analysis showed that the Bilk Creek brachiopod fauna was similar to that of the Eastern Klamath and Quesnellia terranes. This faunal transition to a more Boreal assemblage may mark the local onset of the Permian Chert Event iv

(PCE). While previously thought to be strictly Early Permian, the Bilk Creek Limestone does contain Middle Permian brachiopod taxa as well.

The overlying Permian Volcaniclastic Unit, thought previously to be unfossiliferous, does contain small quantities of articulate brachiopods.

Approximately 54 meters of limestones, dolomites, shales, cherts, and volcanic ash within the overlying Quinn River Formation record deposition in deep marine conditions prior to the Permian-Triassic mass extinction event. Field observations and lab data reveal the presence of brachiopods, sponges, and rugose corals that then disappear with the onset of accumulations of cherts at the end-Guadalupian.

The Permian-Triassic boundary was defined stratigraphically with the use of the distinctive Permo-Triassic negative C excursion, along with early Triassic fauna such as the brachiopod Lingula and the bivalve Claraia. With no evidence of unconformities within the Quinn River Formation, this unit appears to represent a continuous Permo-

Triassic boundary section. v

I would like to dedicate this thesis to my parents, who have always supported me through all my endeavors, my friend Rex Hanger who was instrumental in getting me started on

research about the Permian, to my friend Josh Mathews for being my field assistant

whenever I needed him, to all the friends who have lent an ear for those phone calls

during the first year of graduate school, and finally to my friends who have lent me a

couch to crash on when I visited Whitewater to blow off some steam.

For this I am grateful to all of you. vi

ACKNOWLEDGMENTS

I would like to express my appreciation to Dr. Yacobucci for advising me through the problems that came up during the thesis process. I would also like to thank Josh

Mathews for helping me at the field site and for being my second driver out to Nevada. I would also like to thank the University of Wisconsin-Whitewater Department of Geology and Geography’s Field Study Class for their help with the trenching across the Quinn

River Formation. I would like to express my thanks to Bowling Green State University’s

Department of Geology for the use of laboratory space and supplies during the course of this study. I would also like to thank Chris Wright and Dr. Onasch for showing me how to use the department’s rock preparation equipment. And finally I would like to thank the

Richard D. Hoare Research Scholarship and Explorers Foundation Exploratory Grant for funding my research.

vii

TABLE OF CONTENTS

Page

CHAPTER I. INTRODUCTION ...... 1

CHAPTER II. GEOLOGIC SETTING ...... 9

Regional Geologic Setting...... 9

Stratigraphy & Depositional Environments ...... 13

Bilk Creek Limestone (Pbc) ...... 13

Permian Volcaniclastic Unit (Psv) ...... 14

Quinn River Formation (PTRqr) ...... 14

CHAPTER III. METHODS AND MATERIALS ...... 16

Data Collection Methods ...... 16

Geological Field Methods ...... 16

Laboratory Preparation ...... 17

Fossils ...... 17

Rock Slabs ...... 18

Geochemical Preparation ...... 19

Analyses……...... 20

Paleoecological Analyses ...... 20

Geochemical Analyses ...... 23

CHAPTER IV. SEDIMENTOLOGY & STRATIGRAPHY ...... 25

Measured Sections ...... 25

Bilk Creek Limestone (Pbc) ...... 25 viii

Permian Volcaniclastic Unit (Psv) ...... 26

Quinn River Formation (PTRqr) ...... 28

Biostratigraphy ...... 36

Bilk Creek Limestone (Pbc) ...... 36

Quinn River Formation (PTRqr) ...... 37

Chemostratigraphy ...... 42

CHAPTER V. PALEOECOLOGICAL ANALYSIS ...... 48

Bilk Creek Limestone (Pbc) ...... 48

Permian Volcaniclastic Unit (Psv) ...... 52

Quinn River Formation (PTRqr) ...... 52

CHAPTER VI. DISCUSSION ...... 70

Brachiopods and the Age of the Bilk Creek Limestone ...... 70

The Bilk Creek Limestone-Permian Volcaniclastic Unit and the PCE ...... 70

Permian Mass Extinction and the Quinn River Formation ...... 78

CHAPTER VII. CONCLUSIONS ...... 80

REFERENCES ...... 82

APPENDIX A. DESCRIPTION OF THE BILK CREEK LIMESTONE ...... 88

APPENDIX B. DESCRIPTION OF THE PERMIAN VOLCANICLASTIC UNIT ...... 91

APPENDIX C. DESCRIPTION OF THE QUINN RIVER FORMATION ...... 101

APPENDIX D. LOWER PERMIAN BRACHIOPOD TERRANE DATA ...... 107 ix

LIST OF FIGURES

Figure Page

1 Extinction patterns for marine animals during the Permian-Triassic mass

extinction ...... 3

2 Permian time scale, showing the different epochs and stages ...... 4

3 Paleogeographic world map, showing late Permian Earth ...... 4

4 North America during the Early Permian (290 Ma) ...... 5

5 North America during the Middle Permian (275 Ma) ...... 6

6 North America during start of late Permian (260 Ma) ...... 7

7 North America during start of Early Triassic (245 Ma) ...... 8

8 Map of Nevada showing study area in Bilk Creek Mountains ...... 10

9 Geological map with units at the Bilk Creek Mountains ...... 11

10 Map showing present day position of terranes ...... 12

11 Photograph of lower portion of study area...... 27

12 Photographs of upper portion of study area ...... 30

13 Key for stratigraphic sections...... 30

14 Stratigraphy and biostratigraphy of the Bilk Creek Limestone, Part 1 ...... 31

14 Stratigraphy and biostratigraphy of the Bilk Creek Limestone, Part 2 ...... 32

15 Stratigraphy and biostratigraphy of the Permian Volcaniclastic Unit, Part 1 ...... 33

15 Stratigraphy and biostratigraphy of the Permian Volcaniclastic Unit, Part 2 ...... 34

16 Stratigraphy and biostratigraphy of the Quinn River Formation ...... 35

17 Bilk Creek Formation fossils in the field ...... 39

18 Permian-Triassic fossils from the Quinn River Formation ...... 40 x

19 Triassic fossils from the Quinn River Formation ...... 41

20 Stratigraphy and chemostratigraphy of the Quinn River Formation...... 45

21 Enlarged section of the stratigraphy and chemostratigraphy of the Quinn River

Formation surrounding the P/TR ...... 46

22 Chemostratigraphy of other Permo-Triassic boundary sections ...... 47

23 Stratigraphic breakdown of phyla for the Bilk Creek Limestone ...... 55-57

24 Taxonomic breakdown of Brachiopoda for the Bilk Creek Limestone...... 57-59

25 Taxonomic breakdown of Mollusca, for the Bilk Creek Limestone ...... 60

26 Breakdown of Bryozoa colony type for the Bilk Creek Limestone ...... 60-61

27 Pooled rarefaction curve for the Bilk Creek Limestone ...... 63

28 Q-mode cluster diagram based on Raup-Crick similarities for Bilk Creek

Formation samples ...... 64

29 Cluster diagram of early Permian terranes based on the Simpson index of

brachiopod faunas ...... 67

30 Cluster diagram of early Permian terranes based on the Raup-Crick index of

brachiopod faunas ...... 68

31 Paleogeographic map showing ocean currents during the early Permian ...... 74

32 Paleogeographic map showing ocean currents during the late early Permian...... 75

33 Paleogeographic map showing ocean currents during the end of the middle and

start of the late Permian...... 76

34 Paleogeographic map showing ocean currents during the latest Permian-earliest

Triassic ...... 77

LIST OF TABLES

Tables Page

1 Organic Carbon Isotopic Values for the Quinn River Formation ...... 44

2 Abundance Data for the Bilk Creek Limestone ...... 54

3 Diversity Indices for the Bilk Creek Limestone and Quinn River Formation ...... 62

4 Similarity Indices for Units in the Bilk Creek Limestone ...... 62

5 Similarity Indices for the Bilk Creek and other Lower Permian Locations ...... 63-66

6 Abundance Data for the Quinn River Formation ...... 69

Chapter I: Introduction

The Permo-Triassic mass extinction event (250 million years ago) is recognized as one of the most severe events in the history of Earth’s biota (Erwin, 1990); when up to 95% of all marine species became (Raup, 1979) (Figure 1). Current research questions on the Permo-

Triassic boundary include: 1) the pattern of extinction and recovery (Twitchett, 1999), 2) the duration of the event (Mundil et al., 2001) and 3) possible causes of the event (Benton and

Twitchett, 2003).

Study of the Permo-Triassic (Figure 2) mass extinction is hindered by the relatively small number of conformable boundary sections that have been identified, possibly due to the coeval, global regression of sea level. Alvarez and O’Connor (2002) suggest that the record across the

Permo-Triassic boundary in the Southwestern United States may be complete and conformable.

The primary line of evidence being the occurrence of deep water facies across the boundary, indicating transgression rather than regression. Testing of this hypothesis requires detailed paleontologic and stratigraphic data from the rocks in the immediate vicinity of the currently mapped (and considered disconformable) boundary (Alvarez and O’Connor, 2002).

The Bilk Creek Mountains of Humboldt County in northwestern Nevada contain rocks from both the Permian (Figure 3) and Triassic periods (Kenter and Wardlaw, 1981). Detailed mapping in the range (Jones, 1990) shows the presence of three rock units deposited during these geologic periods (Figures 4,5,6,7): the Lower Permian Bilk Creek Limestone, overlain by an unfossiliferous Permian volcaniclastic unit, topped by the Middle Permian through Triassic

Quinn River Formation (Jones, 1990, Figure 9). These rocks are part of the Black Rock Terrane. 2

The oldest Permian rocks in the Quinn River Formation are dated as Guadalupian, or

Middle Permian, and have been interpreted as representing deep shelf environments (Blome and

Reed, 1995; Rigby and Hanger, 1999). These rocks then are overlain by what has been interpreted by Blome and Reed as deeper water siltstones and bedded cherts with no apparent unconformity. Some Late Permian and Early Triassic radiolarians have been described from these deep water facies (Blome and Reed, 1995; Sperling and Ingle, 2006).

The position of the Permian-Triassic boundary has been placed just above these bedded cherts (Sperling and Ingle, 2006). The boundary was identified by the presence of the distinctive negative carbon isotope excursion at the end of the Permian, due to an influx of relatively depleted organic carbon into the ocean system at this time due to environmental perturbations

(Sperling and Ingle, 2006). As such, this section represents the Permian-Triassic target stratigraphic situation described by Alvarez and O’Connor (2002).

The primary goal of this study is to use paleontological, geochemical ( C), and sedimentological data to determine if a complete Permian-Triassic boundary section is present at the Bilk Creek Mountains of Northwestern Nevada.

The second goal of the study is to determine if there are changes in paleocommunity structure for marine invertebrates in these units, and to establish if there is a shift in the fauna as time progressed from the Early to the Late Permian?

The third goal is to establish paleogeographic trends along the western/northwestern margin of Pangea, by comparing faunal data from the Bilk Creek Mountains of the Black Rock

Terrane to that of other terranes along the western/northwestern margin of Pangea.

Figure 1: Extinction patterns for marine animals during the Permian-Triassic mass extinction. Changxingian on the table is the end of the Permian and Scythian is the beginning of the Triassic (modified from Raup, 1979).

Figure 2: Permian time scale, showing the different epochs and stages (modified from Gradstein et al., 2004).

Figure 3: Paleogeographic world map, showing late Permian Earth. Potential conformable boundary section in Nevada is marked by the yellow star (modified from Scotese, 2001).

Figure 4: North America during the Early Permian (290 Ma). White star is the approximate location of the Black Rock Terrane (modified from Blakey, 2005). 6

Figure 5: North America during the Middle Permian (275 Ma). White star is the approximate location of the Black Rock Terrane (modified from Blakey, 2005). 7

Figure 6: North America during start of Late Permian (260 Ma).White star is the approximate location of the Black Rock Terrane (modified from Blakey, 2005). 8

Figure 7: North America during start of Early Triassic (245 Ma). White star is the approximate location of the Black Rock Terrane (modified from Blakey, 2005). 9

Chapter II: Geologic Setting

Regional Geologic Setting

The study site is located near Quinn River Crossing in the southern part of the Bilk Creek

Mountains of Humboldt County in northwestern Nevada (Figure 8 and 9). During the late

Paleozoic, these rocks were part of what is now called the Black Rock Terrane (Jones, 1990).

The Black Rock Terrane contains Paleozoic and Early Mesozoic rocks, both siliciclastic and carbonate units, with small quantities of volcanic rocks, reflecting sedimentation within a marine environment (Darby et al., 2000). Jones (1990) suggested that both the Black Rock Terrane at

Quinn River Crossing and the Eastern Klamath Terrane located in northeastern California formed in the same basin as part of a volcanic arc complex, based on the biogeographic, structural, and lithologic similarities between the two terranes (Figure 10). However, the lack of volcaniclastic rocks in the Black Rock Terrane compared to that of the Klamath Terrane implies that the Black Rock Terrane was further from the volcanic source. The strata at Quinn River

Crossing include both accreted Paleozoic/ Mesozoic terranes and native Cenozoic rocks (Kenter and Wardlaw, 1981), but it is also noted by Jones (1990) that the present positions of the terranes in northwestern Nevada may be a result of post-mid-Mesozoic tectonic events, and are not related to their original paleogeographic position.

Humboldt County Nevada Figure 8: Map of Nevada showing Study Area study area in Bilk Creek Mountains.

Figure 9: Geological map with units at the Bilk Creek Mountains. (Pbc) is the Permian Bilk Creek Limestone Unit. (Psv) is the Permian Volcaniclastic Unit. (PTRqr) is the Quinn River Formation. Red line indicates study area (modified from Jones, 1990). 12

eKT

Figure 10: Map showing present day position of some terranes (modified from Beatty et al., 2006). 13

Stratigraphy & Depositional Environments

The southernmost part of the Bilk Creek Mountains is made up of three distinctive stratigraphic units, the Lower Permian Bilk Creek Limestone, the Lower to Middle Permian

Volcaniclastic Unit, and finally the Middle Permian to Middle Triassic Quinn River Formation

(Kenter and Wardlaw, 1981).

Bilk Creek Limestone (Pbc)

The oldest of the units in the Bilk Creek Mountains is the Bilk Creek Limestone, which consists of more than 900 m of massively bedded biosparite, in which fossils are mostly silicified

(Jones, 1990). In 1981, Kenter and Wardlaw showed that the lowermost portion of the limestone contains both solitary and colonial rugose and syringoporoid corals, which are associated with fusulinid mounds that are 0.7m in diameter. The corals appeared to be in growth position. The fusulinids in the lower part of the limestone are Sakmarian – Kungurian (Lower Permian) in age.

In the lowermost portion of the unit, limestone beds are only a few centimeters thick and are interbedded with cherts and silty crinoidal wackestone.

Further up-section, the limestone beds become thicker, and some of the fossiliferous beds have slumped and are overlain by turbidites. According to Kenter and Wardlaw (1981), the turbidites reflect deposition in shallow water based on the presence of Hindeodus sp. conodonts.

It is important to note the lack of brachiopods throughout the middle portion of the Bilk Creek

Limestone, which are deeper water limestones (Kenter and Wardlaw, 1981); only the basal and upper parts contain numerous brachiopods. Brachiopods reappear in great abundances within debris flow packages, disturbed neighborhoods, and bioherms in the uppermost part of the Bilk

Creek Limestone, where the limestones become more silty (Kenter and Wardlaw, 1981; personal 14 observation on summer 2004 and 2006 trips). This might indicate that proximity between the

Bilk Creek portion of the Black Rock Terrane and a volcanic arc complex became closer.

Permian Volcaniclastic Unit (Psv)

The Bilk Creek Limestone is conformably overlain by Permian volcaniclastic rocks.

