Geology: Ordovician Paleogeography and the Evolution of the Iapetus Ocean
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
The Geology of England – Critical Examples of Earth History – an Overview
The Geology of England – critical examples of Earth history – an overview Mark A. Woods*, Jonathan R. Lee British Geological Survey, Environmental Science Centre, Keyworth, Nottingham, NG12 5GG *Corresponding Author: Mark A. Woods, email: [email protected] Abstract Over the past one billion years, England has experienced a remarkable geological journey. At times it has formed part of ancient volcanic island arcs, mountain ranges and arid deserts; lain beneath deep oceans, shallow tropical seas, extensive coal swamps and vast ice sheets; been inhabited by the earliest complex life forms, dinosaurs, and finally, witnessed the evolution of humans to a level where they now utilise and change the natural environment to meet their societal and economic needs. Evidence of this journey is recorded in the landscape and the rocks and sediments beneath our feet, and this article provides an overview of these events and the themed contributions to this Special Issue of Proceedings of the Geologists’ Association, which focuses on ‘The Geology of England – critical examples of Earth History’. Rather than being a stratigraphic account of English geology, this paper and the Special Issue attempts to place the Geology of England within the broader context of key ‘shifts’ and ‘tipping points’ that have occurred during Earth History. 1. Introduction England, together with the wider British Isles, is blessed with huge diversity of geology, reflected by the variety of natural landscapes and abundant geological resources that have underpinned economic growth during and since the Industrial Revolution. Industrialisation provided a practical impetus for better understanding the nature and pattern of the geological record, reflected by the publication in 1815 of the first geological map of Britain by William Smith (Winchester, 2001), and in 1835 by the founding of a national geological survey. -
Redalyc.Sr, C and O Isotope Composition of Marbles from The
Geologica Acta: an international earth science journal ISSN: 1695-6133 [email protected] Universitat de Barcelona España Murra, J.A.; Baldo, E.G.; Galindo, C.; Casquet, C.; Pankhurst, R.J.; Rapela, C.W.; Dahlquist, J. Sr, C and O isotope composition of marbles from the Sierra de Ancasti, Eastern Sierras Pampeanas, Argentina: age and constraints for the Neoproterozoic-Lower Paleozoic evolution of the proto- Gondwana margin Geologica Acta: an international earth science journal, vol. 9, núm. 1, marzo, 2011, pp. 79-92 Universitat de Barcelona Barcelona, España Available in: http://www.redalyc.org/articulo.oa?id=50522124008 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 Geologica Acta, Vol.9, Nº 1, March 2011, 79-92 DOI: 10.1344/105.000001645 Available online at www.geologica-acta.com Sr, C and O isotope composition of marbles from the Sierra de Ancasti, Eastern Sierras Pampeanas, Argentina: age and constraints for the Neoproterozoic–Lower Paleozoic evolution of the proto-Gondwana margin 1 1 2 2 3 4 1 J.A. MURRA E.G. BALDO C. GALINDO C. CASQUET R.J. PANKHURST C.W. RAPELA J. DAHLQUIST 1 CICTERRA (Universidad Nacional de Córdoba - Conicet) Av. Vélez Sarsfield 1611, 5016 Córdoba, Argentina. Murra E-mail: [email protected] Baldo E-mail: [email protected] Dahlquist E-mail: [email protected] 2 Departamento. Petrología y Geoquímica Facultad de Ciencias Geológicas, Inst. -
Hydrographic Development of the Aral Sea During the Last 2000 Years Based on a Quantitative Analysis of Dinoflagellate Cysts
