DOCSLIB.ORG

Stratigraphic Trends in Detrital Zircon Geochronology of Upper

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read 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. The appearance of an arch (Fig. 1). age peaks and groups and therefore possibly detrital zircon age data of these Neo protero- In recent U-Pb detrital zircon geochronol- similar changes in provenance. Zircon ages in zoic–lower Paleozoic passive margin units ogy studies, researchers have proposed the upper Neoproterozoic–lower Cambrian strata in record a provenance change within the Transcontinental Arch as a barrier to sediment Utah (Lawton et al., 2010; Gehrels and Pecha, Osgood Mountain Quartzite. Comparison delivery from the central Laurentian craton to its 2014; Yonkee et al., 2014), Idaho (Yonkee et al., of these data with the work of others reveals western margin in early Paleozoic time (Amato 2014), and Nevada (Gehrels and Pecha, 2014; that this change in provenance occurred in and Mack, 2012; Gehrels and Pecha, 2014; Yonkee et al., 2014) change from predomi- correlative strata throughout an east-west Yonkee et al., 2014). Amato and Mack (2012) nantly Mesoproterozoic in the older strata to transect of the Great Basin. From latest Neo- documented evidence from the Bliss Sandstone upper Mesoproterozoic–Paleoproterozoic in the proterozoic through earliest Cambrian time, for the existence of the Transcontinental Arch younger strata. most grains were shed from the 1.0–1.2 Ga by at least the late Cambrian; they explained The only previous detrital zircon study of the Grenville orogen. After that time, drain- the differences in detrital zircon populations Osgood Mountain Quartzite was that of Gehrels age patterns changed and most grains were between the Tapeats Sandstone west of the arch and Dickinson (1995), who sampled from the derived from the 1.6–1.8 Ga Yavapai and and the Cambrian sandstones east of the arch by upper part of the formation. The Preble Forma- Mazatzal provinces; very few grains from the the uplift of the arch possibly as early as early tion has never been the subject of a published Grenville orogen were found in the younger Cambrian time. Gehrels and Pecha (2014) esti- detrital zircon study. strata. We suggest that this shift records the mated the uplift of the arch by early Cambrian We dated detrital zircons from three localities uplift, in early Cambrian time, of the Trans- time. Others have noted the possibility of early of the upper Neoproterozoic–lower Cambrian continental Arch. Our data also support our Cambrian uplift of the arch as the cause of the Osgood Mountain Quartzite and three locali- interpretation that the Osgood Mountain differences in detrital zircon age peaks and ties of the upper Cambrian–lower Ordovician Quartzite and the Preble Formation are cor- groups in passive margin strata in Utah (Yonkee Preble Formation in the Osgood Mountains relative to other contemporaneous passive et al., 2014). and near Edna Mountain, north-central Nevada margin strata in western Laurentia. Upper Neoproterozoic–lower Cambrian silici- (Fig. 2B; Table 1). We show that the detrital clastic rocks on the western Laurentian passive zircon ages shift within the Osgood Moun- INTRODUCTION margin record sedimentation that initiated after tain Quartzite; detrital zircons from the older rifting and continental separation (e.g., Stewart, samples are predominantly Mesoproterozoic, The Transcontinental Arch, a region of 1972; Poole et al., 1992). These passive mar- while detrital zircons from the younger sample, uplift that extends from the southwestern U.S. gin rocks were deposited on a discontinuously and all of the Preble Formation samples, are to south-central Ontario, Canada (Fig. 1), is exposed succession of diamictite and vol canic predominantly upper Mesoproterozoic–Paleo- Geosphere; December 2014; v. 10; no. 6; p. 1402–1410; doi:10.1130/GES01048.1; 7 fi gures; 1 table; 1 supplemental fi le. Received 4 March 2014 ♦ Revision received 1 August 2014 ♦ Accepted 10 August 2014 ♦ Published online 7 October 2014 1402 For permission to copy, contact [email protected] © 2014 Geological Society of America Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/10/6/1402/3338869/1402.pdf by guest on 28 September 2021 Detrital zircon geochronology of the Osgood Mountain Quartzite and Preble Formation in Nevada 50N passive margin section from the northwest U.S. 140W0 100W100W 60W to Sonora, Mexico (e.g., Lawton et al., 2010; SU CordilleranCordilleran HE Gehrels and Pecha, 2014; Yonkee et al., 2014). PassivePassive MarginMargin In contrast, the 1.8–1.6 Ga Yavapai-Mazatzal CanadaCanada Peri-LaurentianPeri-Laurentian and 1.48–1.34 Ga mid-continent granite rhyo- USA Peri-GondwananPeri-Gondwanan CORD WY lite provinces within the North America craton (720–400(720–400 Ma)Ma) (Fig. 1) were the dominant sediment sources Grenville orogen higher in the passive margin section (e.g., (1.2–1.0(1.2–1.0 Ga)Ga) ? ? Lawton et al., 2010; Gehrels and Pecha, 2014; 1.48–1.341.48–1.34 GaGa ? MMagmaticagmatic ProvProv ? NorthNorth Yonkee et al., 2014). The Osgood Mountain Quartzite and Preble Mazatzal/YavapaiMazatzal/Yavapai ? (1.8–1.6(1.8–1.6 Ga)Ga) ? Formation in northern Nevada