DOCSLIB.ORG

Structural Geology of Parautochthonous and Allochthonous Terranes of the Penokean Orogeny in Upper Michigan Comparisons with Northern Appalachian Tectonics

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Structural Geology of Parautochthonous and Allochthonous Terranes of the Penokean Orogeny in Upper Michigan Comparisons with Northern Appalachian Tectonics Structural Geology of Parautochthonous and Allochthonous Terranes of the Penokean Orogeny in Upper Michigan Comparisons with Northern Appalachian Tectonics U.S. GEOLOGICAL SURVEY BULLETIN 1904-Q AVAILABILITY OF BOOKS AND MAPS OF THE U.S. GEOLOGICAL SURVEY Instructions on ordering publications of the U.S. Geological Survey, along with the last offerings, are given in the current-year issues of the monthly catalog "New Publications of the U.S. Geological Survey." Prices of available U.S. Geological Survey publications released prior to the current year are listed in the most recent annual "Price and Availability List." Publications that are listed in various U.S. Geological Survey catalogs (see back inside cover) but not listed in the most recent annual "Price and Availability List" are no longer available. Prices of reports released to the open files are given in the listing "U.S. Geological Survey Open-File Reports," updated monthly, which is for sale in microfiche from the U.S. Geological Survey, Book and Open-File Report Sales, Box 25286, Building 810, Denver Federal Center, Denver, CO 80225 Order U.S. Geological Survey publications by mail or over the counter from the offices given below. BY MAIL OVER THE COUNTER Books Books Professional Papers, Bulletins, Water-Supply Papers, Tech­ Books of the U.S. Geological Survey are available over the niques of Water-Resources Investigations, Circulars, publications counter at the following U.S. Geological Survey offices, all of of general interest (such as leaflets, pamphlets, booklets), single which are authorized agents of the Superintendent of Documents. copies of periodicals (Earthquakes & Volcanoes, Preliminary De­ termination of Epicenters), and some miscellaneous reports, includ­ ANCHORAGE, Alaska-Rm. 101,4230 University Dr. ing some of the foregoing series that have gone out of print at the Superintendent of Documents, are obtainable by mail from LAKEWOOD, Colorado-Federal Center, Bldg. 810 MENLO PARK, California-Bldg. 3, Rm. 3128, U.S. Geological Survey, 345 Middlefield Rd. Book and Open-File Report Sales Box 25286, RESTON, Virginia-USGS National Center, Rm. 1C402, Denver, CO 80225 12201 Sunrise Valley Dr. SALT LAKE CITY, Utah-Federal Bldg., Rm. 8105, Subscriptions to periodicals (Earthquakes & Volcanoes and 125 South State St. Preliminary Determination of Epicenters) can be obtained ONLY from SPOKANE, Washington-U.S. Courthouse, Rm. 678, West 920 Riverside Ave. Superintendent of Documents WASHINGTON, D.C.-U.S. Department of the Interior Bldg., U.S. Government Printing Office Rm. 2650,1849 C St., NW. Washington, DC 20402 Maps (Check or money order must be payable to Superintendent of Documents.) Maps may be purchased over the counter at the U.S. Geolog­ ical Survey offices where books are sold (all addresses in above list) Maps and at the following Geological Survey offices: For maps, address mail order to ROLLA, Missouri-1400 Independence Rd. USGS Map Distribution FAIRBANKS, Alaska-New Federal Building, Box 25286, Building 810 101 Twelfth Ave. Denver Federal Center STENNIS SPACE CENTER, Mississippi-Bldg. 3101 Denver, CO 80225 Residents of Alaska may order maps from U.S. Geological Survey, Map Sales 101 Twelfth Ave., Box 12 Fairbanks, AK 99701 Chapter Q Structural Geology of Parautochthonous and Allochthonous Terranes of the Penokean Orogeny in Upper Michigan Comparisons with Northern Appalachian Tectonics By WILLIAM J. GREGG U.S. GEOLOGICAL SURVEY BULLETIN 1904 CONTRIBUTIONS TO PRECAMBRIAN GEOLOGY OF LAKE