DOCSLIB.ORG

Variscan Accretionary Complex of Northwest Iberia: Terrane Correlation and Succession of Tectonothermal Events

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Variscan Accretionary Complex of Northwest Iberia: Terrane Correlation and Succession of Tectonothermal Events View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by EPrints Complutense Variscan accretionary complex of northwest Iberia: Terrane correlation and succession of tectonothermal events Jose R. Martlnez Catalan Departamento de Geologia, Unlversldad de Salamanca, 37008 Salamanca, Spain Ricardo Arenas Departamento de Petroiogia y Geoquimlca, Unlversldad Complutense, 28040 Madrid, Spain Florentino Diaz Garcia Departamento de Geologia, Unlversldad de OVledo, 33005 OVledo, Spain Jacobo Abati Departamento de Petroiogia y Geoquimlca, Unlversldad Complutense, 28040 Madrid, Spain ABSTRACT The allochthonous terranes of northwest Iberia can be correlated with specific pale ogeo­ graphic realms of the continental masses and intervening oceans involved in the Variscan colli­ sion. Assuming that the existing ophiolites represent the suture formed by the closure of the Rheic ocean, the units in the fo otwall to the suture correspond to the outer edge of the Good­ waDa continentalmargin, and the units in the hanging waD are interpreted as fragments of the conjugate margin, represented by the Me guma terrane. This correlation establishes a precise link betweencircum-Atlantic terranes, and makes it possible to draw a relatively simple sce­ nario of the successive tectonothermal events recorded. Following the amalgamation of Avalon to LaUl'entia, the remaining outboard terranes underwent a progressive accretion to this conti­ nent that ended with the collision between Laurentia and Gondwana. INTRODUCTION position in the nappe pile: basal, intermediate, granulite, amphibolite and greenschist facies. The allochthonousterranes of northwest Iberia and upper units. Because the intermediate units The ophiolitic nappes were stacked during the outcrop in five synforms or structural basins as show clear oceanicaffinities, they are referred to closure of the Rheic ocean. The thrustsshow east megaklippen (Fig. 1), and consist of a pile of as ophioliticand are interpreted as thesuture sep­ vergence, and the coeval amphibolite facies foli­ units, stacked in the first stages of theVariscan aratingtwo paleogeographic realms. ationwas formed�390--380m.y.ago (Dalhneyer orogeny, duringthe Lower and :MiddleDevonian. The basal unitsconsist of schists, paragneisses, et al., 1991, 40Ar/39 Ar on hornblende concen­ The nappe pile was subsequently thrust, during and alternations of igneous felsic and mafic trates), closely following oceanic crust genera­ the Upper Devonian-Lower Carboniferous, over rocks. Granitic and peralkaline orthogneisses tion as young as 395 Ma (Dunning et al., 1997, a Paleozoicsedimentary sequence that forms the have yielded ages of 480-460 Ma (Van Calsteren U-Pb on zircons). upper part of its relative autochthon (Martinez et al., 1979, Rb-Sr whole rock; Santos Zalduegui The upper units structurally overlie the ophio­ Catallmet al., 1996; Dal1meyer et al., 1997). et al., 1995, U-Pb on zircons). The magmatism lites and can be subdivided into high-pressure We outline a correlation of the allochthonous reflects an Ordovician rifting episode (Ribeiro and intermediate-pressure units. The high­ units ofnorthwest Iberia with specific paleogeo­ and Floor, 1987). Becausethere are no ophiolites pressure units occupy the lower relativestruc­ graphic realms of the continental masses in­ separating them from their relative autochthon, tural position.They consist of paragneisses and volved in the Variscan collision, as well as an in­ the basal units are considered part of the conti­ mafic and ultramafic rocks. The characteristic tervening ocean, and describe their accretionary nental