DOCSLIB.ORG

EF-Tinuous Sequence, Locally As Much As 3000 M

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
EF-Tinuous Sequence, Locally As Much As 3000 M CAMBRIAN AND LATEST PRECAMBRIAN PALEOGEOGRAPHY AND TECTONICS IN THE WESTERN UNITED STATES John H. Stewart U.S. Geological Survey, Menlo Park, California 94025 Christopher A. Suczek Geology Department, Stanford University, Stanford, California 94305 ABSTRACT ' The upper Precambrian and Cambrian rocks of the ' crn United States are mostly shallow water Thsits that formed on a broad shelf along the jjsrn margin of the North American craton. iltively deep water deposits, some perhaps tec- j lly emplaced from distant depositional sites, =9 out in a few areas near the western margin of ffshelf. The upper Precambrian and Cambrian shelf ‘F its are divided into three main lithogenetic }~nces. These are, in ascending order: (1) a _EF-tinuous sequence, locally as much as 3,000 m :?k, of diamictite, mudstone, sandstone, conglom- and mafic volcanic rocks of Precambrian _ER, age; :a*westward-thickeningwedge, locally more than 33 m thick, of upper Precambrian and Lower '79 :n terrigenous detrital rocks of shallow- :-, in part tidal, origin; and (3) a Middle and "‘ Cambrian sequence of predominantly shallow carbonate rocks generally about 2,000 m The rate of accumulation of strata in the _ fé eran geosyncline was apparently greatest in is Cambrian and presumably also in late 7km-rian time and decreased progressively through ‘Q cian and perhaps younger early Paleozoic time. _gate of accumulation and inferred subsidence '; s to decline exponentially with a time constant 3} t 50 m.y. Accumulation and subsidence rates jée thermal contraction in the Cretaceous to ‘}=ue Atlantic and Gulf shelves of the United ?r are also exponential with a similar time '3 nt, as are subsidence rates for oceanic crust :_ -g away from a mid-oceanic ridge. In these _f, thermal contraction followed an uplift related "E ting at a spreading center. The exponential OUTCROP OF BELT SUPERGROUP in the rate of subsidence in the Cordilleran 'fi;:e AND TEMPORALLY EQUIVALENT ROCKS “flécline suggests a similar history of thermal .s--I--‘-"'-L ‘5‘ tion after some initial heating event, perhaps *1» to fragmentation and reshaping of the western APPROXIMATE WESTWARD EXTENT OF OUTCROPS "'6 of the United States by rifting in the late OF PRECAMBRIAN CRYSTALLINE BASEMENT ROCKS _§:~rian. The diamictite and volcanic sequence A "7-e been deposited in a rift valley formed ISOLATED OUTCROP OF PRECAMBRIAN ;h an early stage of the rifting; the terrige- CRYSTALLJNE BASEMENT ROCKS Jfiatrital be related to erosion of sequence may ‘RR T7w:1ly expanded area near the rift, and the 7h:te to shallow-water shelf SAN ANDREAS FAULT sequence widespread 'f;utation after destruction of the thermally ARROWS INDICATE RELATIVE MOVEMENT §_ed area by cooling and thermal contraction and ‘R-sion. Figure 1. Distribution of crystalline basement INTRODUCTION rocks (2,400-1,450 m.y.) and Belt—age (1,450-900? m.y.) unmetamorphosed sedimentary and volcanic rocks $4: upper Precambrian and Cambrian rocks of the in the western United States. Based in part on King Tfif- United States consist of as much as 10,000 m (1976) and Armstrong(l975). 2 STETM4Rfl'.4AM7 SUKEHHK .,, DEATH VALLEY SCHELL CREEK HUNTSVILLE POCATELLO METALINE :1: CALIFORNIA RANGE UTAH IDAHO DISTRICT :3 NEVADA wAsHINSToN U1 2 0RDOV|ClAN O a 7 O 1 °- 2 E -I 5 LIMESTONE I % ._._,__._:, 3.3.3.3-‘.3 DOLOMITE 1 ';"_"___'.'_': 712" - E32522 '._' vn7.£S7Al _ '. SANDY DOLOMITE -"‘5_“'_“' SHALE on ARGILLITE _ '.°-"5.f3'.*’3.“ "33 ‘ )4 no a '.:| 0 00 O CONGLOMERATE j___?__fi ? 