SUPERIOR REGION P.K. SIMS and L.M.H. CARTER, Editors U.S. DEPARTMENT OF THE INTERIOR BRUCE BABBITT, Secretary U.S. GEOLOGICAL SURVEY Dallas L. Peck, Director 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. UNITED STATES GOVERNMENT PRINTING OFFICE: 1993 For sale by USGS Map Distribution Box 25286, Building 810 Denver Federal Center Denver, CO 80225 Library of Congress Cataloging-in-Publication Data Cregg, William J. Structural geology of parautochthonous and allochthonous terranes of the Penokean orogeny in upper Michigan comparisons with northern Appalachian tectonics / by William j. Cregg. p. cm. (U.S. Geological Survey bulletin ; 1904-Q) (Contributions to Precambrian geology of Lake Superior region; ch. Q) Includes bibliographical references. Supt. of Docs, no.: I 19.3:B1904-Q 1. Geology, Stratigraphic Precambrian. 2. Geology, Structural Michigan. I. Title. II. Series. III. Series: Contributions to Precambrian geology of Lake Superior region; ch. Q. QE75.B9 no. 1904-Q [QE653] 557.3 s dc20 92-27843 [551.7'1'09774] CIP CONTENTS Abstract Ql Introduction Ql Acknowledgments Q3 Structural setting in northern Baraga County Q4 Structures in the Huron River parautochthon Q5 Folds Q5 Foliations Q5 Strain associated with BI deformation Q5 Faults Q6 Structures in the Falls River slice Q6 Folds Q6 Foliations Q12 Strain associated with BI deformation Q14 Faults Q15 Implications for Penokean tectonics in Michigan and Minnesota Q15 Nappe structures Q15 Correlation of thrust boundaries Q17 Correlation of mesoscopic structures Q17 Comparisons with northern Appalachian tectonics Q20 Similarity in terrane assemblages Q20 Origin of gneiss domes Q21 Basement detachments in the Penokean orogen Q21 Origin of metamorphic nodes Q25 Rotation of gneiss domes Q25 References cited Q26 FIGURES 1. Map showing tectonic setting of the Early Proterozoic of Upper Michigan Q2 2. Map showing macroscopic structural setting of the Baraga belt Q4 3. Sketches of typical BI fold profiles in Huron River parautochthon and Falls River allochthon Q7 4. Equal-area hemispherical plots showing mesoscopic structures from Keweenaw Bay to the Falls River and Little Mountain Q8 5. Photomicrographs of chlorite-white mica aggregates in slate of the Michigamme Formation of the Huron River parautochthon Q9 6. Photomicrograph showing microstructure of large opaque minerals in slate of the Michigamme Formation of the Huron River parautochthon Q10 7. Modified Flinn diagram of reduction spot measurements from the slate of the Michi­ gamme Formation of the Baraga belt Qll 8. Sketch of telescoped iron-rich cherty bed in slate of the Michigamme Formation Q12 9. Equal-area hemispherical plots of faults and related features in the Baraga belt Q13 10. Photomicrographs of microstructures in slate of the Michigamme Formation Q14 Contents III 11. Graph of strain distribution shown by reduction spots in slate of the Michigamme Formation Q15 12. Photographs showing mylonites from Penokean thrust faults in Upper Michigan Q16 13. Equal-area hemispherical plots showing rotation of BI structural elements by the Covington section fault Q18 14. Photomicrographs showing microscopic structures in slates, Carl ton County, Minnesota Q19 15. Sketch section comparing tectonic terranes in the Northern Appalachians and Upper Michigan Q22 16. Map and structural model for the development of late Penokean faults in northern Michigan Q24 TABLES 1. Correlation chart of Early Proterozoic rocks in northern Michigan Q3 2. Reduction spot data for slate of the Michigamme Formation Q12 IV Contents CONTRIBUTIONS TO PRECAMBRIAN GEOLOGY OF LAKE SUPERIOR REGION Structural Geology of Parautochthonous and Allochthonous Terranes of the Penokean Orogeny in Upper Michigan Comparisons with Northern Appalachian Tectonics By William J. Gregg1 Abstract In northern (Upper) Michigan this structural setting is part of a regional terrane