Seismic Velocity Structure of the Continental Lithosphere from Controlled Source Data
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Durham Research Online
Durham Research Online Deposited in DRO: 13 April 2015 Version of attached le: Published Version Peer-review status of attached le: Peer-reviewed Citation for published item: Kaislaniemi, L. and van Hunen, J. (2014) 'Dynamics of lithospheric thinning and mantle melting by edge-driven convection : application to Moroccan Atlas mountains.', Geochemistry, geophysics, geosystems., 15 (8). pp. 3175-3189. Further information on publisher's website: http://dx.doi.org/10.1002/2014GC005414 Publisher's copyright statement: c 2014. The Authors. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modications or adaptations are made. Additional information: Use policy The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that: • a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders. Please consult the full DRO policy for further details. Durham University Library, Stockton Road, Durham DH1 3LY, United Kingdom Tel : +44 (0)191 334 3042 | Fax : +44 (0)191 334 2971 https://dro.dur.ac.uk PUBLICATIONS Geochemistry, -
Morocco): Clues from Trace Elements and Sr–Nd–Pb–Hf Isotopes
Lithos 205 (2014) 247–265 Contents lists available at ScienceDirect Lithos journal homepage: www.elsevier.com/locate/lithos Lithospheric origin for Neogene–Quaternary Middle Atlas lavas (Morocco): Clues from trace elements and Sr–Nd–Pb–Hf isotopes Delphine Bosch a,⁎, René C. Maury b,M'hammedElAzzouzib,c,ClaireBollingerd, Hervé Bellon b, Patrick Verdoux e a UMR-UM2-CNRS 5243 Géosciences Montpellier, Université de Montpellier II, place E. Bataillon, c.c. 060, 34095 Montpellier, France b UMR-CNRS 6538 Domaines océaniques, Institut Universitaire Européen de la Mer (IUEM), IUEM, Université de Brest, Université Européenne de Bretagne, place Nicolas Copernic, 29280 Plouzané, France c Faculté des Sciences, Université Mohammed-V, av. Ibn Batouta, BP 1014, 10100 Rabat, Maroc d UMS-CNRS 3113 Pôle de spectrométrie océan, IUEM, Université de Brest, Université Européenne de Bretagne, place Nicolas Copernic, 29280 Plouzané, France e Laboratoire de Géochimie Isotopique environnementale, Université de Nîmes/Site GIS, UMR-CNRS 7330, rue Georges Besse, 30035 Nîmes Cedex 1, France article info abstract Article history: This study presents new geochemical data on 26 mafic lavas from the Middle Atlas and Central Morocco volcanic Received 17 April 2014 provinces, including Miocene nephelinites and Pliocene–Quaternary (3.9–0.6 Ma) nephelinites, basanites, alkali Accepted 11 July 2014 and subalkaline basalts. Most of them represent near-primary magmas, although some alkali basalts were derived Available online 21 July 2014 from the minor fractionation of olivine and diopside phenocrysts. These evolved samples and the subalkaline basalt display higher 207Pb/204Pb and Zr/Nb ratios and lower εNd consistent with their contamination by lower crustal Keywords: Intraplate alkali basalts granulites during an open fractionation process. -
D6 Lithosphere, Asthenosphere, Mesosphere
200 Chapter d FAMILIAR WORLD The Present is the Key to the Past: HUGH RANCE d6 Lithosphere, asthenosphere, mesosphere < plastic zone > The terms lithosphere and asthenosphere stem from Joseph Barell’s 1914-15 papers on isostasy, entitled The Strength of the Earth's Crust, in the Journal of Geology.1 In the 1960s, seismic studies revealed a zone of rock weakness worldwide near the top of the upper part of the mantle. This zone of weakness is called the asthenosphere (Gk. asthenes, weak). The asthenosphere turned out to be of revolutionary significance for historical geology (see Topic d7, plate tectonic theory). Within the asthenosphere, rock behaves plastically at rates of deformation measured in cm/yr over lineal distances of thousands of kilometers. Above the asthenosphere, at the same rate of deformation, rock behaves elastically and, being brittle, it can break (fault). The shell of rock above the asthenosphere is called the lithosphere (Gk. lithos, stone). The lithosphere as its name implies is more rigid than the asthenosphere. It is important to remember that the names crust and