3 ‘AAAAGAAA,¢,A J DIAMICTITE lvvvw/_VVVV MIDDLE AND 5. UPPER CAMBRIAN v0LcAN|C ROCK CARBONATE SEQUENCE ' 4. TERRIGENEOUS DETRITAL 1": SE°”E”°E DIABASE SILL °" 3. DIAMICTITE AND voLcANIc _____ ;,__\—‘__,‘, SEQUENCE 3w‘-‘-' GNEISS AND SCHIST 2. BELT SUPERGROUP AND TEMPORALLY EQUIVALENT ROCKS I. PRECAMBRIAN CRYSTALLINE BASEMENT Figure 2. Generalized diagram showing lithologic types and correlation of late Precambrian and Cambrian strat at selected localities in the western United States. Sources of data: Death Valley, Hazzard (1937), Stewart (1970), Wright, Troxel, Williams, Roberts, and Diehl (1974); Shell Creek Range, Young (1960), Hose and Blake (1976); Huntsville, Crittenden and Wallace (1973), Sorensen and Crittenden (1976); Pocatello, Trimble (1976); Metaline district, Park and Cannon (1943), Dings and Whitebread (1965), and Yates (1976). of generally shallow water sediments deposited on a States, and of relatively unmetamorphosed sedimen-1 broad shelf. This paper describes the paleogeo- tary and volcanic rocks of the Belt and of the United Supergroup graphy western States during late temporally equivalent rocks (Fig. 1). The Belt Precambrian and Cambrian time, as well as the Supergroup and temporally equivalent rocks occur tectonic events that led to the deposition of this deep epicratonic troughs, some containing as much thick sequence of rocks. This report focuses on three major sequences of Precambrian and Cambrian rocks: an upper Precambrian diamictite and volcanic sequence (900? to 800? m.y.), an uppermost Precambrian and Lower Figure 3. Distribution and maximum thickness Cambrian terrigenous detrital sequence (650? to 540 of Precambrian (900?-800? m.y.) diamictite and m.y.), and a Middle and Upper Cambrian carbonate volcanic sequence in the western United States. sequence (540-S00 m.y.). Rocks older than these Based on many sources, including Cohenour (1959), sequences consist of Precambrian crystalline meta- Wright and Troxel (1967), Crittenden, Scheaffer, morphic and intrusive rocks (about 2,400 to 1,450 Trimble, and Woodward (1971), Miller and Clark m.y.), the oldest rocks in the western United (1975), and Yates (1976). CAMBRIAN AND LATEST PRECAMBRIAN PALEOGEOGRAPHY 3 -v I3l° 121° DCCURRENCE or DIAMICTITE ' AND VOLCANIC szomzncz 59 u Major outcrop X Isolated outcrop GI Drill hole ‘S V .5. mnc VOLCANIC ROCK /A p 4 .STEMU4R7' AND SUCZEK and consist of flows, breccias, 20,000 m of sediment (Harrison and others, 1974), or primarily greenstone and minor amounts of tuff (Crittenden and others, are widespread, relatively thin shelf deposits. Miller and Pillow More detailed information on the crystalline base- 1971; Clark, 1975; Yates, 1976)., ment rocks and the Belt Supergroup and temporally greenstones are reported locally (Aalto, 1971; equivalent rocks is given elsewhere (Harrison and Stewart, 1972; Crittenden and Wallace, 1973). others, 1974; King, 1976). Although the greenstone is highly altered, much of it seems to have been a basalt that was perhaps in DIAMICTITE AND VOLCANIC SEQUENCE (900? T0 800? M.Y.) part tholeiitic (Stewart, 1972; Miller and Clark, 1975; Yates, 1976). The diamictite and volcanic sequence consists The age of the diamictite and volcanic se- is known. The direct is of as much as 3,000 m of diamictite, mudstone, quence poorly only dating argillite, sandstone, and conglomerate, and locally of greenstone in northeastern Washington; where thick units of volcanic rocks. The highly distinc- potassium-argon ages on whole rocks and mineral tive diamictite (a rock composed of large clasts set separates are between 827 and 918 m.y. (Miller and in a finer grained matrix) is considered to be of others, 1973). The of striated glacial origin. The sequence was grouped by Stewart presence dropstones, clasts, (1972) with the overlying terrigenous detrital and massive diamictite suggests a glacial origin for of the rocks in the diamictite and sequence but is here described separately because of many sedimentary its possible tectonic importance. volcanic sequence (Aalto, 1971; Crittenden and Aalto indicates a In some areas, the diamictite and volcanic Wallace, 1973). (1971) glacial marine environment with unstratified sequence rests unconformably on crystalline basement along a coast, till inland and flow rocks, whereas in other areas it rests unconform- subglacial turbidity deposits oceanward. ably, for the most part, on the Belt Supergroup and temporally equivalent rocks. Near the United In the Death Valley region of eastern States-Canada border, the Belt Supergroup and California, the diamictite and volcanic sequence accumulated in a fault-bounded or equivalent Purcell Supergroup of Canada were apparently trough uplifted and mildly folded during the East Kootenay rift valley basin. Here the diamictite-bearing Peak Formation in thickness from 0 orogeny (White, 1959) before deposition of the Kingston ranges to over m.within a few kilometers. An area diamictite and volcanic sequence. 