DOCSLIB.ORG

Geology of Tlie Rodeo Greek N and Eureka Cbunty, Nevada

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Geology of Tlie Rodeo Greek N and Eureka Cbunty, Nevada Geology of tlie Rodeo Greek N and Eureka-.-.-, ..-.' *.":. -.Cbunty, '.: '' .-J- ' ,>. ;'.: / ' y -- ..'Nevada ..;. G t d L o Wi c A L s v IE Y BULLETIN 1473 Geology of the Rodeo Creek NE and Welches Canyon Quadrangles, Eureka County, Nevada flv JAMES G. EVANS G K () 1, () <; I C A I, S U R V E Y BULLETIN 1473 I'M'IKI) SIAIKS (IOVKRNMKN'1 1 I'KIN'I'INC OFFICE. tt'ASHIXC'FON : 1SWIP UNITED STATES DEPARTMENT OF THE INTERIOR CECIL D. ANDRUS, Secretary GEOLOGICAL SURVEY H. William Menard, Director Library of Congress Cataloging in Publication Data Evans, James George, 1938- Geology of the Rodeo Creek NE and Welches Canyon quadrangles, Eureka County, Nevada. Bibliography: p. Supt. of Docs, no.: I 19.3:1^73 1. Geology--Nevada Eureka Co. I. Title. II. Series: United States. Geological Survey. Bulletin ; 1^73, QE75.B9 no. 1^73 [QE138.E8] 557.3s [557.93'32] 80-607 llj-2 For sale by the Superintendent of Documents, U. S. Government Printing Office Washington, D. C. 20402 CONTENTS Page Abstract --_-___---_--_-_-_-___-__'__-_-____-___-_-_--_--_-__--_-----_----..- 1 Introduction -_-__-..__-_-__-_.__-___-_.___-___-.-_-_-_---_-__------_-_____ 2 Location and geologic interest ------------------------------------------ 2 Previous work ...__.___.__.___--____.________.________________--_-____ 3 Acknowledgments-_-____-______-___._._-_____._.__-____-_____--_-__-_-_ 3 General statigraphy of Paleozoic rocks ---------------------------------- 4 Descriptions of the Paleozoic rocks ------------------------------------------ 5 Carbonate (eastern) assemblage _-______-___-__________--__-__----____-- 5 Hamburg Dolomite ------------------------------------------------ 5 Pogonip Group __---___-_---_-_--__-_.-_-_-___-_-_-_-__-----_-__-__- 6 Eureka Quartzite -------------------------------------------------- 11 Hanson Creek Formation -_-_-..______-_.._-_._-_.___-_---_-_-_-_-- 14 Roberts Mountains Formaton ______________________________________ 18 Popovich Formation _.__________.___.___....________.______-._._-___ 26 Silurian and Devonian limestone undifferentiated-------------------- 33 Epithermally altered Silurian and Devonian limestone __.______-_.__ 37 Siliceous (western) assemblage------------.--------.---------.-------..--- 39 Transitional assemblage------------------------------------------------ 47 Geological summary of Paleozoic rocks ---------------------------------- 47 Igneous rocks --_----___-_-_-_____--_--___--_--_____-_-_--____---_--__-._--- 55 Basalt --------------------------------------------------------------- 55 Cretaceous granodiorite -_-_-___-_--____-_.-____-____-____-_--_-__----__ 56 Quartz monzonite ------------------------------------------------------ 57 Rhyodacite __-_..____-__-__--_--_-_-_____.___.-___._______.--_-_____-___ 60 Andesite --------___..__..._....._._....____-------_.... 60 Tertiary granodiorite ---_-_-_-_--_-_____--_-_._._____.___-_-_---__._.__ 62 Quartz latite ---_------.__.__------._..-----...._._.__.__ -__-._._.--_ 63 Intrusive breccia __----__._._-___-.-_-_____-_..____-_____--______._-___ 64 Pyroclastic rocks --________--_--_-_____.-._________._..._________--..__.__- 67 Tertiary and Quaternary sedimentary rocks and deposits -------------------- 70 Carlin Formation .___._-..___..._._.___._____________.___._._____._.__. 70 Siltstone -------------------------------------------------------------- 71 Fanglomerate.--_---------.--------_----_---_---_-----------------_---- 71 Landslide deposits ---__--_-_-_-_-.__._-._______-__.__-____----___.____ 72 Alluvium----__-----____.___--_-___-__________-.. 72 Structural geology -------_-_...___-___.___._..________....______-_...._.__ 72 References ci ted _---__-.-_____-___..__._________._..._._._._.