lithosphere are not synonyms. The crust, the upper part of the lithosphere, is continental rock (granitic) in some places and is oceanic rock (basaltic) elsewhere. The lower part of lithosphere is mantle rock (peridotite); cooler but of like composition to the asthenosphere. The asthenosphere’s top (Figure d6.1) has an average depth of 95 km worldwide below 70+ million year old oceanic lithosphere.2 It shallows below oceanic rises to near seafloor at oceanic ridge crests. The rigidity difference between the lithosphere and the asthenosphere exists because downward through the asthenosphere, the weakening effect of increasing temperature exceeds the strengthening effect of increasing pressure. -
INTERIOR of the EARTH / an El/EMEI^TARY Xdescrrpntion
N \ N I 1i/ / ' /' \ \ 1/ / / s v N N I ' / ' f , / X GEOLOGICAL SURVEY CIRCULAR 532 / N X \ i INTERIOR OF THE EARTH / AN El/EMEI^TARY xDESCRrPNTION The Interior of the Earth An Elementary Description By Eugene C. Robertson GEOLOGICAL SURVEY CIRCULAR 532 Washington 1966 United States Department of the Interior CECIL D. ANDRUS, Secretary Geological Survey H. William Menard, Director First printing 1966 Second printing 1967 Third printing 1969 Fourth printing 1970 Fifth printing 1972 Sixth printing 1976 Seventh printing 1980 Free on application to Branch of Distribution, U.S. Geological Survey 1200 South Eads Street, Arlington, VA 22202 CONTENTS Page Abstract ......................................................... 1 Introduction ..................................................... 1 Surface observations .............................................. 1 Openings underground in various rocks .......................... 2 Diamond pipes and salt domes .................................. 3 The crust ............................................... f ........ 4 Earthquakes and the earth's crust ............................... 4 Oceanic and continental crust .................................. 5 The mantle ...................................................... 7 The core ......................................................... 8 Earth and moon .................................................. 9 Questions and answers ............................................. 9 Suggested reading ................................................ 10 ILLUSTRATIONS -
Asthenosphere–Lithospheric Mantle Interaction in an Extensional Regime
Chemical Geology 233 (2006) 309–327 www.elsevier.com/locate/chemgeo Asthenosphere–lithospheric mantle interaction in an extensional regime: Implication from the geochemistry of Cenozoic basalts from Taihang Mountains, North China Craton ⁎ Yan-Jie Tang , Hong-Fu Zhang, Ji-Feng Ying State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, P.O. Box 9825, Beijing 100029, PR China Received 25 July 2005; received in revised form 27 March 2006; accepted 30 March 2006 Abstract Compositions of Cenozoic basalts from the Fansi (26.3–24.3 Ma), Xiyang–Pingding (7.9–7.3 Ma) and Zuoquan (∼5.6 Ma) volcanic fields in the Taihang Mountains provide insight into the nature of their mantle sources and evidence for asthenosphere– lithospheric mantle interaction beneath the North China Craton. These basalts are mainly alkaline (SiO2 =44–50 wt.%, Na2O+ K2O=3.9–6.0 wt.%) and have OIB-like characteristics, as shown in trace element distribution patterns, incompatible elemental (Ba/Nb=6–22, La/Nb=0.5–1.0, Ce/Pb=15–30, Nb/U=29–50) and isotopic ratios (87Sr/86Sr=0.7038–0.7054, 143Nd/ 144 Nd=0.5124–0.5129). Based on TiO2 contents, the Fansi lavas can be classified into two groups: high-Ti and low-Ti. The Fansi high-Ti and Xiyang–Pingding basalts were dominantly derived from an asthenospheric source, while the Zuoquan and Fansi low-Ti basalts show isotopic imprints (higher 87Sr/86Sr and lower 143Nd/144Nd ratios) compatible with some contributions of sub- continental lithospheric mantle. The variation in geochemical compositions of these basalts resulted from the low degree partial melting of asthenosphere and the interaction of asthenosphere-derived magma with old heterogeneous lithospheric mantle in an extensional regime, possibly related to the far effect of the India–Eurasia collision. -
Tectonics and Crustal Evolution