These rocks can be recognized by the first appearance of predominantly silty material, and include thin interbeds of dark gray spicular argillite, bright green tuffaceous argillite, and brown and yellow volcaniclastics (Kenter and Wardlaw, 1981; Jones, 1990). The mafic volcaniclastic rocks of this unit are interpreted to indicate proximity to an active arc source terrane. Most of the volcanic material is waterlain, representative of submarine deposition by turbidity currents

(Jones, 1990). Detailed observation and mapping in the summer of 2006 showed the section to be 308 meters thick and recognizable by its interbedded cherts and siltstones that are interrupted by turbidites with channelized sandstones. The unit, previously thought to be unfossiliferous, does contain rare articulate brachiopods.

Lithological trends from the carbonate of the Bilk Creek Limestone to the interbedded spicular argillite and volcaniclastic rocks indicate that deposition occurred in a subsiding basin adjacent to an active island arc receiving an influx of volcaniclastic sediment (Kenter and

Wardlaw, 1981; Jones, 1990).

Quinn River Formation (PTRqr)

The Quinn River Formation is the uppermost unit of the study area. The base of the

Quinn River is made up of a thin, green, siliceous tuff overlain by 2 m of brown bioclastic limestone (Jones, 1990; Blome and Reed, 1995). The oldest dated rocks of the Quinn River

Formation are Late Wordian (Middle Guadalupian), based on the brachiopods Ctenalosia fixata 15 and Stenocisma (Kenter and Wardlaw, 1981; Blome and Reed, 1995) and sponges (Rigby and

Hanger, 1999) found in a 15 m unit of dolomite above the 2 m of brown limestone. The dolomite is interpreted as representing deep water shelf environments based on the presence of large quantities of the rhizomorine sponge Haplistion aeluroglossa (Blome and Reed; 1995, Rigby and

Hanger, 1999).

The dolomite is topped by 25 m of interbedded gray and red radiolarian chert and argillite. Radiolarian biostratigraphy indicates the cherts are Late Permian in age (Blome and

Reed, 1995). Above the chert is a 30 m thick section of Permian - Triassic age, that consists of gray to black carbonaceous siltstones. Interbedded with these siltstones are laminated shales, radiolarian cherts, and volcaniclastic rocks. These cherts and siltstones indicate deeper marine environments than the underlying dolomites (Blome and Reed, 1995).

The position of the Permian-Triassic boundary has been placed just above the bedded cherts. The boundary was identified by the presence of the widespread negative carbon isotope excursion at the end of the Permian (Sperling and Ingle, 2006). Jones (1990) argued that a disconformity is present between the Guadalupian and the Lower Triassic strata, but radiolarian biostratigraphy from Blome and Reed (1995) and Sperling and Ingle (2006) show that latest

Permian and Early Triassic radiolarians are present in the Permian bedded chert and the Triassic siltstone.

Chapter III: Methods and Materials

Data Collection Methods

Data for this study came from two sources: original data and secondary data from published literature. Original data included measured sections and rock and fossil samples collected from the Bilk Creek Limestone, Permian Volcaniclastic Unit, and the Quinn River

Formation of the Bilk Creek Mountains of Northwestern Nevada. Published data from geological maps was used to determine positions of lithologic units. Published paleoecological studies from other areas were used for comparison to the faunas described by me.

Geological Field Methods

The southernmost part of the Bilk Creek Mountains of northwestern Nevada was visited for a previous study during late July of 2004. Aerial photographs and published geological maps

(Jones 1990; Figure 9) were used to determine the location of the three distinct units and to approximate the location of the Permo-Triassic (P-T) boundary within the Quinn River

Formation.

More intensive study of the three stratigraphic units took place in late April through the middle of May, 2006. Stratigraphic units were measured and photographed with the help of my field assistant, Josh Mathews. Measured sections included the upper most 70 meters of the Bilk

Creek Limestone, all of the Permian Volcaniclastic Unit, and the lower most 50 meters of the

Quinn River Formation. Trenching was done in parts of the Quinn River Formation, due to siltstone and shale scree covering much of the formation. Trenching was done with the help of the University of Wisconsin-Whitewater Department of Geology and Geography’s Field Study

Class. 17

Bulk rock and fossil samples were collected throughout the Lower Permian Bilk Creek

Limestone, the Permian Volcaniclastic Unit, and the Quinn River Formation. Sampling within the Bilk Creek Limestone was done at regular intervals at each distinct bed, except at beds that proved to be unbreakable due to the strong induration of the beds, with the main purpose of collecting fossils for the paleoecological portion of this study. Collection of samples from the

Permian Volcaniclastic Unit was done with the anticipation of recovering fossils from a unit that was primarily known as unfossiliferous. Sampling within the Quinn River Formation was done at high resolution with sampling at the millimeter and centimeter scale, for the purpose of collecting fossil data for biostratigraphy and paleoecological analyses, as well as rock samples for stable isotopic analyses and chemostratigraphy.

Laboratory Preparation

Once rock and fossil samples arrived back at BGSU, they were cleaned, photographed, and sorted based on stratigraphic location.

Fossils

Fossil samples were collected from the Bilk Creek Limestone, Permian Volcaniclastic

Unit, and the Quinn River Formation. Fossils from the Bilk Creek Limestone were generally silicified and consisted of brachiopods, rugose and syringoporoid corals, bryozoans, gastropods, and crinoids. The Permian Volcaniclastic Unit contained rare brachiopods. The Quinn River

Formation fossils were mainly brachiopods, sponges, corals, conodonts, ammonoids and trace fossils in the form of burrows.

Limestone blocks that contained silicified fossils and that weighed between 1 and 1.5 kg were washed in water and cleaned. The underside of each limestone block was coated with latex 18 and allowed to dry for at least 12 hours. The covered surface of the limestone allowed for the acid to dissolve the limestone only from the top and sides, thus allowing the freed fossils to settle gently on top of the block rather than getting crushed on the bottom (Cooper and Grant, 1972).

Latexed blocks were then placed latex side down on 1 mm diameter nylon mesh netting within a 2 gallon plastic bin and placed under a fume hood. Dilute (20-30%) hydrochloric acid was added to the bin until the entire block was completely immersed. The acid baths were changed daily as the limestone dissolved away. Once the block had been completely dissolved, the fossil residue was washed and placed in a water bath for about 24 hours. The fossil residue was then removed from the water and sieved in .0049 to .157 inches sieves to separate the fossil residue into different sizes.

Since silicified fossils are very fragile, each individual fossil was hardened with a mixture of acetone and polyvinyl acetate. Once hardened, fossils were identified with the use of the reference materials, such as the Permian Brachiopods from Central Oregon (Cooper, 1959) and

Permian Brachiopods of West Texas, II, III and IV (Cooper and Grant, 1972, 1974, 1975 and

1976), and counted.

Rock Slabs

Rock samples collected from the three units at the Bilk Creek Mountains were cut with the use of oil and water saws. After samples were cut, they were polished by the use of lapidary wheels. After samples were all polished, a coat of varnish was sprayed on the polished surfaces to further enhance the reflectances and colors of the samples. Samples were then scanned by an

EPSON PERFECTION 4490 PHOTO scanner at 12800dpi resolution, with an image type of 48 bit color. Images were then processed and visualized with the use of a Dell computer and flatscreen LCD monitor. Images were lightened and sharpened, using Adobe Photoshop and 19

Photoshop Elements. These imaging techniques were all done to further support field observations and identification of lithologic samples.

Geochemical Preparation

The chemostratigraphy portion of this study focused on the Quinn River

Formation. Previously only one study done by Sperling and Ingle (2006) had subjected the

Quinn River Formation to chemostratigraphic analysis. In that study, chemostratigraphic analysis was done to determine whether the distinctive Permo-Triassic negative C excursion was present, and to determine if anoxic conditions were present during the time of deposition of the

Quinn River Formation, with the use of authigenic uranium and vanadium/chromium ratios.

Unlike the Sperling and Ingle (2006) paper, this study focused only on the C chemostratigraphy of the Quinn River Formation, for the purpose of evaluating the placement of the distinctive Permo-Triassic negative C excursion, in comparison to the stratigraphic placement of the brachiopod Lingula and the bivalve Claraia (Figure 18), to see if they truly represent an Early Triassic disaster fauna in the Quinn River Formation.

The source of C for this study came from organic matter derived from marine plankton that were deposited in siltstone and shales. A total of 39 samples that consisted of shales, paper shales, and siltstones were cleaned with distilled water and ground into a powder using a ceramic pestle and mortar. The powder samples were then moistened with distilled water and placed in a vacuum distillatory, in which samples were exposed to HCl vapor for 6 hours to remove any carbonate from the samples so that only organic C would be analyzed. Samples were then placed in an oven and dried at 60°C for 4 hours (Harris et al., 2001). Once samples were dried, they were packed into tin capsules, which were then sealed and placed into a sample tray and shipped to the stable isotope facility at the University of California at Davis. Once samples 20 arrived at Davis, they were placed into a ANCA-GSL-HYDRA 20/20 mass spectrometer for isotopic analysis, in which the standard analytical uncertainty per sample for C is 0.1‰.

Analyses

Paleoecological Analyses

After all fossils were counted and identified from the dissolved blocks of Bilk Creek

Limestone, fossil occurrences were then entered into a spreadsheet as both relative abundance and presence/absence. Presence/absence data were then compared to published data from other lower Permian localities on the margin of northwestern Pangea. Since one of the goals of this study was to make quantitative assessment of the biodiversity of the community as time progressed forward, I created a matrix in which fossil species were on one axis and sampling horizons were on the other, with abundances for each species input in the matrix. This matrix was then analyzed by using a paleontology statistical program called PAST (Hammer et al.,

2003).

For biodiversity assessment of the Bilk Creek Limestone, both alpha and beta diversities were used. Alpha diversity is used to calculate the diversity in a given locality, while beta diversity is the between-habitat diversity, and is used to calculate variation of diversities between local areas (Hammer and Harper, 2006). To calculate both the alpha and beta diversities, four different diversity metrics were used: taxonomic richness (S), and the Shannon-Wiener (H’),

Fisher’s alpha (α) and Margalef (M) indices (Hammer and Harper, 2006).

The alpha and beta diversity measures are used to make quantitative assessments of biodiversity of a community. Taxonomic richness is calculated by the count of species or higher taxa (S) in a particular sample; it is important to note that the count of taxonomic richness in a 21 sample will usually be an underestimate for total taxonomic richness, as sample taxonomic richness generally increases with sample size. The Shannon-Wiener index;

Eq. 1 H’ =-∑ pi ln pi

is a complex measurement of diversity based on probability; it is designed to predict the species of the next collected individual, while making adjustments based on the size of the sample. Here, pi is the proportion of taxon i in the sample. The Fisher’s (α) diversity index;

Eq. 2 S= α ln(1 + n/α)

where S is the number of taxa and n is the number of individuals, assumes that relative abundances are distributed according to a logarithmic abundance model. The last diversity index used is the Margalef’s richness index;

Eq. 3 M=(S-1)/ln(n)

where S is the number of taxa and n is the number of individuals. This index takes into account that individual numbers will increase as taxonomic richness increases (Hammer and

Harper, 2006). For all of the above mentioned indices, confidence intervals were estimated by bootstrapping, in which a subset of individuals are selected at random with replacement from the sample or samples, and the diversity index is calculated. This process is then repeated many times, giving a bootstrapped distribution of diversity values. A 95% confidence interval is then given as the interval from the lower 2.5% end to the upper 2.5% end of bootstrapped values

(Hammer and Harper, 2006).

Rarefaction analyses were run to evaluate the effects of sample size on fossil counts, and to compare fossil counts in samples of different sizes. Rarefaction curves show the expected number of sampled species S(n) as a function of sample size n, where n is the total number of individuals collected. If the rarefaction curve flattens out at your actual sample size, you can 22 assume that your sample collecting has recovered most of the species that are present (Hammer and Harper, 2006).

To measure the similarity between different horizons within the Bilk Creek Formation and between different lower Permian localities, I calculated four association similarity indices, the Jaccard similarity index (J), the Dice index (D), the Raup and Crick similarity, and the

Simpson’s coefficient of similarity (Sim) (Hammer and Harper, 2006). Association similarity indices are used to provide distances for cluster analysis; they are specifically used in biogeographical analyses, where the presence of a taxon marks a point in its geographical range.

The data required to calculate association similarity indices come in the form of binary presence/absence taxon data from at least two samples (Hammer and Harper, 2006). The Jaccard similarity index;

Eq. 4 J=M/(M+N)

reflects the number of shared taxa in two localities(M) divided by the total number of taxa (M+N), which means that absences in both samples are ignored. The Dice index;

Eq. 5 D= M/((2M + N)/2) = 2M/(2M + N)

is similar to the Jaccard index but it normalizes with respect to the average rather than the total number of species in the two samples. Also, the Dice index puts more emphasis on matches than on mismatches. The similarity between two samples can also be tested using a randomization method, in which the two samples are compared to pooled and random samples, in which this is done a number of times. If the similarity index used is the number of shared taxa

(M), then the probability p that two samples came from the same population is known as the

Raup-Crick similarity index (Hammer and Harper, 2006). The last index used was the Simpson’s coefficient of similarity; 23

Eq. 6 Sim=M/S

where S is the smaller number of taxa in each of the two samples; only taxa present in the smaller sample can contribute to M and/or S.

Q mode multivariate cluster analyses were performed using the Jaccard, Dice, Simpson’s and Raup and Crick similarity indices. Q mode multivariate cluster analyses compared different lithological units and beds within the Bilk Creek Mountains based on what species are in common. Thus, I was able to compare the faunal composition of different stratigraphic beds within the Bilk Creek Limestone.

Cluster analysis was also used to compare the Bilk Creek Limestone fauna with those of other known early Permian terrane-derived communities along the northwestern margin of

Pangea.

Geochemical Analyses

The isotopic composition of C is reported using the standard delta notation

13 12 13 12 13 ( C/ C)spl ( C/ C)std 3 Eq. 7 δ C 13 12 10 ‰ ( C/ C)std where spl= sample, std= standard, the standard is PDB. Positive C values indicate that C is enriched in 13C relative to the PDB standard, and thus negative values of C mean that it is depleted in C (Faure and Mensing, 2005). Isotopic data were input into a spreadsheet where they were sorted stratigraphically, and plotted on a graph to determine stratigraphic trends and to evaluate whether the distinctive Permo-Triassic negative C excursion was present within the

Quinn River Formation. This graph was then compared to three other Permo-Triassic boundary sites, including the rarer deeper water sections of Dongpon (South China; Zhang et al., 2006) and the Maitai Group (New Zealand; Krull et al., 2000) and one other, shallower water site, the 24

Meishan section (China; Zhang et al., 2006). These comparisons were done to evaluate if there are any differences in the trends in C values between deeper water and shallower water sites.

Chapter IV: Sedimentology & Stratigraphy

Measured Sections

Sections through the three stratigraphic units were measured along a transect within the

Bilk Creek Mountains (Figures 11 and 12). Each of the units displayed distinctive lithologies.