-____._______._ 78 ILLL'SIRAIIONS PLATE 1. Geologic map of the Rodeo Creek NE quadrangle, Nevada --In pocket 2. Geologic map of the Welches Canyon quadrangle, Nevada __In pocket HI IV CONTENTS FIGURE 1. Index map of study area in north-central Nevada ....... 2 2. Stratigraphic column showing Paleozoic rocks of Lynn Window, Rodeo Creek NE and Welches Canyon quadrangles ....... 5 3. Diagrammatic stratigraphic sections of Pogonip Group showing position of fossil collections ..... ......... ...... ...... 8 4. Photograph of typical exposure of dark-gray thick-bedded Hanson Creek Formation --_____._.-_-._..._._._...-._...-.-... .. 16 5. Columnar section of Hanson Creek Formation showing positions of fossil collections-----_---.-.--..........-.-...-.. ........... .. 20 6. Photograph of typical exposure of Roberts Mountains Formation 21 7. Photograph of metamorphosed Roberts Mountains Formation . 24 8. Columnar section of Roberts Mountains Formation showing po­ sitions of fossil collections -.-_--.__-__--.-.---.-.-.-.- ....... 27 9. Photograph of intraformational breccia in Popovich Formation . 28 10. Columnar section of Popovich Formation showing positions of fos­ sil collections --------_--_-...-_-.__.-....-.-.-.- .-..._.-.._. 32 11-14. Photographs of: 11. Epithermally altered Silurian and Devonian limestone 40 12. Laminated chert, siliceous assemblage ....-.-.-.-.-.... 41 13. Typical exposure of black chert, siliceous assemblage . 42 14. Thin-bedded limestone with chert lenses, siliceous as­ semblage '---.---_---_..._.-__--.-.--.--.-_-..- .-.-... 43 15. Photomicrograph of intrusive breccia -.-.-----.-._--.-.---.-... 66 16. Photomicrograph of rhyolitic welded tuff ..._..-.......-....... 68 17. Photographs of Roberts Mountains thrust in main pit at Carlin goldmine -.---_---. --_----_--._-.-.-.--.._.-.-.-....-..... 74 18. Photograph of Richmond Mountain thrust -.-.-.--..-.-._..... 75 19. Equal-area diagram of 73 fold axes from the siliceous assemblage 76 20. Equal-area diagram of 300 poles to bedding in carbonate as­ semblage rocks on Richmond Mountain ..__-._.-.-._._..._. 77 21. Photograph of West Lynn thrust .............................. 78 TABLKS TABLE 1. Fossils from Pogonip Group -.- ._..___...._....___..__. ___....... 10 2. Fossils from Hanson Creek Formation ........ --_.'..-._.-.__ 19 3. Graptolites from Roberts Mountains Formation .............. 25 4. Conodonts, ostracods, and brachiopods from Roberts Mountains Formation .__-----_.-_-__----_.........-...-.__.......-..... 26 5. Conodonts from Popovich Formation - ..-...-.-.---.-.-...... 34 6. Ostracods, brachiopods, and trilobites from Popovich Formation 37 7. Additional fossils collected from Popovich Formation ........ 38 8. Conodonts and ostracods from Silurian and Devonian limestone undifferentiated ....-.-..--._.-..-..-.. ... ........'.._ ... 39 9. Conodonts from limestones in siliceous assemblage ............ 46 10. Graptolithina from the siliceous assemblage ............ .... 48 11. Conodonts from the transitional assemblage .._..-...._... 50 12. Analysis of basalt from SW'/tSE'/t sec. 5. T. 33 N., R. 51 E., Welches Canyon quadrangle -..-..---.-----.-.---..-.----. 56 CONTENTS V Page TABLES 13-18. Chemical analyses and CIPW norms: 13. Cretaceous granodiorite---------------------------- 58 14. Quartz monzonite.--------------------------------- 59 15. Rhyodacite..-.-----.-.---------------------------- 61 16. Tertiary granodiorite ------------------------------ 63 17. Quartz latite -.---------------.-------------------- 65 18. Rhyolitic welded tuff .................._......