margin of Gondwana. However, these rocks are metabasites, commonly garnet­ history, based mainly on the tectonothermal units are considered to be allochthonousbecause clinopyroxene granulites and eclogites, retro­ eventsrecognized in thedifferent unitsand on the there is a dramatic change in the metamorphic graded to the amphibolite facies. Gabbros occur isotopic age dataavailable. evolutionbetween them and their relative autoch­ in several stages of transformation, from virtu­ thon. The basal units registered an initial high­ ally undeformed and unmetamorphosed, to DESCRIPTION OF UNITS pressure metamorphic event, and are viewed as coronitic metagabbros and high-pressure gran­ The relativeautochthon formed part of the con­ part of the external edge of Gondwana after the ulites. In the less-deformedgabbros, subophitic tinentalmargin ofGondwanaduring the Late Prot­ opening of the Rheic ocean, having undergone a and diabase textures have been preserved, indi­ erozoicand Paleozoic.TIris marginpreserves evi­ westward subduction (in present coordinates) cating an emplacement at relatively shallow denceof the Cacbmian (Pan-African) orogeny as 380--370 m.y. ago, under an accretionary wedge levels. The chemical characteristics of the well as of a Cambrian-Ordoviciancontinental rift­ consisting of a pile formed by theophiolitic and gabbros, comparable to modem continental ing process that resulted in thepulling apart of the upper units (Arenas et al., 1995; Martinez tholeiites, are compatible with a continental rift Avaloo microcontinentfrom the Goodwana main­ Catallmet al., 1996). provenance (Van Calsteren and Den Tex, 1978). land and the opening of theRheic ocean (Cocks The ophiolitic units include basalts, pillow­ For the mafic rocks, Lower Ordovician ages, and Fortey, 1988). The extensional magmatic breccias, diabases, metagabbros, plagiogranites, between 490 and 480 Ma (Peucat et aL, 1990, activity has been dated at 490-465 Ma (U-Pb on amphibolites, and ultramafics. They occur in U-Pb on zircons), are considered to be protolith zircons: Lancelotet al., 1985; Gebauer, 1993). severalthrust sheets, and depict a wide variety of agesbased on differentiationby cathodolumines­ For the allochthon, it is useful to classifytheir metamorphic grades, ranging from low-grade, cence of magmatic and metamorphic zircon units into threegroups, according to theirrelative high-pressureconditions to intermediate-pressure domains (SchaJer et al., 1993, ion-microprobe CABO ORTEGAL INTERMEDIATE -PRESSURE UPPER HIGH UNITS -PRESSURE } OPHIOLlTIC UNITS Figure 1. Geologic map of northwest Iberia outlining BASAL UNITS allochthonous units and the l I t ! RELATIVE AUTOCHTHON megaklippenwhere theycrop PALEOZOIC out: Cabo Ortegal, Ordenes, D and Malpica-Tui in Spain, � UPPER � PROTEROZOIC and Braganlfa and Morais in � PRE-VARISCAN Portugal. For location, see � ORTHOGNEISSES Figure 2. o 50 km Is .H.I SPANISH-PORTUGUESE BORDER: U-Pb). Based on the age of the YOlmgest detrital Grand Banks of Newfoundland (Fig. 2). The of therelative autochthon (Lancelot et al., 1985; zircon grain (507 Ma), Schafer et al. (1993) sug­ outermost terraneidentified in the Appalachians Gebauer, 1993), are similar to those of the west gested that at least part of the metasediments are of Maritime Canada is Meguma, the main com­ African craton, and point to a common Gond­ younger than the Cambrian. The high-pressure ponent of which, the Meguma Group, consists wanan basement for Meguma, the upper and metamorphism has been dated as between 405 of a thick sequence of as much as 10 000 m of basal units, and the relative autochthon of Iberia. and 390 Ma, and the subsequent retrograde am­ Cambrian-Ordovician detrital rocks, often tur­ However, while the upper units are separated phibolite facies metamorphism is dated as biditic (Keppie and Dallmeyer, 1987). A Late from the basal units and their autochthon