DOCSLIB.ORG

Bedrock Geology Harvey Thorleifson, Director St

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Bedrock Geology Harvey Thorleifson, Director St R. 19 W. Prepared and Published with the Support of COUNTY ATLAS SERIES THE CARLTON COUNTY BOARD OF COMMISSIONERS, ATLAS C-19, PART A MINNESOTA GEOLOGICAL SURVEY R. 18 W. THE MINNESOTA DEPARTMENT OF NATURAL RESOURCES, DIVISION OF WATERS, AND Plate 2—Bedrock Geology Harvey Thorleifson, Director St. Louis the Fond du Lac Band of LAKE Superior Chippewa CORRELATION OF MAP UNITS 380 420 T. 51 N. Brookston 36 31 35 34 MIDCONTINENT RIFT SYSTEM PENOKEAN OROGEN 400 MAP SYMBOLS 420 ¤2 Keweenawan Supergroup Animikie basin Fold-and-thrust belt 1 6 Inferred geologic contact—Located from aeromagnetic data and limited 2 3 BEDROCK GEOLOGY Hinckley outcrop and drill hole information. 400 mh 440 Sandstone Inferred fault—Interpreted from aeromagnetic data and breaks in Brook River Martin400 Martin 400 Fond du Lac electromagnetic conductor trends. Lake e dr 400 mf ) Jo 400 Formation ) 440 Inferred thrust fault or structural discontinuity—Sawteeth denote the upper 460 By mi Chengwatana plate and indicate dip direction; interpreted from aeromagnetic data. 420 mc Volcanic Group 400 ( MESOPROTEROZOIC ( Carlton dikes Malmo structural discontinuity—An inferred thrust fault; sawteeth denote 400 92°30' 400 420 440 Terrence J. Boerboom Esko oxide Tamarack the upper plate and indicate dip direction; see introduction for details. 400 R. 17 W. gabbro peridotite dn 18 Airborne electromagnetic conductor—Compiled by McSwiggen (1987), STONEY BROOK du Thomson External Internal ARROWHEAD d from unpublished data by Rocky Mountain Energy Company and USX T. 50 N. 2009 Formation zone zone 400 me mt dc (formerly U.S. Steel). dr 420 unconformity 400 th M Axial surface trace of F2 folds—Inferred from the map pattern of bedrock Twin to F LOCATION DIAGRAM units; anticline, syncline. Plunge is generally shallow east and west. er BREVATOR deformed only by second deformation FOND DU LACiv BAND 400 R Lakes unconformity o Strike and dip of inclined bedding—Angle in degrees from horizontal. deformed by first and second deformation 400 r Lost Simian tt Strike and dip of bedding showing younging direction—Angle in degrees Lake from horizontal; inclined, vertical. pc tm Lake pg 400 tg Strike and dip of cleavage—Angle in degrees from horizontal; inclined, Ê Brook È 400 vertical. Cleavages dipping less than 60° are generally S , those greater 420 Creek unconformity and possible thrust fault 1 400 36 31 are generally S2. 34 OF LAKE SUPERIOR 420 36 ? 92°45' gs ? S Y 31 mg Trend and plunge of minor fold axis—Angle in degrees from horizontal. T 93°00' Pcscs N ST. LOUIS COUNTY ST. LOUIS COUNTY R. 20 W. 420 R. 16 W. Y thrust fault R. 21 W. thrust fault Location of recent exploratory boring with short descriptive well log U Hardwood 400 400 O thrust Lake 400 400 abandonment reports. C Elm PALEOPROTEROZOIC ( 380 360 fault 6 380 N 1 1 S I ( ( Creek ( Location of scientific bore hole—Completed by the Minnesota Geological t 6 420 . K 1 400 400 6 ( 6 H 6 1 a 1 400 L T st Simian 6 1 ca I y o me Mille Lacs Survey, with core or cuttings samples available, or water well holes with u A i Ê s 400 Group cutting sets stored at the Minnesota Geological Survey. CHIPPEWA RESERVATION420 46°45' 400 46°45' Dead 400 400 vg Fish )33 ! Location of exploratory bore hole—Derived mainly by private mineral Lake 400 Creek 400 400 exploration interests. Locations are from Severson and others (2003). 