_._._ 67 By JAMES G. EVANS ABSTRACT The Lynn Window in the Roberts Mountains thrust exposes 2,572 m of strata, pre­ dominantly carbonate rock, of Cambrian through Late Devonian age (carbonate, or eastern, assemblage). These strata include Hamburg Dolomite, Pogonip Group, Eureka Quartzite, Hanson Creek Formation, Roberts Mountains Formation, and Popovich Formation. The upper plate of the Roberts Mountains thrust is predomi­ nantly shale and chert (siliceous, or western, assemblage) or Ordovician and Silurian age that could represent at least 3,000 m of section. Thrust slices of an Upper Devonian limestone with abundant sand-sized clasts of quartz and chert (transitional as­ semblage) occur within the upper plate. The total known thickness of this limestone is 915 m. Several kinds of igneous rock intruded the Paleozoic sedimentary rocks, possibly as early as Paleozoic time and as late as Tertiary. Most of the intrusions are minor. In the Cretaceous, however, granodiorite (121±5 m.y.) and quartz monzonite (106±2 m.y.) intruded Paleozoic rocks, producing large contact metamorphic aureoles. In the early Tertiary, granodiorite (37±0.8 m.y.) and quartz latite (36.6±0.7 m.y.) intruded the siliceous rocks south of the Lynn Window, producing narrow contact metamorphic aureoles. Rhyodacite flows of Cretaceous or early Tertiary age were deposited on the Paleozoic siliceous rocks south of the Lynn Window. Rhyolitic welded tuff (14.2±3 m.y.) was deposited just west of the Lynn Window, probably contemporaneously with part of the Carlin Formation (sandstone, siltstone) of Regnier on the east side of the window. Deposits of late Tertiary and Quaternary age occur on both flanks of the window. The Antler orogeny in Late Devonian to Early Mississippian time produced the earliest deformation recorded in the area. The allochthonous siliceous and transitional assemblages were imbricated and brought into the area in the upper plate of the Roberts Mountains thrust. Large and minor folds in the allochthon are predominantly gently plunging to the north-northeast and south-southwest. During this episode, the autochthonous carbonate assemblage was severely deformed by thrusting. In the late Paleozoic or Mesozoic the carbonate aissembage was folded into a broad asymmetric anticline plunging
Load more

Recommended publications
  • GEOLOGICAL SURVEY RESEARCH 1972 Chapter B
    GEOLOGICAL SURVEY RESEARCH 1972 Chapter B GEOLOGICAL SURVEY PROFESSIONAL PAPER 800-8 Scientific notes and summaries of investigations in geology, hydrology, and related fields UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON: 1972 UNITED STATES DEPARTMENT OF THE INTERIOR ROGERS C. B. MORTON, Secretary GEOLOGICAL SURVEY V. E. McKelvey, Director For sale by the Superintendent of Documents, U.S. Qovernment Printing Office, Washington, D.C., 20402 - Price $2.26 CONTENTS GEOLOGIC STUDIES Marine geology Page Structural features of the continental margin, northeastern Gulf of Mexico, by R. G. Martin, Jr. Marine geology of Yakutat Bay, Alaska, by F. F. Wright . Paleontology and stratigraphy Leiosphaeridio (Acritarcha) in the Mesozoic oil shales of northern Alaska, by R. F. Boneham and I. L. Tailleur . Quartzsand-bearing zone and Early Silurian age of upper part of the Hanson Creek Formation in Eureka County, Nev., by T. E. MullensandF.G.Poole ................................................................................... Trend-surface analysis of the thickness of the High Bridge Group (Middle Ordovician) of central Kentucky and its bearing on the nature of the post-Knox unconformity, by D. E. Wolcott, E. R. Cressman, and J. J. Connor . Glacial geology The Ingraham esker, Chazy, N.Y ., by C. S. Denny . Economic geology High-purity veins of soda-niter, NaN03, and associated saline minerals in the Chilean nitrate deposits, by G. E. Ericksen and M. E. Mrose ................................................................................................. Thorium distribution in a ganite stock near Bull Canyon, Lemhi County, Idaho, by M. H. Staatz, C. M. Bunker, and C. A. Bush . White clay deposits of Centre, Blair, Huntingdon, and Bedford Counties, Pa., by J. W. Hosterman . Reconnaissance geology and mineral potential of Thomas, Keg, and Desert calderas, central Juab County, Utah, by D.
