Western Washington University Western CEDAR WWU Graduate School Collection WWU Graduate and Undergraduate Scholarship Spring 1972 Biostratigraphy of the Bilk Limestone (Permian), Northwestern Nevada Erich Thomas Western Washington University Follow this and additional works at: https://cedar.wwu.edu/wwuet Part of the Geology Commons Recommended Citation Thomas, Erich, "Biostratigraphy of the Bilk Limestone (Permian), Northwestern Nevada" (1972). WWU Graduate School Collection. 731. https://cedar.wwu.edu/wwuet/731 This Masters Thesis is brought to you for free and open access by the WWU Graduate and Undergraduate Scholarship at Western CEDAR. It has been accepted for inclusion in WWU Graduate School Collection by an authorized administrator of Western CEDAR. For more information, please contact [email protected]. BIOSTRATIGRAPHY OF THE BILK LIIffiSTONE (PERMIAN), NORTHWESTERN NEVADA A Thesis Presented to The Facvilty of Western Washington State College In Partial Fxilfillment of the Requirements for the Degree Master of Science ty Erich Thomas May 1972 BIOSTRATIGRAPHY OF THE BILK LB'fESTONE (PERMIAN), NORTHWESTERN NEVADA tiy Erich Thomas Accepted in Partial Completion of the Requirements for the Degree Master of Science Advisory Committee Chairman MASTER'S THESIS In presenting thisthesis in partial fulfillment of the requirements for a master's degree at Western Washington University, I grant to Western Washington University the non-exclusive royalty-free rightto archive, reproduce, distribute, and display the thesis in any and all forms, including electronic format, via any digital library mechanisms maintained by WWU. I represent and warrant this is my original work and does not infringe or violate any rights of others. 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TABLE OF CONTENTS Page Introduction ....................................................... 1 Previous Investigations .......................................... 6 Geologic Setting .... .......................................... 9 Structure...................... 13 Stratigraphy and Petrography ....................................... 21 Paleoecology ....................................................... ^9 Systematic Paleontology ........................................... 51 Genus Pseudofusulinella .................................... 51 Genus Eoparafusulina............................ 59 Genus Schvagerina............................................ 63 Genus Paraschvagerina........................................72 Genus Parafusulina............................................ 82 Conclusions........................................................ 90 References.......................................................... 97 i TABLE OF ILLUSTRATIONS Plates Plate Facing Page 1 Pseudofusulinella rotunda, P. .leffordsi. P. pusilla, Eoparafusulina bellula, Eoparafusulina sp. A ............. 98 2 Schvagerina sp. A, Schvagerina sp. B, Schvagerina sp. C, Schvagerina sp. D, Schvagerina sp. E, Paraschvagerina sp A, Paraschvagerina sp. B................. ....................... 100 3 Paraschvagerina sp. B, Paraschvagerina ampla, Para­ schvagerina sp. C.........................................102 U Paraschvagerina sp. C, Paraschvagerina decora, Para- fusulina sp. A............................................. lOU 5 Parafusulina sp. B...................................... 106 6 Parafusulina sp. C . ................. 108 Figvires Figure Facing page 1 Index map shoving location of field area in the Kings River Range.................................. 2 2 Viev of field area from State Highvay 8A.................... ^ 3 Geologic map of field area and immediate surroundings. Measured stratigraphic sections shovn vith dots ..... 10 It Brovn oxidized thrust fault zone betveen Happy Creek Group belov and Bilk Limestone above at the north end of field area.................................. 1^ 5 Fractured limestone vith vhite calcite veins and veinlets typical of field area exposures.................... l6 ii Figures Figure Facing Page 6 Calcite filled fracture zone vith slight fault displace­ ment ....................................................... l8 7 View of medium bedded limestone at south end of field area (location of Section l).............................. 22 8 Coarse calcarenite with crinoid and intraclast allochems . 2h 9 Calcilutite with fusulinid allochems....................... 26 10 Calcarenite with well rounded crinoid and intraclast allochems................................................. 