400 ( dr R 380 ga Little 400 400 Cedar iv Samples are stored at the Minnesota Department of Natural Resources, Lake e 400 ag r Division of Lands and Minerals, Hibbing, Minnesota. Malmo structural discontinuity Tamarack 400 River mm 400 dr Brook 400 g 400 o )73 Cloquet 380 to Bedrock outcrop—Derived mainly from previous mapping. River ? Miller 400 57 Cross 420 o Little Falls Lake 400 360 gg 400 dr Lake Stoney M Formation 420 F 60 400 CLOQUET 58 Midway T. 49 N. 420 420 w 58 Squa 380 M o 400 o T. 49 N. o 400 420 du First F o BESEMAN RED CLOVER PROGRESS PERCH LAKE Lake 70 THOMSON 420 420 o ( Third 28 MF 360 DESCRIPTION OF MAP UNITS <pg Porphyritic metagabbro—Green, medium-grained, variably shear- schist with relict blocky plagioclase crystals, possibly a sheared 400 to ( 400 Lake foliated, carbonate-altered; metamorphosed under lower greenschist- metagabbro sill or mafic tuff. 400 400 MF MF M M o ( MESOPROTEROZOIC ROCKS M ¤61 facies conditions. Local undeformed lozenges contain 5 to 10 < Metagabbro and metabasalt—Green, medium-grained, massive hornblende 420 420 FMF Esko g 400 Rice 400 380 420 420 Big ( 55 F Keweenawan Supergroup percent euhedral, white, sericite- and carbonate-altered plagioclase Portage ( Creek (o metagabbro to fine-grained amphibolitic mafic schist. Metagabbro ¦§35 400 400 Lake Perch dn 400 F phenocrysts up to 3 centimeters in size, but in most places the gabbro intersected in drill holes near the center of this unit is deeply weathered r <mh Hinckley Sandstone—Quartz arenite, tan to orange, fine- to medium- 400 Otte 80 400 360 360 o grained, well-sorted and well-rounded; composed of about 96 percent is strongly shear-foliated and the phenocrysts are broken and strung at the top, and is composed primarily of millimeter-sized blocky 400 400 Y 400 o 400 400 ( (( T out in the foliation plane. The matrix is composed of chlorite, sericite, hornblende and epidote-chlorite altered plagioclase, in a groundmass F F o quartz (Tryhorn and Ojakangas, 1972). The overall distribution is Lake M N 31 d F U 400 o carbonate, minor quartz, sphene/leucoxene and opaque granules, and ( MMF 340 60 well constrained by well log data and rare exposures near Holyoke. of epidote, sphene, and fibrous actinolitic amphibole. A single 31 400 36 k 36 O 36 31 400 31 36 31 45 dc ( M o 300 36 e du Woodbury 380 F C minor disseminated pyrite that is typically strung out in the foliation Lake e ( dn to 31M F outcrop at the southeast end of this unit is composed of fine-grained, Lake r F FMM 36 In Pine County to the south, the Hinckley Sandstone contains karst- S F o Jaskari C 50 400 M ( I Lake 340 45 plane; locally overprinted by late rhombohedral carbonate, and rare, o dark greenish-gray, biotite-bearing amphibolitic schist with minor U 400 F F F like sinkhole features in areas where the sandstone is thinly covered 400 F o 400 o O 400 400 Wild 360 49 Little coarse-grained, muscovite porphyroblasts. The foliation dip varies 400 M F L by sandy glacial till (Shade and others, 2002). disseminated pyrite. The dominant foliation (S ) in this outcrop 1 o F o Gill )210 . Rice r ( F M o 40 e 6 M T from 25° east at the north end of the outcrop area, to 60° southeast Tamarack t M River 6 Cromwell 400 1400 Sawyer Lake t ( 40 5 strikes N. 73° E., but the dip varies from 13° north to 35° south, due 380 4 o 1 S < 1 F n Fond du Lac Formation—Sandstone, mudstone, and conglomerate, light F M F R 6 400 Thomso mf O o 400 F o Creek 6 6 6 o 1 F Wright i 400 Island M v 1 FF Reservoir F 50 50 10 at the south; this is at a high angle to the regional structural grain, to a gentle D fold that plunges 10° west. e 400 F 360 orange to reddish-brown and locally mottled pale green. The base is 2 r River o 1 F 220 9 and may be the result of cleavage refraction through this presumably Lake 400 400 F F 50 < Dolomitic marble and metagraywacke—Dark gray with a tan-weathered