    [Show full text]
  • Paleozoic Geology of the Dobbin Summit-Clear Creek Area, Monitor
    AN ABSTRACT OF THE THESIS OF DIANE CAROL WISE for the degree of MASTER OF SCIENCE in Geology presented on August 13, 1976 Title: PALEOZOIC GEOLOGY OF THE DOBBIN SUMMIT- CLEAR CREEK AREA, MONITOR RANGE, NYiE COUNTY, NEVADA Abstract approved: Redacted for Privacy son Paleozoic limestones, dolomites, quartz arenites, and other clastic rocks were mapped in the vicinity of Dobbin Summit and Clear Creek in the central Monitor Range. Sedimentary rock units present in this area represent the shallow-shelf eastern assemblage and basin and also the basin-slope facies of the traditional limestone- clastic assemblage. The four oldest, Ordovician, units were deposited in shallow shelf environments. The Lower Ordovician Goodwin Formation is composed of about 1200 feet of calcareous shales and thin-bedded limestones. The overlying Antelope Valley Limestone is about 500 feet thick and consists of wackestones, packstones, and rare algal grainstones.The Copenhagen Formation (135 feet thick) is the highest regressive deposit of sandstone, siltstone, and limestone below the transgressive Eureka Quartzite.The Eureka is a quartz arenite 181 feet thick, with an intercalated shallow marine dolomite member. The transition from shallow to deep water conditions can be seen in the change from algal boundstones to laminated lime mud- stones in the Hanson Creek Formation (190 feet thick).The super- jacent Roberts Mountains Formation (285 feet thick) is composed of lime mudstones and allodapic beds deposited in basinal, deep water conditions.During earliest Devonian
    [Show full text]
  • STRATIGRAPHY and STRUCTURE of the SOUTHERN SULPHUR SPRING RANGE, EUREKA COUNTY, NEVADA Redacted for Privacy Abstract Approved: U G
    AN ABSTRACT OF THE THESES OF Joseph T. Lipka IC for the degree ofMaster of Sciencein Geology presented on April 17, 1987 Title:STRATIGRAPHY AND STRUCTURE OF THE SOUTHERN SULPHUR SPRING RANGE, EUREKA COUNTY, NEVADA Redacted for Privacy Abstract approved: U G. Johnson Early Paleozoic limestones and dolomites of the shallow shelf transitional facies belt were mapped in the southern Sulphur Spring Range, Eureka County, Nevada.The four youngest units in the map area are in fault contact with the Lower Devonian rocks and wereprobably transported westward, along a low-angle normal fault. The minoirlal dolomites of the Hanson Creek Formation, dated as latest Ordovician in the map area, were deposited in a low-energy lagoon.Overlying the Hanson Creek Formation, with a gradational contact, is the lower member ofthe Lone Mountain Dolomite, a probable reef complex.The exposed thickness of the lower Lone Mountain Dolomite is estimated to be 250 feet.The Lower Devonian Old Whalen Member of the Lone Mountain Dolomite is composed of well-bedded, alternating brown and gray dolomites.The repetition of rock types in the Old Whalen Member indicates recurring shallow marine environments on a broad carbonate platform.The Old Whalen is estimated to be 1400 feet thick.Directly overlying the Old Whalen Member, is the Kobeh Member of the Mc Colley Canyon Formation.Rocks of the Mc Colley Canyon Formation were deposited on a shallow shelf under normal marine conditions.The mid-Lower Devonian Kobeh Member is sparsely to abundantly fosciliferous and varies from a peloidal wackestone to a peloidal sandy wackestone to a sandy peloidal packstone.The thickness is 276 feet.Overlying the Kobeh Member are the abundantly fossiliferous beds of the lower part of the Bartine.