Palaeogeography, Palaeoclimatology, Palaeoecology 234 (2006) 304–327 www.elsevier.com/locate/palaeo Hydrographic development of the Aral Sea during the last 2000 years based on a quantitative analysis of dinoflagellate cysts P. Sorrel a,b,*, S.-M. Popescu b, M.J. Head c,1, J.P. Suc b, S. Klotz b,d, H. Oberha¨nsli a a GeoForschungsZentrum, Telegraphenberg, D-14473 Potsdam, Germany b Laboratoire Pale´oEnvironnements et Pale´obioSphe`re (UMR CNRS 5125), Universite´ Claude Bernard—Lyon 1, 27-43, boulevard du 11 Novembre, 69622 Villeurbanne Cedex, France c Department of Geography, University of Cambridge, Downing Place, Cambridge CB2 3EN, UK d Institut fu¨r Geowissenschaften, Universita¨t Tu¨bingen, Sigwartstrasse 10, 72070 Tu¨bingen, Germany Received 30 June 2005; received in revised form 4 October 2005; accepted 13 October 2005 Abstract The Aral Sea Basin is a critical area for studying the influence of climate and anthropogenic impact on the development of hydrographic conditions in an endorheic basin. We present organic-walled dinoflagellate cyst analyses with a sampling resolution of 15 to 20 years from a core retrieved at Chernyshov Bay in the NW Large Aral Sea (Kazakhstan). Cysts are present throughout, but species richness is low (seven taxa). The dominant morphotypes are Lingulodinium machaerophorum with varied process length and Impagidinium caspienense, a species recently described from the Caspian Sea. Subordinate species are Caspidinium rugosum, Romanodinium areolatum, Spiniferites cruciformis, cysts of Pentapharsodinium dalei, and round brownish protoper- idiniacean cysts. The chlorococcalean algae Botryococcus and Pediastrum are taken to represent freshwater inflow into the Aral Sea. The data are used to reconstruct salinity as expressed in lake level changes during the past 2000 years. -
A New Record Ofrodinia Break-Up in the Western Sierras Pampeanas of Argentina
A-type magmatism in the sierras ofMaz and Espinal: A new record ofRodinia break-up in the Western Sierras Pampeanas of Argentina Fernando CoIomboa,,,, Edgardo G.A. BaIdoa, Cesar Casquetb, RobertJ. PankhurstC, Carmen Galindob, CarIos W. RapeIa d, Juan A. DahIquista, C. Mark Fanninge a Departamento de Geologfa - FCEFyN, Universidad NacionaI de Cordoba, Wlez Sarsfield 1611, X5016GCA Cordoba, Argentina b Departamento de Petrologfa y Geoquimica, Universidad Complutense, 28040 Madrid, Spain C British Geological Survey, Keyworth, Nottingham NG12 5GG, England, United Kingdom d Centro de Investigaciones Geologicas, Universidad Nacional de La Plata, 1900 La Plata, Argentina e Research School of Earth Sciences, The Australian National University, Canberra, Australia A BST RAC T Two orthogneisses have been recognized in the sierras of Espinal and Maz (Wes tern Sierras Pampeanas, NWArgentina) that were emplaced within a Grenvillian metasedimentary sequence. Microcline, plagio clase and quartz are the main rock-forming minerals, with accessory zircon, apatite-(CaF), magnetite, biotite (Fe/(Fe + Mg) = 0.88-0.91). ferropargasite (Fetotal/(Fetotal + Mg) = 0.88-0.89), titanite (with up to 3 1.61 wt% Y203) and an REE-rich epidote. REE-poor epidote and zoned garnet (Ca and Fe + -rich) are meta Keywords: morphic minerals, while muscovite, carbonates and chlorite are secondary phases. Texture is mylonitic. Rodinia Two representative samples are classified as granite (from Sierra de Espinal) and granodiorite/tonalite U-Pb SHRIMP dating Anorogenic magmatism (from Sierra de Maz) on the grounds of immobile trace elements. Some trace element contents are rather Mesoproterozoic high (Zr: 603 and 891 ppm, Y: 44 and 76 ppm, 10,000 x Ga/AI: 2.39-3.89) and indicate an affiliation with Western Sierras Pampeanas A-type granites (more specifically, the A2 group). -
Early Evolution of the Proto-Andean Margin of South America