o F )210 380 ( 8 marked by an approximately 60-foot (18-meter) thick conglomerate mm 400 Torchlight C F 320 200 more competent unit. The main, presumably S metamorphic foliation reek 1 rind, fine-grained, granoblastic-foliated, locally contains minor, o Lake d MF o d 260 with clasts of vein quartz cemented by pyrite and marcasite. The Tamarack 70 F F o M o ) Y Cole M 210o CarltonF is weakly folded by a later D2 crenulation cleavage. Lake 400 240 thin, deformed veins of recrystallized galena. Lenticular structures, Kettle r F o T conglomerate unconformably overlies the Thomson Formation (unit Lake M M o 7 10 e F Little N M o N tt 26 F 280 River M M FF I < Graphitic slate and metagraywacke—Gray, rhythmically interbedded, 400 Creek St. LouisF 45 10 tg isolated fold hooks, and boudinaged quartz veins indicate a high oO F M 85 U < ), and is overlain by fine- to medium-grained, arkosic to subarkosic M to F 40 30 F S 360 360 M FF O variably graphitic, with scattered pyrite cubes up to 2.5 centimeters ( 7 N degree of deformation; pseudo-bedding and foliation dip 20° south. ( 240 C sandstone interbedded with siltstone and mudstone. Trough cross- 400 o 5 4 260 r o 360 260 Mattlia e 260 O ) S t 23 wide concentrated in carbonaceous/graphitic argillite beds. Bedding Lake t beds in sandstone higher in the stratigraphic section contain clasts Thin argillite beds in marble exhibit strong D2 crenulation cleavage 400 A 21 C O 81 260 Creek Eagle Creek 360 240 L ( Silver S and S1 foliation are typically tightly folded and dislocated, and locally and contain disseminated, oxidized pyrite. I o o G of weathered basalt and reworked sandstone and mudstone at their 400 Lake 400 M 18 70 Merwin o o U transposed, by strong D crenulation cleavage.
Load more

Recommended publications
  • Petrography and Geochemistry of Metasedimentary Rocks from the Taku Schist in Kelantan, North-East Peninsular Malaysia
    Journal of Applied Geology, vol. 5(2), 2020, pp. 124–140 DOI: http://dx.doi.org/10.22146/jag.61183 Petrography and Geochemistry of Metasedimentary Rocks from the Taku Schist in Kelantan, North-East Peninsular Malaysia Muhammad Irman Khalif Ahmad Aminuddin1,2, Nugroho Imam Setiawan*1, I Wayan Warmada1, Kamar Shah Ariffin2, and Kotaro Yonezu3 1Department of Geological Engineering, Faculty of Engineering, Universitas Gadjah Mada, Yogyakarta, Indonesia 2School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, Nibong Tebal, Penang 14300, Malaysia 3Department of Earth Resources Engineering, Kyushu University, 819-0395, Fukuoka, Japan ABSTRACT. The Taku Schist, located in north-east Peninsular Malaysia, is characterized by its North-South oriented elongated body. It forms part of the Indosinian orogenic build-up generated by the convergence of the Sibumasu continental block and Sukhothai Arc. Pet- rographic analyses of the metasedimentary rocks sourced from the Taku Schist revealed that the formation was attributable to greenschist’s metamorphism into amphibolite fa- cies, which could be observed near the Triassic and Cretaceous intrusions of the Kema- hang Granite. The evolution process of the rocks could be linked with the interactions between a contact and regional metamorphisms. The resulting of XRF and ICP-MS geo- chemical analyses upon the assessment disclosed that the metasedimentary rocks of Taku Schist were made up of greywacke and shale, grouped into the quartzose sedimentary protolith, and belonged to the Continental Island Arc (CIA). It reflects the Taku Schist’s episodic contractions, wherein they would lead to the Sibumasu sedimentary cover along with both an accretionary wedge and the genetically-correlated Bentong-Raub mélange to different greenschist.