Each stratigraphic unit has been described individually, and Appendices A, B, and C contain detailed lithologic descriptions for the measured sections, which are presented in Figures 14 to

16. The key for all sections can be found in Figure 13.

Bilk Creek Limestone (Pbc)

The measured section within the Bilk Creek Limestone (Figure 14) reveals a unit consisting of biomicrite, micrite, biosparite, sparite and bedded chert, though most of the section consists of sparite and biosparite. The oldest part of the measured section (BCL-41) consists of 3 meters of massively bedded biomicrite that contains fossils in multiple orientations; the lack of any defining sedimentary structures, such as graded and wavy bedding, and rip-up clasts, suggest that limestone is consistent with deeper water deposition being below storm wave base. Moving up-section about 8 meters (BCL-28), the limestone becomes light gray and consists of biosparite and sparite, where fossil assemblages are either found in life position, neighborhood assemblages, or as small scale debris flows. Based on specific taxa such as brachiopods and the conodont Hindeodus sp. (this study and Kenter and Wardlaw, 1981), this portion of the unit has been determined to be shallower than the previously mentioned section, even though there are no sedimentary structures such as graded and wavy bedding, and rip-up clasts. As such, this would suggest that the rocks in this section of the Bilk Creek Limestone were still being deposited 26 below storm wave base. Whether water depth changed as a result of sea level fall or tectonic forces within the basin has not been determined. Moving even further up section between BCL-

11 and BCL-02, which represent 29 meters of rock, the limestone becomes silty and is interbedded with bedded cherts; again as before there are no primary sedimentary structures to suggest any change in water depth. The appearance of a silty limestone and bedded cherts may indicate proximity to a silica source such as an volcanic arc complex. Also, at the same time, fossil abundance appears to drop.

Permian Volcaniclastic Unit (Psv)

The Bilk Creek Limestone is conformably overlain by Permian volcaniclastic rocks (Figures 11,

15). Detailed observation and mapping during the course of this study showed the section to be about 308 meters thick and recognizable by its interbedded cherts and siltstones that are interrupted by turbidites with channelized sandstones with parallel laminations (Figure 15, all sandstones). The unit was previously thought to be unfossiliferous, but does contain minute quantities of articulate brachiopods approximately 49 meters from the base of the section at PVS-

156. Lithological trends from the carbonate of the Bilk Creek Limestone to the interbedded spicular argillite and volcaniclastic rocks (the sandstones and siltstones have been interpreted by others as volcaniclastic rocks ) indicates that deposition occurred in a subsiding basin receiving an influx of volcaniclastic sediment (Kenter and Wardlaw, 1981; Jones, 1990).

Figure 11: Photograph of lower portion of study area. Red line shows boundary between the Bilk Creek Limestone (yellow arrow) and the Permian Volcaniclastic Unit (red arrow).

Quinn River Formation (PTRqr)

The base of the Quinn River Formation which overlies the Permian Volcaniclastic Unit was not directly viewed during the course of this study due to the nature of the terrain; but other authors have noted that this boundary between the Permian Volcaniclastic Unit and Quinn River

Formation appears to be conformable.

The base of the Quinn River Formation consists of a whitish to pale green fine grained waterlain siliceous tuff, which is then overlain by about 8 meters worth of dark brown bioclastic limestone (QR-01) and tan dolomites (QR-02) (Figure 16). These distinct lithologies create a landmark which can be seen from Nevada State Highway 140 at Quinn River Crossing (Figure

12). The dolomites have been determined to be deep water shelf environments based on the presence of the sponge Haplistion aeluroglossa (Rigby and Hanger 1999), which is found in life position. The dolomites are then topped by a section of cover, which is overlain by red bedded cherts (QR-04 through QR-63), which other studies have interpreted to indicate an increase in water depth at this field site. This either could be evidence for local basin subsidence or may be a sign of the global late Permian sea level rise (Wignall and Twitchett, 2002). Red hematite-rich cherts have also been known to indicate anoxic conditions within the water column during time of deposition (Wignall and Twitchett, 2002). This environmental interpretation will be further evaluated in the chemostratigraphy section (see below). The cherts are then topped by the last measured portion of this study, which consists of paper shales and siltstones, interrupted by ash layers (QR-64 to QR-112). This change from cherts to shales and siltstones has been interpreted at other locations as marking a rise in ocean temperatures, based on the fact that silica becomes less soluble in warm ocean water (Erwin, 2006). 29

The lack of any defining sedimentological evidence such as burrowed or eroded surfaces at the P/TR boundary within the Quinn River Formation is suggestive that there are no hiatuses or nondepositional periods present, and as such no unconformities separating Latest

Permian and Earliest Triassic rocks.

Figure 12: Photographs of upper portion of study area. The dark brown bioclastic limestone and tan dolomites of the lower Quinn River Formation create a distinct landmark, which can be seen from Nevada State Highway 140 at Quinn River Crossing.

Figure 13: Key for stratigraphic sections. 31

BCL-26

BCL-Scree BCL-15 BC L-37 BCL-16

BCL-41

Figure 14: Stratigraphy and biostratigraphy of the Bilk Creek Limestone, Part 1. Note that unit numbers decrease upsection. 32

BCL -08

BCL-01

BCL-02

Figure 14, continued: Stratigraphy and biostratigraphy of the Bilk Creek Limestone, Part 2. 33

PVS 104

PVS 156

PVS 209

Figure 15: Stratigraphy and biostratigraphy of the Permian Volcaniclastic Unit, Part 1. Note that unit numbers decrease upsection. 34

PVS 01

PVS 04

PVS 83

PVS 86

PVS 88

PVS 15

PVS 17

Figure 15, continued: Stratigraphy and biostratigraphy of the Permian Volcaniclastic Unit, Part 2. 35

QR-94

QR-04

QR-112 QR-94

P/TR

QR-110

QR-102

QR-80

QR -02 QR-63

QR-01

QR-63

Figure 16: Stratigraphy and biostratigraphy of the Quinn River Formation. Blown-up portion represents thinly bedded shales, cherts and ashes near P/TR boundary. Red arrow marks the likely location of the P/TR boundary. Note that, unlike previous sections, samples numbers increase upsection.

Biostratigraphy

Five previous studies have focused on the paleontology and biostratigraphy of the Bilk

Creek Mountains (Kenter and Wardlaw, 1981; Jones, 1990; Blome and Reed, 1995; Rigby and

Hanger, 1999; and Sperling and Ingle, 2006). Only two of these studies have included the Lower

Permian Bilk Creek Limestone, while all of them have focused in some way or another on the

Quinn River Formation, mainly due to the importance of evaluating late Permian – early Triassic rocks.

Bilk Creek Limestone (Pbc)

In this study, I will only briefly review the biostratigraphy of this unit, since I only investigated the upper portion of the 900m thick section for biostratigraphic purposes. Other authors have shown that the lowermost portion of the Bilk Creek Limestone contains both solitary and colonial rugose and syringoporoid corals, which are associated with fusulinid mounds (Kenter and Wardlaw, 1981); this lower section of the Bilk Creek also contains large quantities of brachiopods (3500 individuals of 20 different species have been collected, Rex

Hanger, personal communication, 4/04/2005), which are early Permian in age. The lowest documentation of fossils during this study occurred in sample BC-41 (Figure 14), which contains the gastropod Omphalotrochus sp. (Figure 17), which is found as float. After this point, the section contains numerous fossiliferous beds (Figure 17), some of which were sampled for paleoecologic analysis. The fossil in this section of the Bilk Creek limestone are middle Permian in age, based on the presence of brachiopods such as Spiriferella, Neospirifer, Stenoscisma,

Crurithyris sp., Muirwoodia transversa, and Neophricodothyris sp. The last fossil collected occurs at BC-02 (Figure 14) and is a rugose coral in life position. 37

Quinn River Formation (PTRqr)

Previous studies of the Quinn River Formation have revealed the brachiopods Ctenalosia and Stenocisma (Kenter and Wardlaw, 1981) in what I refer to as QR-01 (Figure 16), the brown bioclastic limestone (Appendix C) and the sponge Haplistion aeluroglossa (Rigby and Hanger

1999) in QR-02 (Appendix C, Figure 16), the tan dolomite. Above the dolomite in the cherts, the radiolarians Albaillella levis and A. sp. cf. A. triangularis, Triplanospongos sp. cf. T. dekkasensis and Neoalbaillella sp. aff. N. ornithoformis were identified from lower and uppermost parts of the cherts; these radiolarians indicate that the chert is Abadehian to Djulfian in age (Latest

Permian; Blome and Reed, 1995), which would be equivalent to Kuman / Wuchiapingian in age based on Japanese radiolarian zones (Blome and Reed, 1995). Another radiolarian zone appears about 20 meters above my last measured lithology; this radiolarian zone has been assigned to late

Early Triassic in age by Sperling and Ingle (2006). In 1990, Jones discovered a Middle Triassic ammonoid, which is approximately 110 meters above my last measured lithology.

Biostratigraphical data collected during the course of this study focused on collecting new macrofossil data throughout the Middle Permian-Lower Triassic section of the Quinn River

Formation, since little data had been collected before. The first new fossil discovery occurred in

QR-01 (Figure 16) in the bioclastic limestone with the discovery of a rugose coral (Figure 18).

Previous studies have assigned an age of Late Wordian (Middle Guadalupian) to this bedding plane based on the presence of the brachiopods Ctenalosia and Stenocisma. The next new fossil discovery occurred in QR-02, within the tan dolomite, in which unidentified bryozoans, brachiopods, crinoids, and gastropods were found. They remain unidentified because of their poor preservation. The next discovery occurred in a shale layer at QR-80, in which large quantities of worm burrows (Figures 16 & 18) were discovered; this horizon also marks a change 38 in fossil preservation in the unit from silicification, which started in the Bilk Creek Limestone, to phosphatization in the Quinn River Formation. The next fossil occurrence appears in QR-94, with the appearance of the brachiopod Lingula (figure 18) and the bivalve Claraia, which I have determined to be very Early Triassic in age, based on the fact that Lingula and Claraia have been found together in other Early Triassic rocks as disaster taxa. Based on a previous study by

Sperling and Ingle (2006) and this study, the Permo-Triassic boundary has tentatively been placed at QR-92, which is just 25cm below QR-94. The boundary was placed at QR-92 based on the presence of the distinctive 13C negative excursion. Further up section, two siliceous sponges

(Figure 19) were discovered in a shale at QR-102. The last fossil discovery occurred in a siltstone at QR-112 with the discovery of five poorly preserved and unidentified ammonoids

(Otoceras?) (Figure 19), which are also presumed to be early Triassic in age since they lie 20 meters below the Early Triassic radiolarian zone assigned to the section by Sperling and Ingle

(2006).

Figure 17: Bilk Creek Formation fossils in the field. Left, the gastropod Omphalotrochus, as float within BC-41 of the Bilk Creek Limestone. Below, BCL-21, an example of one of the numerous fossiliferous sections in the Bilk Creek Limestone.

A B

C D

Figure 18: Permian-Triassic fossils from the Quinn River Formation. A: (QR-01) Late Wordian (Middle Guadalupian) rugose coral. B: (QR-80) Late Permian in age worm burrow. C: (QR-94) Early Triassic in age Lingula. D: (QR-102) Early Triassic horizontal burrow in black shale.

A B

Figure 19: Triassic fossils from the Quinn River Formation. A&B: Siliceous sponges from the lower Triassic (QR- 110). C&D:(QR-112) Lower Triassic ammonoid (Otoceras?). C is in normal light and D is in false color. 42

Chemostratigraphy

Of the 39 samples that were evaluated for C, 31 of them produced results that were then entered into a table and sorted stratigraphically (Table 1, Figures 20 and 21). The eight samples (QR-94, 96, 100, 101, 103U, 104, 105, 106, and 112) that did not produce results had carbon values that were too high for the detector (“C too high” in Table 1). The remaining samples produced C values ranging from -14.40‰ and -31.49 . Lab standards had values ranging from -24.13 to -24.37 . Two of my samples (QR-68 and QR-70) had unusually high values (-14.40 and -16.51 , respectively), suggesting possible contamination (Table 1), even though (QR-68 and QR-70) didn’t look obviously different than any of the other samples.

As such this implies that contamination may have been a result of sample perpetration. The remaining samples had values ranging from -21.57 to -31.49 , comparable to those presented in other published studies of the Permo-Triassic interval.

A distinct negative excursion occurs between QR-92, which has a value of -27.50 and

QR-97, which has a value of -31.49 (Figure 19). It must be noted that between QR-92 and

QR-97 two samples were collected (QR-94 and QR-96), but these were part of the group that did not produce results because carbon values saturated the detector. After QR-97, values lie between -31.21 and -29.90 , which results in a plateau on the stratigraphic plot (Figure 20).

The study done by Sperling and Ingle (2006) showed more than one excursion throughout the

Quinn River Formation before values settled down into a more stable signature in the Middle

Triassic portion of the Quinn River Formation. My lack of excursions this low in the section may be an artifact of omitting the six samples that had carbon too high for the detector.

It is useful to compare the carbon isotope signature of the Quinn River Formation to that of the two other deep marine sites (Dongpon (South China; Zhang et al., 2006), the Maitai Group 43

(New Zealand; Krull et al., 2000)) and the one shallow marine site (Meishan section (China;

Zhang et al., 2006)) (Figure 22). The typical observed carbon isotopic values range from

-21.78‰ to -38.20 throughout all sections. The sections that are most similar to each other in terms of carbon isotopic values are, on one hand, the Dongpon and Meishan sections, which include both shallow and deep water deposits and, on the other hand, the Quinn River and the

Maitai Group, which are both deep water deposits. The fact that the deeper water Dongpon

Group from China does not plot up with either New Zealand or Nevada is suggesting that water depth is not controlling carbon isotope values, and that carbon isotope values may be more controlled by latitude, with more positive values at lower latitudes (Krull et al., 2000). The only observed difference between the values in the Quinn River Formation and the Maitai Group is that the Permo-Triassic excursion at Maitai has a 13C minima value of -38.20 while the

Quinn River 13C minima is at -31.49 . Large negative excursions with values like the one in the Maitai group of New Zealand have also been observed in other Permo-Triassic sections around the world, such as the section in southern Israel, and have been construed to indicate proximity to the release of clathrate deposits (Krull et al., 2000 and Sandler et al., 2006).

Table 1: Organic Carbon Isotopic Values for the Quinn River Formation. “C too large” indicates samples containing too much carbon to analyze. Distance is an indication of stratigraphic distances between samples. The analytical uncertainty per sample for C is 0.1‰

Distance Notes Unit C (PDB) (cm) QR-112 C too large 176.6 Detector Saturated QR-109 -30.02 147.8 QR-106 C too large 35.2 Detector Saturated QR-105 -30.21 101.6 QR-104 C too large 0 Detector Saturated QR-103U C too large 107.4 Detector Saturated QR-103L -29.90 99.7 QR-102 -30.19 66.3 QR-101 C too large 43.8 Detector Saturated QR-100 C too large 40.5 Detector Saturated QR-98 -31.17 44.4 QR-97 -31.49 20.3 QR-96 C too large 139.7 Detector Saturated QR-94 C too large 7.91 Detector Saturated QR-92 -27.50 94.9 QR-84 -23.12 3.41 QR-82 -25.94 10.41 QR-80 -25.88 4.11 QR-78 -25.24 22.1 QR-76 -25.48 9.43 QR-74 -23.76 9.43 QR-72 -25.44 14.6 QR-70 -16.51 2.5 possible contamination QR-69 -25.94 3.1 QR-68 -14.40 2.5 possible contamination QR-67 -22.93 2.5 QR-66 -21.57 18.9 QR-64 -24.19 32.3 QR-63 -26.12 5 QR-62 -23.15 5.7 QR-60 -23.08 41.8 QR-58 -27.33 46.9 QR-56 -27.43 463.64 QR-37 -26.00 74.68 QR-26 -26.44 74.6 QR-18 -27.54 19 QR-16 -27.20 56.33 QR-08 -24.52 98.23 QR-04 -24.44 0

Figure 20: Stratigraphy and chemos tratigraphy of the Quinn River Formation. Red arrow marks the likely location of the P/TR boundary. The analytical uncertainty per sample for C is 0.1 , while the vertical uncertainty for each sample is less than 1cm.