Early evolution of the Proto-Andean margin of South America C. W. Rapela Centro de Investigaciones Geológicas, Universidad Nacional de La Plata, Calle 1 No. 644, 1900 La Plata, Argentina R. J. Pankhurst British Antarctic Survey, Cambridge CB30ET, United Kingdom C. Casquet Departamento de Petrología y Geoquímica, Universidad Complutense, 28040 Madrid, Spain E. Baldo J. Saavedra CSIC, Instituto de Agrobiología y Recursos Naturales, 37071 Salamanca, Spain C. Galindo Departamento de Petrología y Geoquímica, Universidad Complutense, 28040 Madrid, Spain ABSTRACT INTRODUCTION From a detailed study of a 500 km transect in the Sierras Pampeanas, central-west Argen- The evolution of the Gondwana margin pro- tina, two pre-Silurian tectono-magmatic episodes are recognized and defined, each culminating posed here is based on new geochemical, isotopic, in micro-continental collisions against the proto-Andean margin of Gondwana. The Pampean petrological, and sedimentological data from a orogeny started in Early Cambrian time with short-lived subduction, indicated by ca. 535 Ma 500 km traverse across the Eastern Sierras Pam- calc-alkaline granitoids. Following Pampean terrane collision, burial to granulite facies condi- peanas and Precordillera (Fig. 1). Pre-Silurian tions (ca. 9 kbar) generated widespread migmatites and ca. 520 Ma highly peraluminous gran- metamorphic and magmatic history is inferred ites in the Eastern Sierras Pampeanas. After brief quiescence, a second major episode, the from (1) dating by conventional U-Pb on abraded Famatinian orogeny, started with subduction ca. 490 Ma, forming a wide continental arc and zircons, U-Pb SHRIMP analyses, and whole-rock ensialic backarc basin. This heralded the approach of Laurentia to Gondwana, during which Rb-Sr and K-Ar, (2) thermo-barometry based on the Precordillera terrane separated from the southern Appalachian region, finally colliding with microprobe mineral analyses, and (3) Nd and Sr Gondwana in Silurian–Devonian time. -
The Taconic Orogeny in Newfoundland: a Three-Stage Process
atlantic geology . volume 43 . 2007 83 geochronology and isotope geology, indicated that this model was incomplete. We will present new evidence that the Taconic orogeny comprises three separate accretionary events starting in the Late Cambrian and finishing in the Late Ordovician. Taconic 1 is represented by ca. 495 Ma west-directed obduc- tion of the ca. 510 Ma Lushs Bight oceanic Tract onto the peri- Laurentian Dashwoods microcontinent. Subduction is inferred to have initiated at a spreading centre abandoned during an inboard ridge jump responsible for separation of Dashwoods from Laurentia. Partial subduction of the buoyant Dashwoods forced subduction to step back into the Humber seaway, which led to formation of the ca. 490 Ma Baie Verte oceanic tract (BVOT). Dextral oblique closure of the Humber seaway first formed the Notre Dame arc (489–477 Ma) built on Dashwoods and the coeval Snooks Arm arc built on the BVOT, followed by their collision with Laurentia (Taconic 2) and each other. The obliquity of convergence induced large-scale translations of continental ribbons of the Laurentian margin from the lati- tude of Labrador to central Newfoundland. After a magmatic gap of c. 7–10 my, the Notre Dame arc records a voluminous flare-up of predominantly tonalite magmatism (464–459 Ma) during the waning stages of Taconic 2. Magmatism overlaps with strong deformation and comprises both arc and non-arc- like tonalite. We relate this flare-up to break-off of the oceanic lithosphere of the downgoing Laurentian slab. Taconic 3 is rep- resented by 455–450 Ma collision between a peri-Laurentian arc terrane and the peri-Gondwanan Popelogan-Exploits arc and their composite accretion to Laurentia. -
2012-Ruiz-Martinez-Etal-EPSL.Pdf