1,800 formation In the western United States, the diamictite close to the presumed margin of the con- tains blocks slide as and volcanic sequence is recognized in the north- gigantic (presumably blocks) and These eastern Washington and northern Idaho area, as well much as 300 m long (Wright others, 1974). relations seem best if the Peak as in southern Idaho, north-central and westernmost explained Kingston Utah, and eastern California (Figs. 2 and 3). In was deposited in a fault-bounded basin. Such an has been and others each of these areas, it is the only unit in the origin proposed by Wright Precambrian and Paleozoic sequence that contains (1974), although they call this feature an aulacogen diamictite, and in most of these same areas it is and suggest that it first developed during deposi- the only unit that contains abundant volcanic tion of the Belt—age Crystal Spring and Beck Spring rocks. These characteristics suggest that its Formations underlying the Kingston Peak Formation. correlation from region to region in the western They indicate, however, that the main stage of United States is reasonable (Crittenden and others, subsidence in the aulacogen occurred during the 1972; Stewart, 1972). In addition, the diamictite deposition of the Kingston Peak Formation. Several in the and Beck and volcanic sequence occurs at approximately the units Crystal Spring Spring Formations are uniform in the Death same stratigraphic position in each area; that is, remarkably area and were above the Belt Supergroup or rocks correlated with Valley perhaps originally widespread shelf In the Peak it on the basis of radiometric dating or the types deposits.
Load more

Recommended publications
  • Tectonic Features of the Precambrian Belt Basin and Their Influence on Post-Belt Structures
    ... Tectonic Features of the .., Precambrian Belt Basin and Their Influence on Post-Belt Structures GEOLOGICAL SURVEY PROFESSIONAL PAPER 866 · Tectonic Features of the · Precambrian Belt Basin and Their Influence on Post-Belt Structures By JACK E. HARRISON, ALLAN B. GRIGGS, and JOHN D. WELLS GEOLOGICAL SURVEY PROFESSIONAL PAPER X66 U N IT ED STATES G 0 V ERN M EN T P R I NT I N G 0 F F I C E, \VAS H I N G T 0 N 19 7 4 UNITED STATES DEPARTMENT OF THE INTERIOR ROGERS C. B. MORTON, Secretary GEOLOGICAL SURVEY V. E. McKelvey, Director Library of Congress catalog-card No. 74-600111 ) For sale by the Superintendent of Documents, U.S. GO\·ernment Printing Office 'Vashington, D.C. 20402 - Price 65 cents (paper cO\·er) Stock Number 2401-02554 CONTENTS Page Page Abstract................................................. 1 Phanerozoic events-Continued Introduction . 1 Late Mesozoic through early Tertiary-Continued Genesis and filling of the Belt basin . 1 Idaho batholith ................................. 7 Is the Belt basin an aulacogen? . 5 Boulder batholith ............................... 8 Precambrian Z events . 5 Northern Montana disturbed belt ................. 8 Phanerozoic events . 5 Tectonics along the Lewis and Clark line .............. 9 Paleozoic through early Mesozoic . 6 Late Cenozoic block faults ........................... 13 Late Mesozoic through early Tertiary . 6 Conclusions ............................................. 13 Kootenay arc and mobile belt . 6 References cited ......................................... 14 ILLUSTRATIONS Page FIGURES 1-4. Maps: 1. Principal basins of sedimentation along the U.S.-Canadian Cordillera during Precambrian Y time (1,600-800 m.y. ago) ............................................................................................... 2 2. Principal tectonic elements of the Belt basin reentrant as inferred from the sedimentation record ............