Corg (‰) 46

Figure 21: Enlarged section of the stratigraphy and chemostratigraphy of the Quinn River Formation surrounding the P/TR boundary. Red arrow marks the likely location of the P/TR boundary. The analytical uncertainty per sample for C is 0.1 while the vertical uncertainty for each sample is less than 1cm.

Corg (‰)

C A B

Figure 22: Chemostratigraphy of other Permo-Triassic boundary sections. Sections (A) Dongpon (South China; Zhang et al., 2006), and (C) Maitai Group (New Zealand; Krull et al., 2000) represents deeper-water sections and (B) Meishan section (China; Zhang et al., 2006) represents shallow marine site. 48

Chapter V: Paleoecological Analysis

Analyses done to determine changes in the paleocommunity structure and biogeographical placement of the fauna from the Bilk Creek Mountains of northwestern Nevada included data from the Lower Permian Bilk Creek Limestone through the Middle Triassic Quinn

River Formation.

Bilk Creek Limestone (Pbc)

In the Lower Permian Bilk Creek Limestone, five different bedding planes in the uppermost part of the section were used to determine the palecommunity structure (Table 2). A total of 1031 individuals of 29 different genera from five different phyla were identified from the five different sampling locations, as well as crinoid columnals (Table 2). Out of all of the specimens identified, brachiopods were the most abundant of the phyla. The brachiopod genus

Stenoscisma was the most abundant, with a total of 245 individuals identified in two of the five sampling sections. The brachiopod Chonetes was the next most abundant, with a total of 227 identified in one of the five sampling sections.

In total, there were three data sets produced to analysis the Bilk Creek Limestone. The first data set was a general abundance data set for all collected sections (Table 2; Figures 23-26) within the Bilk Creek Limestone, for the purpose of performing diversity measures for each sampling site. The next data set created was a presence/absence data set for the purpose of determining what bedding planes grouped together based on their faunal data. The final data set was also a presence/absence data set, but only contains the presence/absence data of brachiopods from the Bilk Creek Limestone. This data was then combined with the presence/absence data of brachiopods from other Lower Permian sections along what was the western and northwestern 49 margin of Pangea (Belasky et al., 2002) (Appendix D) to determine paleobiogeographical relationships between the terranes along western Pangea.

When evaluating diversity of the Bilk Creek Limestone, and to make sure that I sampled thoroughly enough through the section, rarefaction was run on all counts of all individuals in the

Bilk Creek Limestone (Figure 27), and as such rarefaction showed that the Bilk Creek had been sampled thoroughly enough to calculate diversity indices. The BCL-Scree and BCL-15 bedding planes had the most species, 17 and 15, respectively (Table 3). These are the two stratigraphically highest samples (Figure 14). The lowest number of species occurred in BCL-37, with only one species present. The highest Margalef index occurred in the BCL-Scree and BCL-

15, while the lowest occurred in BC-37. The highest Fisher occurs in BCL-15, while the lowest occurs in BCL-37; comparably, the highest dominance occurs in BCL-37, while the lowest occurs in BCL-15. The highest Shannon H' also occur in BCL-15, while the lowest occurs in BCL-37. All of these low values for BCL-37 are an artifact of the fact that BCL-37 only contains one species. After evaluating all the indices, the most diverse section is BCL-15, whereas BCL-16 would be least diverse (excluding BCL-37), although its diversity is very similar to that of BCL-26.

Similarity measures were used to determine which bedding planes grouped together based on their faunal makeup, which indicates which bedding planes had communities that were similar to each other, and thus may have had similar paleoenvironmental conditions. Bedding planes that shared similar faunal assemblages and that scored high in all four similarity indices

(Jaccard, Dice, Simpson’s, Raup and Crick) (Table 4) were BCL-15, BCL-16, and BCL-26, thus indicating that they have a similar faunal assemblage between them. Thus, on the Q mode cluster diagram, they plot close together (Figure 28). It should also be noted that BCL-16 and BCL-26 50 plot closer together than BCL-15. Bedding planes that scored lower in all five similarity measures are the BCL-Scree and BCL-37; as such, they plot separately from the other three sections on the Q-mode cluster diagram (Figure 28). This difference in similarities can be attributed to both the number of species in each bedding plane and which species they have in common. For example, BC-37 only contains one species that is not shared with any of the other bedding planes, thus it would plot by itself on a Q-mode cluster (Figure 28). The BC-Scree bedding plane has only 9 species in common with the other bedding planes. Since changes within the paleocommunity structure appear close to each other stratigraphically, and similarities are viewed far apart. The data suggest that either those communities were being influenced by environmental changes during the time of deposition, by preservational variations, or ecologic patchiness over short stratigraphic intervals are affecting the samples. Due to the short stratigraphic distance and lack of preservational variations (as all fossils are silicified) over such a short distance, preservational variation can be ruled out as a reason why there is such an apparent change in community structure. Ecologic patchiness can be ruled out because of the number of new taxa (numbering six in total) that change in that short stratigraphic distance.

These taxa are not recovered at any point below this level, suggesting they are true new arrivals.

To evaluate the biogeographical relationship of the Bilk Creek Mountains of the Black

Rock Terrane to that of other known early Permian rocks that were deposited along the western and northwestern margin of Pangea, the same four similarity measures that were used to compare bedding planes within the Bilk Creek Limestone were used to compare the Bilk Creek Mountains with that of the other 11 localities (Wrangellia, Eastern Klamath, Quesnellia Harper Ranch,

Northern Urals, Spitsbergen, Canadian Arctic, Yukon-Canadian Rockies, Central Cordillera,

West Texas, South America, and Maping LS China) (Table 5). When using the Dice measure of 51 similarity, the Bilk Creek Limestone is most closely related to the Quesnellia Harper Ranch

Terrane, with the next closest relationship being with the Eastern Klamath Terrane. The Jaccard indices show that the Bilk Creek is most closely related to the Quesnellia Harper Ranch,

Spitsbergen, and the Canadian Arctic. The Quesnellia Harper Ranch Terrane has the highest

Simpson value associated with the Bilk Creek, but since this number is solely based on the number of species present, the Bilk Creek still plots by itself (Figure 29). According to the Raup-

Crick measure, the Quesnellia Harper Ranch, Spitsbergen and Eastern Klamath have the highest correlation with the Bilk Creek, ranging between 0.84-0.97; the only reason that they don’t plot directly with the Bilk Creek is because they share more of a direct correlation with each other

(Table 5, Figure 29).

Following the evaluation of all the similarity indices and the clusters that are based on them, it can be determined that the Bilk Creek Limestone has ties with both the Quesnellia

Harper Ranch and Eastern Klamath Terranes, with the Raup-Crick indices showing the closest relationship of all the metrics (Figures 29-30).

While it must be noted that some compositional overlap exists between the Bilk Creek

Mountains of the Black Rock Terrane and the Eastern Klamath and Quesnellia Harper Ranch

Terranes, the brachiopod faunas of the Bilk Creek are clearly distinct from both the Boreal and

Tethyan realms of Pangea. The brachiopods Spiriferella, Neospirifer, Stenoscisma, Muirwoodia transversa, Neophricodothyris sp., and Derbyia, which are typical of Boreal settings, are found in units BC-15 and BC-Scree, while the more mid-latitude to Tethyan-derived brachiopods such as Crurithyris, Dielasma, Squamularia sp, and Rhynchopora (Stehli and Grant, 1971) are found in units BC-16 and BC-26. The transition between Boreal and mid-latitude communities occurs between BC-16 and BC-Scree, with BC-15 representing a unique mixture of the two different 52 realms. This finding suggests that mid-latitude oceanic / arc communities were not merely an intermediate between their high and low latitude counterparts. Unique arc communities may be an artifact of more locally controlled oceanic conditions, such as sea level, temperature, and nutrient changes.

Permian Volcaniclastic Unit (Pvs)

Although no paleoecological analysis of the Permian Volcaniclastic Unit was done as part of this study, it is important to note that brachiopods were discovered in the unit during this study. All previous studies of these mountains had missed the presence of fossils in this unit.

Quinn River Formation (PTRqr)

Although intense sampling for fossils occurred throughout the Quinn River Formation, paleontological data were not nearly as abundant when compared to what was observed in the

Bilk Creek Limestone section of this study site (Table 6). The five previous studies have recovered only small quantities of benthic macrofossils from the Quinn River Formation; previously recovered fossils include Wordian age brachiopods Ctenalosia and Stenocisma

(Kenter and Wardlaw, 1981), the sponge Haplistion aeluroglossa (Rigby and Hanger, 1999), and a late Spathian to early Anisian ammonoid (Jones, 1990). This study has revealed the presence of additional taxa, including both articulate and inarticulate brachiopods, bryozoans, crinoids, bivalves, sponges, and ammonoids.

All fossil data for the Quinn River Formation were entered into two data sets, which record presence/absence data and abundance data. The abundance data were used to compare diversity measures of the Quinn River Formation with that of diversity measures of the Bilk

Creek Limestone (Table 3); due to the generally unfossiliferous nature of the Quinn River 53

Formation, it is impossible to compare diversity throughout the section. Only a total of eight taxa were used when evaluating diversity, since the total abundances of the recovered fossils from previous studies are unknown. For comparison, the Bilk Creek Limestone data from all five sampled units were pooled.

The total number of individuals collected in this section is only 15, when compared to the

Bilk Creek Limestone, which has 1183. As for the diversity indices, such as the Shannon H’ and

Margalef M, the Bilk Creek is unsurprisingly higher than the Quinn River (Table 3). Again, this may mainly have to do with the fact that the Quinn River has fewer well-preserved fossils in it than the Bilk Creek.

Table 2: Abundance Data for the Bilk Creek Limestone. Units Scree 15 16 26 37 Total Phylum Brachiopoda Spiriferella 35 21 16 10 0 82 Neospirifer 0 17 7 6 0 30 Punctospirifer sp. 4 2 0 0 0 6 Rostranteris sulcatum 0 6 0 0 0 6 Rhynchopora magna 0 5 15 0 0 20 Stenoscisma 188 57 0 0 0 245 Scacchinella 0 4 0 0 0 4 Schuchertella sp. 2 0 0 0 0 2 Wellerella multiplicata 0 16 2 2 0 20 Crurithyris sp. 0 33 60 8 0 101 Derbyia sp. 0 10 0 0 0 10 Muirwoodia transversa 0 14 0 0 0 14 Squamularia sp. 0 0 0 1 0 1 Rostranteris merriami 0 0 10 0 0 10 Neophricodothyris sp. 86 0 0 0 0 86 Dictyoclostid productid 6 0 0 1 0 7 Chonetes sp. 0 0 0 0 227 227 Lissochonetes sp. 6 0 0 0 0 6 Acosarina sp. 26 0 0 0 0 26 Dielasma truncatum 0 0 2 0 0 2 Dielasma brevicostatum 0 0 26 0 0 26 Dielasma sp. 3 0 0 0 0 3

Total Brachiopoda 356 185 138 28 227 934

Phylum Bryozoa Ramose bryozoan 18 0 0 4 0 22 Fenestellid bryozoan 3 0 0 1 0 4

Phylum Mollusca Pernuispira sp. 35 18 0 0 0 53 Acaqthopectea sp. 6 0 0 0 0 6

Phylum Cnidaria Ladochonus sp. 2 1 0 0 0 3

Phylum Foraminifera Foraminifera 3 6 0 0 0 9

Total 423 210 138 33 227 1031

Phylum Echinodermata Crinoid Columnals 89 25 19 17 0 150

Total (all fossils) 512 210 157 50 227 1181

Figure 23: Stratigraphic breakdown of phyla for the Bilk Creek Limestone.

Phylum Breakdown, Unit 37

Phylum Brachiopoda

100%

Phylum Breakdown, Unit 26

34%

Phylum Brachiopoda Phylum Echinodermata Phylum Bryozoa 56%

10%

Figure 23, continued.

Phylum Breakdown, Unit 16

88%

Phylum Brachiopoda Phylum Echinodermata

12%

Phylum Breakdown, Unit 15

6, 3% 25, 11% 1, 0% 18, 8% Phylum Brachiopoda Phylum Mollusca Phylum Cnidaria Phylum Echinodermata Foraminifera

185, 78%

Figure 23, continued.

Phylum Breakdown, Scree

3, 1% 89, 17%

2, 0% Phylum Brachiopoda 41, 8% Phylum Bryozoa Phylum Mollusca Phylum Cnidaria Phylum Echinodermata 21, 4% Phylum Foraminifera 356, 70%

Figure 24: Taxonomic breakdown of Brachiopoda taxa for the Bilk Creek Limestone.

Brachiopoda Breakdown, Unit 37

Chonetes

227, 100% 58

Figure 24, continued.

Brachiopoda Breakdown, Unit 26

2, 7% 1, 4% 1, 4%

8, 29% Squamularia dictyoclostid productid Spiriferella Neospirifer 10, 35% Crurithyris Wellerella

6, 21%

Brachiopoda Breakdown, Unit 16

2, 1% 10, 7% 26, 19% 2, 1%

16, 12% Spiriferella Neospirifer Stenoscisma Crurithyris 7, 5% Dielasma brevicostatum Dielasma truncatum 15, 11% Rostrantteris merriami Wellerella 60, 44%

Figure 24: continued

Brachiopoda Breakdown Unit 15

Spiriferella 10, 5% 4, 2% 21, 11% Punctospirifer sp. 14, 8% 2, 1% Neospirifer 17, 9% Stenoscisma 16, 9% Cruithyris sp. Rostranteris sulcatum Rhynchopora magna Wellerella multiplicata 5, 3% 6, 3% Muirwoodia transversa Derbyia Scacchinella 33, 18% 57, 31%

Brachiopoda Breakdown, Scree

2% 1%1% 2% 7% Stenoscisma sp. Spiriferella sp. Punctospirifer sp. 24% Neophricodothyris sp. Acosarina sp. Lissochonetes sp. 52% Schuchertella sp. Dielasma sp. 1% dictyoclostid productid sp. 10%

Mollusca Breakdown, Scree

15%

Pernuispira sp Acaqthopectea

85%

Figure 25: Taxonomic breakdown of Mollusca for the Bilk Creek Limestone.

Bryozoa Breakdown, Unit 26

20%

ramose bryozoan fenestellid bryozoan

80%

Figure 26: Breakdown of Bryozoa colony type for the Bilk Creek Limestone. 61

Bryozoa Breakdown, Scree

14%

ramose bryozoan fenestellid bryozoan

86%

Figure 26, continued.

Table 3: Diversity Indices, for the Bilk Creek Limestone and Quinn River Formation. 37 26 16 15 Scree BC(Total) QRF(Total) Taxa_S 1 9 9 15 17 30 8 Individuals 227 50 157 235 514 1181 15 Shannon_H 0 1.80 1.80 2.34 1.95 2.51 1.80 Margalef 0 2.04 1.58 2.56 2.56 4.09 2.58 Fisher_alpha 0.134 3.20 2.07 3.57 3.37 5.5 6.96

Table 4: Similarity Indices for Units in the Bilk Creek Limestone. For all indices, higher values mean more similar faunas. Dice Scree 15 16 26 37 Scree 1 0.43 0.15 0.38 0 15 0.43 1 0.5 0.416 0 16 0.15 0.5 1 0.55 0 26 0.38 0.41 0.55 1 0 37 0 0 0 0 1

Jaccard Scree 15 16 26 37 Scree 1 0.28 0.08 0.23 0 15 0.28 1 0.33 0.26 0 16 0.08 0.33 1 0.38 0 26 0.23 0.26 0.38 1 0 37 0 0 0 0 1

Simpsons Scree 15 16 26 37 Scree 1 0.28 0.08 0.23 0 15 0.28 1 0.33 0.26 0 16 0.08 0.33 1 0.38 0 26 0.23 0.26 0.38 1 0 37 0 0 0 0 1

Raup- Crick Scree 15 16 26 37 Scree 1 0.06 0 0.26 0.18 15 0.06 1 0.71 0.44 0.20 16 0 0.71 1 0.91 0.31 26 0.26 0.44 0.91 1 0.31 37 0.18 0.20 0.31 0.31 1

Figure 27: Pooled rarefaction curve for the Bilk Creek Limestone.