    [Show full text]
  • Palaeozoic Collision Between the North and South China Blocks, Triassic Intracontinental Tectonics, and the Problem of the Ultra
    Palaeozoic collision between the North and South China Blocks, Triassic intracontinental tectonics, and the problem of the ultrahigh-pressure metamorphism Michel Faure, Wei Lin, Patrick Monié, Sébastien Meffre To cite this version: Michel Faure, Wei Lin, Patrick Monié, Sébastien Meffre. Palaeozoic collision between the North and South China Blocks, Triassic intracontinental tectonics, and the problem of the ultrahigh- pressure metamorphism. Comptes Rendus Géoscience, Elsevier Masson, 2008, 340, pp.139-150. 10.1016/j.crte.2007.10.007. insu-00191534 HAL Id: insu-00191534 https://hal-insu.archives-ouvertes.fr/insu-00191534 Submitted on 8 Jan 2008 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Comptes Rendus Geoscience Palaeozoic collision between the North and South China blocks, Triassic intracontinental tectonics, and the problem of the ultrahigh-pressure metamorphism Collision paléozoïque entre les blocs de Chine du Nord et du Sud, tectonique intracontinentale triasique et le problème du métamorphisme de ultra-haute pression Michel Faure a, , Wei
    [Show full text]
  • The Metamorphic and Plutonic Rocks of the Southernmost Sierra Nevada, California, and Their Tectonic Framework
    The Metamorphic and Plutonic Rocks of the Southernmost Sierra Nevada, California, and Their Tectonic Framework U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1381 The Metamorphic and Plutonic Rocks of the Southernmost Sierra Nevada, California, and Their Tectonic Framework By DONALD C. ROSS U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1381 UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1989 DEPARTMENT OF THE INTERIOR MANUEL LUJAN, JR., 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 Library of Congress Cataloging-in-Publication Data Ross, Donald Clarence, 1924 The metamorphic and plutonic rocks of the southernmost Sierra Nevada, California, and their tectonic framework / by Donald C. Ross. p. cm. (U.S. Geological Survey professional paper ; 1381) Bibliography: p. Supt.ofDocs.no.: 119.16:1381 1. Rocks, Igneous Sierra Nevada Mountains (Calif, and Nev.) 2. Rocks, Metamorphic Sierra Nevada Mountains (Calif, and Nev.) I. Title. II. Series. QE461.R645 1989 552'.1'097944 dc20 89-6000136 CIP For sale by the Books and Open-File Reports Section U.S. Geological Survey, Federal Center, Box 25425, Denver, CO 80225 CONTENTS Abstract---------------------------- l Plutonic rocks- ------------------------ 23 Introduction- ------------------------- 1 Units north of the Garlock fault- ------------- 23 Acknowledgments----------------------- 3 Granitic rocks related(?) to the San Emigdio- Metamorphic
    [Show full text]
  • Descriptive and Geoenvironmental Model for Cobalt-Copper-Gold Deposits in Metasedimentary Rocks
    Descriptive and Geoenvironmental Model for Cobalt-Copper-Gold Deposits in Metasedimentary Rocks 1 cm Scientific Investigations Report 2010–5070–G U.S. Department of the Interior U.S. Geological Survey COVER. Upper left, Blacktail open pit in the Blackbird district, central Idaho, U.S.A.; view looking approximately northwest (bulldozer for scale in bottom center). Upper right, Skuterud open pit in the Modum district, southern Norway; view looking south (wooden fence on left is about 1.5 meters high). Middle left, South Idaho underground mine in the Blackbird district, showing stratabound lenses and discordant veins of Cu-rich sulfide in dark argillite wall rock. Middle right, hand sample from the Sunshine open pit in the Blackbird district, showing layers of granoblastic cobaltite with a matrix of white quartz and dark green chlorite. Lower left, underground photo of the Skuterud mine showing pink secondary erythrite (a hydrated cobalt arsenate mineral). Lower right, water sampling of acid mine drainage in the Blackbird district, view looking approximately east. Descriptive and Geoenvironmental Model for Cobalt-Copper-Gold Deposits in Metasedimentary Rocks Edited by John F. Slack Chapter G of Mineral Deposit Models for Resource Assessment Scientific Investigations Report 2010–5070–G 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: 2013 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.