    [Show full text]
  • A Chemostratigraphic Investigation of the Late Ordovician Greenhouse to Icehouse Transition: Oceanographic, Climatic, and Tectonic Implications
    A CHEMOSTRATIGRAPHIC INVESTIGATION OF THE LATE ORDOVICIAN GREENHOUSE TO ICEHOUSE TRANSITION: OCEANOGRAPHIC, CLIMATIC, AND TECTONIC IMPLICATIONS DISSERTATION Presented in Partial Fulfillment of the Requirements For the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By Seth Allen Young, M.S. ***** The Ohio State University 2008 Dissertation Committee: Dr. Matthew R. Saltzman, Adviser Dr. Kenneth A. Foland Dr. William I. Ausich Dr. Andrea G. Grottoli ABSTRACT The latest Ordovician (444 million years ago) was a critical period in Earth history. This was a time of significant climatic global change with large-scale continental glaciation. Moreover, the end-Ordovician mass extinction is recognized as the second- most devastating mass extinction to have affected the Earth. The anomalous Late Ordovician icehouse period has perplexed many researchers because all previous model and proxy climate evidence suggest high levels of atmospheric CO2 during the Late Ordovician glaciation. Also associated with this period is a large positive carbon isotope (δ13C) excursion (up to +7‰) that represents a global perturbation of the carbon cycle. Additionally, a large decrease (0.001) in seawater 87Sr/86Sr occurs several million years prior (~460 million years ago); this could reflect an increase in atmospheric CO2 uptake due to weathering of volcanic rocks involved in uplift of the early Appalachian Mountains. To address these Ordovician anomalies, well-studied, thick, and continuous Late Ordovician limestone sequences from eastern West Virginia, south-central Oklahoma, central Nevada, Quebec (Canada), Estonia, and China have been sampled. Carbon and strontium isotopic ratios have been measured on samples from these localities of which Estonian and Chinese sample sites represent separate paleocontinents (Baltica and South ii China) and are compared with other data sets from North America.
    [Show full text]
  • PLEISTOCENE STRATIGRAPHIC UNITS of Wisconsin
    MISCELLANEOUS PAPER 84-1 PLEISTOCENE STRATIGRAPHIC UNITS OF WISCONSiN by David M. Mickelson, Lee Clayton, Robert W. Baker, William N. Mode and Allan F. Schneider available from Geological and Natural History Survey University of Wisconsin-Extension 1815 University Avenue Madison, Wisconsin 53705 MISCELLANEOUS PAPER 84-1 PLEISTOCENE STRATIGRAPHIC UNITS OF WISCONSIN by David M. Mickelson, Lee Clayton, Robert W. Baker, William N. Mode and Allan F. Schneider available from Geological and Natural History Survey University of Wisconsin�Extension 1815 University Avenue Madison, Wisconsin 53705 JUL 1984 CONTENTS Acknowledgements ..................... ..............It ................................................It .................. iv Abstract ............................................................................................................................ I Introduction It .. .. ........ .. .... .. ................ .. ........ .. .. .. ........ .. .. .. .. .. .... ........ .. .... .. .. ............ .. ........ I Principles of Lithostratigraphic Classification in Wisconsin •• •••••••• 2 Summary of Lithostratigraphic Units Defined in this Paper ••••••••••••• 5 Units of Probable Pre-Wisconsinan and Early Wisconsinan Age •••••••• 5 Units of Late Wisconsinan Age ............................................................................ 7 References Cited ............................................................................................................ 12 Appendix 1. Walworth Formation .. ................ ......It .... ....It
    [Show full text]
  • The Stratigraphic Section in the Vicinity of Eureka, Nevada