Figure 28: Q-mode cluster diagram based on Raup-Crick similarities for Bilk Creek Formation samples. Correlation = .938. Numbers at nodes represent percent likelihood of branching. 65

Table 5: Similarity indices for the Bilk Creek and other Lower Permian locations. For all indices, higher values mean more similar faunas. Wrangellia, W; Eastern Klamath, EK; Quesnellia Harper Ranch, QHR; Northern Urals, NU; Spitsbergen, S; Canadian Arctic, CA;Yukon- Canadian Rockies, YCR; Central Cordillera, CC; West Texas, WT; South America, SA; Maping LS, China, MC; Bilk Creek, Nevada, BC Dice W EK QHR NU S CA YCR CC WT SA MC BC W 1 0.390 0.324 0.477 0.368 0.505 0.467 0.482 0.331 0.253 0.366 0.306 EK 0.390 1 0.200 0.321 0.339 0.413 0.217 0.333 0.323 0.235 0.431 0.316 QHR 0.323 0.200 1 0.269 0.356 0.327 0.308 0.171 0.118 0.108 0.275 0.326 NU 0.477 0.321 0.269 1 0.326 0.444 0.538 0.342 0.270 0.282 0.478 0.238 S 0.367 0.339 0.356 0.326 1 0.412 0.351 0.337 0.288 0.250 0.343 0.355 CA 0.505 0.413 0.327 0.444 0.412 1 0.455 0.387 0.278 0.300 0.351 0.333 YCR 0.466 0.217 0.308 0.538 0.351 0.455 1 0.328 0.307 0.292 0.252 0.232 CC 0.482 0.333 0.171 0.342 0.337 0.387 0.328 1 0.481 0.469 0.295 0.322 WT 0.330 0.323 0.118 0.270 0.288 0.278 0.307 0.481 1 0.354 0.255 0.255 SA 0.253 0.235 0.108 0.282 0.250 0.300 0.292 0.469 0.354 1 0.194 0.185 MC 0.365 0.431 0.275 0.478 0.343 0.351 0.252 0.295 0.255 0.194 1 0.294 BC 0.305 0.316 0.326 0.238 0.355 0.333 0.232 0.322 0.255 0.185 0.294 1

Jaccard W EK QHR NU S CA YCR CC WT SA MC BC W 1 0.242 0.193 0.313 0.225 0.338 0.304 0.318 0.198 0.145 0.224 0.181 EK 0.242 1 0.111 0.191 0.204 0.260 0.122 0.200 0.193 0.133 0.275 0.188 QHR 0.193 0.111 1 0.155 0.216 0.195 0.182 0.094 0.063 0.057 0.159 0.194 NU 0.313 0.191 0.155 1 0.194 0.286 0.368 0.207 0.156 0.164 0.314 0.135 S 0.225 0.204 0.216 0.194 1 0.259 0.213 0.203 0.169 0.143 0.207 0.216 CA 0.338 0.260 0.195 0.286 0.259 1 0.295 0.240 0.161 0.176 0.213 0.200 YCR 0.304 0.122 0.182 0.368 0.213 0.295 1 0.196 0.181 0.171 0.144 0.131 CC 0.318 0.200 0.094 0.207 0.203 0.240 0.196 1 0.316 0.306 0.173 0.192 WT 0.198 0.193 0.063 0.156 0.169 0.161 0.181 0.316 1 0.215 0.146 0.146 SA 0.145 0.133 0.057 0.164 0.143 0.176 0.171 0.306 0.215 1 0.107 0.102 MC 0.224 0.275 0.159 0.314 0.207 0.213 0.144 0.173 0.146 0.107 1 0.172 BC 0.181 0.188 0.194 0.135 0.216 0.200 0.131 0.192 0.146 0.102 0.172 1 66

Table 5, continued; Similarity indices for the Bilk Creek and other Lower Permian locations. Wrangellia, W; Eastern Klamath, EK; Quesnellia Harper Ranch, QHR; Northern Urals, NU; Spitsbergen, S; Canadian Arctic, CA;Yukon- Canadian Rockies, YCR; Central Cordillera, CC; West Texas, WT; South America, SA; Maping LS, China, MC; Bilk Creek, Nevada, BC

Simpson W EK QHR NU S CA YCR CC WT SA MC BC W 1 0.593 0.846 0.481 0.500 0.639 0.509 0.491 0.382 0.417 0.447 0.433 EK 0.593 1 0.308 0.481 0.370 0.481 0.370 0.519 0.593 0.250 0.519 0.333 QHR 0.846 0.308 1 0.692 0.615 0.615 0.923 0.462 0.385 0.154 0.538 0.538 NU 0.481 0.481 0.692 1 0.438 0.556 0.593 0.352 0.315 0.458 0.579 0.333 S 0.500 0.370 0.615 0.438 1 0.438 0.531 0.469 0.469 0.292 0.375 0.367 CA 0.639 0.481 0.615 0.556 0.438 1 0.639 0.500 0.417 0.375 0.361 0.367 YCR 0.509 0.370 0.923 0.593 0.531 0.639 1 0.351 0.323 0.542 0.342 0.367 CC 0.491 0.519 0.462 0.352 0.469 0.500 0.351 1 0.544 0.792 0.368 0.467 WT 0.382 0.593 0.385 0.315 0.469 0.417 0.323 0.544 1 0.708 0.368 0.433 SA 0.417 0.250 0.154 0.458 0.292 0.375 0.542 0.792 0.708 1 0.250 0.208 MC 0.447 0.519 0.538 0.579 0.375 0.361 0.342 0.368 0.368 0.250 1 0.333 BC 0.433 0.333 0.538 0.333 0.367 0.367 0.367 0.467 0.433 0.208 0.333 1

Raup-Crick W EK QHR NU S CA YCR CC WT SA MC BC W 1 0.950 1 0.885 0.820 1 0.685 0.878 0.003 0.370 0.625 0.538 EK 0.950 1 0.760 0.755 0.940 0.973 0.128 0.813 0.703 0.608 1 0.843 QHR 1 0.760 1 0.980 0.998 0.988 1 0.498 0.090 0.345 0.948 0.970 NU 0.885 0.755 0.980 1 0.555 0.973 0.983 0.083 0 0.630 0.985 0.135 S 0.820 0.940 0.998 0.555 1 0.963 0.673 0.623 0.175 0.635 0.850 0.903 CA 1 0.973 0.988 0.973 0.963 1 0.983 0.790 0.048 0.793 0.843 0.835 YCR 0.685 0.128 1 0.983 0.673 0.983 1 0.015 0 0.688 0.008 0.043 CC 0.878 0.813 0.498 0.083 0.623 0.790 0.015 1 0.723 1 0.190 0.585 WT 0.003 0.703 0.090 0 0.175 0.048 0 0.723 1 0.963 0.008 0.098 SA 0.370 0.608 0.345 0.630 0.635 0.793 0.688 1 0.963 1 0.243 0.348 MC 0.625 1 0.948 0.985 0.850 0.843 0.008 0.190 0.008 0.243 1 0.638 BC 0.538 0.843 0.970 0.135 0.903 0.835 0.043 0.585 0.098 0.348 0.638 1 67

Figure 29: Cluster diagram of early Permian terranes based on the Simpson index of brachiopod faunas. Numbers at nodes represent percent of likelihood of branching. See Table 5 for terrane abbreviations.

Figure 30: Cluster diagram of early Permian terranes based on the Raup-Crick index of brachiopod faunas. Numbers at nodes represent percent likelihood of branching. See Table 5 for terrane abbreviations.

Table 6: Abundance Data for the Quinn River Formation.

Phylum Brachiopoda Lingula 2 unidentified 2

Phylum Bryozoa ramose bryozoans 1 fenestellid bryozoans 1

Phylum Cnidaria Rugose 1

Phylum Mollusca Claraia 1 Ammonoids 6

Phylum Porifera unidentified 2 Total 16

Haplistion aeluroglossa 220

Phylum Echinodermata Crinoid Columnals 10

Chapter VI: Discussion

Brachiopods and the Age of the Bilk Creek Limestone

Since its first description, the Bilk Creek Limestone has generally been characterized as just Early Permian in age. Kenter and Wardlaw (1981) noted that the uppermost part of the Bilk

Creek Limestone may be middle Permian in age based on brachiopod species collected, but more sampling was need to determine if this was true. As this study progressed and the brachiopods collected were identified, it became apparent that my sampled portion was middle Permian in age, based on the presence of certain types of brachiopods such as Spiriferella, Neospirifer,

Stenoscisma, Crurithyris sp, Muirwoodia transversa, and Neophricodothyris sp., which are diagnostic as middle Permian brachiopods in other areas of the world such as Japan (Tazawa,

2002), the Canadian Arctic (Stehli and Grant, 1971), and Texas (Cooper and

Grant,1972,1974,1975 and 1976). As a result, the uppermost portions of the Bilk Creek

Limestone are almost definitely middle Permian in age. Whether all of the Bilk Creek Limestone is one continuous section from the Early Permian to Middle Permian has not been determined by this study, and future studies should focus on whether it is a continuous section or not.

The Bilk Creek Limestone-Permian Volcaniclastic Unit and the PCE

While the Bilk Creek Limestone and the Permian Volcaniclastic Unit represent in general two distinctive lithologies (limestone and bedded chert sequences), these lithologies hold the possibility of hiding a distinctive paleoceanographic and paleoclimate signal within them, which was present and ongoing along the western/northwestern margin of Pangea from the end of the

Early Permian up through the end of the Middle Permian. This paleoceanographic and 71 paleoclimate signature has been dubbed the Permian Chert Event (PCE) (Beauchamp and Baud,

2001).

The Permian Chert Event (PCE) was a 30-million year interval of biogenic chert accumulation along the northwestern margin of Pangea. The beginning of the PCE occurred at the Sakmarian-Artinskian boundary (Figures 31-32), in what is now the Canadian Arctic, where it coincides with a maximum flooding event (Beauchamp and Baud, 2001). The PCE continues along the northwestern margin of Pangaea through the Middle Permian until the earliest

Lopingian (Late Permian), when biogenic chert factories suddenly shut down (Figures 33-34).

The formation of large accumulations of biogenic chert around the planet is not seen again until the end of the early Triassic, an 8-10 million year gap (Beauchamp and Baud, 2001).

The commencement and expansion of the PCE from the Sakmarian to the early

Lopingian led to a shift to more cool water carbonates in the areas that are in proximity to biogenic chert accumulation. This shift to cool water carbonates reaches its utmost extent by the conclusion of the Guadalupian. This extent of cold water and impoverished carbonates is seen as far south as the Phosphoria basin in the western United States (Beauchamp and Baud, 2001).

When evaluating the Bilk Creek Limestone and the Permian Volcaniclastic Unit for evidence of the presence of the PCE, one must note that the Bilk Creek Limestone and the

Permian Volcaniclastic Unit contain a unique faunal transition and sedimentological transition.

When looking at the different sampled bedding planes of the Bilk Creek Limestone, two different faunal signatures become apparent almost immediately. These two groups are made of the following units, group 1 (BCL-26 and BCL-16) and group 2 (BCL-15 and BCL-Scree). The transition and separation of these groups are marked by the appearance and the abundance of

Boreal brachiopods such as Spiriferella, Neospirifer, Stenoscisma, Muirwoodia transversa, 72

Neophricodothyris sp., and Derbyia (Stehli and Grant, 1971) as seen in group 2, while the more mid-latitude to Tethyan-derived brachiopods such as Crurithyris, Dielasma, Squamularia sp, and

Rhynchopora (Stehli and Grant, 1971) are confined to group 1. This shift in fauna occurs relatively abruptly, with bedding plane BCL-16 containing a Tethyan-type fauna and the immediately overlying BCL-15 containing a mixed fauna. This transition to a Boreal-derived fauna may mark a significant shift in oceanic currents, bringing cooler water from the pole to the mid-latitudes. As such, this faunal change may mark the onset of the PCE in this region during the middle Permian.

Interestingly, the transition to a Boreal fauna takes place first, before any significant sedimentological change such as the deposition of large packages of bedded chert. The first appearance of bedded chert occurs at BCL-08, which marks a 9-meter bedded chert package, and thus may signify the presence of the PCE in the Bilk Creek Mountains before being temporarily relaxed by a possible shift in currents, until its reappearance at the Bilk Creek Limestone-

Permian Volcaniclastic boundary (BC-01/ PVS-209) just under 8 meters later. From the

BCL/PVS boundary onward, the PVS is identified by the presence of large quantities of bedded chert.

Even though the transition to a Boreal faunal signature is limited to a few select horizons in the Bilk Creek Limestone, both the faunal and sedimentological signatures show clear distinct changes that have been observed at other locations, such as the Canadian Arctic during the onset and continuation of the PCE (Beauchamp and Baud, 2001), and as such may represent the first documented occurrence of the PCE in this region. Furthermore, the cool water Boreal signature continues up into the Quinn River Formation, QR-01 and QR-02, with the presence of the 73 brachiopod Stenocisma (Kenter and Wardlaw, 1981) and the sponge Haplistion aeluroglossa, which is known from other locations in the Canadian Arctic (Rigby and Hanger 1999).

The shift to a Boreal fauna caused by cool water currents from the north would also help explain why a faunal compositional overlap exists in the Bilk Creek between the Boreal and the

Tethyan realms of Pangea, as observed in similarity indices based on brachiopod data from the

Bilk Creek Limestone and its relationship to other Permian terranes. Cool water brachiopod larvae could be transported from the north by cool water currents, causing the observed change in faunal composition. The end of the PCE and the end-Guadalupian occur somewhere between

QR-04 and QR-63 in the red bedded cherts, before the deposition of siltstones.

Figure 31: Paleogeographic map showing ocean currents during the early Permian. Yellow arrows are upwelling, dashed blue are cool water currents, dashed red are warm water currents. (modified from Beauchamp and Baud 2001; Blakey, 2005)

Figure 32: Paleogeographic map showing ocean currents during the late early Permian. Yellow arrows are upwelling, dashed blue are cool water currents, dashed red are warm water currents, and thick blue is thermohaline circulation. Polygons are extent of chert formation (modified from Beauchamp and Baud 2001; Blakey, 2005.)

Figure 33: Paleogeographic map showing ocean currents during the end of the middle and start of the late Permian. Yellow arrows are upwelling, dashed blue are cool water currents, dashed red are warm water currents, and thick blue is thermohaline circulation. Polygons are extent of chert formation, and grey dots are seasonal ice coverage (modified from (Beauchamp and Baud 2001; Blakey, 2005).

Figure 34: Paleogeographic map showing ocean currents during the latest Permian-earliest Triassic. Yellow arrows are upwelling, dashed blue are cool water currents, dashed red are warm water currents, and thick blue is thermohaline circulation (modified from Beauchamp and Baud 2001; Blakey, 2005).

Permian Mass Extinction and the Quinn River Formation

Over the years, many processes have been put forth as the cause or as the contributor of the Permian mass extinction. These processes include the Siberian flood basalts (Renne and

Basu, 1991) and the release of clathrate deposits (Krull et al., 2000 and Sandler et al., 2006), both of which would contribute to global warming and the distinctive negative carbon isotope excursion seen at the boundary sections around the world. One by itself is not enough to produce such negative carbon values (Krull et al., 2000; Erwin, 2006 and Sandler et al., 2006). Another cause that has been put forth is the release of anoxic bottom waters by either rising sea levels

(Wignall and Twitchett, 1996 and 2002) or by stratified ocean turnover (Rampino et al., 1996).