Tectonics and crustal evolution Chris J. Hawkesworth, Department of Earth Sciences, University peaks and troughs of ages. Much of it has focused discussion on of Bristol, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, the extent to which the generation and evolution of Earth’s crust is UK; and Department of Earth Sciences, University of St. Andrews, driven by deep-seated processes, such as mantle plumes, or is North Street, St. Andrews KY16 9AL, UK, c.j.hawkesworth@bristol primarily in response to plate tectonic processes that dominate at .ac.uk; Peter A. Cawood, Department of Earth Sciences, University relatively shallow levels. of St. Andrews, North Street, St. Andrews KY16 9AL, UK; and Bruno The cyclical nature of the geological record has been recog- Dhuime, Department of Earth Sciences, University of Bristol, Wills nized since James Hutton noted in the eighteenth century that Memorial Building, Queens Road, Bristol BS8 1RJ, UK even the oldest rocks are made up of “materials furnished from the ruins of former continents” (Hutton, 1785). The history of ABSTRACT the continental crust, at least since the end of the Archean, is marked by geological cycles that on different scales include those The continental crust is the archive of Earth’s history. Its rock shaped by individual mountain building events, and by the units record events that are heterogeneous in time with distinctive cyclic development and dispersal of supercontinents in response peaks and troughs of ages for igneous crystallization, metamor- to plate tectonics (Nance et al., 2014, and references therein). phism, continental margins, and mineralization. This temporal Successive cycles may have different features, reflecting in part distribution is argued largely to reflect the different preservation the cooling of the earth and the changing nature of the litho- potential of rocks generated in different tectonic settings, rather sphere. -
Essentials of Geology
INSTRUCTOR’S MANUAL AND TEST BANK Essentials of Geology Fourth Edition Stephen Marshak Instructor’s Manual by John Werner SEMINOLE STATE COLLEGE OF FLORIDA Test Bank by Jacalyn Gorczynski TEXAS A&M UNIVERSITY– CORPUS CHRISTI Heather L. Lehto ANGELO STATE UNIVERSITY Daniel Wynne SACRAMENTO COMMUNITY COLLEGE B W • W • NORTON & COMPANY • NEW YORK • LONDON —-1 —0 —+1 5577-50734_ch00_2P.indd77-50734_ch00_2P.indd iiiiii 110/5/120/5/12 55:41:41 PPMM W. W. Norton & Company has been in de pen dent since its founding in 1923, when William Warder Norton and Mary D. Herter Norton fi rst published lectures delivered at the People’s Institute, the adult education division of New York City’s Cooper Union. The Nortons soon expanded their program beyond the Institute, publishing books by celebrated academics from America and abroad. By mid- century, the two major pillars of Norton’s publishing program— trade books and college texts— were fi rmly established. In the 1950s, the Norton family transferred control of the company to its employees, and today— with a staff of four hundred and a comparable number of trade, college, and professional titles published each year— W. W. Norton & Company stands as the largest and oldest publishing house owned wholly by its employees. Copyright © 2013, 2009, 2007, 2004 by W. W. Norton & Company, Inc. All rights reserved. Printed in the United States of America. Associate Editor, Supplements: Callinda Taylor. Project Editor: Thom Foley. Production Manager: Benjamin Reynolds. Editorial Assistant, Supplements: Paula Iborra. Composition and project management: Westchester Publishing Ser vices. Art by CodeMantra and Precision Graphics. -
Physiography of the Seafloor Hypsometric Curve for Earth’S Solid Surface