    [Show full text]
  • 40Ar/39Ar Mineral Dates from Retrogressed Eclogites Within the Baltoscandian Miogeocline: Implications for a Polyphase Caledonian Orogenic Evolution
    40Ar/39Ar mineral dates from retrogressed eclogites within the Baltoscandian miogeocline: Implications for a polyphase Caledonian orogenic evolution R. D. DALLMEYER Department of Geology, University of Georgia, Athens, Georgia 30602 D. G. GEE Geological Survey of Sweden, Box 670, S-751 28 Uppsala, Sweden ABSTRACT Late Silurian to Early Devonian transport suggest that this tectonic activity occurred while onto the Baltoscandian Platform. Baltica and Laurentia were separated by a con- Late Proterozcic, rift-fades dolerite dikes siderable expanse of the Iapetus Ocean (Ilruton within Baltoscandian rocks of the Seve INTRODUCTION and Bockelie, 1980). Nappe Complex locally underwent eclogite A comprehensive geochronological program metamorphism during Caledonian orogen- Scandinavian portions of the Caledonian oro- is underway to more fully document the ;xtent esis. Hornblende from retrograde amphibo- gen are represented by a succession of far- and character of the pre-Scandian tectono- lite selvages developed around two eclogite traveled allochthons which were emplaced onto thermal record within the Scandinavian Cal- boudins exposed at Grapesvare, Norrbotten the Baltoscandian Platform during the early to edonides. This report presents new 40Ar/39Ar County, Sweden, record identical 40Ar/39Ar middle Paleozoic (Fig. 1). Medium- and high- data for hornblende in retrograde selvages plateau dates of 491 ± 8 Ma. Phengitic mus- grade Baltoscandian rocks of the Seve Nappe developed from eclogite assemblages within covite from host schists records plateau dates Complex constitute one of the major tectonic Seve rocks. These results bear directly ori both of 447 ± 7 Ma and 436 ± 7 Ma. Coexisting units in central parts of the orogen (Zachrisson, the chronology and nature of pre-Scandian oro- biotite yields plateau dates of 594 ± 10 Ma 1973).
    [Show full text]
  • GSA TODAY North-Central, P
    Vol. 9, No. 10 October 1999 INSIDE • 1999 Honorary Fellows, p. 16 • Awards Nominations, p. 18, 20 • 2000 Section Meetings GSA TODAY North-Central, p. 27 A Publication of the Geological Society of America Rocky Mountain, p. 28 Cordilleran, p. 30 Refining Rodinia: Geologic Evidence for the Australia–Western U.S. connection in the Proterozoic Karl E. Karlstrom, [email protected], Stephen S. Harlan*, Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, NM 87131 Michael L. Williams, Department of Geosciences, University of Massachusetts, Amherst, MA, 01003-5820, [email protected] James McLelland, Department of Geology, Colgate University, Hamilton, NY 13346, [email protected] John W. Geissman, Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, NM 87131, [email protected] Karl-Inge Åhäll, Earth Sciences Centre, Göteborg University, Box 460, SE-405 30 Göteborg, Sweden, [email protected] ABSTRACT BALTICA Prior to the Grenvillian continent- continent collision at about 1.0 Ga, the southern margin of Laurentia was a long-lived convergent margin that SWEAT TRANSSCANDINAVIAN extended from Greenland to southern W. GOTHIAM California. The truncation of these 1.8–1.0 Ga orogenic belts in southwest- ern and northeastern Laurentia suggests KETILIDEAN that they once extended farther. We propose that Australia contains the con- tinuation of these belts to the southwest LABRADORIAN and that Baltica was the continuation to the northeast. The combined orogenic LAURENTIA system was comparable in
    [Show full text]