assemblage that is strikingly similar to that The Precambrian terrane of Michigan's Upper Peninsula of the northern Appalachians. Both regions contain a parau­ consists largely of Archean massifs and mantled gneiss domes tochthonous and allochthonous foreland, followed laterally by surrounded by weakly to highly strained belts of Proterozoic a detached basement massif, a tightly appressed metasedimen­ metasedimentary rocks deformed during the Penokean orog­ tary synform, and a compressional mantled gneiss dome- eny, about 1 .85 Ca. The rocks in these Early Proterozoic belts synform complex. The two regions differ in that the deforma­ consist of a thin lower sequence of shelf and shallow-water tion of both basement and cover rocks is of higher intensity in sediments, overlain by a thick upper sequence of slate, silt- the Appalachians. stone, and discontinuous graywacke units, known as the upper In northern Michigan, curved metamorphic isograds may slate member of the Michigamme Formation. The Baraga belt, be related to relative structural position in the gneiss dome- in northern Baraga County, typifies the structural setting of the synform terrane, with the highest metamorphic grade being in upper slate member. The belt can be divided into a weakly the deep synformal hinges. The gneiss domes may have been deformed terrane, the Huron River parautochthon, to the rotated from an initial east-west trend by late Penokean faults north, and a polyphase-deformed terrane, the allochthonous produced by north-northeast-directed tectonic indentation by Falls River slice, to the south. The change in structural style and an irregular projection on the north edge of the Wisconsin finite strain between the two terranes occurs abruptly along the magmatic arc terranes. east-west-trending Falls River thrust, which appears to corre­ The tectonic interpretations presented in this report sug­ late with a similar, previously recognized boundary in Carlton gest that at the beginning of the Proterozoic, the southern com­ County, Minnesota. plex and possibly part of the
Load more

Recommended publications
  • Tectonic Imbrication and Foredeep Development in the Penokean
    Tectonic Imbrication and Foredeep Development in the Penokean Orogen, East-Central Minnesota An Interpretation Based on Regional Geophysics and the Results of Test-Drilling The Penokean Orogeny in Minnesota and Upper Michigan A Comparison of Structural Geology U.S. GEOLOGICAL SURVEY BULLETIN 1904-C, D AVAILABILITY OF BOOKS AND MAPS OF THE U.S. GEOLOGICAL SURVEY Instructions on ordering publications of the U.S. Geological Survey, along with prices of the last offerings, are given in the cur­ rent-year issues of the monthly catalog "New Publications of the U.S. Geological Survey." Prices of available U.S. Geological Sur­ vey publications released prior to the current year are listed in the most recent annual "Price and Availability List." Publications that are listed in various U.S. Geological Survey catalogs (see back inside cover) but not listed in the most recent annual "Price and Availability List" are no longer available. Prices of reports released to the open files are given in the listing "U.S. Geological Survey Open-File Reports," updated month­ ly, which is for sale in microfiche from the U.S. Geological Survey, Books and Open-File Reports Section, Federal Center, Box 25425, Denver, CO 80225. Reports released through the NTIS may be obtained by writing to the National Technical Information Service, U.S. Department of Commerce, Springfield, VA 22161; please include NTIS report number with inquiry. Order U.S. Geological Survey publications by mail or over the counter from the offices given below. BY MAIL OVER THE COUNTER Books Books Professional Papers, Bulletins, Water-Supply Papers, Techniques of Water-Resources Investigations, Circulars, publications of general in­ Books of the U.S.