Earth and Planetary Science Letters 331-332 (2012) 67–79 Contents lists available at SciVerse ScienceDirect Earth and Planetary Science Letters journal homepage: www.elsevier.com/locate/epsl Earth at 200 Ma: Global palaeogeography refined from CAMP palaeomagnetic data Vicente Carlos Ruiz-Martínez a,b,⁎, Trond H. Torsvik b,c,d,e, Douwe J.J. van Hinsbergen b,c, Carmen Gaina b,c a Departamento de Geofísica y Meteorología, Facultad de Física, Universidad Complutense de Madrid, Avda. Complutense s/n, 28040 Madrid, Spain b Center for Physics of Geological Processes, University of Oslo, 0316 Oslo, Norway c Center of Advanced Study, Norwegian Academy of Science and Letters, 0271 Oslo, Norway d Geodynamics, NGU, N-7491 Trondheim, Norway e School of Geosciences, University of the Witwatersrand, WITS, 2050, South Africa article info abstract Article history: The Central Atlantic Magmatic Province was formed approximately 200 Ma ago as a prelude to the breakup of Received 21 November 2011 Pangea, and may have been a cause of the Triassic–Jurassic mass extinction. Based on a combination of (i) a Received in revised form 26 January 2012 new palaeomagnetic pole from the CAMP related Argana lavas (Moroccan Meseta Block), (ii) a global compila- Accepted 2 March 2012 tion of 190–210 Ma poles, and (iii) a re-evaluation of relative fits between NW Africa, the Moroccan Meseta Available online xxxx Block and Iberia, we calculate a new global 200 Ma pole (latitude=70.1° S, longitude=56.7° E and A95 =2.7°; Editor: P. DeMenocal N=40 poles; NW Africa co-ordinates). We consider the palaeomagnetic database to be robust at 200±10 Ma, which allows us to craft precise reconstructions near the Triassic–Jurassic boundary: at this very important Keywords: time in Earth history, Pangea was near-equatorially centered, the western sector was dominated by plate conver- palaeomagnetism gence and subduction, while in the eastern sector, the Palaeotethys oceanic domain was almost consumed palaeogeography because of a widening Neothethys. -
Glacial Geomorphology☆ John Menzies, Brock University, St
Glacial Geomorphology☆ John Menzies, Brock University, St. Catharines, ON, Canada © 2018 Elsevier Inc. All rights reserved. This is an update of H. French and J. Harbor, 8.1 The Development and History of Glacial and Periglacial Geomorphology, In Treatise on Geomorphology, edited by John F. Shroder, Academic Press, San Diego, 2013. Introduction 1 Glacial Landscapes 3 Advances and Paradigm Shifts 3 Glacial Erosion—Processes 7 Glacial Transport—Processes 10 Glacial Deposition—Processes 10 “Linkages” Within Glacial Geomorphology 10 Future Prospects 11 References 11 Further Reading 16 Introduction The scientific study of glacial processes and landforms formed in front of, beneath and along the margins of valley glaciers, ice sheets and other ice masses on the Earth’s surface, both on land and in ocean basins, constitutes glacial geomorphology. The processes include understanding how ice masses move, erode, transport and deposit sediment. The landforms, developed and shaped by glaciation, supply topographic, morphologic and sedimentologic knowledge regarding these glacial processes. Likewise, glacial geomorphology studies all aspects of the mapped and interpreted effects of glaciation both modern and past on the Earth’s landscapes. The influence of glaciations is only too visible in those landscapes of the world only recently glaciated in the recent past and during the Quaternary. The impact on people living and working in those once glaciated environments is enormous in terms, for example, of groundwater resources, building materials and agriculture. The cities of Glasgow and Boston, their distinctive street patterns and numerable small hills (drumlins) attest to the effect of Quaternary glaciations on urban development and planning. It is problematic to precisely determine when the concept of glaciation first developed. -