OCN 201 Physiography of the Seafloor Hypsometric Curve for Earth’s solid surface Note histogram Hypsometric curve of Earth shows two modes. Hypsometric curve of Venus shows only one! Why? Ocean Depth vs. Height of the Land Why do we have dry land? • Solid surface of Earth is Hypsometric curve dominated by two levels: – Land with a mean elevation of +840 m = 0.5 mi. (29% of Earth surface area). – Ocean floor with mean depth of -3800 m = 2.4 mi. (71% of Earth surface area). If Earth were smooth, depth of oceans would be 2450 m = 1.5 mi. over the entire globe! Origin of Continents and Oceans • Crust is formed by differentiation from mantle. • A small fraction of mantle melts. • Melt has a different composition from mantle. • Melt rises to form crust, of two types: 1) Oceanic 2) Continental Two Types of Crust on Earth • Oceanic Crust – About 6 km thick – Density is 2.9 g/cm3 – Bulk composition: basalt (Hawaiian islands are made of basalt.) • Continental Crust – About 35 km thick – Density is 2.7 g/cm3 – Bulk composition: andesite Concept of Isostasy: I If I drop a several blocks of wood into a bucket of water, which block will float higher? A. A thick block made of dense wood (koa or oak) B. A thin block made of light wood (balsa or pine) C. A thick block made of light wood (balsa or pine) D. A thin block made of dense wood (koa or oak) Concept of Isostasy: II • Derived from Greek: – Iso equal – Stasia standing • Density and thickness of a body determine how high it will float (and how deep it will sink). -
Controls of Subduction Geometry, Location of Magmatic Arcs, and Tectonics of Arc and Back-Arc Regions
Controls of subduction geometry, location of magmatic arcs, and tectonics of arc and back-arc regions TIMOTHY A. CROSS Exxon Production Research Company, P.O. Box 2189, Houston, Texas 77001 REX H. PILGER, JR. Department of Geology, Louisiana State University, Baton Rouge, Louisiana 70803 ABSTRACT States), intra-arc extension (for example, convergence rate, direction and rate of the Basin and Range province), foreland absolute upper-plate motion, age of the de- Most variation in geometry and angle of fold and thrust belts, and Laramide-style scending plate, and subduction of aseismic inclination of subducted oceanic lithosphere tectonics. ridges, oceanic plateaus, or intraplate is caused by four interdependent factors. island-seamount chains. It is crucial to Combinations of (1) rapid absolute upper- INTRODUCTION recognize that, in the natural system of the plate motion toward the trench and active Earth, the major factors may interact and, overriding of the subducted plate, (2) rapid Since Luyendyk's (1970) pioneer attempt therefore, are interdependent variables. De- relative plate convergence, and (3) subduc- to relate subduction-zone geometry to some pending on the associations among them, in tion of intraplate island-seamount chains, fundamental aspect(s) of plate kinematics a historical and spatial context, their aseismic ridges, and oceanic plateaus and dynamics, subsequent investigations effects on the geometry of subducted litho- (anomalously low-density oceanic litho- have suggested an increasing variety and sphere can be additive, or by contrast, one sphere) cause low-angle subduction. Under complexity among possible controls and variable can act in opposition to another conditions of low-angle subduction, the resultant configurations of subduction variable and result in total or partial cancel- upper surface of the subducted plate is in zones. -
Energy in Africa Challenges and Opportunities
SPRINGER BRIEFS IN ENERGY Manfred Hafner · Simone Tagliapietra Lucia de Strasser Energy in Africa Challenges and Opportunities SpringerBriefs in Energy SpringerBriefs in Energy presents concise summaries of cutting-edge research and practical applications in all aspects of Energy. Featuring compact volumes of 50– 125 pages, the series covers a range of content from professional to academic. Typical topics might include: • A snapshot of a hot or emerging topic • A contextual literature review • A timely report of state-of-the art analytical techniques • An in-depth case study • A presentation of core concepts that students must understand in order to make independent contributions. Briefs allow authors to present their ideas and readers to absorb them with minimal time investment. Briefs will be published as part of Springer’s eBook collection, with millions of users worldwide. In addition, Briefs will be available for individual print and electronic purchase. Briefs are characterized by fast, global electronic dissemina- tion, standard publishing contracts, easy-to-use manuscript preparation and formatting guidelines, and expedited production schedules. We aim for