DOCSLIB.ORG

Fracture Analysis of Circum-Bighorn Basin Anticlines

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Fracture Analysis of Circum-Bighorn Basin Anticlines FRACTURE ANALYSIS OF CIRCUM-BIGHORN BASIN ANTICLINES, WYOMING-MONTANA by Julian Stahl A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Earth Science MONTANA STATE UNIVERSITY Bozeman, Montana November 2015 ©COPYRIGHT by Julian Stahl 2015 All Rights Reserved ii DEDICATION I dedicate this thesis to my brother, Manuel Stahl, who provided me with the inspiration and drive to pursue a degree that I am truly passionate about. iii ACKNOWLEDGEMENTS The research presented in this document would not have been as thought- provoking and thorough without the help of my mentors and peers. My advisor, Dr. David Lageson helped formulate the project idea and was fundamental throughout the course of my study in leading me in the right direction and always being available to answer questions. I would also like to extend my gratitude to my committee members, Dr. Colin Shaw and Dr. Jean Dixon, for providing me with the necessary assistance and expertise. I would also like to thank my fellow geology peers at Montana State University. Without the constant communication and discussions with Mr. Jacob Thacker, Mr. Travis Corthouts and Mrs. Anita Moore-Nall this project would not have come to fruition. I would also like to offer my sincere appreciation to my two field assistants, Mr. Evan Monroe and Miss Amy Yoder, for taking the time out of their lives to help unravel the geology of the Bighorn Basin in the field. I would like to express my gratitude to my entire family, Dr. Johannes Stahl, Ms. Gabriele Stahl and Mr. Roman Stahl, for supporting me and giving me inspiration to pursue my passion for geology throughout my undergrad and graduate career. This project would not have been possible without the financial support of Rocky Mountain Association of Geologists, Tobacco Root Geological Society, American Association of Petroleum Geologists, and Montana Geological Society. iv TABLE OF CONTENTS 1. INTRODUCTION ...........................................................................................................1 Bighorn Basin, Wyoming-Montana .................................................................................1 Research Objectives .........................................................................................................3 Research Question ...................................................................................................6 Previous Work .................................................................................................................7 Research Importance ........................................................................................................9 2. GEOLOGIC SETTING .................................................................................................10 Regional Stratigraphy ....................................................................................................10 Paleozoic ................................................................................................................10 Triassic and Jurassic ..............................................................................................13 Cretaceous ..............................................................................................................13 Cloverly Formation ....................................................................................14 Thermopolis Shale .....................................................................................14 Muddy Sandstone and Mowry Shale .........................................................15 Frontier Formation .....................................................................................15 Cody Shale .................................................................................................15 Mesaverde Formation ................................................................................16 Meeteetse Formation ..................................................................................16 Regional Structural Geology..........................................................................................17 Sevier and Laramide Orogeny ...............................................................................17 Foreland Basins of the Rocky Mountain Region ...................................................19 Bounding Tectonic Structures of the Bighorn Region ...........................................20 Timing of Adjacent Laramide Uplifts....................................................................22 Anticline Formation Mechanism ...........................................................................22 Laramide Deformation Styles ........................................................................................24 Non-crustal Shortening Models .............................................................................24 Crustal Shortening Models ....................................................................................25 3. METHODS ....................................................................................................................29 Google Earth Pro Lineaments ........................................................................................29 Data Collection ......................................................................................................29 GIS Processing and Rose Diagrams ......................................................................30 Google Earth Pro Accuracy ...................................................................................31 Outcrop Fracture Measurements ....................................................................................32 Data Collection ......................................................................................................33 Stereonet ................................................................................................................34 Statistical Comparison ...........................................................................................35 v TABLE OF CONTENTS - CONTINUED 4. RESULTS ......................................................................................................................36 Introduction ....................................................................................................................36 Elk Basin Anticline ........................................................................................................37 Overview ................................................................................................................37 Fold Classification .................................................................................................37 Lineament Analysis ...............................................................................................38 Fracture Analysis ...................................................................................................40 Horse Center Anticline Analysis ...................................................................................42 Overview ................................................................................................................42 Fold Classification .................................................................................................43 Lineament Analysis ...............................................................................................45 Fracture Analysis ...................................................................................................45 Oregon Basin Anticline ..................................................................................................46 Overview ................................................................................................................46 Fold Classification .................................................................................................48 Lineament Analysis ...............................................................................................49 Fracture Analysis ...................................................................................................49 Little Buffalo Basin Anticline ........................................................................................52 Overview ................................................................................................................52 Fold Classification .................................................................................................53 Lineament Analysis ...............................................................................................53 Fracture Analysis ...................................................................................................54 Crass Creek Anticline ....................................................................................................57 Overview ................................................................................................................57 Fold Classification .................................................................................................58 Lineament Analysis ...............................................................................................58 Fracture Analysis ...................................................................................................59 Thermopolis Anticline ...................................................................................................62 Overview ................................................................................................................62
Load more

Recommended publications
  • Morrison Formation 37 Cretaceous System 48 Cloverly Formation 48 Sykes Mountain Formation 51 Thermopolis Shale 55 Mowry Shale 56
    THE STRUCTURAL AND STRATIGRAPHIC FRAMEWORK OF THE WARM SPRINGS RANCH AREA, HOT SPRINGS COUNTY, WYOMING By CHRISTOPHER JAY CARSON Bachelor of Science Oklahoma State University 1998 Submitted to the Faculty of the Graduate College of the Oklahoma State University in partial fulfillment of the requirements for the Degree of MASTER OF SCIENCE July, 2000 THE STRUCTURAL AND STRATIGRAPHIC FRAMEWORK OF THE WARM SPRINGS RANCH AREA, HOT SPRINGS COUNTY, WYOMING Thesis Approved: Thesis Advisor ~~L. ... ~. ----'-"'-....D~e~e:.-g-e----- II ACKNOWLEDGEMENTS I wish to express appreciation to my advisor Dr. Arthur Cleaves for providing me with the opportunity to compile this thesis, and his help carrying out the fieldwork portion of the thesis. My sincere appreciation is extended to my advisory committee members: Dr. Stan Paxton, Dr. Gary Stewart, and Mr. David Schmude. I wish to thank Mr. Schmude especially for the great deal of personal effort he put forth toward the completion of this thesis. His efforts included financial, and time contributions, along with invaluable injections of enthusiasm, advice, and friendship. I extend my most sincere thank you to Dr. Burkhard Pohl, The Big Hom Basin Foundation, and the Wyoming Dinosaur Center. Without whose input and financial support this thesis would not have been possible. In conjunction I would like to thank the staff of the Wyoming Dinosaur Center for the great deal of help that I received during my stay in Thermopolis. Finally I wish to thank my friends and family. To my friends who have pursued this process before me, and with me; thank you very much.
    [Show full text]
  • Copper King Mine, Silver Crown District, Wyoming (Preliminary Report)
    2012 Copper King Mine, Silver Crown District, Wyoming (Preliminary Report) W. Dan Hausel Independent Geologist, Gilbert, Arizona 11/14/2012 COPPER KING MINE, SILVER CROWN DISTRICT W. Dan Hausel, Independent Geologist Gilbert, Arizona Introduction The Silver Crown district (also known as Hecla) lies 20 miles west of Cheyenne and immediately east of Curt Gowdy State Park along the eastern flank of the Laramie Range. The district is visible on Google Earth (search for ‘Hecla, Cheyenne, WY’) and lies within the boundaries of the Laramie 1:100,000 sheet. This area was initially investigated by Klein (1974) as a thesis project, and also by the Wyoming Geological Survey as a potential target for low-grade, large-tonnage, bulk minable gold and copper (Hausel and Jones, 1982). Nearly all mining and exploration activity in the district centered on the Copper King mine and the Hecla ghost-town with its mill constructed to support mining operations in the area (Figure 1). However, the mill was so poorly designed that rejected tailings often assayed higher than the mill concentrates (Figure 2) (Ferguson, 1965). This has been a common problem with many mines in the West – poorly designed mills. For example, four mills constructed nearby in the Colorado-Wyoming State Line district to extract diamonds, rather than copper and gold from 1979 to 1995, also had recovery problems. The last mill built at the Kelsey Lake mine (40o59’38”N; 105o30’05”W) was not only constructed on a portion of the ore body, but also lost many diamonds. After several months of processing, tailings were checked and the first test sample yielded several diamonds including a 6.2 carat stone.