  • Strain Analysis on the Sub-Lay Dam Unconformity Near
    Alabama Geological Society 2012 Annual Field Trip COMBINED REFERENCES Abrams, C.E., and McConnell, K.I., 1981, Stratigraphy Bieler, D. B., 1993, Correlation of Emuckfaw Group of the area around the Austell-Frolona metagraywackes with the Wedowee Group, antiform, west-central Georgia, in Wigley, Southern Piedmont, Alabama: implications P.B., ed., Latest thinking on the stratigraphy for the interpretation of the Alexander City of selected areas in Georgia; Volume 1: fault, Geological Society of America Georgia Geological Survey Information Abstracts with Programs, v. 25, No. 4, p. 3-4. Circular, no. 54-A, p. 55-67. Bream, B.R., 2003, Tectonic implications of para- and Adams, G. I., 1926, The crystalline rocks, in Adams, ortho gneiss geochronology and G. I., Butts, C., Stephenson, L. W., and geochemistry from the Southern Cooke, C. W., eds., Geology of Alabama: Appalachian crystalline core [Ph.D. thesis]: Alabama Geological Survey Special Report Knoxville, University of Tennessee, 310 p. 14, p. 25-40. Butts, C., 1926, The Paleozoic rocks, in Adams, G.I., Allison, D.T., 1992, Structural evolution and et al., eds., Geology of Alabama: Alabama metamorphic petrogenesis of a Geological Survey Special Report, v. 14, p. metasediment and metaigneous complex, 40-223. Coosa County, Alabama, (Ph.D. Butts, C., 1940, Description of the Montevallo and dissertation): Tallahassee, Florida, Florida Columbiana Quadrangles: U.S. Geological State University, 378 p. Survey Atlas, Folio 226, p. 0–19. Alsop, G.I. and Holdsworth, R.E., Sheath folds as Carter, W.W., 1985, Geology of Cedar and Talladega discriminators of bulk strain type, Journal of Mountains, Clay County, Alabama [M.S.
    [Show full text]
  • Geology-Of-The-Appalachian
    2 3 GEOLOGY OF THE APPALACHIAN-CALEDONIAN OROGEN IN CANADA AND GREENLAND Geological Survey of Canada, Geology of Canada, No. 6 Edited by Harold Williams, 1995 Chapter 1 – Introduction (by Harold Williams) PREAMBLE AND DEFINITION The Canadian Appalachian region includes the provinces of insular Newfoundland, Nova Scotia, New Brunswick, Prince Edward Island, and the southern part of Quebec along the south side of the St. Lawrence River (Fig. 1.1). It has an area of approximately 500000 km2 and it is widest (600 km) at the Canada-United States International Boundary in New Brunswick and Nova Scotia. A larger unexposed area of Appalachian rocks and structures extends across the Gulf of St. Lawrence and seaward to the Atlantic continental edge. Because of its coastal setting and insular makeup, the region offers tremendous shoreline exposures along marine passages. The Appalachian region is a Paleozoic geological mountain belt or orogen. This means that its rocks have been affected by orogeny, the combined effects of folding, faulting, metamorphism, and plutonism. Paleozoic folds and faults of several generations trend northeastward. Regional metamorphic rocks occupy continuous belts in interior parts of the orogen, and granitic batholiths are common throughout its length (Maps 1 and 2). 4 5 The word "Appalachian" was first used in a geographic context for the morphological mountains in the southeast United States. It has displaced the word "Acadian" formerly applied to this region of eastern Canada. In the present context, the word "Appalachian" is used for the geological mountain belt without regard for its morphological expression. Like the Cordilleran and Innuitian orogens, the Appalachian Orogen occupies a position peripheral to the stable interior craton of North America (Fig.