by 390-380 Ma (Schafer et aI., 1993; Santos Ordovician-Early Devonian bimodal vo1canism ophiolites, the Meguma terrane is in fault contact Zalduegui et aI., 1996, U-Pb on zircons, mon­ was reported by Keppie and Dalhneyer (1987), with the larger Avalon terrane, and no ophiolites azites, and titanites). and Dallmeyer and Keppie (1987) cited a 450 occur between them. The thick detritic sequence The overlying intermediate-pressure units m.y. old granite (Rb-Sr whole rock). that characterizes Meguma should be linked to a include a very thick sequence of terrigenous A correlation can be established between the large emerged area. We suggest that Meguma metasedimentaryrocks, large bodiesof amphibo­ upper unitsin the allochthonous terranesof Iberia may represent the southeastern continental lites, and intrusive augengneisses and gabbros. and Meguma. Both terranesinclude thick terrige­ margin of Avalon because of its position and also The augengneisses have yielded Lower Ordovi­ nous successions with commonflyschoid charac­ the age of its sediments, which fit the separation cian ages of 460-496 Ma (U-Pb on zircons: teristics and ages, and registered a lower Paleo­ of Avalon from Gondwana in the Ordovician Kuijper, 1980; Dallmeyer and Tucker, 1993). The zoic bimodal magmatism. Furthermore, the (Cocks and Fortey, 1988). Meguma is viewed gabbros commonly have subophitic and diabase similarity in the oldest ages obtained from upper as the conjugate rift pair of the Gondwana mar­ textures. The gradeof metamorphism varies from intercepts and inherited zircons from Meguma gin represented by the basal units and their the greenschist to the intermediate-pressure and the Iberian upper units, between2.7 and l.8 autochthon in Iberia. granulitefacies. Ga, reflects the provenance from a common source (Kuijper, 1980; Peucat et al., 1990; Krogh ACCRETIONARY HISTORY CORRELATION OF THE UPPER UNITS and Keppie, 1990; Dalhneyer and Tucker, 1993; The accretion of Avalon to Laurentia occurred In a late Paleozoic reconstruction of Pangea
Load more

Recommended publications
  • The Acadian Fold Belt in the Meguma Terrane, Nova Scotia: Cross Sections, Fold Mechanisms, and Tectonic Implications
    TECTONICS, VOL. 25, TC3007, doi:10.1029/2004TC001752, 2006 The Acadian fold belt in the Meguma Terrane, Nova Scotia: Cross sections, fold mechanisms, and tectonic implications Nicholas Culshaw1 and Sharon K. Y. Lee1 Received 6 October 2004; revised 10 January 2006; accepted 20 February 2006; published 20 May 2006. [1] Structural data and cross sections from the eastern from the Avalon Terrane (Figure 1). An Acadian fold belt part of the Devonian-Carboniferous fold belt of the affects its sedimentary component, the Cambrian–Early Meguma Terrane give insight into its structural Ordovician Meguma Group and latest Ordovician-Devonian development and crustal tectonics. The sandy White Rock, Kentville, and Torbrook formations. The fold Goldenville Formation, the active competent member belt is notable for its apparent simplicity: the locally during buckling, formed a multilayer several kilometers periclinal folds have mostly upright axial surfaces and horizontal hinges, with kilometric spacing between axial thick that lay beneath the denser, softer muds and silts of traces that are up to several tens of kilometers in length. the Halifax Formation. Cross sections reveal 2 orders of Given the external position of the Meguma Group relative folds: 11–18 km wavelength folds are interpreted as to the Appalachian orogen, the simple geometry of the resulting from buckling under the influence of gravity; Acadian fold belt is of interest, for, although resembling 4–6 km wavelength folds reflect the thickness of the an external foreland fold and thrust belt, thrusts are absent at multilayer with buckle shortening in the range 32– the present level of exposure. Also, the presence or absence 44%.