Paleozoic 3: Alabama in the Paleozoic
UNIVERSITY OF SOUTH ALABAMA GY 112: Earth History Paleozoic 3: Alabama in the Paleozoic Instructor: Dr. Douglas W. Haywick Last Time The Paleozoic Part 2 1) Back to Newfoundland 2) Eastern Laurentian Orogenies (Appalachians) 3) Other Laurentian Orogenies (Antler, Ouachita) (web notes 25) Laurentia (Paleozoic North America) Even though this coastline of Laurentia was a passive continental margin, a plate tectonic boundary was rapidly approaching… A B A B Laurentia (Paleozoic North America) The resulting Taconic Orogeny first depressed the seafloor Laurentia (localized transgression) and A Island arc then pushed previously deposited passive continental B margin sediments up into thrust fault mountains. Baltica There was only minimal metamorphism and igneous A intrusions. B Middle Ordovician Laurentia (Paleozoic North America) Laurentia Baltica Middle Ordovician Laurentia (Paleozoic North America) Laurentia Baltica Middle Ordovician Laurentia (Paleozoic North America) The next tectonic event (the Acadian Orogeny) was caused Laurentia by the approach of Baltica A B Baltica A B Baltica Baltica Late Ordovician Laurentia (Paleozoic North America) The Acadian Orogeny was more extensive and more intense (metamorphism and A lots of igneous intrusions) B A B Early Devonian Laurentia (Paleozoic North America) The Acadian Orogeny was more extensive and more intense (metamorphism and lots of igneous intrusions) Early Devonian Laurentia (Paleozoic North America) Lastly, along comes Gondwanna and…. …well you get the idea. A B B A B Mississippian Laurentia (Paleozoic North America) Lastly, along comes Gondwanna and…. …well you get the idea. A B B A B Pennsylvannian Suture zone Laurentia (Paleozoic North America) Lastly, along comes Gondwanna and…. …well you get the idea. -
A History of Proterozoic Terranes in Southern South America: from Rodinia to Gondwana
+ MODEL GEOSCIENCE FRONTIERS -(-) (2011) 1e9 available at www.sciencedirect.com China University of Geosciences (Beijing) GEOSCIENCE FRONTIERS journal homepage: www.elsevier.com/locate/gsf REVIEW A history of Proterozoic terranes in southern South America: From Rodinia to Gondwana C. Casquet a,*, C.W. Rapela b, R.J. Pankhurst c, E.G. Baldo d, C. Galindo a, C.M. Fanning e, J.A. Dahlquist d, J. Saavedra f a Departamento de Petrologıa y Geoquımica, IGEO (Universidad Complutense, CSIC), 28040 Madrid, Spain b Centro de Investigaciones Geologicas (CONICET-UNLP), 1900 La Plata, Argentina c Visiting Research Associate, British Geological Survey, Keyworth, Nottingham NG12 5GG, United Kingdom d CICTERRA (CONICET-UNC), 5000 Cordoba, Argentina e Research School of Earth Sciences, The Australian National University, Canberra, Australia f Instituto de Agrobiologıa y Recursos Naturales CSIC, 37071 Salamanca, Spain Received 3 August 2011; accepted 8 November 2011 KEYWORDS Abstract The role played by Paleoproterozoic cratons in southern South America from the Mesopro- Paleoproterozoic; terozoic to the Early Cambrian is reconsidered here. This period involved protracted continental amal- Cratons; gamation that led to formation of the supercontinent Rodinia, followed by Neoproterozoic continental Grenvillian; break-up, with the consequent opening of Clymene and Iapetus oceans, and finally continental Neoproterozoic rifting; re-assembly as Gondwana through complex oblique collisions in the Late Neoproterozoic to Early SW Gondwana assembly Cambrian. The evidence for this is based mainly on a combination of precise U-Pb SHRMP dating and radiogenic isotope data for igneous and metamorphic rocks from a large area extending from the Rio de la Plata craton in the east to the Argentine Precordillera in the west and as far north as Arequipa in Peru. -
CURRICULUM VITAE RAMOS, Victor Alberto Nacido En Buenos Aires, 22