    [Show full text]
  • U.S. DEPARTMENT of the INTERIOR U.S.GEOLOGICAL SURVEY ALK.BIB a Selected Bibliography of Alkaline Igneous Rocks and Related Mine
    U.S. DEPARTMENT OF THE INTERIOR U.S.GEOLOGICAL SURVEY ALK.BIB A selected bibliography of alkaline igneous rocks and related mineral deposits, with an emphasis on western North America compiled by Felix E. Mutschler, D. Chad Johnson, and Thomas C. Mooney Open-File Report 94-624 1994 This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards and stratigraphic nomenclature. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. INTRODUCTION This bibliography contains 3,406 references on alkaline igneous rocks and related mineral deposits compiled in conjunction with ongoing studies of alkaline igneous rocks, metallogeny, and tectonics in western North America. Much of the literature on these topics is not readily recovered by searches of current bibliographies and computerized reference systems. We hope that by making this bibliography available, it will help other workers to access this occasionally hard to find literature. The bibliography is available in two formats: (1) paper hardcopy and (2) Apple Macintosh computer-readable 3.5 inch double density diskette. The computer-readable version of the bibliography is a 725 KB WORD (version 5.0) document. Individual literature citations are arranged alphabetically by author(s) and the order of items in each citation follows the standard U.S. Geological Survey format. Version 3.4 1 February 1994 BIBLIOGRAPHY Abbott, J. G., Gordey, S. P., and Tempelman-Kluit, D. J., 1986, Setting of stratiform, sediment- hosted lead-zinc deposits in Yukon and northeastern British Columbia, in Morin, J.
    [Show full text]
  • GSA TODAY North-Central, P
    Vol. 9, No. 10 October 1999 INSIDE • 1999 Honorary Fellows, p. 16 • Awards Nominations, p. 18, 20 • 2000 Section Meetings GSA TODAY North-Central, p. 27 A Publication of the Geological Society of America Rocky Mountain, p. 28 Cordilleran, p. 30 Refining Rodinia: Geologic Evidence for the Australia–Western U.S. connection in the Proterozoic Karl E. Karlstrom, [email protected], Stephen S. Harlan*, Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, NM 87131 Michael L. Williams, Department of Geosciences, University of Massachusetts, Amherst, MA, 01003-5820, [email protected] James McLelland, Department of Geology, Colgate University, Hamilton, NY 13346, [email protected] John W. Geissman, Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, NM 87131, [email protected] Karl-Inge Åhäll, Earth Sciences Centre, Göteborg University, Box 460, SE-405 30 Göteborg, Sweden, [email protected] ABSTRACT BALTICA Prior to the Grenvillian continent- continent collision at about 1.0 Ga, the southern margin of Laurentia was a long-lived convergent margin that SWEAT TRANSSCANDINAVIAN extended from Greenland to southern W. GOTHIAM California. The truncation of these 1.8–1.0 Ga orogenic belts in southwest- ern and northeastern Laurentia suggests KETILIDEAN that they once extended farther. We propose that Australia contains the con- tinuation of these belts to the southwest LABRADORIAN and that Baltica was the continuation to the northeast. The combined orogenic LAURENTIA system was comparable in
    [Show full text]
  • Stratigraphic Trends in Detrital Zircon Geochronology of Upper
    Stratigraphic trends in detrital zircon geochronology of upper Neoproterozoic and Cambrian strata, Osgood Mountains, Nevada, and elsewhere in the Cordilleran miogeocline: Evidence for early Cambrian uplift of the Transcontinental Arch Gwen M. Linde1, Patricia H. Cashman1, James H. Trexler, Jr.1, and William R. Dickinson2 1Department of Geological Sciences and Engineering, University of Nevada, Reno, Nevada 89557, USA 2Department of Geosciences, University of Arizona, Tucson, Arizona 85721-0077, USA ABSTRACT a funda mental feature of the lower Paleozoic strata that reflect initial rifting (e.g., Poole Laurentian craton. It was fi rst recognized from et al., 1992; Yonkee et al., 2014, and references U-Pb detrital zircon geochronology pro- broad structures and Phanerozoic sedimentation therein). These strata are mostly quartzite, with vides insight into the provenance of the patterns in the mid-continent (Fig. 1) (Keith, some siltstone, argillite, and phyllite; carbon- upper Neoproterozoic–lower Cambrian 1928). Sloss (1963, 1988) noted the deposition ate intervals are present in some locations (e.g., Osgood Mountain Quartzite and the upper of the middle and lowermost upper Cambrian Stewart, 1991; Poole et al., 1992). These units Cambrian–lower Ordovician Preble Forma- Sauk II sequence onlapping from the craton have been correlated across a broad region of tion in the Osgood Mountains of northern margin onto the Transcontinental Arch (Fig. 1). western North America (e.g., Poole et al., 1992). Nevada (USA). We analyzed 535 detrital zir- Carlson (1999) proposed, instead of a discrete Previous detrital zircon studies of upper Neo- con grains from six samples of quartz arenite arch, a platform, a discontinuous zone with proterozoic–lower Paleozoic passive margin by laser ablation–multicollector–inductively highs and lows and fl anking basins that give the strata record similar changes in detrital zircon coupled plasma–mass spectrometry.