    [Show full text]
  • Classification of Metamorphic Rocks
    BRITISH GEOLOGICAL SURVEY RESEARCH REPORT NUMBER RR 99–02 BGS Rock Classification Scheme Volume 2 Classification of metamorphic rocks S Robertson Subject index Rock classification, metamorphic rocks Bibliographical Reference Robertson, S. 1999. BGS Rock Classification Scheme Volume 2 Classification of metamorphic rocks. British Geological Survey Research Report, RR 99–02. © NERC Copyright 1999 British Geological Survey Keyworth Nottingham NG12 5GG UK HOW TO NAVIGATE THIS DOCUMENT HOW TO NAVIGATE THIS DOCUMENT ❑ The general pagination is designed for hard copy use and does not correspond to PDF thumbnail pagination. ❑ The main elements of the table of contents are bookmarked enabling direct links to be followed to the principal section headings and sub-headings, figures and tables irrespective of which part of the document the user is viewing. ❑ In addition, the report contains links: ✤ from the principal section and sub-section headings back to the contents page, ✤ from each reference to a figure or table directly to the corresponding figure or table, ✤ from each figure or table caption to the first place that figure or table is mentioned in the text and ✤ from each page number back to the contents page. Return to contents page Contents 1 Introduction 10.3 Colour qualifiers 1.1 Definition of metamorphism 10.4 Qualifiers based on protolith structures 1.2 Basic principles References 2 Metamorphic rock nomenclature Appendix List of approved rock names 2.1 Construction of rock names. 2.2 How to use the classification scheme Figures 3 Sedimentary
    [Show full text]
  • Early Tertiary Continental Borderland of Central California
    S·edimentation and Tectonics in the Early Tertiary Continental Borderland Of Central California \ GEOLOGICAL SURVEY PROFESSIONAL PAPER 925 mJJRl£A[21 Of r:.r~~l~~: !UBRARV £?OKANE, WASN. , !;;'·"'-' iQ 'll '1 ,t.gAJ!, :(~fA~£ R~~·. _·,,._\ [©1 Sedimentation· and Tectonics in the Early Tertiary Continental Borderland Of Central California By TOR H. NILSEN and SAMUEL H. CLARKE, Jr. GEOLOGICAL SURVEY PROFESSIONAL PAPER 925 UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1975 UNITED STATES DEPARTMENT OF THE INTERIOR ROGERS C. B. MORTON, Secretary GEOLOGICAL SURVEY V. E. McKelvey, Director Library of Congress catalog- card No.7 6-7 6 2 4 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 CONTENTS Page Page Abstract 1 Lower Tertiary stratigraphic units-Continued Introduction _______________________________________________ _ 1 Southeastern area -------------------------------------- 24 Acknowledgments _____________________________________ _ 3 Cadon Pass area ---~-------------------------------- 24 Summary of Mesozoic tectonic history-----------------------­ 3 Orocopia Mountains -------------------------------- 24 Lower Tertiary stratigraphic units -------------------------- 4 Southwestern'area ______________________________________ 24 ~orthwestern area _____________________________________ _ 6 Ortega Hill, Pine Mountain, Santa Ynez Mountains, (}ualala area ---------------------------------------- 6 and Topatopa Mountains areas -------------------- 25 Point Reyes --.--------------------------------------
    [Show full text]
  • Magnetic Structure of the Continental Crust As Revealed by the Wutai-Jining Crustal Cross-Section in the North China Craton
    __________________________________________________________________________www.paper.edu.cn Journal of Geodynamics 29 (2000) 1±13 Magnetic structure of the continental crust as revealed by the Wutai-Jining crustal cross-section in the North China craton Liu Qingsheng a,*, Gao Shan b, c, Liu Yongsheng c aDepartment of Applied Geophysics, China University of Geosciences, Wuhan, 430074, China bDepartment of Geology, Northwest University, Xi'an, 710069, China cFaculty of Earth Sciences, China University of Geosciences, Wuhan, 430074, China Received 3 December 1998; received in revised form 9 July 1999; accepted 14 July 1999 Abstract The Wutai-Jining crustal cross-section is located in the central North China Craton. The upper crustal cross-section is represented by the Wutai granite-greenstone terrain and overlying post-Archean sedimentary rocks, the middle crust by the comparable Henshan and Fuping amphibolite- to granulite- facies terrains, and the upper lower crust by the granulite-facies Jining terrain. Correlation of measured seismic velocities of rocks from the crustal cross-section with data on seismic refractions suggests that the section is likely to represent a ca 30 km crust column with the 5 km thick lowermost crust being not exposed (Kern, H., Gao Shan, Liu Qingsheng, 1996. Earth Planet. Sci. Lett. 139, 439±455). Forty-four samples from the cross-section, some of which were used for measurements of seismic velocities and densities (Kern et al., 1996), are analyzed for saturation magnetization (Js) and saturation isothermal remanent magnetization (SIRM). Rock magnetism depends primarily on metamorphic grade and thus on dierent depth of mineral equilibrium. Lithology plays a less important role. Rocks of greenschist-, amphibolite- and granulite-facies have average Js of 58.7, 686 and 1068 A/m, respectively.