CURRICULUM VITAE RAMOS, Victor Alberto Nacido en Buenos Aires, 22 de abril de 1945 DNI 4523394 Matrícula Profesional N° 485 Domicilio laboral Instituto de Estudios Andinos Don Pablo Groeber Laboratorio de Tectónica Andina Departamento de Ciencias Geológicas Facultad de Ciencias Exactas y Naturales (UBA) Ciudad Universitaria. Pabellón II Buenos Aires (1428) Teléfono 4576-3300/3309 interno 238. 1.- ESTUDIOS UNIVERSITARIOS DE GRADO Y POST-GRADO 1965 - Licenciado en Ciencias Geológicas de la Universidad de Buenos Aires. 1966 - Photogeologist en el International Training Centre for Aerial Survey, Delft, Holanda 1968 - Master of Science in Photointerpretation for Geology en el International Institute for Aerial Survey and Earth Sciences, Delft, Holanda 1970 - Doctor en Geología de la Universidad de Buenos Aires. 2.- ANTECEDENTES EN LA DOCENCIA, INVESTIGACIÓN Y GESTIÓN UNIVERSITARIA 2011 a la fecha. Profesor Titular Emérito, Universidad de Buenos Aires. 2011/2013. Director Organizador del Instituto de Estudios Andinos Don Pablo Groeber, Universidad de Buenos Aires – CONICET. 2011. Profesor Visitante de Tectónica Andina, Universidad Nacional de Colombia, sede Bogotá. 2011. Profesor Titular Consulto, Universidad de Buenos Aires. 2010/2013- Consejero del claustro de profesores del Consejo Directivo de la Facultad de Ciencias Exactas y Naturales de la Universidad de Buenos Aires. 2009 - Profesor Visitante de Tectónica Andina, Universidad de Ouro Preto, Brasil. 2008/2011. Profesor Titular Plenario de la Universidad de Buenos Aires. 2007/2008 - Jack Oliver Visiting Professorship, Department of Earth and Atmospheric Sciences, Cornell University. 2005/2006 - Adjunct Professor of the Institute for the Study of the Continents in the Cornell University. 2004 a la fecha. Investigador Superior del CONICET por invitación del Directorio. -
Geology and Topography of Dutchess County (.Pdf)
Chapter 3: The Geology and Topography of Dutchess County Chapter 3: Geology and Topography of Dutchess County, NY ______________________________________________________________________________ Roy T. Budnik, Jeffery R. Walker, and Kirsten Menking1 May 2010 INTRODUCTION The topography, settlement patterns, and mineral resources of Chapter Contents Dutchess County are all influenced by the underlying geology. Geologic History For example, the highest mountains contain the hardest rocks, Bedrock Formations Structural Geology communities in the county are generally located in areas of Surficial Deposits sand and gravel because of the relatively level terrain and Mineral Resources Topography abundant water supplies they contain, and construction Trends and Changes Over aggregates are mined where suitable deposits are found. Time Implications for Decision- Understanding geologic materials and processes is essential to Making sound resource management because the geology affects the Resources 1 This chapter was written during 2010 by Dr. Roy T. Budnik (President, Roy T. Budnik & Associates), Dr. Jeffrey R. Walker (Professor of Earth Science & Geography, Vassar College), and Dr. Kirsten Menking (Associate Professor of Earth Science and Geography, Vassar College). It is an updated and expanded version of the Hydrology chapter of the 1985 document Natural Resources, Dutchess County, NY (NRI). Natural Resource Inventory of Dutchess County, NY 1 Chapter 3: The Geology and Topography of Dutchess County quality and quantity of groundwater resources, the migration of pollutants, potential hazards to inhabitants, drainage patterns, mineral resources, and soil characteristics. Geology is the study of the earth, including all materials found at and below the earth’s surface. Geologists analyze the composition, origin, and ongoing changes in the rocks and sediments that compose the earth.