    [Show full text]
  • Redalyc.Detrital Zircon Geochronology of Neoproterozoic to Middle Cambrian Miogeoclinal and Platformal Strata: Northwest Sonor
    Geofísica Internacional ISSN: 0016-7169 [email protected] Universidad Nacional Autónoma de México México Gross, Essa L.; Stewart, John H.; Gehrels, George E. Detrital zircon geochronology of Neoproterozoic to Middle Cambrian miogeoclinal and platformal strata: Northwest Sonora, Mexico Geofísica Internacional, vol. 39, núm. 4, october-december, 2000, pp. 295-308 Universidad Nacional Autónoma de México Distrito Federal, México Available in: http://www.redalyc.org/articulo.oa?id=56839401 How to cite Complete issue Scientific Information System More information about this article Network of Scientific Journals from Latin America, the Caribbean, Spain and Portugal Journal's homepage in redalyc.org Non-profit academic project, developed under the open access initiative Geofísica Internacional (2000), Vol. 39, Num. 4, pp. 295-308 Detrital zircon geochronology of Neoproterozoic to Middle Cambrian miogeoclinal and platformal strata: Northwest Sonora, Mexico Essa L. Gross1, John H. Stewart2 and George E. Gehrels3 1 Department of Geosciences, University of Arizona, Tucson, Arizona, USA 2 United States Geological Survey, Menlo Park, California, USA 3 Department of Geosciences, University of Arizona, Tucson, Arizona, USA Received: May 28, 1999; accepted: May 09, 2000. RESUMEN Ochenta y cinco circones detritales provenientes de estratos sedimentarios del Mesoproterozoico y/o Neoproterozoico al Cámbrico Medio del noroeste de Sonora, México, han sido analizados para determinar los terrenos fuente y delimitar las edades de deposición de las unidades. Los conjuntos de circones de la Formación El Alamo y la unidad El Aguila del Mesoproterozoico y/o Neoproterozoico tienen edades entre 1.06 Ga y 2.67 Ga, con predominio de edades de 1.1 a 1.2 Ga.
    [Show full text]
  • Proterozoic Multistage (Ca. 1.1 and 0.8 Ga) Extension Recorded in The
    Proterozoic multistage (ca. 1.1 and 0.8 Ga) extension recorded in the Grand Canyon Supergroup and establishment of northwest- and north-trending tectonic grains in the southwestern United States J. Michael Timmons* Karl E. Karlstrom Carol M. Dehler John W. Geissman Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, New Mexico 87131, USA Matthew T. Heizler New Mexico Bureau of Mines and Mineral Resources, Socorro, New Mexico 87801, USA ABSTRACT tures and ca. 800±700 Ma north-trending cord of intracratonic extensional tectonism extensional structures created regional and sedimentation inboard of the plate mar- The Grand Canyon Supergroup records fault networks that were tectonically in- gins. We recognize at least two discrete epi- at least two distinct periods of intracratonic verted during formation of the Ancestral sodes of Proterozoic extension in Grand Can- extension and sedimentation in the late Me- Rocky Mountains and Laramide contrac- yon, one at ca. 1100±900 Ma and another at soproterozoic and Neoproterozoic. New tion and reactivated during Tertiary 800±700 Ma. Two different structural trends 40Ar/39Ar age determinations indicate that extension. were associated with these two episodes of ex- the Mesoproterozoic Unkar Group was de- tension: northwest-striking faults are associ- posited between ca. 1.2 and 1.1 Ga. Basins Keywords: Chuar Group, Grand Canyon, ated with deposition and tilting of the Unkar in which the Unkar Group was deposited growth faults, intracratonic basins, Neopro- Group and north-striking faults were active and the related northwest-striking faults terozoic, Proterozoic rifting. during deposition of the Chuar Group (Fig.