    [Show full text]
  • Stratigraphic Framework of the Cretaceous Mowry Shale, Frontier
    Chapter 15 Stratigraphic Framework of the Cretaceous Mowry Shale, Frontier Formation and Adjacent Units, Southwestern Wyoming Province, Volume Title Page Wyoming, Colorado, and Utah By Mark A. Kirschbaum and Laura N.R. Roberts Chapter 15 of Petroleum Systems and Geologic Assessment of Oil and Gas in the Southwestern Wyoming Province, Wyoming, Colorado, and Utah By USGS Southwestern Wyoming Province Assessment Team U.S. Geological Survey Digital Data Series DDS–69–D U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior Gale A. Norton, Secretary U.S. Geological Survey Charles G. Groat, Director U.S. Geological Survey, Denver, Colorado: Version 1, 2005 For sale by U.S. Geological Survey, Information Services Box 25286, Denver Federal Center Denver, CO 80225 For product and ordering information: World Wide Web: http://www.usgs.gov/pubprod Telephone: 1-888-ASK-USGS For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment: World Wide Web: http://www.usgs.gov Telephone: 1-888-ASK-USGS Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted materials contained within this report. Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government. Manuscript approved for publication May 10, 2005 ISBN= 0-607-99027-9 Contents Abstract ………………………………………………………………………………………
    [Show full text]
  • Eocene Green River Formation, Western United States
    Synoptic reconstruction of a major ancient lake system: Eocene Green River Formation, western United States M. Elliot Smith* Alan R. Carroll Brad S. Singer Department of Geology and Geophysics, University of Wisconsin, 1215 West Dayton Street, Madison, Wisconsin 53706, USA ABSTRACT Members. Sediment accumulation patterns than being confi ned to a single episode of arid thus refl ect basin-center–focused accumula- climate. Evaporative terminal sinks were Numerous 40Ar/39Ar experiments on sani- tion rates when the basin was underfi lled, initially located in the Greater Green River dine and biotite from 22 ash beds and 3 and supply-limited accumulation when the and Piceance Creek Basins (51.3–48.9 Ma), volcaniclastic sand beds from the Greater basin was balanced fi lled to overfi lled. Sedi- then gradually migrated southward to the Green River, Piceance Creek, and Uinta ment accumulation in the Uinta Basin, at Uinta Basin (47.1–45.2 Ma). This history is Basins of Wyoming, Colorado, and Utah Indian Canyon, Utah, was relatively con- likely related to progressive southward con- constrain ~8 m.y. of the Eocene Epoch. Mul- stant at ~150 mm/k.y. during deposition of struction of the Absaroka Volcanic Prov- tiple analyses were conducted per sample over 5 m.y. of both evaporative and fl uctuat- ince, which constituted a major topographic using laser fusion and incremental heating ing profundal facies, which likely refl ects the and thermal anomaly that contributed to a techniques to differentiate inheritance, 40Ar basin-margin position of the measured sec- regional north to south hydrologic gradient. loss, and 39Ar recoil.
    [Show full text]
  • A Preliminary Assessment of Paleontological Resources at Bighorn Canyon National Recreation Area, Montana and Wyoming
    A PRELIMINARY ASSESSMENT OF PALEONTOLOGICAL RESOURCES AT BIGHORN CANYON NATIONAL RECREATION AREA, MONTANA AND WYOMING Vincent L. Santucci1, David Hays2, James Staebler2 And Michael Milstein3 1National Park Service, P.O. Box 592, Kemmerer, WY 83101 2Bighorn Canyon National Recreation Area, P.O. Box 7458, Fort Smith, MT 59035 3P.O. Box 821, Cody, WY 82414 ____________________ ABSTRACT - Paleontological resources occur throughout the Paleozoic and Mesozoic formations exposed in Bighorn Canyon National Recreation Area. Isolated research on specific geologic units within Bighorn Canyon has yielded data on a wide diversity of fossil forms. A comprehensive paleonotological survey has not been previously undertaken at Bighorn Canyon. Preliminary paleontologic resource data is presented in this report as an effort to establish baseline data. ____________________ INTRODUCTION ighorn Canyon National Recreation Area (BICA) consists of approximately 120,000 acres within the Bighorn Mountains of north-central Wyoming and south-central Montana B (Figure 1). The northwestern trending Bighorn Mountains consist of over 9,000 feet of sedimentary rock. The predominantly marine and near shore sedimentary units range from the Cambrian through the Lower Cretaceous. Many of these formations are extremely fossiliferous. The Bighorn Mountains were uplifted during the Laramide Orogeny beginning approximately 70 million years ago. Large volumes of sediments, rich in early Tertiary paleontological resources, were deposited in the adjoining basins. This report provides a preliminary assessment of paleontological resources identified at Bighorn Canyon National Recreation Area. STRATIGRAPHY The stratigraphic record at Bighorn Canyon National Recreation Area extends from the Cambrian through the Cretaceous (Figure 2). The only time period during this interval that is not represented is the Silurian.