    The Stratigraphic Section in the Vicinity of Eureka, Nevada GEOLOGICAL SURVEY PROFESSIONAL PAPER 276 The Stratigraphic Section in the Vicinity of Eureka, Nevada By T. B. NOLAN, C. W. MERRIAM, and J. S. WILLIAMS GEOLOGICAL SURVEY PROFESSIONAL PAPER 276 Revision of the pre- Tertiary stratigraphy of east-central Nevada UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1956 UNITED STATES DEPARTMENT OF THE INTERIOR Douglas McKay, Secretary GEOLOGICAL SURVEY W. E. Wrather, Director For sale by the Superintendent of Documents, U. S. Government Printing Office Washington 25, D. C. - Price $1.00 (paper cover) CONTENTS Page Page Abstract_ _____________________ 1 Silurian system.___________________________ 36 Introduction. _--___-______--___- 2 Roberts Mountains formation.__________ 36 Acknowledgments- --.-_---___-_-. 3 Lone Mountain dolomite__________... 37 Structural setting._______________ 3 Devonian system.__________-_-_-__--_____. 40 Economic significance. _-__._. 5 Nevada formation_________--______--. 40 Cambrian system.________________ 5 Beacon Peak dolomite member. 42 Prospect Mountain quartzite.. 6 Oxyoke Canyon sandstone member... 43 Pioche shale_______--_-_-_.__. 7 Sentinel Mountain dolomite member. 43 Eldorado dolomite___________ 9 Woodpecker limestone member. 44 Geddes limestone.___________ 11 Bay State dolomite member.--...--. 45 Secret Canyon shale._________ 12 Devils Gate limestone._________________ 48 Lower shale member. .... 13 Meister member.__________________ 49 Hayes Canyon member.____________ 49 Clarks Spring member.._ 14 Devonian and Mississippian systems. ________ 52 Hamburg dolomite.___-_.____ 16 Pilot shale________-__-_-___--__---_-_. 52 Dunderberg shale.___________ 18 Carboniferous systems_.____-__-______-__- 54 Windfall formation.__________ 19 Mississippian system._________--,___-_- 54 Catlin member._________ 20 Joana limestone,___________________ 54 Bullwhacker member.
    [Show full text]
  • Carpenter, R.M., Pandolfi, J.M., P.M. Sheehan. 1986. the Late Ordovian and Silurian of the Eastern Great
    MILWAUKEE PUBLIC MUSEUM Contributions . In BIOLOGY and GEOLOGY Number 69 August 1, 1986 The Late Ordovician and Silurian of the Eastern Great Basin, Part 6: The Upper Ordovician Carbonate Ramp Roger M. Carpenter John M. Pandolfi Peter M. Sheehan MILWAUKEE PUBLIC MUSEUM Contributions . In BIOLOGY and GEOLOGY Number 69 August 1, 1986 The Late Ordovician and Silurian of the Eastern Great Basin, Part 6: The Upper Ordovician Carbonate Ramp Roger M. Carpenter, Department of Geology, Conoco Inc., 202 Rue Iberville, Lafayette, LA 70508; John M. Pandolfi, Department of Geology, University of California, Davis, California, 95616; Peter M. Sheehan, Department of Geology, Milwaukee Public Museum, 800W. Wells St., Milwaukee, Wisconsin 53233 ISBN 0-89326-122-X © 1986 Milwaukee Public Museum Abstract Two east-west transects examined in western Utah and eastern Nevada preserve Upper Ordovician-Lower Silurian lithofacies along a carbonate ramp transitional between a shelf and basin. Previous investigators have reconstructed this margin as a classic carbonate shelf with an abrupt, linear margin between shelf and slope. However, lithofacies change gradually between shelf and slope and are better explained by a carbonate ramp model. Intertidal and shallow subtidal dolomites are present to the east, with progressively deeper water limestones with increasing fine grained terrigenous content toward the west. Shelf edge reefs or shallow water carbonate margin buildups are absent. Latest Ordovician glacio-eustatic decline in sea level produced a period ofsubaerial exposure in the shallow eastern region. However, deposition continued deeper on the ramp, where shallow-water, cross laminated, massive dolomites were deposited during the glacio-eustatic regression. The carbonate ramp pattern was disrupted in the Middle or early part of the Late Llandovery, when an abrupt margin was established by listric growth faulting.