    [Show full text]
  • Geological and Seismic Evidence for the Tectonic Evolution of the NE Oman Continental Margin and Gulf of Oman GEOSPHERE, V
    Research Paper GEOSPHERE Geological and seismic evidence for the tectonic evolution of the NE Oman continental margin and Gulf of Oman GEOSPHERE, v. 17, no. X Bruce Levell1, Michael Searle1, Adrian White1,*, Lauren Kedar1,†, Henk Droste1, and Mia Van Steenwinkel2 1Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK https://doi.org/10.1130/GES02376.1 2Locquetstraat 11, Hombeek, 2811, Belgium 15 figures ABSTRACT Arabian shelf or platform (Glennie et al., 1973, 1974; Searle, 2007). Restoration CORRESPONDENCE: [email protected] of the thrust sheets records several hundred kilometers of shortening in the Late Cretaceous obduction of the Semail ophiolite and underlying thrust Neo-Tethyan continental margin to slope (Sumeini complex), basin (Hawasina CITATION: Levell, B., Searle, M., White, A., Kedar, L., Droste, H., and Van Steenwinkel, M., 2021, Geological sheets of Neo-Tethyan oceanic sediments onto the submerged continental complex), and trench (Haybi complex) facies rocks during ophiolite emplace- and seismic evidence for the tectonic evolution of the margin of Oman involved thin-skinned SW-vergent thrusting above a thick ment (Searle, 1985, 2007; Cooper, 1988; Searle et al., 2004). The present-day NE Oman continental margin and Gulf of Oman: Geo- Guadalupian–Cenomanian shelf-carbonate sequence. A flexural foreland basin southwestward extent of the ophiolite and Hawasina complex thrust sheets is sphere, v. 17, no. X, p. 1– 22, https:// doi .org /10.1130 /GES02376.1. (Muti and Aruma Basin) developed due to the thrust loading. Newly available at least 150 km across the Arabian continental margin. The obduction, which seismic reflection data, tied to wells in the Gulf of Oman, suggest indirectly spanned the Cenomanian to Early Maastrichtian (ca 95–72 Ma; Searle et al., Science Editor: David E.
    [Show full text]
  • Nd Isotope Mapping of the Grenvillian Allochthon Boundary Thrust in Algonquin Park, Ontario
    Canadian Journal of Earth Sciences Nd isotope mapping of the Grenvillian Allochthon Boundary Thrust in Algonquin Park, Ontario Journal: Canadian Journal of Earth Sciences Manuscript ID cjes-2018-0142.R1 Manuscript Type: Article Date Submitted by the 26-Sep-2018 Author: Complete List of Authors: Dickin, Alan; School of Geography and Geology Strong, Jacob; School of Geography and Geology Keyword: Nd isotopes,Draft Model ages, Grenville Province Is the invited manuscript for consideration in a Special Not applicable (regular submission) Issue? : https://mc06.manuscriptcentral.com/cjes-pubs Page 1 of 34 Canadian Journal of Earth Sciences 1 Nd isotope mapping of the Grenvillian Allochthon Boundary Thrust in Algonquin Park, 2 Ontario 3 4 A.P. Dickin and J.W.D. Strong 5 School of Geography and Earth Sciences, McMaster University, Hamilton ON, Canada 6 7 Abstract 8 Over fifty new Nd isotope analyses are presented for high-grade orthogneisses from 9 Algonquin Park and surrounding region in order to map major Grenvillian thrust boundaries. Nd 10 model ages display a consistent geographical pattern that allows detailed mapping of the 11 boundary between the Algonquin and MuskokaDraft domains, here interpreted as the local trajectory 12 of the Ottawan-age Allochthon Boundary Thrust (ABT). The ABT is underlain by a domain with 13 Paleoproterozoic Nd model ages, interpreted as a tectonic duplex entrained onto the base of the 14 main allochthon. The boundaries determined using Nd isotope mapping are consistent with field 15 mapping and with remotely sensed aeromagnetic and digital elevation data. The precise location 16 of the ABT can be observed in a road-cut on Highway 60, on the north shore of the Lake of Two 17 Rivers in the centre of Algonquin Park.