28 11 Pelletiferous microsparite showing current reworking by- parallel orientation of pellets ......................... 30 12 Fossiliferous calcilutite ..... ......... ........... 32 13 Interbedded limestone and nodules and stringers of darker chert typ-ical of field area section. White material in center of photograph is due to the erosive effect of an ephemeral, stream........................................... 35 lU Chert (gray) partially replacing a fusulinid in limestone . 37 15 Mottled light gray dolomite with dark gray limestone .... UO 16 Coarse anhedral cadcite filling fractures and veinlets ... h2 17 Allochems floating in recrystallized calcite ............... 18 Fossil ghosts (light gray) showing evidence of recrystal­ lization .................................................... 19 Measxured stratigraphic sections showing occurrence of fusulinid species; datrk line represents Wolfcampian— Leonardian time boundary .............................. .. 88 20 'Stratigraphic ranges of mere common fusulinid genera (After Skinner and V/ilde, i9o5)........ ................ 93 iii Figures Figure Facing page 21 Time ranges of stratigraphic sections measured in this paper ............................................... 95 iv ■’I Introduction The Billc Limestone (new manuscript name) described in this report is a carbonate sequence located in the Bilk Creek Mountains at the south­ ernmost end of the Kings River Range (fig. 1), about 30 miles south of the town Denio in north-central Humboldt Coianty, Nevada. This study investigates the biostratigraphy and general paleoecology of about 2900 feet of limestone of early to middle Permian (middle Wolfcampian to middle Leonardian) age. The limestone is interbedded with nodular chert and is considerably altered by faulting ana fracturing with associated epigenetic dolomitization. The fossil content is varied, and in this report stress is placed on fusulinid identification and their use as age indicators. They, as well as the carbonate patrology, yield impor­ tant information for studying the paleoenvironment. The fossil content and lithology are notably distinct from any previously described carbo­ nate of similar age in other areas. Acknowledgements The writer expresses his sincere thanks to Professor Charles A. Ross for his helpful suggestions in the field, in laboratory techniques, and in the critical reading of the first draft. Drs. Ada Swineford and David A. Rahm offered helpful suggestions in reviewing the manuscript. Donald McQuarrie kindly helped as field assistant. Theresa Druzak was instrumental in helping prepare the thin sections. Linda Wilcox kindly typed the final, draft. 1 Fig. 1 Index map shoving location of field area in the Kings River Range. 2 3 Fig. 2 Viev of field area from State Highway 8a. k 5 Previous Investigations Roberts et al. (1958) first mention a late Paleozoic limestone succession near the Quinn River Crossing in the Kings River Range and suggest that this carbonate sequence may be a northern extension of the Antler Peak Limestone vhich is exposed in north-central Nevada about 60 miles south of the Quinn River Crossing section. The Antler Peak Lime­ stone has a similar lithology and ranges in age from late Pennsylvanian to early Permian. Willden (l96it) published a more extensive report on this limestone succession in a reconnaissance project encompassing the geology and mineral deposits of Humboldt County and referred to. it as the Unnamed Limestone. He described the deposit as generally consisting of 1000 feet of medium- bedded to massive limestone with associated chert and fossil-rich beds. From samples Willden had collected, a number of fossils were identified by U.S. Geological Svirvey specialists. Similar fossils were fomid in limestones of other localities, ranging in age from late Pennsylvanian to late Permian. Of the rugose corals a plerophyllid coral similar to one found in the middle to late Permian Edna Mountain Formation (in the Sonoma Range and Edna Mountain in Humboldt Coxinty) was identified. The bryozoans in the Quinn River Crossing section include some Rhomboporella which are fairly common in the Antler Peak Limestone (approximately Phosphoria age). The brachiopods also suggest an age equivalence to that of the Antler Peak Limestone. The foraminiferal specimens identi­ fied for Willden (l96i+, p. 3^) suggest that the Bilk Limestone may be about the same age