    [Show full text]
  • Map: Basement-Cover Relationships
    Downloaded from http://sp.lyellcollection.org/ by guest on September 30, 2021 • BASEMENT-COVER RELATIONSHIPS Downloaded from http://sp.lyellcollection.org/ by guest on September 30, 2021 BASEMENT-COVER RELATIONSHIPS FLINN ET AL~g~ JOHNSTONE ET AL RATHBONE ~ HARRIS~'~ RAMSAY & STURT SANDERSi I & VAN BREEMEN BREWER ET AL" 0 km 100 I I WATSON & DUNNING- GENERAL REVIEW KENNAN ET AL-- PARATECTONIC IRELAND BAMFORD-- SEISMIC CONSTRAINTS Downloaded from http://sp.lyellcollection.org/ by guest on September 30, 2021 The Caledonides of the British Isles--reviewed. 1979. Geological Society of London. Basement-cover relations in the British Caledonides Janet Watson & F. W. Dunning CONTENTS 1. Introduction 67 2. The Metamorphic Caledonides 68 a The Lewisian complex and related rocks 68 b Pre-Caledonian cover units 70 c Other possible basement units 72 d The Caledonian orogenic front 73 e Grenville activity in the northern Caledonian province 74 3. The Non-metamorphic Caledonides 76 a Basic facts relating to the belt in general 76 b The Midland Valley Transition Zone 77 c The Southern Uplands-Longford-Down-Clare Inliers Belt 83 d The Iapetus Suture 84 e The Lake District-Isle of Man-Leinster Belt 84 f The Irish Sea Horst 85 g The Welsh Basin and its eastern borders 85 h Eastern England 86 j The Midland Craton 86 4. Conclusions 87 5. Acknowledgements 88 6. References 88 1. Introduction underlying the Metamorphic Caledonides (which Although the conventional regional subdivi- consists mainly of gneisses) and that underlying sion of the British and Irish
    [Show full text]
  • Assessment of Geothermal Resources in Onshore Nova Scotia
    FINAL REPORT Assessment of geothermal resources in onshore Nova Scotia Setting the stage, demonstrating value, and identifying next steps Félix-Antoine Comeau1 Stephan Séjourné 2 Jasmin Raymond1 1Institut national de la recherche scientifique (INRS), Centre Eau Terre Environnement 2Enki GeoSolutions inc. Rapport de recherche R2002 Prepared for the account of: Offshore Energy Research Association (OERA) December 1st, 2020 © INRS, Centre - Eau Terre Environnement, 2020 Tous droits réservés ISBN : 978-2-89146-939-5 (version électronique) Dépôt légal - Bibliothèque et Archives nationales du Québec, 2020 Dépôt légal - Bibliothèque et Archives Canada, 2020 Table of Contents ACKNOWLEDGEMENTS.................................................................................................................. 13 FOREWORD ......................................................................................................................................... 15 EXECUTIVE SUMMARY ................................................................................................................... 17 1. OVERVIEW OF THE GEOTHERMAL RESOURCE TYPES ............................................... 21 1.1 Geothermal systems ............................................................................................................... 21 1.1.1 Magmatic .......................................................................................................................... 25 1.1.2 Sedimentary basins ..........................................................................................................
    [Show full text]
  • Juan Gómez-Barreiro Dear Editor, Thanks for Your Message. It Is
    To Topical Editor: Juan Gómez-Barreiro Dear editor, Thanks for your message. It is rather unusual to receive a third revision from an editor, but we have tried to follow your last remarks. See below some explanations, because we have not properly understood some of your queries. A) It is not clear how the authors choose the studied areas in the Iberian Massif. A short description on these criteria could be very useful for the interested reader. The criteria for the selection of the targeted study areas was (and still is) explained at the end of the Introduction section. “Until now the Toledanian and Sardic magmatic events had been studied on different areas and interpreted separately, without taking into account their similarities and differences. In this work, the geochemical affinities of the Furongian–Early Ordovician (Toledanian) and Early–Late Ordovician (Sardic) felsic magmatic activities recorded in the Central Iberian and Galicia-Trás-os-Montes Zones, Pyrenees, Occitan Domain and Sardinia are compared. The re-appraisal is based on 17 new samples from the Pyrenees, Montagne Noire and Sardinia, completing the absence of analysis in these areas and wide- ranging a dataset of 93 previously published geochemical analyses throughout the study region in south-western Europe”. • Besides, according to up-to-date references (e.g. Martínez Catalán et al 2019; https://doi.org/10.1007/978-3-030-10519-8_4), the Cantabrian, Westasturian-Leonese and Central Iberian zones were part of the Gondwana margin at that time span (broadly autochthon), while in the Galicia -Trás-os-Montes zone (Allochthon), only those units below the Ophiolites are clearly of that affinity (Basal and Parautochthon units).