    [Show full text]
  • Glacial Tectonics: a Deeper Perspective Robert M
    Quaternary Science Reviews 19 (2000) 1391}1398 Glacial tectonics: a deeper perspective Robert M. Thorson* Department of Geology and Geophysics, University of Connecticut, 345 Mansxeld Road (U-45), Storrs, CT 06269, USA Abstract The upper 5}10 km of the lithosphere is sensitive to slight changes ((0.1 MPa) in local stress caused by di!erential loading, #uid #ow, the mechanical transfer of strain between faults, and viscoelastic relaxation in the aesthenosphere. Lithospheric stresses induced by mass and #uid transfers associated with Quaternary ice sheets a!ected the tectonic regimes of stable cratons and active plate margins. In the latter case, it is di$cult to di!erentiate glacially induced fault displacements from nonglacial ones, particularly if residual glacial stresses are considered. Glaciotectonics, a sub-subdiscipline within Quaternary geology is historically focussed on reconstructing past glacier regimes and, by de"nition, does not include these e!ects. The term `glacial tectonicsa is hereby suggested for investigations focussed on the past and continuing in#uences of ice sheets on contemporary tectonics. ( 2000 Elsevier Science Ltd. All rights reserved. 1. Introduction e!ects of glacial mass transfers is blurring the distinction between the study of tectonics, per se, and the study of Presently, there is a conceptual shift in the geosciences `glaciotectonicsa, which, historically, has been primarily away from increasing specialization, towards more inte- concerned with deformed glacial deposits. grative problems at global scales, a shift embodied by the In this paper I show how the physical coupling be- phrase `Earth System Sciencea (Kump et al., 1999). Si- tween glaciation and crustal deformation extends far multaneously, technologically driven advances in instru- beyond the decollement between ice and its substrate (i.e.
    [Show full text]
  • "Preserve Analysis : Saddle Mountain"
    PRESERVE ANALYSIS: SADDLE MOUNTAIN Pre pare d by PAUL B. ALABACK ROB ERT E. FRENKE L OREGON NATURAL AREA PRESERVES ADVISORY COMMITTEE to the STATE LAND BOARD Salem. Oregon October, 1978 NATURAL AREA PRESERVES ADVISORY COMMITTEE to the STATE LAND BOARD Robert Straub Nonna Paul us Governor Clay Myers Secretary of State State Treasurer Members Robert Frenkel (Chairman), Corvallis Bill Burley (Vice Chainnan), Siletz Charles Collins, Roseburg Bruce Nolf, Bend Patricia Harris, Eugene Jean L. Siddall, Lake Oswego Ex-Officio Members Bob Maben Wi 11 i am S. Phe 1ps Department of Fish and Wildlife State Forestry Department Peter Bond J. Morris Johnson State Parks and Recreation Branch State System of Higher Education PRESERVE ANALYSIS: SADDLE MOUNTAIN prepared by Paul B. Alaback and Robert E. Frenkel Oregon Natural Area Preserves Advisory Committee to the State Land Board Salem, Oregon October, 1978 ----------- ------- iii PREFACE The purpose of this preserve analysis is to assemble and document the significant natural values of Saddle Mountain State Park to aid in deciding whether to recommend the dedication of a portion of Saddle r10untain State Park as a natural area preserve within the Oregon System of I~atural Areas. Preserve management, agency agreements, and manage­ ment planning are therefore not a function of this document. Because of the outstanding assemblage of wildflowers, many of which are rare, Saddle r·1ountain has long been a mecca for· botanists. It was from Oregon's botanists that the Committee initially received its first documentation of the natural area values of Saddle Mountain. Several Committee members and others contributed to the report through survey and documentation.