In this scenario, anoxic seawater charged with carbon dioxide inducing hypercapnia has been put forth as the cause of the marine extinction. One option that has been put forth for inducing oceanic turnover is one or more bolide impacs. Evidence for a bolide impact includes at least one potential crater (Becker, 2002), and the presence of chondrites in Permian-Triassic sections both in China and Antarctica (Asish et al., 2003).

While the Quinn River Formation does not contain all the signatures for all the causes of the Permian mass extinction, it does contain evidence for at least two of the causes, anoxic conditions and rising ocean temperatures due to global warming. Evidence for anoxic conditions come in the form of red hematite-rich cherts of Late Permian age, which are known to indicate anoxic conditions within the water column during time of deposition (Wignall and Twitchett,

2002). Furthermore, previous geochemical work done by Sperling and Ingle (2006) showed that anoxic conditions were present in these cherts (QR-04 through QR-63) and the siltstones that top them (QR-64-QR-112). This change from cherts to shales and siltstones has been interpreted at other locations in the world as marking a rise in ocean temperatures, based on that fact that silica 79 becomes less soluble in warm ocean water (Erwin, 2006), and thus is a line of evidence for global warming, which may have been caused by the release of carbon dioxide from the Siberian flood basalts (Renne and Basu, 1991) or methane from clathrate deposits (Krull et al., 2000;

Sandler et al., 2006).

While the fossil data is limited in the Quinn River Formation, it does coincide with the negative carbon excursion and anoxic conditions found in the rock record. The relationship of

Lingula and Claraia found in anoxic conditions within the Quinn River Formation has been observed at other Permo-Triassic localities that have displayed anoxic conditions (Erwin, 2006).

Lingula and Claraia have also been found together as disaster taxa (Rodland and Bottjer, 2001) in other Early Triassic sections, such as the Dinwoody Formation and the Sinbad Formation of the western United States.

Chapter VII: Conclusions

Analysis of the Permian units of the Bilk Creek Mountains has revealed the presence of abundant fossiliferous strata existing in the Bilk Creek Limestone, in which fossils are silicified and dominated by brachiopods. While the Bilk Creek Limestone has generally been considered

Early Permian in age, the brachiopod fossils recovered include both Early and Middle Permian taxa. These fossils reveal two distinct communities within the Bilk Creek Limestone, a later one that is indicative of the Boreal realm and an earlier one that represents a more mid-latitude community with some Tethyan components. This mixture of communities is obvious when comparing the fauna of the Bilk Creek Limestone to that of other Permian terranes, since similarity indices and the clusters that are based on them show that the Bilk Creek Limestone has ties with both the Quesnellia Harper Ranch and Eastern Klamath Terranes. The shift in faunal composition may also mark the onset of the Permian Chert Event (PCE) (Beauchamp and Baud,

2001).

The overlying Permian Volcaniclastic Unit and Permian/Triassic Quinn River

Formation are significantly less fossiliferous, and preservation is both in the form of silicification

(middle to Late Permian) and phosphatization (Latest Permian). Notable is the presence of brachiopods in the Volcaniclastic Unit, previously thought to be unfossiliferous.

The C values of organic carbon in siltstones and shales from the Quinn River

Formation across the Permo-Triassic boundary are consistent with previously published data for other locations, with the exception of the exceptionally large negative excursions reported in

New Zealand and southern Israel, which have been interpreted to indicate proximity to the release of clathrate deposits (Krull et al., 2000; Sandler et al., 2006). Hence, the position of the 81

P/T boundary can be determined via 13C chemostratigraphy, in particular the pronounced negative excursion seen worldwide.

Sedimentological data have revealed no visible signs of unconformities, such as paraconformities or disconformities in the Quinn River Formation, and the presence of distinctive paleontological data, such as lower Triassic disaster taxa, coupled with the presence of the distinctive Upper Permian-Lower Triassic negative C excursions (this study; Sperling and Ingle, 2006), suggest that the Quinn River Formation represents a complete Permo-Triassic boundary.

Future studies of the Bilk Creek Mountains should focus on three things. The first goal is a more extensive paleoecological survey of the Bilk Creek Limestone for the purpose of evaluating relationships between the Bilk Creek Limestone and other Permian terranes along the western and northwestern margin of Pangea, to determine if Boreal faunas have invaded the region before or whether the shift to Boreal faunas in the upper portion of the Bilk Creek

Limestone represents the onset of the PCE. Second should be to determine the effects of the

PCE on faunal diversity and abundance in the Bilk Creek Limestone, for the purpose of evaluating whether Permian biogenic chert formation and thermohaline circulation repressed the

Permian fauna biogeographically to such an extent that this paleoceanographic shift contributed to the Guadalupian extinction. The final goal should be to obtain more benthic macrofossils from the Quinn River Formation, for the purpose of assembling a more complete community view of late Permian and early Triassic life and assessing the impact of the P-T extinction.

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Appendix A

Description of the Bilk Creek Limestone

Detailed lithologic descriptions for the Bilk Creek Limestone, which is presented in Figure 14.

The key for the section can be found in Figure 13.

BCL 41-284.4cm-massively bedded black fossiliferous micrite. Top portion of the unit has wavy fabric bedding, with thin lenses of fossils. Otherwise the only other fossil found in this unit was the gastropod Omphalotrochus sp., which is found as float.

BCL 40-121.9 cm-cover.

BCL 39-34.2cm-massively bedded biosparite with a few brachiopods scattered throughout as float.

BCL 38-78.7 cm-bedded biosparite, with brachiopods in multiple directions.

BCL 37-22.8 cm-bedded biosparite, with brachiopods stacked up on each other in one direction.

BCL 36-185.4 cm- massively bedded light grey biosparite with chert nodules; fossils are in multiple orientations and are silicified; fossils present are crinoids and brachiopods in a debris flow package.

BCL 35-50.8 cm-sandy sparite, with some forams scattered throughout.

BCL 34-40.6 cm-massively bedded sandy biosparite, with brachiopods and forams scattered throughout as float. Top 5 cm forms a crinoid packstone.

BCL 33-38.1 cm-massively bedded biosparite, with crinoids and forams as float.

BCL 32-60.9 cm-massively bedded biosparite, with forams.

BCL 31-10.1 cm-biosparite; brachiopod orientation indicates a debris package.

BCL 30-31.1 cm-massively bedded sparite with chert nodules.

BCL 29-33.2 cm-massively bedded crinoid packstone. 89

BCL 28-31.7 cm-biosparite, with brachiopod fragments scattered throughout as float.

BCL 27-73.6 cm-cover.

BCL 26-76.8 cm-dark grey biosparite with chert nodules; fossils scattered throughout as float.

BCL 25-91.4 cm-massively bedded sparite.

BCL 24-205.7 cm-bedded chert.

BCL 23-203.2 cm-massively bedded biosparite, with fossil scattered throughout.

BCL 22-81.2 cm- nodular bedded biosparite with chert nodules and fossils in the form of brachiopods and crinoids which appear to be oriented in multiple directions as a debris flow.

BCL 21-200.6 cm-massively bedded biosparite with chert nodules; fossils in the form of brachiopods, and crinoids appear to be in life position.

BCL 20-396.2 cm-cover and heavy scree.

BCL 19-40.6 cm-wavy bedded biosparite; fossils in the form of brachiopods, and forams appear to be oriented in multiple directions as a debris flow.

BCL 18-93.9 cm-wavy bedded biosparite with chert nodules; fossils in the form of brachiopods and forams appear to be oriented in multiple directions as a debris flow.

BCL 17-243.8cm-massive nodular bedding with large chert nodules; fossils in the form of brachiopods and forams appear to be oriented in multiple directions as a debris flow.

BCL 16-32.5 cm-nodular bedded biosparite, fossils appear as a disturbed neighborhood.

BCL 15-41.2 cm-sandy biosparite; fossils are made up of brachiopods, crinoids, gastropods, forams, and rugose corals. Fossil arrangement indicates that the fossils are in life position.

BCL 14-991.4 cm-cover in the form of heavy scree.

BCL 13-45.7 cm-nodular bedded biosparite; fossils are heavily silicified and appear to be in a debris flow with brachiopods oriented in multiple directions. 90

BCL 12-93.9 cm-gray biosparite; contains brachiopods and crinoids which are heavily silicified; fossil position indicates a disturbed neighborhood.

BCL 11-30.4 cm-sandy biosparite; fossils are not in life position.

BCL 10-137.1 cm-massively bedded light grey biosparite with chert nodules; fossils are in multiple orientations and are silicified; fossils present are forams and brachiopods.

BCL 09- 1071.8 cm-cover and heavy scree.

BCL 08-915.6 cm-fine grained green siltstone and chert with calcite veins.

BCL 07-246.3 cm-massively bedded sandy biosparite with chert nodules and extremely silicified fossils.

BCL 06-175.2 cm-massively bedded sandy biosparite with brachiopods, rugose corals, gastropods, and crinoids; fossils appear to be in a debris flow.

BCL 05-125. cm-massively bedded biosparite with brachiopods; brachiopod orientation indicates a disturbed neighborhood.

BCL 04-107.9 cm-massively bedded sandy biosparite with silicified brachiopods in float position.

BCL 03-143.5 cm-massively bedded sandy biosparite with silicified rugose coral in life position, with brachiopod and crinoid fragments.

BCL 02-121.9 cm-massively bedded sandy biosparite with silicified rugose coral in life position and brachiopod fragments.

BCL 01- gradational contact between the Bilk Creek Limestone and the Permian Volcaniclastic

Unit, where the Bilk Creek Limestone is a sandy biosparite and the Permian Volcaniclastic Unit is a chert.

Appendix B

Description of the Permian Volcaniclastic Unit

Detailed lithologic descriptions for the Permian Volcaniclastic Unit, which is presented in Figure

15. The key for the section can be found in Figure 13.

PVS 209-30.4 cm-bedded chert with a lens of fine grained, well rounded, well sorted sandstone.

PVS 208-106.6 cm-bedded chert.

PVS 207-7.6 cm- fine grained, well rounded, well sorted paper shale.

PVS 206-30.4 cm-bedded chert, with a lens of very sandy biosparite, that contains brachiopods, forams, and crinoids preserved as a debris flow.

PVS 205-27.9 cm-bedded chert.

PVS 204-5.0 cm-fine grained, well rounded, well sorted shale.

PVS 203-19.6 cm-fine grained, well rounded, well sorted sandstone, interbedded with biosparite that consists of brachiopods and forams.

PVS 202-665.4 cm-cover.

PVS 201-236.2 cm-interbedded cherts and siltstones.

PVS 200-0.63 cm-fine grained, well rounded, well sorted siltstone.

PVS 199-27.2 cm-bedded chert.

PVS 198-10.1 cm-fine grained, well rounded, well sorted paper shale.

PVS 197-17.7 cm-bedded chert.

PVS 196-0.63 cm-fine grained, well rounded, well sorted paper shale.

PVS 195-10.1 cm-bedded chert.

PVS 194-5.0 cm-fine grained, well rounded, well sorted paper shale.

PVS 193-22.8 cm-chert. 92

PVS 192-0.63 cm-fine grained, well rounded, well sorted green shale.

PVS 191-27.9 cm-bedded chert.

PVS 190-10.1 cm-fine grained, well rounded, well sorted siltstone.

PVS 189-6.3 cm-fine grained, well rounded, well sorted paper shale.

PVS 188-25.4 cm-bedded chert.

PVS 187-0.63 cm-fine grained, well rounded, well sorted paper shale.

PVS 186-12.7 cm-bedded chert.

PVS 185-2.5 cm-fine grained, well rounded, well sorted paper shale.

PVS 184-60.9 cm-bedded chert.

PVS 183-3.8 cm-fine grained, well rounded, well sorted siltstone.

PVS 182-71.1 cm-bedded chert.

PVS 181-1.2 cm-fine grained, well rounded, well sorted paper shale.

PVS 180-35.5 cm-bedded chert.

PVS 179-83.8 cm-bedded chert.

PVS 178-10.1 cm-fine grained, well rounded, well sorted paper shale.

PVS 177-129.5 cm-bedded chert.

PVS 176-43.1 cm-medium grained, well rounded, well sorted sandstone.

PVS 175-137.1 cm-bedded chert.

PVS 174-25.4 cm-medium grained, well rounded, well sorted sandstone.

PVS 173-347.9 cm-bedded chert.

PVS 172-104.1 cm-bedded chert.

PVS 171-.63 cm-fine grained, well rounded, well sorted paper shale.

PVS 170-53.3 cm-bedded chert. 93

PVS 169-0.63 cm-fine grained, well rounded, well sorted paper shale.

PVS 168-48.2 cm-bedded chert.

PVS 167-6.3 cm-coarse grained, well rounded, well sorted sandstone.

PVS 166-0.25 cm-fine grained, well rounded, well sorted paper shale.

PVS 165-4.4 cm-coarse grained, well rounded, well sorted sandstone.

PVS 164-0.25 cm-fine grained, well rounded, well sorted paper shale.

PVS 163-0.63 cm-coarse grained, well rounded, well sorted sandstone.

PVS 162-640.0 cm-bedded cherts.

PVS 161-845.8 cm-interbedded cherts and fine grained, well rounded, well sorted siltstones.

PVS 160-81.2 cm-fine grained, well rounded, well sorted, siltstone with a medium grained, well rounded, well sorted laminated sandstone lens.

PVS 159-426.7 cm-bedded chert.

PVS 158-243.8 cm-bedded chert.

PVS 157-66.0 cm-fine grained, well rounded, well sorted siltstone.

PVS 156-60.9 cm-heavily silicified limestone, with fossil vugs.

PVS 155-30.4 cm-coarse grained, well rounded, well sorted cross-bedded sandstone.

PVS 154-83.8 cm-bedded chert.

PVS 153-0.25 cm-fine grained, well rounded, well sorted paper shale.

PVS 152-63.5 cm-bedded chert.

PVS 151-17.7 cm-fine grained, well rounded, well sorted siltstone.

PVS 150-55.8 cm-bedded chert.

PVS 149-0.63 cm-fine grained, well rounded, well sorted, paper shale.

PVS 148-63.5 cm-bedded chert. 94

PVS 147-3.1 cm-fine grained, well rounded, well sorted, paper shale.

PVS 146-43.1 cm-bedded chert.

PVS 145-0.63 cm-fine grained, well rounded, well sorted paper shale.

PVS 144-5.0 cm-bedded chert.

PVS 143-0.63 cm-fine grained, well rounded, well sorted paper shale.

PVS 142-25.4 cm-bedded chert.

PVS 141-7.6 cm-fine grained, well rounded, well sorted paper shale.

PVS 140-182.8 cm-bedded chert.

PVS 139-312.5 cm-fine grained, well rounded, well sorted siltstone.

PVS 138-218.4 cm-bedded chert.

PVS 137-40.6 cm-fine grained, well rounded, well sorted siltstone, with medium grained, well rounded, well sorted laminated sandstone lenses.

PVS 136-53.3 cm-bedded chert.

PVS 135-29.8 cm-bedded chert.

PVS 134-30.4 cm-fine grained, well rounded, well sorted siltstone.

PVS 133-60.6 cm-bedded chert.

PVS 132-30.4 cm-medium grained, well rounded, well sorted, laminated sandstone.

PVS 131-7.62 cm-fine grained, well rounded, well sorted siltstone.

PVS 130-40.6 cm-bedded chert.

PVS 129-0.63 cm-fine grained, well rounded, well sorted paper shale.

PVS 126-182.8 cm-bedded chert.

PVS 125-45.7 cm-medium grained, well rounded, well sorted siltstone.

PVS 124-114.3 cm-bedded chert. 95

PVS 123-25.4 cm-medium grained, well rounded, well sorted, laminated sandstone.