    [Show full text]
  • Dickinson2004.Pdf
    7 Apr 2004 20:19 AR AR211-EA32-02.tex AR211-EA32-02.sgm LaTeX2e(2002/01/18) P1: GCE 10.1146/annurev.earth.32.101802.120257 Annu. Rev. Earth Planet. Sci. 2004. 32:13–45 doi: 10.1146/annurev.earth.32.101802.120257 Copyright c 2004 by Annual Reviews. All rights reserved First published online as a Review in Advance on November 10, 2003 EVOLUTION OF THE NORTH AMERICAN CORDILLERA William R. Dickinson Department of Geosciences, University of Arizona, Tucson, Arizona 85721; email: [email protected] Key Words continental margin, crustal genesis, geologic history, orogen, tectonics ■ Abstract The Cordilleran orogen of western North America is a segment of the Circum-Pacific orogenic belt where subduction of oceanic lithosphere has been under- way along a great circle of the globe since breakup of the supercontinent Pangea began in Triassic time. Early stages of Cordilleran evolution involved Neoproterozoic rifting of the supercontinent Rodinia to trigger miogeoclinal sedimentation along a passive continental margin until Late Devonian time, and overthrusting of oceanic allochthons across the miogeoclinal belt from Late Devonian to Early Triassic time. Subsequent evolution of the Cordilleran arc-trench system was punctuated by tectonic accretion of intraoceanic island arcs that further expanded the Cordilleran continental margin during mid-Mesozoic time, and later produced a Cretaceous batholith belt along the Cordilleran trend. Cenozoic interaction with intra-Pacific seafloor spreading systems fostered transform faulting along the Cordilleran continental margin and promoted incipient rupture of continental crust within the adjacent continental block. INTRODUCTION Geologic analysis of the Cordilleran orogen, forming the western mountain system of North America, raises the following questions: 1.
    [Show full text]
  • Early Mississippian Ocean Anoxia Triggering
    University of New Mexico UNM Digital Repository Earth and Planetary Sciences ETDs Electronic Theses and Dissertations Summer 7-10-2019 Early Mississippian ocean anoxia triggering organic carbon burial and enhancing Late Paleozoic Ice Age onset: evidence from uranium isotopes of marine limestones Keyi Cheng Earth and Planetary Sciences Follow this and additional works at: https://digitalrepository.unm.edu/eps_etds Part of the Geology Commons Recommended Citation Cheng, Keyi. "Early Mississippian ocean anoxia triggering organic carbon burial and enhancing Late Paleozoic Ice Age onset: evidence from uranium isotopes of marine limestones." (2019). https://digitalrepository.unm.edu/eps_etds/261 This Thesis is brought to you for free and open access by the Electronic Theses and Dissertations at UNM Digital Repository. It has been accepted for inclusion in Earth and Planetary Sciences ETDs by an authorized administrator of UNM Digital Repository. For more information, please contact [email protected]. Keyi Cheng Candidate Earth and Planetary Sciences Department This thesis is approved, and it is acceptable in quality and form for publication: Approved by the Thesis Committee: Dr. Maya Elrick, Earth and Planetary Sciences, Chairperson Dr. Stephen Romaniello, Arizona State University Dr. Peter Fawcett, Earth and Planetary Sciences i EARLY MISSISSIPPIAN OCEAN ANOXIA TRIGGERING ORGANIC CARBON BURIAL AND ENHANCING LATE PALEOZOIC ICE AGE ONSET: EVIDENCE FROM URANIUM ISOTOPES OF MARINE LIMESTONES by KEYI CHENG BACHELOR OF SCIENCE, GEOCHEMISTRY CHINA UNIVERSITY OF GEOSCIENCES (WUHAN), 2016 THESIS Submitted in Partial Fulfillment of the Requirements for the Degree of Master of Science Earth and Planetary Sciences The University of New Mexico Albuquerque, New Mexico July, 2019 ii ACKNOWLEDGMENTS I sincerely acknowledge my advisor and dissertation chair, Dr.
    [Show full text]