    [Show full text]
  • Geotectonic Model of the Alpine Development of Lakavica Graben in the Eastern Part of the Vardar Zone in the Republic of Macedonia
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by UGD Academic Repository Geologica Macedonica, Vol. 27, No. 1, pp. 87–93 (2013) GEOME 2 ISSN 0352 – 1206 Manuscript received: May 17, 2013 UDC: 551.245.03(497.71/.73) Accepted: October 25, 2013 Original scientific paper GEOTECTONIC MODEL OF THE ALPINE DEVELOPMENT OF LAKAVICA GRABEN IN THE EASTERN PART OF THE VARDAR ZONE IN THE REPUBLIC OF MACEDONIA Goše Petrov, Violeta Stojanova, Gorgi Dimov Faculty of Natural and Technical Sciences, “Goce Delčev” University, P.O.Box 201, MK 2000 Štip, Republic of Macedonia [email protected]//[email protected] A b s t r a c t: Lakavica graben is located in the eastern subzone of the Vardar zone, which during the Alpine orogenesis was covered with very complex processes of tectogenesis. On the area of about 200 km2, in the Lakavica graben, are present geological units from the oldest geological periods (Precam- brian) to the youngest (Neogene and Quaternary). Tectonic structure, or rupture tectonic, is very intense developed and gives possibility for analysis of the geotectonic processes in the Alpine orogen phase. This paper presents the possible model for geotectonic processes in the Lakavica graben, according to which can be generalized geotectonic processes in the Vardar zone during the Alpine orogeny. Key words: Lakavica graben; geotectonic model; Alpine orogeny; Vardar zone INTRODUCTION Vardar zone as a tectonic unit, for the first niki Gulf (Greece), than bent eastward and crosses time, is separated and showed on the "Geological- the ophiolite zone Izmir–Ankara (Turkey).
    [Show full text]
  • Map: Basement-Cover Relationships
    Downloaded from http://sp.lyellcollection.org/ by guest on September 30, 2021 • BASEMENT-COVER RELATIONSHIPS Downloaded from http://sp.lyellcollection.org/ by guest on September 30, 2021 BASEMENT-COVER RELATIONSHIPS FLINN ET AL~g~ JOHNSTONE ET AL RATHBONE ~ HARRIS~'~ RAMSAY & STURT SANDERSi I & VAN BREEMEN BREWER ET AL" 0 km 100 I I WATSON & DUNNING- GENERAL REVIEW KENNAN ET AL-- PARATECTONIC IRELAND BAMFORD-- SEISMIC CONSTRAINTS Downloaded from http://sp.lyellcollection.org/ by guest on September 30, 2021 The Caledonides of the British Isles--reviewed. 1979. Geological Society of London. Basement-cover relations in the British Caledonides Janet Watson & F. W. Dunning CONTENTS 1. Introduction 67 2. The Metamorphic Caledonides 68 a The Lewisian complex and related rocks 68 b Pre-Caledonian cover units 70 c Other possible basement units 72 d The Caledonian orogenic front 73 e Grenville activity in the northern Caledonian province 74 3. The Non-metamorphic Caledonides 76 a Basic facts relating to the belt in general 76 b The Midland Valley Transition Zone 77 c The Southern Uplands-Longford-Down-Clare Inliers Belt 83 d The Iapetus Suture 84 e The Lake District-Isle of Man-Leinster Belt 84 f The Irish Sea Horst 85 g The Welsh Basin and its eastern borders 85 h Eastern England 86 j The Midland Craton 86 4. Conclusions 87 5. Acknowledgements 88 6. References 88 1. Introduction underlying the Metamorphic Caledonides (which Although the conventional regional subdivi- consists mainly of gneisses) and that underlying sion of the British and Irish
    [Show full text]
  • From Orogeny to Rifting: When and How Does Rifting Begin? Insights from the Norwegian ‘Reactivation Phase’
    EGU21-469 https://doi.org/10.5194/egusphere-egu21-469 EGU General Assembly 2021 © Author(s) 2021. This work is distributed under the Creative Commons Attribution 4.0 License. From orogeny to rifting: when and how does rifting begin? Insights from the Norwegian ‘reactivation phase’. Gwenn Peron-Pinvidic1,2, Per Terje Osmundsen2, Loic Fourel1, and Susanne Buiter3 1NGU - Geological Survey of Norway, 7040 Trondheim, Norway 2NTNU - Norwegian University of Science and Technology, 7491 Trondheim, Norway 3Tectonics and Geodynamics, RWTH Aachen University, 52064 Aachen, Germany Following the Wilson Cycle theory, most rifts and rifted margins around the world developed on former orogenic suture zones (Wilson, 1966). This implies that the pre-rift lithospheric configuration is heterogeneous in most cases. However, for convenience and lack of robust information, most models envisage the onset of rifting based on a homogeneously layered lithosphere (e.g. Lavier and Manatschal, 2006). In the last decade this has seen a change, thanks to the increased academic access to high-resolution, deeply imaging seismic datasets, and numerous studies have focused on the impact of inheritance on the architecture of rifts and rifted margins. The pre-rift tectonic history has often been shown as strongly influencing the subsequent rift phases (e.g. the North Sea case - Phillips et al., 2016). In the case of rifts developing on former orogens, one important question relates to the distinction between extensional structures formed during the orogenic collapse and the ones related to the proper onset of rifting. The collapse deformation is generally associated with polarity reversal along orogenic thrusts, ductile to brittle deformation and important crustal thinning with exhumation of deeply buried rocks (Andersen et al., 1994; Fossen, 2000).