    [Show full text]
  • Structural Geology of Parautochthonous and Allochthonous Terranes of the Penokean Orogeny in Upper Michigan Comparisons with Northern Appalachian Tectonics
    Structural Geology of Parautochthonous and Allochthonous Terranes of the Penokean Orogeny in Upper Michigan Comparisons with Northern Appalachian Tectonics U.S. GEOLOGICAL SURVEY BULLETIN 1904-Q AVAILABILITY OF BOOKS AND MAPS OF THE U.S. GEOLOGICAL SURVEY Instructions on ordering publications of the U.S. Geological Survey, along with the last offerings, are given in the current-year issues of the monthly catalog "New Publications of the U.S. Geological Survey." Prices of available U.S. Geological Survey publications released prior to the current year are listed in the most recent annual "Price and Availability List." Publications that are listed in various U.S. Geological Survey catalogs (see back inside cover) but not listed in the most recent annual "Price and Availability List" are no longer available. Prices of reports released to the open files are given in the listing "U.S. Geological Survey Open-File Reports," updated monthly, which is for sale in microfiche from the U.S. Geological Survey, Book and Open-File Report Sales, Box 25286, Building 810, Denver Federal Center, Denver, CO 80225 Order U.S. Geological Survey publications by mail or over the counter from the offices given below. BY MAIL OVER THE COUNTER Books Books Professional Papers, Bulletins, Water-Supply Papers, Tech­ Books of the U.S. Geological Survey are available over the niques of Water-Resources Investigations, Circulars, publications counter at the following U.S. Geological Survey offices, all of of general interest (such as leaflets, pamphlets, booklets), single which are authorized agents of the Superintendent of Documents. copies of periodicals (Earthquakes & Volcanoes, Preliminary De­ termination of Epicenters), and some miscellaneous reports, includ­ ANCHORAGE, Alaska-Rm.
    [Show full text]
  • Caledonian Nappe Sequence of Finnmark, Northern Norway, and the Timing of Orogenic Deformation and Metamorphism
    Caledonian Nappe Sequence of Finnmark, Northern Norway, and the Timing of Orogenic Deformation and Metamorphism B. A. STURT Geologisk Institutt, adv. A, Joachim Frielesgt. 1, Bergen, Norway I. R. PRINGLE Department of Geophysics, Madingley Road, Cambridge, England D. ROBERTS Norges Geologiske Undersakelse, Postboks 3006, Trondheim, Norway ABSTRACT and have a varying metamorphic state, reaching at least into garnet grade (Holtedahl and others, 1960). The exact relation between On the basis of regional, structural, and metamorphic studies these rocks on Mageray and the older Caledonian metamorphic combined with age determinations, it is demonstrated that the in- complex of the Kalak Nappe are, however, not yet established. ternal metamorphic fabrics of the main nappe sequence of Finn- Correlations made by a number of authors equate, with the mark, northern Norway, developed during an Early Ordovician obvious exception of the younger sedimentary rocks of Magertfy, phase of the Caledonian orogeny (Grampian?); the cleavage de- the rocks of the Finnmark nappe pile with the upper Pre- velopment in the autochthon also belongs to this phase. The final cambrian-Tremadoc sequence of the foreland autochthon. This mise-en-place of the thrust-nappe sequence, however, appears to correlation indicates that- the entire Caledonian sequence of the belong to a later phase of Caledonian orogenic development, prob- nappe pile (without Mageroy) and immediately underlying au- ably toward the end of the Silurian Period, as does the deformation tochthon is upper Precambrian, passing conformably up at least and metamorphism of the Silurian sequence of Mageray. The into the lower part of the Tremadoc. The nappe units beneath the geochronological results also give information regarding the posi- Kalak Nappe, although of lower metamorphic grade, have a simi- tioning of the lower boundaries to the Cambrian and Ordovician lar structural sequence.