publication 8–12 weeks after acceptance. Both solicited and unsolicited manuscripts are considered for publication in this series. Briefs can also arise from the scale up of a planned chapter. Instead of simply contributing to an edited volume, the author gets an authored book with the space necessary to provide more data, fundamentals and background on the subject, methodology, future outlook, etc. SpringerBriefs in Energy contains a distinct subseries focusing on Energy Analysis and edited by Charles Hall, State University of New York. Books for this subseries will emphasize quantitative accounting of energy use and availability, including the potential and limitations of new technologies in terms of energy returned on energy invested. -
Berber Languages and Linguistics Mena B
Berber Languages and Linguistics Mena B. Lafkioui LAST MODIFIED: 24 MAY 2018 DOI: 10.1093/OBO/9780199772810-0219 Introduction Berber (aka Tamazight) is a branch of the Afro-Asiatic language phylum and counts about forty languages, which entirely cover North Africa, stretching from Morocco to Egypt, as well as from the Mediterranean Sea to the Sahara and the northern and western Sahel, including Mali, Niger, and Burkina Faso. The number of Berber speakers is estimated at more than forty million, of which the majority lives in Morocco (about 70 percent speaks Berber, mainly along with other languages). Berber has a general “continuum” makeup, which means that one Berber language gradually merges into another Berber language when they are contiguous. As a result, Berber forms a tightly knit and coherent bloc, which makes its subclassification very tricky. On the typological level, three major subdivisions can be made. The first is Northern Berber, which mainly contains Tarifit (including Senhaja Berber; North, Northeast, and Northwest Morocco), Tamazight of the Middle Atlas (Central Morocco), Figuig Berber (East Morocco), Kabyle Berber (North Algeria), Tashawit (Aures, Northeast Algeria), and some oasis languages like Berber of Mzab (South Algeria) and of Ouargla (South Algeria). The second is Southern Berber, which comprises languages such as Zenaga (Mauritania), Tashelhit (South Morocco), and Tetserret and Tuareg Berber (Sahara, Sahel). The third is Eastern Berber, which includes languages such as Berber spoken in Siwa (West Egypt), Sokna and El-Fogaha (Fezzan, Central Libya), Yefren and Zuara (Tripolitania, North Libya), and Ghadames (East Libya), as well as all the Berber languages of Tunisia (e.g., Jerba, Tamazret, and Sened). -
Planet Earth in Cross Section by Michael Osborn Fayetteville-Manlius HS
Planet Earth in Cross Section By Michael Osborn Fayetteville-Manlius HS Objectives Devise a model of the layers of the Earth to scale. Background Planet Earth is organized into layers of varying thickness. This solid, rocky planet becomes denser as one travels into its interior. Gravity has caused the planet to differentiate, meaning that denser material have been pulled towards Earth’s center. Relatively less dense material migrates to the surface. What follows is a brief description1 of each layer beginning at the center of the Earth and working out towards the atmosphere. Inner Core – The solid innermost sphere of the Earth, about 1271 kilometers in radius. Examination of meteorites has led geologists to infer that the inner core is composed of iron and nickel. Outer Core - A layer surrounding the inner core that is about 2270 kilometers thick and which has the properties of a liquid. Mantle – A solid, 2885-kilometer thick layer of ultra-mafic rock located below the crust. This is the thickest layer of the earth. Asthenosphere – A partially melted layer of ultra-mafic rock in the mantle situated below the lithosphere. Tectonic plates slide along this layer. Lithosphere – The solid outer portion of the Earth that is capable of movement. The lithosphere is a rock layer composed of the crust (felsic continental crust and mafic ocean crust) and the portion of the mafic upper mantle situated above the asthenosphere. Hydrosphere – Refers to the water portion at or near Earth’s surface. The hydrosphere is primarily composed of oceans, but also includes, lakes, streams and groundwater.