have been inter- Trans-HudsonTrans-Hudson ? APP 30N (2.0–1.8(2.0–1.8 Ga)Ga) USAU preted as passive margin strata; they both have ? ArcheanArchean (>2.5(>2.5 GaGa)) MexicoM co ? an interesting position and tectonic and meta- OA morphic histories. They are far to the west of Transcontinental Arches most other passive margin units and are over- Carlson (1999) thrusted by both the Roberts Mountains alloch- Sloss (1988) 1000 kmkm thon and the Golconda allochthon (Burchfi el Keith (1928) et al., 1992; Poole et al., 1992). The Preble Formation is metamorphosed to greenschist ? Mazatzal/Yavapai ? Boundary facies, and has refolded folds (Cashman et al., 2011); it has been interpreted as being in con- formable stratigraphic succession with the Figure 1. Location of the main age provinces in North America that are potential source Osgood Mountain Quartzite (Fig. 3), based on terranes for the late Neoproterozoic–early Cambrian western Laurentian passive margin. map relationships and compositional similarity Hypothesized transcontinental arches are superimposed (Keith, 1928; Sloss, 1988; Carlson, of an upper member of the Osgood Mountain 1999). WY—Wyoming province; HE—Hearn province; SU—Superior province; CORD— Quartzite to the Preble Formation (Hotz and Cordilleran; APP—Appalachian; OA—Ouachita-Marathon. Figure is after Gehrels et al. Willden, 1964). (2011) and adapted from Anderson and Morrison (1992), Bickford et al. (1986), Hoffman Structurally, the Osgood Mountains comprise (1989), Burchfi el et al. (1992), Bickford and Anderson (1993), Van Schmus et al. (1993), a large, northeast-trending anticline with a sub- Dickinson and Lawton (2001), and Dickinson and Gehrels (2009). horizontal axis (Fig. 2B). The Preble Formation is exposed only on the fl anks of the anticline proterozoic. Coeval passive margin strata in margin units? (4) If a consistent stratigraphic (Fig. 2B). Late Paleozoic rocks are thrust over other studies throughout the Great Basin (e.g., pattern of detrital zircon ages exists in all Neo- the anticline in the northern and western parts of Lawton et al., 2010; Gehrels and Pecha, 2014; proterozoic–Cambrian sections, what caused a the range, and the southern extent of the Osgood Yonkee et al., 2014) show the same shift in ages. widespread change in detrital zircon ages with Mountains is overlain by Cenozoic andesite This suggests that a change in provenance in time in these units? fl ows (Fig. 2B) (Hotz and Willden, 1964). The these passive margin strata is widely recorded in Osgood Mountain Quartzite and Preble Forma- this region of western Laurentia. GEOLOGIC SETTING tion are primarily exposed in the central and In this paper we present new U-Pb zircon southern portions of the range (Fig. 2B). ages from the Osgood Mountain Quartzite and The North American craton contains several The Osgood Mountain Quartzite consists the Preble Formation. The dates were obtained Proterozoic and Archean age provinces, thus mostly of fi ne- to medium-grained quartz using laser ablation–multicollector–inductively providing geographically distinguishable crustal arenite , with some silty and shaly beds (Fig.
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]
  • 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]
  • Construction of Tectonic Subsidence Curves for The
    Construction of tectonic subsidence curves for the early Paleozoic miogeocline, southern Canadian Rocky Mountains: Implications for subsidence mechanisms, age of breakup, and crustal thinning GERARD C. BOND Lamont-Doherty Geological Observatory of Columbia University, Palisades, New York 10964 MICHELLE A. KOMINZ ABSTRACT interpreted by Stewart (1971, 1972) and by sections in the thrust and fold belt of the south- Burchfiel and Davis (1972) as evidence that a ern Canadian Rockies, where the strata are ex- A quantitative procedure has been developed passive continental margin was initiated at some ceptionally well exposed and good stratigraphic for calculating tectonic subsidence in fully lithi- time in the late Precambrian along the western and structural controls have been established. fied strata and has been applied to stratigraphic edge of the North American craton. This inter- The results of the analysis are compared with sections in the early Paleozoic miogeocline of pretation was based on a comparison of the thermal-mechanical models of passive margins the southern Canadian Rocky Mountains. The geology of the miogeocline with the generalized to identify the mechanisms that controlled the results indicate that tectonic subsidence along and largely descriptive models of passive mar- subsidence and to obtain a new estimate for the inner edge of the miogeocline was controlled gins that were available at the time. the age of continental breakup and initiation of mainly by thermal contraction of heated litho- In recent years, new quantitative methods and the passive margin in the southern Canadian sphere. Comparison of a palinspastically restored geophysical models have been developed for Rockies cross section of the inner part of the miogeocline analyzing the evolution of modern passive mar- with a cross section constructed from a two- gins (Keen, 1982; Watts, 1981).
    [Show full text]