    [Show full text]
  • Maps Showing Thermal Maturity of Upper Cretaceous Marine Shales in the Bighorn Basin, Wyoming and Montana
    Maps Showing Thermal Maturity of Upper Cretaceous Marine Shales in the Bighorn Basin, Wyoming and Montana Scientific Investigations Map 3285 U.S. Department of the Interior U.S. Geological Survey Cover photograph: Upper part of Cody Shale near Greybull, Wyoming, east flank of the Bighorn Basin. Photograph by R.C. Johnson, 1994. Maps Showing Thermal Maturity of Upper Cretaceous Marine Shales in the Bighorn Basin, Wyoming and Montana By Thomas M. Finn and Mark J. Pawlewicz Scientific Investigations Map 3285 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior SALLY JEWELL, Secretary U.S. Geological Survey Suzette M. Kimball, Acting Director U.S. Geological Survey, Reston, Virginia: 2014 For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment, visit http://www.usgs.gov or call 1–888–ASK–USGS. For an overview of USGS information products, including maps, imagery, and publications, visit http://www.usgs.gov/pubprod To order this and other USGS information products, visit http://store.usgs.gov Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner. Suggested citation: Finn, T.M., and Pawlewicz, M.J., 2014, Maps showing thermal maturity of Upper Cretaceous marine shales in the Bighorn Basin, Wyoming and Montana: U.S.
    [Show full text]
  • Geology of Wyoming—Nearly 4 Billion Years of Earth History
    8/28/12 1 Geology of Wyoming—nearly 4 billion years of Earth history GEOL 4050, Instructor: A. W. Snoke ([email protected]) Class meetings: MWF, 11:00–11:50 pm, Engineering Building, Room 3106 Office hours: M: 2:00–3:00 pm, W: 2:00–3:00 pm, Th: 2:00–3:00 pm or by appointment. Note: Assigned readings are on the University Libraries e-reserves. Recommended reference: Bates, R. L., and Jackson, J. A., eds., 1984, Dictionary of Geological Terms (3rd edition): New York, Anchor Books, 571 p. Apparently, copies of this book are available in the “Trade Book” section of the University Bookstore (First Floor). General references: Love, J. D., and Christiansen, Ann Coe, 1985, Geologic map of Wyoming: U.S. Geological Survey, scale 1:500,000. (A strongly recommended purchase.) Love, J. D., Christiansen, Ann Coe, and Ver Ploeg, A. J., 1993, Stratigraphic chart showing Phanerozoic nomenclature for the State of Wyoming: Geological Survey of Wyoming MS- 41. (This chart is very useful for sorting out the complex Phanerozoic stratigraphic nomenclature of Wyoming.) Snoke, A. W., Steidtmann, J. R., and Roberts, S. M., eds., 1993, Geology of Wyoming (2 volumes + map pocket): Geological Survey of Wyoming Memoir No. 5, 937 p. (This set was reprinted in 2002, and now is available in soft-back cover with a CD containing all oversized foldout plates. Please see Mr. Brendon Orr in the S.H. Knight Geology Building, Room 135, if you wish to purchase a set of these volumes.) Please note that the purchase of these volumes is NOT required by the instructor—all pertinent papers from these volumes are available in the Brinkerhoff Earth Resources Information Center.