    [Show full text]
  • Virtual Tour of Multidimensional Orders of Scale
    University of Texas at El Paso DigitalCommons@UTEP Open Access Theses & Dissertations 2018-01-01 Grenvillian Tectonomagmatic Evolution Of Southwestern Laurentia; Virtual Tour Of Multidimensional Orders Of Scale; Two Methods To Describe The aV stness Of Time; Math Concepts Utilizing Google Earth; Systematic Approach To Motion Analyses; Mathematics And Earth Science-Based Knowledge And Learning Anthony M. Alvarez University of Texas at El Paso, [email protected] Follow this and additional works at: https://digitalcommons.utep.edu/open_etd Part of the Education Commons, Geology Commons, and the Oil, Gas, and Energy Commons Recommended Citation Alvarez, Anthony M., "Grenvillian Tectonomagmatic Evolution Of Southwestern Laurentia; Virtual Tour Of Multidimensional Orders Of Scale; Two Methods To Describe The asV tness Of Time; Math Concepts Utilizing Google Earth; Systematic Approach To Motion Analyses; Mathematics And Earth Science-Based Knowledge And Learning" (2018). Open Access Theses & Dissertations. 1395. https://digitalcommons.utep.edu/open_etd/1395 This is brought to you for free and open access by DigitalCommons@UTEP. It has been accepted for inclusion in Open Access Theses & Dissertations by an authorized administrator of DigitalCommons@UTEP. For more information, please contact [email protected]. GRENVILLIAN TECTONOMAGMATIC EVOLUTION OF SOUTHWESTERN LAURENTIA; VIRTUAL TOUR OF MULTIDIMENSIONAL ORDERS OF SCALE; TWO METHODS TO DESCRIBE THE VASTNESS OF TIME; MATH CONCEPTS UTILIZING GOOGLE EARTH; SYSTEMATIC APPROACH TO MOTION ANALYSES; MATHEMATICS AND EARTH SCIENCE-BASED KNOWLEDGE AND LEARNING TRENDS: A MULTI-TIERED INVESTIGATION AND RATIONALE ANTHONY M. ALVAREZ Doctoral Program in Geological Sciences APPROVED: Philip Goodell, Ph.D., Chair Eric Kappus, Ph.D. Munazzam Ali Mahar, Ph.D. Richard Jarvis, Ph.D.
    [Show full text]
  • Tectonic Evolution of the North China Block: from Orogen to Craton to Orogen
    Downloaded from http://sp.lyellcollection.org/ by guest on September 28, 2021 Tectonic evolution of the North China Block: from orogen to craton to orogen T. M. KUSKY1, B. F. WINDLEY2 & M.-G. ZHAI3 1Department of Earth and Atmospheric Sciences, St. Louis University, St. Louis, MO 63103, USA (e-mail: [email protected]) 2Department of Geology, University of Leicester, Leicester LE1 7RH, UK 3Key Laboratory of Mineral Resources, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China Abstract: The North China Craton contains one of the longest, most complex records of magma- tism, sedimentation, and deformation on Earth, with deformation spanning the interval from the Early Archaean (3.8 Ga) to the present. The Early to Middle Archaean record preserves remnants of generally gneissic meta-igneous and metasedimentary rock terranes bounded by anastomosing shear zones. The Late Archaean record is marked by a collision between a passive margin sequence developed on an amalgamated Eastern Block, and an oceanic arc–ophiolitic assemblage preserved in the 1600 km long Central Orogenic Belt, an Archaean–Palaeoproterozoic orogen that preserves remnants of oceanic basin(s) that closed between the Eastern and Western Blocks. Foreland basin sediments related to this collision are overlain by 2.4 Ga flood basalts and shallow marine–continental sediments, all strongly deformed and metamorphosed in a 1.85 Ga Himalayan-style collision along the northern margin of the craton. The North China Craton saw rela- tive quiescence until 700 Ma when subduction under the present southern margin formed the Qingling–Dabie Shan–Sulu orogen (700–250 Ma), the northern margin experienced orogenesis during closure of the Solonker Ocean (500–250 Ma), and subduction beneath the palaeo-Pacific margin affected easternmost China (200–100 Ma).