    [Show full text]
  • Development of the Rocky Mountain Foreland Basin: Combined Structural
    University of Montana ScholarWorks at University of Montana Graduate Student Theses, Dissertations, & Professional Papers Graduate School 2007 DEVELOPMENT OF THE ROCKY MOUNTAIN FORELAND BASIN: COMBINED STRUCTURAL, MINERALOGICAL, AND GEOCHEMICAL ANALYSIS OF BASIN EVOLUTION, ROCKY MOUNTAIN THRUST FRONT, NORTHWEST MONTANA Emily Geraghty Ward The University of Montana Follow this and additional works at: https://scholarworks.umt.edu/etd Let us know how access to this document benefits ou.y Recommended Citation Ward, Emily Geraghty, "DEVELOPMENT OF THE ROCKY MOUNTAIN FORELAND BASIN: COMBINED STRUCTURAL, MINERALOGICAL, AND GEOCHEMICAL ANALYSIS OF BASIN EVOLUTION, ROCKY MOUNTAIN THRUST FRONT, NORTHWEST MONTANA" (2007). Graduate Student Theses, Dissertations, & Professional Papers. 1234. https://scholarworks.umt.edu/etd/1234 This Dissertation is brought to you for free and open access by the Graduate School at ScholarWorks at University of Montana. It has been accepted for inclusion in Graduate Student Theses, Dissertations, & Professional Papers by an authorized administrator of ScholarWorks at University of Montana. For more information, please contact [email protected]. DEVELOPMENT OF THE ROCKY MOUNTAIN FORELAND BASIN: COMBINED STRUCTURAL, MINERALOGICAL, AND GEOCHEMICAL ANALYSIS OF BASIN EVOLUTION ROCKY MOUNTAIN THRUST FRONT, NORTHWEST MONTANA By Emily M. Geraghty Ward B.A., Whitman College, Walla Walla, WA, 1999 M.S., Washington State University, Pullman, WA, 2002 Dissertation presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Geology The University of Montana Missoula, MT Spring 2007 Approved by: Dr. David A. Strobel, Dean Graduate School James W. Sears, Chair Department of Geosciences Julia A. Baldwin Department of Geosciences Marc S. Hendrix Department of Geosciences Steven D.
    [Show full text]
  • Juan Gómez-Barreiro Dear Editor, Thanks for Your Message. It Is
    To Topical Editor: Juan Gómez-Barreiro Dear editor, Thanks for your message. It is rather unusual to receive a third revision from an editor, but we have tried to follow your last remarks. See below some explanations, because we have not properly understood some of your queries. A) It is not clear how the authors choose the studied areas in the Iberian Massif. A short description on these criteria could be very useful for the interested reader. The criteria for the selection of the targeted study areas was (and still is) explained at the end of the Introduction section. “Until now the Toledanian and Sardic magmatic events had been studied on different areas and interpreted separately, without taking into account their similarities and differences. In this work, the geochemical affinities of the Furongian–Early Ordovician (Toledanian) and Early–Late Ordovician (Sardic) felsic magmatic activities recorded in the Central Iberian and Galicia-Trás-os-Montes Zones, Pyrenees, Occitan Domain and Sardinia are compared. The re-appraisal is based on 17 new samples from the Pyrenees, Montagne Noire and Sardinia, completing the absence of analysis in these areas and wide- ranging a dataset of 93 previously published geochemical analyses throughout the study region in south-western Europe”. • Besides, according to up-to-date references (e.g. Martínez Catalán et al 2019; https://doi.org/10.1007/978-3-030-10519-8_4), the Cantabrian, Westasturian-Leonese and Central Iberian zones were part of the Gondwana margin at that time span (broadly autochthon), while in the Galicia -Trás-os-Montes zone (Allochthon), only those units below the Ophiolites are clearly of that affinity (Basal and Parautochthon units).