PVS 122-10.1 cm-fine grained, well rounded, well sorted paper shale.

PVS 121-19.0 cm-bedded chert.

PVS 120-5.0 cm-fine grained, well rounded, well sorted siltstone.

PVS 119-15.2 cm-bedded chert.

PVS 118-1.27 cm-recrystallized limestone.

PVS 117-15.2 cm-bedded chert.

PVS 116-7.6 cm-fine grained, well rounded, well sorted siltstone.

PVS 115-14.05 cm-bedded chert.

PVS 114-0.63 cm-fine grained, well rounded, well sorted paper shale.

PVS 113-25.4 cm-bedded chert.

PVS 112-0.63 cm-fine grained, well rounded, well sorted paper shale.

PVS 111-48.2 cm-bedded chert.

PVS 110-0.63 cm-fine grained, well rounded, well sorted paper shale.

PVS 109-36.7 cm-bedded chert.

PVS 108-5.0 cm-fine grained, well rounded, well sorted paper shale.

PVS 107-12.7 cm-bedded chert.

PVS 106-5.0 cm-fine grained, well rounded, well sorted siltstone.

PVS 105-243.8 cm-bedded chert.

PVS 104-436.8 cm-scree.

PVS 103-274.3 cm-bedded chert.

PVS 102-182.8 cm-fine grained, well rounded, well sorted, laminated siltstone.

PVS 101-81.2 cm-bedded chert. 96

PVS 100-190.5 cm-fine grained, well rounded, well sorted siltstone, with 30.48cm of a fine grained, well rounded, well sorted, laminated sandstone.

PVS 99-165.1 cm-bedded chert.

PVS 98-50.8 cm-fine grained, well rounded, well sorted siltstone.

PVS 97-30.4 cm-bedded chert.

PVS 96-12.7 cm-fine grained, well rounded, well sorted, laminated sandstone.

PVS 95-7.6 cm-fine grained, well rounded, well sorted siltstone.

PVS 94-50.8 cm-fine grained, well rounded, well sorted siltstone.

PVS 93-20.3 cm –bedded chert.

PVS 92-48.7 cm-fine grained, well rounded, well sorted siltstone.

PVS 91-48.2 cm-bedded chert.

PVS 90-30.4 cm-bedded chert.

PVS 89-716.2 cm-scree.

PVS 88-93.9 cm-bedded chert.

PVS 87-426.7 cm-scree.

PVS 86-12.7 cm-fine grained, well rounded, well sorted, laminated sandstone.

PVS 85-88.9 cm-bedded chert.

PVS 84-231.1 cm-cover.

PVS 83-40.6 cm-fine grained, well rounded, well sorted, laminated sandstone.

PVS 82-53.3 cm-fine grained, well rounded, well sorted siltstone.

PVS 81-27.9 cm-bedded chert.

PVS 80-121.9 cm-medium grained, well rounded, well sorted siltstone.

PVS 79-7.6 cm-bedded chert. 97

PVS 78-2.5 cm- fine grained, well rounded, well sorted, laminated sandstone.

PVS 77-20.3 cm- bedded chert.

PVS 76-5.0 cm-fine grained, well rounded, well sorted siltstone.

PVS 75-20.3 cm-bedded chert.

PVS 74-5.0 cm-fine grained, well rounded, well sorted paper shale.

PVS 73-2.5 cm-chert.

PVS 72-5.5 cm-recrystallized limestone with fossil vugs.

PVS 71-26.6 cm-bedded chert.

PVS 70-0.63 cm-coarse grained, well rounded, well sorted siltstone.

PVS 69-2.5 cm-fine grained, well rounded, well sorted siltstone.

PVS 68-15.2 cm-bedded chert.

PVS 67-7.6 cm-fine grained, well rounded, well sorted siltstone.

PVS 66-15.2 cm-bedded chert.

PVS 65-2.5 cm-fine grained, well rounded, well sorted paper shale.

PVS 64-10.1 cm-bedded chert.

PVS 63-6.9 cm-fine grained, well rounded, well sorted paper shale.

PVS 62-27.9 cm-bedded chert.

PVS 61-60.9 cm-fine grained, well rounded, well sorted siltstone.

PVS 60-71.1 cm-bedded chert.

PVS 59-60.9 cm-fine grained, well rounded, well sorted siltstone.

PVS 58-81.2 cm-bedded chert.

PVS 57-25.4 cm-fine grained, well rounded, well sorted, laminated sandstone.

PVS 56-45.7 cm-bedded chert. 98

PVS 55-11.4 cm-fine grained, well rounded, well sorted paper shale.

PVS 54-139.7 cm-bedded chert.

PVS 53-8.8 cm-fine grained, well rounded, well sorted paper shale

PVS 52-20.3 cm-bedded chert.

PVS 51-12.7 cm-fine grained, well rounded, well sorted siltstone.

PVS 50-139.7 cm-medium grained, well rounded, well sorted siltstone.

PVS 49-111.7 cm-bedded chert.

PVS 48-15.2 cm-fine grained, well rounded, well sorted siltstone.

PVS 47-10.1 cm-fine grained, well rounded, well sorted paper shale.

PVS 46-132.0 cm-bedded chert.

PVS 45-6.9 cm-fine grained, well rounded, well sorted paper shale.

PVS 44-7.6 cm-bedded chert.

PVS 43-5.08 cm-fine grained, well rounded, well sorted siltstone.

PVS 42-10.1 cm-bedded chert.

PVS 41-5.08 cm-fine grained, well rounded, well sorted siltstone.

PVS 40-7.6 cm-bedded chert.

PVS 39-2.5 cm-fine grained, well rounded, well sorted siltstone.

PVS 38-6.3 cm-bedded chert.

PVS 37-0.63 cm-fine grained, well rounded, well sorted siltstone.

PVS 36-5.0 cm-bedded chert.

PVS 35-0.63 cm-fine grained, well rounded, well sorted siltstone.

PVS 34-39.9 cm-bedded chert.

PVS 33-10.1 cm-fine grained, well rounded, well sorted siltstone. 99

PVS 32-17.10 cm-bedded chert.

PVS 31-5 cm-fine grained, well rounded, well sorted siltstone.

PVS 30-8.2 cm-bedded chert.

PVS 29-7.6 cm-fine grained, well rounded, well sorted siltstone.

PVS 28-112.7 cm-bedded chert and fine grained, well rounded, well sorted siltstone.

PVS 27-20.3 cm-fine grained, well rounded, well sorted siltstone.

PVS 26-284.4 cm-bedded chert.

PVS 25-114.3 cm-fine grained, well rounded, well sorted siltstone.

PVS 24-566.4 cm-bedded chert.

PVS 23-91.4 cm-fine grained, well rounded, well sorted siltstone.

PVS 22-81.2 cm-bedded chert.

PVS 21-132.0 cm-fine grained, well rounded, well sorted siltstone.

PVS 20-304.8 cm-bedded chert.

PVS 19-457.2 cm-interbedded chert and fine grained, well rounded, well sorted laminated siltstone.

PVS 18-22.8 cm-fine grained, well rounded, well sorted laminated siltstone.

PVS 17-86.3 cm-bedded chert.

PVS 16-307.3 cm-cover.

PVS 15-119.3 cm- fine grained, well rounded, well sorted laminated siltstone.

PVS 14-447.0 cm-cover.

PVS 13-477.5 cm-bedded chert.

PVS 12-220.9 cm-bedded chert.

PVS 11-15.8 cm-bedded chert. 100

PVS 10-81.2 cm- fine grained, well rounded, well sorted laminated siltstone.

PVS 09-8.2 cm-bedded chert.

PVS 08-13.9 cm-fine grained, well rounded, well sorted, laminated sandstone.

PVS 07-99.0 cm-bedded chert.

PVS 06-25.4 cm-heavy recrystallized limestone.

PVS 05-66.0 cm-bedded chert.

PVS 04-60.9 cm-fine grained, well rounded, well sorted laminated siltstone.

PVS 03- 2250.4 cm-cover.

PVS 02-39.3 cm-fine grained, well rounded, well sorted, laminated sandstone.

PVS 01-13.9 cm- fine grained, well rounded, well sorted, cross-bedded sandstone.

101

Appendix C

Description of the Quinn River Formation

Detailed lithologic descriptions for the Quinn River Formation, which is presented in Figure 16.

The key for the section can be found in Figure 13.

QR 01-198.4 cm-massive bioclastic limestone, with crinoids and brachiopods.

QR 02-564.8 cm-massive tan dolomite that contains brachiopods, corals, bryozoans, and sponges.

QR 03-1676.4 cm-cover.

QR 04-10.1 cm-bedded chert.

QR 05-0.63 cm-fine grained, well rounded, well sorted green to light gray siltstone.

QR 06-57.1 cm-slightly weathered ash.

QR 07-30.4 cm-bedded chert.

QR 08-1.2 cm-fine grained, well rounded, well sorted paper shale.

QR 09-15.2 cm-bedded chert.

QR 10-0.63 cm- fine grained, well rounded, well sorted paper shale.

QR 11-17.7 cm-bedded chert.

QR 12-0.63 cm- fine grained, well rounded, well sorted paper shale.

QR 13-15.2 cm-bedded chert.

QR 14-7.6 cm- fine grained, well rounded, well sorted paper shale.

QR 15-16.5 cm-bedded chert.

QR 16-11.4 cm-fine grained, well rounded, well sorted, green cross-stratified siltstone.

QR 17-7.6 cm-bedded chert.

QR 18-27.9 cm-fine grained, well rounded, well sorted sandstone. 102

QR 19-7.1 cm-bedded chert.

QR 20-4.4 cm-fine grained, well rounded, well sorted, siltstone.

QR 21-8.1 cm-bedded chert.

QR 22-3.1 cm-fine grained, well rounded, well sorted paper shale.

QR 23-10.1 cm-bedded chert.

QR 24-1.2 cm-fine grained, well rounded, well sorted paper shale.

QR 25-12.7 cm-bedded chert.

QR 26-5.0 cm-fine grained, well rounded, well sorted paper shale.

QR 27-10.1 cm-bedded chert.

QR 28-5.0 cm-fine grained, well rounded, well sorted paper shale.

QR 29-17.7 cm-bedded chert.

QR 30-0.63 cm-fine grained, well rounded, well sorted paper shale.

QR 31-5.0 cm-bedded chert.

QR 32-0.25 cm-fine grained, well rounded, well sorted paper shale.

QR 33-16.5 cm-bedded chert.

QR 34-7.6 cm-bedded chert.

QR 35-2.5 cm-fine grained, well rounded, well sorted paper shale.

QR 36-5.0 cm-bedded chert.

QR 37-0.25 cm-fine grained, well rounded, well sorted paper shale.

QR 38-67.3 cm-bedded chert.

QR 39-10.1 cm-fine grained, well rounded, well sorted paper shale, with a fine grained, well rounded, well sorted sandstone lens.

QR 40-12.7 cm-bedded chert. 103

QR 41-0.63 cm-fine grained, well rounded, well sorted paper shale.

QR 42-8.8 cm-bedded chert.

QR 43-2.5 cm-fine grained, well rounded, well sorted paper shale.

QR 44-8.8 cm-bedded chert.

QR 45-0.63 cm-fine grained, well rounded, well sorted siltstone.

QR 46-5.0 cm-bedded chert.

QR 47-0.63 cm-fine grained, well rounded, well sorted paper shale.

QR 48-7.6 cm-bedded chert.

QR 49-152.4 cm-cover.

QR 50-27.8 cm-bedded chert.

QR 51-118.1 cm-cover.

QR 52-24.1 cm-bedded chert.

QR 53-1.2 cm-fine grained, well rounded, well sorted siltstone.

QR 54-10.1 cm-bedded chert.

QR 55-5.0 cm-fine grained, well rounded, well sorted paper shale.

QR 56-16.5 cm-bedded chert.

QR 57-30.4 cm-bedded chert.

QR 58-1.2 cm-fine grained, well rounded, well sorted paper shale.

QR 59-40.6 cm-ash.

QR 60-3.8 cm-fine grained, well rounded, well sorted siltstone.

QR 61-1.9 cm-ash.

QR 62-5.0 cm-fine grained, well rounded, well sorted siltstone.

QR 63-32.3 cm-bedded chert. 104

QR 64-5.0 cm-fine grained, well rounded, well sorted siltstone

QR 65-13.9 cm-extremely weathered ash.

QR 66-2.5 cm cm-fine grained, well rounded, well sorted paper shale.

QR 67-2.5 cm-fine grained, well rounded, well sorted siltstone.

QR 68-3.1 cm-fine grained, well rounded, well sorted paper shale.

QR 69-2.5 cm-fine grained, well rounded, well sorted siltstone.

QR 70-1.9 cm-fine grained, well rounded, well sorted siltstone.

QR 71-12.7 cm-bedded chert.

QR 72-0.63 cm-fine grained, well rounded, well sorted paper shale.

QR 73-8.8 cm-bedded chert.

QR 74-0.63 cm-fine grained, well rounded, well sorted paper shale.

QR 75-8.8 cm-bedded chert.

QR 76-4.4 cm-fine grained, well rounded, well sorted paper shale.

QR 77-17.7 cm-bedded chert.

QR 78-0.31 cm-fine grained, well rounded, well sorted paper shale.

QR 79-3.8 cm-extremely weathered ash.

QR 80-0.31 cm-fine grained, well rounded, well sorted paper shale.

QR 81-10.1 cm-bedded chert.

QR 82-0.31 cm-fine grained, well rounded, well sorted paper shale.

QR 83-3.1 cm- bedded chert.

QR 84-2.5 cm-fine grained, well rounded, well sorted paper shale.

QR 85-12.7 cm-bedded chert.

QR 86-12.7 cm-extremely weathered ash. 105

QR 87-39.3 cm-bedded chert.

QR 88-5.0 cm-extremely weathered ash.

QR 89-15.2 cm-bedded chert

QR 90-5.0 cm-ash

QR 91-2.5 cm-bedded chert.

QR 92-0.31 cm-fine grained, well sorted paper shale.

QR 93-7.6 cm-bedded chert.

QR 94-127 cm-fine grained, well rounded, well sorted laminated siltstone; fossils are present.

QR 95-12.7 cm-extremely weathered ash.

QR 96-20.3 cm-fine grained, well rounded, well sorted, thinly bedded siltstone.

QR 97-44.4 cm-fine grained, well rounded, well sorted, thinly bedded siltstone.

QR 98-10.1 cm-fine grained, well rounded, well sorted siltstone.

QR 99-30.4 cm-extremely weathered ash.

QR 100-43.8 cm-fine grained, well rounded, well sorted finely laminated siltstone.

QR 101-66.3 cm-fine grained, well rounded, well sorted, brown shale.

QR 102-99.7 cm-fine grained, well rounded, well sorted, black shale.

QR 103-157.4 cm-fine grained, well rounded, well sorted, laminated siltstone.

QR 104-101.6 cm-fine grained, well rounded, well sorted, finely laminated purple siltstone.

QR 105-35.2 cm-fine grained, well rounded, well sorted siltstone.

QR 106-26.3 cm-fine grained, well rounded, well sorted black shale.

QR 107-36.1 cm-fine grained, well rounded, well sorted, finely laminated purple siltstone.

QR 108-58.4 cm-fine grained, well rounded, well sorted black shale.

QR 109-10.1 cm-fine grained, well rounded, well sorted siltstone. 106

QR 110-109.7 cm-fine grained, well rounded, well sorted siltstone, with sponges.

QR 111-56.8 cm-extremely weathered ash.

QR 112-457.2cm- fine grained, well rounded, well sorted siltstone with ammonoids.