    [Show full text]
  • Possible Evidence for a Protracted Gold-Forming System
    Further Re-Os Arsenopyrite Geochronology from Selected Meguma Au Deposits, Meguma Terrane, Nova Scotia: Possible Evidence for a Protracted Gold-forming System by Lin Chen A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science Department of Earth and Atmospheric Sciences University of Alberta ©Lin Chen, 2015 Abstract The Meguma terrane, Nova Scotia, is dominated by two rock types; regionally deformed and metamorphosed Cambro-Ordovician metasedimentary rocks and ca. 380-370 Ma meta- to peraluminous granites. The metasedimentary rocks host numerous orogenic-type, vein-hosted gold deposits which occur throughout the metasandstone-dominated Goldenville Group rather than the overlying metasiltstone- and metamudstone-dominated Halifax Group. These mineralized veins are dominated by quartz-carbonate-sulfide assemblages and occupy structures consistent with emplacement during late-stage fold tightening of the regional, northeast-trending, upright folds that formed during the Acadian orogenic event at ca. 410-400 Ma. From previous work, vein formation, hence gold emplacement, spanned 30-40 Ma, as constrained from field observations and radiometric dating. The former indicates veins post-date cleavage formation given that cleaved wall-rock fragments occur in some veins, and that rarely; veins post-date hornfels related to 380 Ma granites. Existing absolute age dating indicates two events at 408 Ma (Re-Os Arsenopyrite; 40Ar/39Ar whole rock) and 380-362 Ma (Re-Os Arsenopyrite; 40Ar/39Ar Muscovite, Biotite, whole rock). Here we report new Re-Os geochronological data generated from arsenopyrite in gold-bearing veins for two deposits sampled, all of which lie in the same stratigraphic-structural position in the lower part of the Goldenville Group.
    [Show full text]
  • Morphotectonic Analysis Along the Northern Margin of Samos Island, Related to the Seismic Activity of October 2020, Aegean Sea, Greece
    geosciences Article Morphotectonic Analysis along the Northern Margin of Samos Island, Related to the Seismic Activity of October 2020, Aegean Sea, Greece Paraskevi Nomikou 1,* , Dimitris Evangelidis 2, Dimitrios Papanikolaou 1, Danai Lampridou 1, Dimitris Litsas 2, Yannis Tsaparas 2 and Ilias Koliopanos 2 1 Department of Geology and Geoenvironment, National and Kapodistrian University of Athens, Panepistimioupoli Zografou, 15784 Athens, Greece; [email protected] (D.P.); [email protected] (D.L.) 2 Hellenic Navy Hydrographic Service, Mesogeion 229, TGN 1040 Cholargos, Greece; [email protected] (D.E.); [email protected] (D.L.); [email protected] (Y.T.); [email protected] (I.K.) * Correspondence: [email protected] Abstract: On 30 October 2020, a strong earthquake of magnitude 7.0 occurred north of Samos Island at the Eastern Aegean Sea, whose earthquake mechanism corresponds to an E-W normal fault dipping to the north. During the aftershock period in December 2020, a hydrographic survey off the northern coastal margin of Samos Island was conducted onboard R/V NAFTILOS. The result was a detailed bathymetric map with 15 m grid interval and 50 m isobaths and a morphological slope map. The morphotectonic analysis showed the E-W fault zone running along the coastal zone with 30–50◦ of Citation: Nomikou, P.; Evangelidis, slope, forming a half-graben structure. Numerous landslides and canyons trending N-S, transversal D.; Papanikolaou, D.; Lampridou, D.; Litsas, D.; Tsaparas, Y.; Koliopanos, I. to the main direction of the Samos coastline, are observed between 600 and 100 m water depth. The Morphotectonic Analysis along the ENE-WSW oriented western Samos coastline forms the SE margin of the neighboring deeper Ikaria Northern Margin of Samos Island, Basin.