    [Show full text]
  • The First Record of Freshwater Plesiosaurian from the Middle
    Gao et al. Journal of Palaeogeography (2019) 8:27 https://doi.org/10.1186/s42501-019-0043-5 Journal of Palaeogeography ORIGINALARTICLE Open Access The first record of freshwater plesiosaurian from the Middle Jurassic of Gansu, NW China, with its implications to the local palaeobiogeography Ting Gao, Da-Qing Li* , Long-Feng Li and Jing-Tao Yang Abstract Plesiosaurs are one of the common groups of aquatic reptiles in the Mesozoic, which mainly lived in marine environments. Freshwater plesiosaurs are rare in the world, especially from the Jurassic. The present paper reports the first freshwater plesiosaur, represented by four isolated teeth from the Middle Jurassic fluviolacustrine strata of Qingtujing area, Jinchang City, Gansu Province, Northwest China. These teeth are considered to come from one individual. The comparative analysis of the corresponding relationship between the body and tooth sizes of the known freshwater plesiosaur shows that Jinchang teeth represent a small-sized plesiosaurian. Based on the adaptive radiation of plesiosaurs and the palaeobiogeographical context, we propose a scenario of a river leading to the Meso-Tethys in the Late Middle Jurassic in Jinchang area, which may have provided a channel for the seasonal migration of plesiosaurs. Keywords: Freshwater plesiosaur, Middle Jurassic, Jinchang, Gansu Province, Palaeobiogeography 1 Introduction Warren 1980;Satoetal.2003; Kear 2012). Up to now, Plesiosaurs are one of the most familiar groups of Mesozoic the taxonomic affinities of most freshwater plesio- marine reptiles, which mainly lived in marine environ- saurs have remained unclear; some of them are re- ments. The records of plesiosaurs in non-marine deposits ferred to Plesiosauroidea (Cruickshank and Fordyce are sparse in comparison to those from marine sediments.
    [Show full text]
  • CORRELATION of the UPPER CRETACEOUS STRATA of WYOMING Stratigraphic Chart Director and State Geologist Upper Cretaceous Laramie, Wyoming by Ranie M
    WYOMING STATE GEOLOGICAL SURVEY Open File Report 2017-3 Thomas A. Drean CORRELATION OF THE UPPER CRETACEOUS STRATA OF WYOMING Stratigraphic Chart Director and State Geologist Upper Cretaceous Laramie, Wyoming by Ranie M. Lynds and Joshua S. Slattery Wyoming Interpreting the past, providing for the future 2017 Western Hanna Laramie Bighorn Denver Greater Green River Basin Wind River Basin Powder River Basin Wyoming Basin Basin Basin Basin A B C D E F G H I J K L M N O P Q R S T U V W X Y Age Period Epoch Stage and Stage Polarity U.S. Western Interior U.S. Western Interior U.S. Western Interior North American U.S. Western Interior Southern Jackson Northwestern Southern Eastern Eastern Atlantic Rocky Point Separation Lost Soldier Tully Rawlins Hanna Laramie Western Southern and Eastern Bighorn Northwestern Salt Creek Southwestern Southeastern Central Northwestern Denver (Ma) Boundary Chron Radiometric Ammonite Inoceramid Land Vertebrate Palynostratigraphic Thrust Belt Hole and Rock Springs Rock Springs Rock Springs Washakie Rim Rim Ranch Draw Basin Basin, Wind River Central Wind Wind River Basin Powder Powder Powder River Black Hills Black Hills Basin (Ma) Age (Ma) Biozone Biozone Age Biozone Hoback Basin Uplift Uplift Uplift Basin Rock River Basin River Basin Basin River Basin River Basin Basin (7, 56, 77) (7, 56, 74) (8, 49, 54, 55, 56, 69, 72) (7, 23, 25, 56, 74) (7, 56, 74) (2, 33, 35, 77) (50) (6, 10, 29, 30, 47, 53, (6, 11, 12, 22, 32, 37, (12, 26, 30, 64, 72, (12, 26, 30, 36, 63, 64, (12, 19, 20, 26, 29, 30, (1, 12, 21, 30, 36, 58,
    [Show full text]
  • A Cladistic Analysis and Taxonomic Revision of the Plesiosauria (Reptilia: Sauropterygia) F
    Marshall University Marshall Digital Scholar Biological Sciences Faculty Research Biological Sciences 12-2001 A Cladistic Analysis and Taxonomic Revision of the Plesiosauria (Reptilia: Sauropterygia) F. Robin O’Keefe Marshall University, [email protected] Follow this and additional works at: http://mds.marshall.edu/bio_sciences_faculty Part of the Aquaculture and Fisheries Commons, and the Other Animal Sciences Commons Recommended Citation Frank Robin O’Keefe (2001). A cladistic analysis and taxonomic revision of the Plesiosauria (Reptilia: Sauropterygia). ). Acta Zoologica Fennica 213: 1-63. This Article is brought to you for free and open access by the Biological Sciences at Marshall Digital Scholar. It has been accepted for inclusion in Biological Sciences Faculty Research by an authorized administrator of Marshall Digital Scholar. For