    [Show full text]
  • AWG SANTA CATALINA ISLAND FIELDTRIP Association of Women Geoscientists, SDSU Student Chapter August 31 - September 3, 2018 Bonnie Bloeser, Emma Vierra, Bonnie Flynn
    AWG SANTA CATALINA ISLAND FIELDTRIP Association of Women Geoscientists, SDSU Student Chapter August 31 - September 3, 2018 Bonnie Bloeser, Emma Vierra, Bonnie Flynn Objective: We will visit Santa Catalina Island, a ridge crest in the California continental borderland geomorphic province, to examine Mesozoic metamorphic basement complexes (Catalina schist terrane of blueschist, greenschist and amphibolite facies) and the Miocene Catalina Pluton, a lower Miocene quartz diorite stock. Airport STOP 1 Little Harbor STOP 2 (Franciscan complex in purple) East End Quarry Grove and Bebout, 1995 https://keckgeology.org/2017/12/ catalinagateway2018/ Friday, August 31 Arrive on the island and proceed to Hermit Gulch Campground via the Tour Plaza. Bonnie B. will meet the group at the boat dock upon arrival, distribute island maps, and give an overview of Avalon’s points of interest while en route to the campground. We will briefly stop at the Tour Plaza, the location of Saturday’s 7:30 am departure on the Conservancy’s Wildlands Express Service, to insure you’re familiar with this meeting location. Hermit Gulch Campground is a ~2.4 km walk from the Catalina Express boat, located in Avalon Canyon near the Nature Center and the Wrigley Memorial and Botanical Gardens. Amenities include coin-operated hot showers (quarters only), BBQ stands, picnic tables, outdoor kitchen sinks, and vending machines. There is a Ranger at the campground. Friday afternoon activities are on your own. Suggestions for excursions and restaurants are noted on the website below. A recommended hike is directly behind your campsite, the Hermit Gulch Trail, which winds up the mountain to the crest of the island.
    [Show full text]
  • Tectonic Evolution of a Complex Orogenic System: Evidence from the Northern Qinling Belt, Central China ⇑ Li Tang A, M
    Journal of Asian Earth Sciences 113 (2015) 544–559 Contents lists available at ScienceDirect Journal of Asian Earth Sciences journal homepage: www.elsevier.com/locate/jseaes Tectonic evolution of a complex orogenic system: Evidence from the northern Qinling belt, Central China ⇑ Li Tang a, M. Santosh a,b,c, , Yunpeng Dong b a School of Earth Sciences and Resources, China University of Geosciences Beijing, 29 Xueyuan Road, Beijing 100083, China b State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi’an 710069, China c Centre for Tectonics Resources and Exploration, Department of Earth Sciences, University of Adelaide, SA 5005, Australia article info abstract Article history: The Qinling orogenic belt preserves the records of a long evolution history of convergence between the Received 29 December 2014 North China Craton and the South China Craton. In this study, we present results from new geological, Received in revised form 12 March 2015 geochemical, zircon U–Pb geochronological and Lu–Hf isotopic investigations on a suite of orthogneisses Accepted 13 March 2015 from the Taihua Group (THG) and Tietonggou Group (TGG). We also present geochronological data on Available online 27 March 2015 schist and migmatite from the North Qinling belt (NQB) and metasedimentary rocks from the Wuguan unit (WGU) which is exposed along the southern side of the Shangdan suture zone. Two orthogneisses Keywords: from the THG define several stages of arc magmatism at 2.51 Ga, 2.34 Ga, 2.28 Ga and 2.16 Ga, Geochemistry followed by metamorphism at 1930 ± 31 Ma. Zircons from the TGG trace a tectonothermal event at Zircon U–Pb geochronology Lu–Hf isotopes 1897 ± 15 Ma.
    [Show full text]