107

Appendix D

Lower Permian Brachiopod Terrane Data

The presence(1)/absence(0) data below were used to compare the Bilk Creek Limestone fauna with those of other known early Permian communities along the northwestern/western margin of

Pangea and that of some Tethyan communities. Data have been compiled from this study and a study done by Belasky et al. (2002) on Early Permian paleobiogeography.

Wrangellia, W; Eastern Klamath, EK; Quesnellia Harper Ranch, QHR Northern Urals, NU; Spitsbergen, S; Canadian Arctic, CA; Yukon- Canadian Rockies, YCR; Central Cordillera, CC; West Texas, WT South America, SA; Maping LS, China, MC; Bilk Creek, Nevada, BC

Brachiopod localities: W EK QHR NU S CA YCR CC WT SA MC BC Acosarina 0 0 0 0 0 0 0 0 1 0 0 1 Acritosia 0 0 0 0 0 0 1 0 1 0 0 0 Alispiriferella 0 0 0 0 0 0 1 0 0 0 0 0 Altiplecus 0 0 0 0 0 0 0 0 1 0 0 0 Anemonaria 1 0 0 0 0 1 1 0 0 0 0 0 Anidanthus 1 0 0 0 1 0 1 1 0 0 0 1 Antiquatonia 1 0 0 0 0 0 1 1 1 1 0 1 Arctitreta 0 0 0 0 0 1 0 0 0 0 0 0 Atelestegastus 0 0 0 0 0 0 0 0 1 0 0 0 Aulosteges 0 0 0 0 1 0 0 0 0 0 0 0 Avonia 0 0 0 1 0 0 0 0 0 0 0 0 Bathymyonaria 1 0 0 0 0 0 0 0 0 0 0 0 Bathymyonia 1 0 0 0 0 1 0 1 0 0 0 0 Beecheria 0 0 0 0 1 0 0 0 1 0 0 1 Bothrostegium 0 0 0 0 0 0 0 0 0 0 0 1 Brachythyrina 0 0 0 1 0 0 0 0 0 0 1 0 Brachythyris 0 0 0 1 0 0 1 0 0 0 0 0 Bryorhynchus 0 0 0 0 0 0 0 1 0 0 0 0 Buxtonia 0 0 0 0 0 0 0 1 0 0 0 0 Calliprotonia 1 0 0 1 1 0 1 1 1 0 1 0 Callispirina 0 0 0 1 0 0 0 0 0 0 1 0 Camarelasma 0 0 0 0 0 0 0 0 1 0 0 0 Camarophoria 0 0 0 1 0 0 0 0 0 0 0 0 Camerisma 1 1 0 1 0 1 1 0 0 0 1 0 Cancrinella 1 0 1 1 1 1 1 1 1 1 0 0 Cenorhynchia 0 0 0 0 0 0 0 1 1 0 0 0 Chaoella 1 0 0 1 1 0 0 0 0 1 1 0 Chelononia 0 0 0 0 0 0 0 0 1 0 0 0 108

Chondronia 0 0 0 0 0 0 0 0 1 0 0 0 Chonetes 0 0 0 1 0 0 0 0 0 0 1 1 Chonetina 1 0 0 0 0 0 0 0 0 0 0 0 Chonetinella 1 1 0 1 0 0 0 1 1 0 0 0 Choristites 1 0 0 1 0 0 1 0 0 0 0 0 Cleiothyridina 1 1 1 0 1 1 0 1 1 0 1 0 Composita 0 0 0 0 1 0 1 1 1 1 0 0 Compresso productus 0 0 0 0 0 0 0 0 0 0 1 0 Cooperina 0 0 0 0 0 0 0 0 1 0 0 0 Costellarina 0 0 0 0 0 0 0 1 0 0 0 0 Costispinifera 0 0 0 0 0 0 1 0 0 0 0 0 Crenispirifer 0 0 0 0 0 0 0 1 0 0 0 0 Cruricella 0 1 0 0 0 0 0 0 0 0 0 0 Crurithyris 0 0 0 0 1 1 1 1 1 1 0 1 Ctenalosia 0 0 0 0 0 0 0 0 1 0 0 0 Denticulophora 1 0 0 0 0 0 0 0 0 0 0 0 Derbyia 1 1 0 1 1 1 0 1 1 0 1 1 Derbyoides 0 0 0 0 0 0 0 0 1 0 0 0 Dictyoclostid productid 0 0 0 0 0 0 0 0 0 0 0 1 Dictyoclostus 0 0 0 1 0 0 0 0 0 0 0 0 Dielasma sp. 0 1 1 1 1 0 1 1 0 1 1 1 Dielasma brevicostatum 0 0 0 0 0 0 0 0 0 0 0 1 Dielasma truncatum 0 0 0 0 0 0 0 0 0 0 0 1 Diplanus 0 0 0 0 0 0 0 0 1 0 0 0 Domochotia 0 0 0 0 0 0 1 0 0 0 0 0 Dyoros 1 0 0 1 0 0 1 0 0 0 0 0 Echinaria 1 1 0 0 0 0 0 0 1 0 0 0 Echinauris 0 0 0 0 0 0 0 1 1 0 0 0 Echinoconchus 0 0 0 1 1 0 0 0 0 0 0 0 Echinosteges 0 0 0 0 0 0 0 0 1 0 0 0 Ella 0 0 0 1 0 0 0 0 0 0 0 0 Eliva 0 0 0 1 0 0 0 0 0 0 1 0 Elivina 0 0 0 1 0 0 0 0 0 0 1 0 Elliotella 0 0 0 0 0 0 0 1 0 0 0 0 Enteletes 0 0 0 0 0 0 0 0 1 1 0 0 Eolyttonoa 0 0 0 0 0 0 0 0 1 0 0 0 Eridmatus 0 0 0 0 0 0 0 0 1 0 0 0 Fimbriaria 1 0 0 0 0 0 0 0 0 0 0 0 Fimbrina 0 0 0 0 0 0 1 0 1 1 0 0 Geyerella 0 0 0 0 0 0 0 0 1 0 0 0 Girtyella 0 0 0 0 0 0 0 1 0 0 0 0 Globiella 0 0 0 0 0 0 1 0 0 0 0 0 Glossothyropsis 0 1 0 0 0 0 0 0 0 0 0 0 Goniarina 0 0 0 0 0 0 0 0 1 0 0 0 Gyrospirifer 0 0 0 0 0 0 0 1 1 1 0 0 Hemileurus 0 0 0 0 0 0 0 0 1 0 0 0 Heteralasma 0 0 0 0 0 0 0 1 0 0 0 0 Horrodonia 1 0 0 0 1 1 1 0 0 0 0 0 109

Hustedia 1 1 0 1 0 1 1 1 1 1 0 0 Hyposia 0 0 0 0 0 0 0 0 1 0 0 0 Hystriculina 0 0 0 0 0 0 0 0 1 1 0 0 Institina 1 0 0 0 0 0 0 0 0 0 0 0 Isogramma 0 0 0 0 0 0 0 0 1 0 0 0 Jakutoproductus 0 0 0 0 0 1 1 0 0 0 0 0 Juresania 1 0 0 1 1 0 0 1 1 0 1 0 Kiangsiella 0 0 0 0 1 0 0 0 0 0 0 0 Kochiproductus 1 1 0 1 0 1 1 1 1 0 0 0 Komiella 0 0 0 0 0 0 1 0 0 0 0 0 Kozlowskia 0 0 0 1 0 0 1 1 1 1 0 0 Krotovia 1 0 1 1 1 0 1 0 0 0 1 0 Kutorginella 0 0 0 1 0 1 1 1 1 1 0 0 Kuvelosia 0 0 0 0 0 1 0 0 0 0 0 0 Larispirifer 0 0 0 0 0 0 1 0 0 0 0 0 Leiorhynchus 0 0 0 0 0 0 0 1 0 0 0 0 Lepidocrania 0 0 0 0 0 0 0 0 1 0 0 0 Leurosina 0 0 0 0 0 0 0 1 0 0 0 0 Levicamera 0 0 0 0 1 0 0 0 0 0 0 0 Licharewia 0 0 0 0 0 0 0 0 0 0 1 0 Limbella 0 0 0 0 0 0 0 0 1 0 0 0 Linoproductus 1 1 0 1 1 1 1 1 1 1 1 0 Liosotella 1 0 1 1 0 1 1 1 0 0 1 1 Lissochonetes 1 0 1 1 0 0 1 1 1 0 0 1 Lowenstamia 0 0 0 0 0 0 0 1 1 0 0 0 Marginifera 1 1 0 1 0 0 0 0 0 0 1 0 Martinia 0 0 0 1 0 1 1 0 1 0 1 0 Martiniopsis 0 1 0 1 0 0 0 0 0 0 1 0 Meekella 0 1 0 0 1 0 0 1 1 0 1 1 Megousia 1 0 1 1 0 1 1 0 0 0 0 0 Mesolobus 0 0 0 0 1 0 0 0 0 0 0 0 Muirwoodia 1 0 0 0 0 0 0 1 0 0 0 1 Neochonetes 1 0 0 0 1 0 1 1 1 0 0 0 Neophrycodothyris 0 1 0 0 1 1 0 0 0 0 0 1 Neospirifer 1 1 1 0 1 1 1 1 1 0 1 1 Nothopindax 0 0 0 0 0 0 0 0 1 0 0 0 Notothyris 0 0 0 0 0 0 0 0 0 0 1 0 Nudauris 0 0 0 0 0 0 0 0 1 0 0 0 Odontospirifer 0 0 0 0 0 0 1 0 0 0 0 0 Ogilviecoelia 0 0 0 0 0 0 1 0 0 0 0 0 Orbicoelia 0 1 0 0 0 0 0 0 0 0 0 0 Orbiculoidea 0 0 0 0 0 0 1 0 0 0 0 0 Orthotella 0 0 0 0 0 0 0 0 1 0 0 0 Orthotetis 0 0 0 0 0 0 1 0 0 1 0 0 Orthotichia 1 1 0 1 0 1 1 1 1 0 1 0 Ovatia 0 0 0 1 0 0 0 0 0 0 0 0 Paeckelamannia 0 0 0 0 1 1 0 0 0 0 0 0 Paraspiriferina 0 0 0 0 0 0 0 0 1 0 0 1 110

Parentheletes 0 0 0 0 0 0 0 0 1 0 1 0 Peniculauris 1 0 0 0 0 0 0 1 0 0 1 0 Permophriodothyris 0 0 0 0 0 0 1 0 0 0 1 0 Phricodothyris 0 0 0 0 0 1 0 1 0 1 0 0 Plicatifera 1 0 0 0 0 0 0 0 0 0 0 0 Pontisia 0 0 0 0 0 0 0 1 1 0 0 0 Protoanidanthus 0 0 0 0 0 0 1 0 0 0 0 0 Pseudodielasma 0 0 0 0 0 0 0 1 0 0 0 0 Pseudoleptodus 0 0 0 0 0 0 0 0 1 0 0 0 Pseudomartina 1 0 0 0 0 0 0 0 0 0 0 0 Pseudosyrinx 0 0 0 0 0 1 0 0 0 0 0 0 Psilocamera 0 0 0 0 0 0 0 1 1 0 0 0 Pterospirifer 1 0 1 0 0 0 1 0 0 0 0 0 Pugnax 0 0 0 1 0 0 0 0 0 0 0 0 Punctospirifer 1 1 0 0 0 0 0 1 0 1 0 1 Purdonella 0 0 0 1 0 0 1 0 0 0 0 0 Quadrochonetes 0 0 0 0 0 1 0 0 0 0 0 0 Reticulariina 0 0 0 0 0 0 0 1 1 1 0 0 Reticulatia 1 0 0 1 0 0 1 1 1 1 0 0 Retimarginifera 0 0 0 0 0 0 0 0 0 0 1 0 Rhipidomella 1 1 0 0 0 1 0 1 1 1 1 0 Rhynoleichus 0 0 0 0 0 0 1 0 0 0 0 0 Rhynchopora 1 1 0 1 1 1 1 1 1 0 0 1 Rostranteris 0 0 0 0 0 0 0 0 0 0 0 1 Rostrantteris Merriami 0 0 0 0 0 0 0 0 0 0 0 1 Rugatia 0 0 0 1 0 0 0 1 0 1 0 0 Rugivestis 0 0 0 1 0 0 1 0 0 0 0 0 Rugosochonetes 1 0 0 0 0 0 0 0 0 0 0 0 Scacchinella 0 0 0 0 0 0 0 0 1 0 0 1 Schellweinella 0 0 0 0 1 0 0 0 0 0 0 0 Schrenkiella 0 0 0 1 0 0 1 0 0 0 0 0 Schuchertella 0 1 0 0 0 0 0 0 1 0 1 1 Septacamera 0 1 0 1 1 1 1 0 0 0 0 0 Septospirifer 1 0 0 0 0 0 0 0 0 0 0 0 Sowerbina 1 0 0 1 0 1 1 0 0 0 0 0 Sphenalosia 0 0 0 0 0 0 0 1 0 0 0 0 Sphenosteges 0 0 0 0 0 0 0 1 0 0 0 0 Spirelytha 0 0 0 0 0 0 1 0 0 0 0 0 Spiriferella 1 0 1 1 1 1 1 0 0 0 0 1 Spirifirellina 1 1 0 0 0 0 0 1 1 1 0 0 Spiriferina 0 0 0 0 1 0 0 0 0 0 0 0 Spyridiophora 0 0 0 0 0 0 0 0 1 0 0 0 Squamaria 0 0 0 0 0 0 0 1 0 0 0 0 Squamularia 1 0 0 0 0 1 0 1 0 0 0 1 Stenoscisma 1 1 1 1 1 1 1 0 1 0 1 1 Stepanoviella 1 0 0 0 0 0 0 0 0 0 0 0 Streptorhynchus 0 1 0 0 0 0 0 0 0 0 1 0 Striatifera 0 0 0 0 0 0 0 0 1 0 0 0 111

Strophalosia 1 0 0 0 0 0 0 1 0 0 0 0 Sulcataria 0 0 0 0 0 0 0 0 1 0 0 0 Teguliferina 0 1 0 0 0 0 0 0 1 0 0 0 Terebratuloidea 0 0 0 0 0 0 0 0 0 0 1 0 Terrakea 1 0 0 0 0 0 0 0 0 0 0 0 Thamnosia 1 0 0 1 0 1 1 0 0 0 0 0 Timaniella 0 0 0 0 0 0 1 0 0 0 0 0 Tiramnia 0 0 0 1 0 0 0 0 0 0 0 0 Tityrophoria 0 0 0 0 0 0 1 0 0 0 0 0 Tomiopsis 0 0 1 0 1 0 1 0 0 0 0 0 Tornquistia 0 0 0 0 0 0 1 0 0 0 0 0 Transennatia 0 0 0 0 0 0 0 0 0 0 1 0 Tropidielasma 0 0 0 0 0 0 0 0 1 0 0 0 Tubersulculus 0 0 0 1 0 0 1 0 0 0 0 0 Tumarinia 0 0 0 0 0 0 1 0 0 0 0 0 Uncinunellina 0 0 0 0 0 0 0 0 0 0 1 0 Unispirifer 1 0 0 0 0 0 0 0 0 0 0 0 Uraloproductus 0 0 0 1 0 0 1 0 0 0 0 0 Urushtenia 0 0 0 1 0 0 0 0 0 0 0 0 Waagenoconcha 1 0 0 1 1 1 1 1 1 1 1 0 Wellerella 0 0 0 1 0 1 0 1 0 1 1 1 Wilberrya 0 0 0 0 0 0 0 1 0 0 0 0 Yakovlevia 1 0 1 1 0 1 1 0 0 0 1 1 Yukonella 0 0 0 0 0 0 1 0 0 0 0 0 Yukonospirifer 0 0 0 0 0 0 1 0 0 0 0 0