    [Show full text]
  • Geology of the Applebush Hill Area, South Antelope
    GEOLOGY OF THE APPLEBUSH HILL AREA, SOUTH ANTELOPE VALLEY, NYE COUNTY, NEVADA A THESIS SUBMITTED TO THE FACULTY OF THE UNIVERSITY OF NEVADA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE By Bert Scales Reno, Nevada May, 1961 Approved by Director of Theais Approved by Major Professor Approved by Chairman of Graduate Committee i. CONTENTS Page Abstract ........................................................ 1 Introduction .................................................... 2 Location and Accessibility ............................... 2 Geography.................. ............................ 2 Physical Features ......................................... 4 Scope of Investigation ...... ....................... 5 Method of Investigation ................................... 5 Previous Investigations ................................... 5 Acknowledgements.................... .................... 6 Stratigraphy .................................................... 8 Introduction ....................................... 0 . 8 Cambrian Syst e m .......................................... , 10 Windfall Formation.......... .................... 11 Bullwacker M e m b e r ............................... 11 Ordovician System................ .............. 15 Pogonip G r o u p .................. 16 Goodwin Limestone ............................. 16 Antelope Valley Limestone 20 Copenhagen Formation . .............. „ ............ 24 Eureka Quartzite ................... 27 Hanson Creek Formation ....................... .... 30
    [Show full text]
  • University of Nevada, Reno Paleozoic Stratigraphy and Structure at Iron
    University of Nevada, Reno Paleozoic Stratigraphy and Structure at Iron Point, Humboldt County, North-Central Nevada A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Geology By: Erica Leanne Key Dr. Patricia H. Cashman/Thesis Advisor May, 2015 © by Erica Leanne Key 2015 All Rights Reserved THE GRADUATE SCHOOL We recommend that the thesis prepared under our supervision by ERICA L. KEY Entitled Paleozoic Stratigraphy And Structure At Iron Point, Humboldt County, North-Central Nevada be accepted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Patricia H. Cashman, Ph. D., Advisor James H. Trexler Jr., Ph. D., Committee Member Jill Heaton, Ph. D., Graduate School Representative David W. Zeh, Ph.D., Dean, Graduate School May, 2015 i ABSTRACT Detailed mapping and reconsideration of biostratigraphic data provide new insights into how the Comus Formation at its type locality at Iron Point, Humboldt County, Nevada fits into the regional stratigraphic framework. The age designation of the Comus Formation was reevaluated by this study using the most current understanding of Ordovician graptolite biostratigraphy. Previous studies at Iron Point had determined that the graptolites found in the siltstone units in the Comus Formation were middle Ordovician. This study determined that the species of graptolites found at Iron Point had been reclassified as late Ordovician since the original biostratigraphic study had been performed. A portion of the Vinini Formation at Iron Point was remapped in this study as the uppermost unit of the Comus Formation. Originally, this part of the Vinini Formation was mapped as a thrust “klippe” over the Comus Formation.
    [Show full text]
  • Geology and Structure of Winters Creek, Jerritt Canyon District, Elko County
    University of Nevada, Reno Geology and Structure of Winters Creek, Jerritt Canyon District, Elko County, Nevada A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Geology by Jessica B. Doyle Dr. Tommy B. Thompson/Thesis Advisor December 2007 UMI Number: 1447627 Copyright 2007 by Doyle, Jessica B. All rights reserved. UMI Microform 1447627 Copyright 2008 by ProQuest Information and Learning Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. ProQuest Information and Learning Company 300 North Zeeb Road P.O. Box 1346 Ann Arbor, MI 48106-1346 Copyright by Jessica B. Doyle 2007 All Rights Reserved THE GRADUATE SCHOOL We recommend that the thesis prepared under our supervision by JESSICA B. DOYLE Entitled Geology and Structure of Winters Creek, Jerritt Canyon District, Elko County , Nevada be accepted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Tommy B. Thompson, Ph. D., Advisor Alan R. Wallace, Ph. D, Committee Member Jaak J. K. Daemen, Ph. D., Graduate School Representative Marsha H. Read, Ph. D., Associate Dean, Graduate School December, 2007 i Abstract The Winters Creek area is located in the Jerritt Canyon district within the northern Independence Range, Nevada. The district contains Carlin-type gold deposits characterized by submicroscopic gold hosted in autochthonous assemblage silty carbonates. At the Winters Creek open pit, ore is hosted in the autochthonous assemblage Roberts Mountains Formation. However, north of the deposit, are predominantly allochthonous, siliciclastic marine sediments, which were thrust over the autochthonous facies during the Devonian- Mississippian Antler Orogeny.