    [Show full text]
  • Antler Orogeny and Foreland Basin: a Model: Discussion and Reply
    Antler orogeny and foreland basin: A model: Discussion and reply Discussion J. G. JOHNSON ) „ , r, . _ „„,,, ANNE PENDERGAST I ®ePartmenl °J Geology, Oregon Slate University, Corvallis, Oregon 97331 We deny that rocks of the Antler allochthon have been southern part of the Pine Valley quadrangle, south of Pony Creek, redistributed by probable Mesozoic thrust nappes along the the sequence is: Nevada Group carbonates, Pilot Shale, "Chainman Roberts Mountains thrust front between the latitudes of Eureka Shale," Roberts Mountains allochthon (Johnson and Pendergast, and Elko, as was represented by Speed and Sleep (1982, Fig. 1). 1981, p. 653). The important paper on the Antler orogeny by Speed and Throughout the rest of the Pinyon Range, mapped by Smith Sleep (1982) proposed a model which should be revised in the light and Ketner (1975, PI. 1; 1978) or discussed by them as regards of new interpretations of central Nevada geology made by Johnson timing of deformation (1977), two facts stand out consistently. (1) and Pendergast (1981) and published while the Speed and Sleep Wherever the base of the allochthon has been mapped, it overlies manuscript was in press. The most significant of these is that Lower Lower Mississippian (Kinderhookian) rocks. (2) Wherever the Mississippian rocks are in both the autochthon and the allochthon stratigraphic sequence is exposed, the lowest Mississippian beds along the thrust front. Specifically, we refer to allochthonous overlie Devonian autochthonous rocks. Ordovician-Devonian rocks in the belt from Devils Gate to the Because Smith and Ketner (1968) mapped Kinderhookian Roberts Mountains, from the west flank of the Sulphur Spring Webb Formation as overlying both autochthon and allochthon, Range, and including rocks as young as Kinderhookian at several they (apparently) assumed that any structurally higher allochthon localities in the Pinyon Range.
    [Show full text]
  • Geologic Map of Washington - Northwest Quadrant
    GEOLOGIC MAP OF WASHINGTON - NORTHWEST QUADRANT by JOE D. DRAGOVICH, ROBERT L. LOGAN, HENRY W. SCHASSE, TIMOTHY J. WALSH, WILLIAM S. LINGLEY, JR., DAVID K . NORMAN, WENDY J. GERSTEL, THOMAS J. LAPEN, J. ERIC SCHUSTER, AND KAREN D. MEYERS WASHINGTON DIVISION Of GEOLOGY AND EARTH RESOURCES GEOLOGIC MAP GM-50 2002 •• WASHINGTON STATE DEPARTMENTOF 4 r Natural Resources Doug Sutherland· Commissioner of Pubhc Lands Division ol Geology and Earth Resources Ron Telssera, Slate Geologist WASHINGTON DIVISION OF GEOLOGY AND EARTH RESOURCES Ron Teissere, State Geologist David K. Norman, Assistant State Geologist GEOLOGIC MAP OF WASHINGTON­ NORTHWEST QUADRANT by Joe D. Dragovich, Robert L. Logan, Henry W. Schasse, Timothy J. Walsh, William S. Lingley, Jr., David K. Norman, Wendy J. Gerstel, Thomas J. Lapen, J. Eric Schuster, and Karen D. Meyers This publication is dedicated to Rowland W. Tabor, U.S. Geological Survey, retired, in recognition and appreciation of his fundamental contributions to geologic mapping and geologic understanding in the Cascade Range and Olympic Mountains. WASHINGTON DIVISION OF GEOLOGY AND EARTH RESOURCES GEOLOGIC MAP GM-50 2002 Envelope photo: View to the northeast from Hurricane Ridge in the Olympic Mountains across the eastern Strait of Juan de Fuca to the northern Cascade Range. The Dungeness River lowland, capped by late Pleistocene glacial sedi­ ments, is in the center foreground. Holocene Dungeness Spit is in the lower left foreground. Fidalgo Island and Mount Erie, composed of Jurassic intrusive and Jurassic to Cretaceous sedimentary rocks of the Fidalgo Complex, are visible as the first high point of land directly across the strait from Dungeness Spit.