    [Show full text]
  • Shear Zone-Related Folds
    Journal of Structural Geology 27 (2005) 1229–1251 www.elsevier.com/locate/jsg Shear zone-related folds Jordi Carreras, Elena Druguet*, Albert Griera Departament de Geologia, Universitat Auto`noma de Barcelona, 08193 Bellaterra, Spain Received 18 April 2003; received in revised form 27 February 2004; accepted 14 June 2004 Available online 30 November 2004 Abstract Folds in ductile shear zones are common structures that have a variety of origins. These can be pre-existing folds that become modified or folds developed during the shearing event. Among the syn-shearing folds, a second subdivision is based on the relative age of the folded surface, which can be pre-existing or newly formed during the shearing event. In each of the three categories final fold geometry and orientation show complex relationships with the kinematic frame. The final fold geometry depends on the vorticity within the shear zone, the rheology and the initial orientation of the folded surface relative to the kinematic framework. It follows that folds are complex structures, difficult to use as kinematic indicators. However, in shear zones where undeformed wall rocks with pre-shear structures are accessible and where kinematics can be well established, folds can provide a valuable natural means to understand the initiation and evolution of structures under non-coaxial regimes. We point to the need of discriminating among different plausible categories, based on the nature of the folded surface and on the inherent structural features of each category. q 2004 Elsevier Ltd. All rights reserved. Keywords: Fold; Shear zone; Geometry; Kinematics; Cap de Creus 1. Introduction final geometry, symmetry and orientation of a shear-related fold are influenced by many variables other than the shear Folds are common structures in many ductile shear sense.
    [Show full text]
  • Collision Orogeny
    Downloaded from http://sp.lyellcollection.org/ by guest on October 6, 2021 PROCESSES OF COLLISION OROGENY Downloaded from http://sp.lyellcollection.org/ by guest on October 6, 2021 Downloaded from http://sp.lyellcollection.org/ by guest on October 6, 2021 Shortening of continental lithosphere: the neotectonics of Eastern Anatolia a young collision zone J.F. Dewey, M.R. Hempton, W.S.F. Kidd, F. Saroglu & A.M.C. ~eng6r SUMMARY: We use the tectonics of Eastern Anatolia to exemplify many of the different aspects of collision tectonics, namely the formation of plateaux, thrust belts, foreland flexures, widespread foreland/hinterland deformation zones and orogenic collapse/distension zones. Eastern Anatolia is a 2 km high plateau bounded to the S by the southward-verging Bitlis Thrust Zone and to the N by the Pontide/Minor Caucasus Zone. It has developed as the surface expression of a zone of progressively thickening crust beginning about 12 Ma in the medial Miocene and has resulted from the squeezing and shortening of Eastern Anatolia between the Arabian and European Plates following the Serravallian demise of the last oceanic or quasi- oceanic tract between Arabia and Eurasia. Thickening of the crust to about 52 km has been accompanied by major strike-slip faulting on the rightqateral N Anatolian Transform Fault (NATF) and the left-lateral E Anatolian Transform Fault (EATF) which approximately bound an Anatolian Wedge that is being driven westwards to override the oceanic lithosphere of the Mediterranean along subduction zones from Cephalonia to Crete, and Rhodes to Cyprus. This neotectonic regime began about 12 Ma in Late Serravallian times with uplift from wide- spread littoral/neritic marine conditions to open seasonal wooded savanna with coiluvial, fluvial and limnic environments, and the deposition of the thick Tortonian Kythrean Flysch in the Eastern Mediterranean.
    [Show full text]