more information, please contact [email protected], [email protected]. Acta Zool. Fennica 213: 1–63 ISBN 951-9481-58-3 ISSN 0001-7299 Helsinki 11 December 2001 © Finnish Zoological and Botanical Publishing Board 2001 A cladistic analysis and taxonomic revision of the Plesiosauria (Reptilia: Sauropterygia) Frank Robin O’Keefe Department of Anatomy, New York College of Osteopathic Medicine, Old Westbury, New York 11568, U.S.A Received 13 February 2001, accepted 17 September 2001 O’Keefe F. R. 2001: A cladistic analysis and taxonomic revision of the Plesio- sauria (Reptilia: Sauropterygia). — Acta Zool. Fennica 213: 1–63. The Plesiosauria (Reptilia: Sauropterygia) is a group of Mesozoic marine reptiles known from abundant material, with specimens described from all continents. The group originated very near the Triassic–Jurassic boundary and persisted to the end- Cretaceous mass extinction. This study describes the results of a specimen-based cladistic study of the Plesiosauria, based on examination of 34 taxa scored for 166 morphological characters.
    [Show full text]
  • Paleontological Resources Technical Report Riley Ridge to Natrona Project DECEMBER 2018
    U.S. Department of the Interior Bureau of Land Management Paleontological Resources Technical Report Riley Ridge to Natrona Project DECEMBER 2018 Table of Contents 1.0 Introduction ......................................................................................................................................... 1 2.0 Regional Setting .................................................................................................................................. 1 3.0 Inventory Methodology ....................................................................................................................... 1 4.0 Potential Fossil-Bearing Geologic Formations ................................................................................... 4 4.1 Browns Park Formation (PFYC 3) ............................................................................................ 4 4.2 White River Formation or Group (PFYC 5) .............................................................................. 5 4.3 Wind River Formation (PFYC 5) .............................................................................................. 5 4.4 Green River Formation (PFYC 5) ............................................................................................. 5 4.5 Wasatch Formation (PFYC 5) ................................................................................................... 5 4.6 Battle Spring Formation (PFYC 3)............................................................................................ 6 4.7 Bridger Formation
    [Show full text]
  • Neogene-Quaternary Tectonics and Volcanism of Southern Jackson Hole, Wyoming and Southeastern Idaho
    Lageson and others -- Neogene-Quaternary Tectonics and Volcanism 115 Neogene-Quaternary Tectonics and Volcanism of Southern Jackson Hole, Wyoming and Southeastern Idaho David R. Lageson Department of Earth Sciences, Montana State University, Bozeman, MT 59717 David C. Adams Department of Earth Sciences, Montana State University, Bozeman, MT 59717 Lisa Morgan U.S. Geological Survey, Box 25046, MS-966, Federal Center, Denver, CO 80225 Kenneth L. Pierce U.S. Geological Survey, Box 25046, MS-980, Federal Center, Denver, CO 80225 Robert B. Smith Department of Geology and Geophysics, 717 W.C. Browning Building, University of Utah, Salt Lake City, UT 84112 INTRODUCTION This field trip guide focuses on the region south of the Snake volcanic rocks of the Snake River Plain Yellowstone region River Plain between Pocatello, Idaho and Jackson, Wyoming (Fig. (Adams, 1997). The second aspect involves a reinterpretation of 1). Our intent is not to rewrite the excellent geologic field guides large slide blocks found primarily within the Grand-Swan Valley that have already been published (e.g., Love and Reed, 1971; of southeast Idaho. We (Morgan and Lageson) suggest an alter- Love and Love, 1983; Love and Love, 1988; Love, 1989; Smith native hypothesis to the slow creep model of emplacement and Downs, 1989; Smith et al., 1990; Pierce and Good, 1992; (Boyer and Hossack, 1992), namely that some slide blocks may Good and Pierce, 1996), but rather to synthesize regional tec- have been emplaced catastrophically during large magnitude earth- tonic relations and present new information relative to the mag- quakes associated with large-volume silicic eruptions in the Heise matic and structural history of the region.
    [Show full text]