    [Show full text]
  • Evolution of Ancient Lake Ohrid: a Tectonic Perspective
    Biogeosciences, 7, 3377–3386, 2010 www.biogeosciences.net/7/3377/2010/ Biogeosciences doi:10.5194/bg-7-3377-2010 © Author(s) 2010. CC Attribution 3.0 License. Evolution of ancient Lake Ohrid: a tectonic perspective N. Hoffmann1, K. Reicherter1, T. Fernandez-Steeger´ 2, and C. Grutzner¨ 1 1Institute of Neotectonics and Natural Hazards, RWTH Aachen University, Aachen, Germany 2Chair of Engineering Geology and Hydrogeology, RWTH Aachen University, Aachen, Germany Received: 14 May 2010 – Published in Biogeosciences Discuss.: 16 June 2010 Revised: 3 September 2010 – Accepted: 21 September 2010 – Published: 29 October 2010 Abstract. Lake Ohrid Basin is a graben structure situated in 1 Introduction the Dinarides at the border of the Former Yugoslavian Re- public of Macedonia (FYROM) and Albania. It hosts one of Lake Ohrid (693 m a.s.l.) in the southwest of the Former Yu- the oldest lakes in Europe and is characterized by a basin and goslavian Republic of Macedonia (FYROM, in the following range-like geological setting together with the halfgraben referred to as Macedonia) and the east of Albania (Fig. 1) basins of Korca, Erseka and Debar. The basin is surrounded is regarded as one of the oldest lakes of Europe. Biologi- by Paleozoic metamorphics in the northeast and north and cal studies on endemic fauna give hints on a Pliocene age Mesozoic ultramafic, carbonatic and magmatic rocks in the (Stankovic, 1960). With a length of 30 km and a width of east, northwest, west and south. Paleocene to Pliocene units 15 km it covers an area of 360 km2 that is larger than the are present in the southwest.
    [Show full text]
  • Tectonic Events Since Early Paleozoic in the Carlin-Pinon Range Area, Nevada
    Tectonic Events Since Early Paleozoic in the Carlin-Pinon Range Area, Nevada GEOLOGICAL SURVEY PROFESSIONAL PAPER 867-C Prepared in cooperation with Nevada Bureau of Mines and Geology Tectonic Events Since Early Paleozoic in the Carlin-Pinon Range Area, Nevada By]. FRED S~fiTH, JR., and KEITH B. KETNER GEOLOGY OF THE CARLIN-PINON RANGE AREA, NEVADA. GEOLOGICAL SURVEY PROFESSIONAL PAPER 867-C Prepared in coopPration ·with N n'ada Bureau of Mines and Geology Of Sf''Vf'n rPcognizPd dPformational episodes thP ParliPst occurrPd in Late Devonian to Early Mississippian. tim£' and a prirtcipal orogrnic evpnf occurred in Mesozoic tim£' UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON: 1977 UNITED STATES DEPARTMENT OF THE INTERIOR CECIL D. ANDRUS, Secretary GEOLOGICAL SURVEY V. E. McKelvey, Director Library of Congress Cataloging in Publication Data Smith, Joe Fred, 1911- Tectonic events since early Paleozoic in the Carlin-Pinon Range area, Nevada. (Geology of the Carlin-Pinon Range area, Nevada) (Geological Survey Professional Paper 867-C) Bibliography: p. Supt. of Docs. no.: I 19.16:867-C 1. Geology-Nevada-Elko Co. 2. Geology-Nevada-Eureka Co. I. Ketner, Keith Brindley, 1921- joint author. II. Nevada. Bureau of Mines and Geology. III. Title. IV. Series. V. Series: United States Geological Survey Professional Pa Paper 867-C. QE138.E4S64 551.8'09793' 16 76-608351 For -,ale by the Superintendent of Documents, U.S. Go\'ernment Printing Office Washington, D.C. 20402 Stock Number 024-001-02953-7 CONTENTS Page i\bstract ------------------------------------------------------------------------------
    [Show full text]