    [Show full text]
  • The Ordovician: a Window Toward Understanding Abundance
    THE ORDOVICIAN: A WINDOW TOWARD UNDERSTANDING ABUNDANCE AND MIGRATION PATTERNS OF BIOGENIC CHERT AND IMPLICATIONS FOR PALEOCLIMATE A thesis presented to the faculty of the College of Arts and Sciences of Ohio University In partial fulfillment of the requirements for the degree Master of Science Iulia Tomescu August 2004 © 2004 Iulia Tomescu All Rights Reserved This thesis entitled THE ORDOVICIAN: A WINDOW TOWARD UNDERSTANDING ABUNDANCE AND MIGRATION PATTERNS OF BIOGENIC CHERT AND IMPLICATIONS FOR PALEOCLIMATE BY IULIA TOMESCU has been approved for the Department of Geological Sciences and the College of Arts and Sciences by David L. Kidder Associate Professor of Geological Sciences Leslie A. Flemming Dean, College of Arts and Sciences TOMESCU, IULIA. M.S. August 2004. Geological Sciences The Ordovician: a window toward understanding abundance and migration patterns of biogenic chert and implications for paleoclimate (228 pp.) Director of Thesis: David L. Kidder The comprehensive global survey of Ordovician chert deposits undertaken in this study reveals that most of them are biogenic, and documents significant paleoceanographic relationships. Peritidal/lagoonal and shelf cherts hosted mainly by carbonate facies are nodular, and formed predominantly by lithistid demosponges. Slope/basinal cherts are bedded, hosted by siliciclastic sediments, and bear radiolarians. Lower Ordovician cherts are abundant in all settings. The Middle Ordovician shows a decrease in cherts characterized by a strong decline in silica burial within peritidal/lagoonal and shelf environments. The distribution of silica secreting biotas suggests an Arenigian- Llanvirnian onshore-offshore migration whereby siliceous sponges migrate from peritidal/lagoonal to shelf-basinal environments, and radiolarians move to basinal settings. The Caradocian marks the highest peak in the abundance of Ordovician cherts, in both shelf and slope/basinal environments, that appears to correlate with a warming interval.
    [Show full text]
  • Stratigraphy and Structure of the Northern Part of the Fish Creek Range, Eureka County, Nevada
    AN ABSTRACT OF THE THESIS OF Jill M. Bird for the degree ofMaster of Science in Geology presented on February 17. 1989 . Title: Stratigraohy and Structure of the Northern Part of the Fish Creek Range, Eureka County, Nevada. Redacted for Privacy Abstract approved: J.G.\Johnson ) Upper Cambrian through Middle Devonian carbonate and clastic sequences of the northern part of the Fish Creek Range represent shallow-shelf sedimentation in the Cordilleran miogeosyncline. The lower and middle Paleozoic section exposed in the northern Fish Creek Range fits well within regional facies patterns and paleogeographic reconstructions. The Upper Cambrian Dunderberg Shale was deposited in a muddy outer shelf embayment which extended eastward into the Eureka area. The embayment was eliminated as seas regressed in late Dresbachian time and marine carbonate sedimentation (repre- sented by the Catlin Member of the Windfall Formation) was established. The argillaceous Bullwhacker Member of the Windfall was deposited in deeper shelf waters as the sea transgressed briefly during Trempeleauian time. Shallow-shelf carbonates of the Lower Ordovician Goodwin Limestone are succeeded by Ninemile Formation strata represen- ting deposition in a muddy embayment, similar to the Late Cambrian embayment in the Eureka area. Regression followed, and a shallow-water Girvanella-rich carbonate bank prograded westward during Whiterockian (early Middle Ordovician) time, represented by the lower part of the Antelope Valley Limestone. Mudstone and wackestone of the upper part of the Antelope Valley Limestone was deposited in quieter, deeper, or more protected environments shoreward of the bank margin. Basal sands of the Eureka Quartzite prograded westward across the carbonate shelf during the Middle Ordovician.
    [Show full text]