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Glacial Rebound and Plate Spreading: Results from the First Countrywide GPS Observations in Iceland
Geophys. J. Int. (2009) 177, 691–716 doi: 10.1111/j.1365-246X.2008.04059.x Glacial rebound and plate spreading: results from the first countrywide GPS observations in Iceland ∗ T. Arnad´ ottir,´ 1 B. Lund,2 W. Jiang,1 H. Geirsson,3 H. Bjornsson,¨ 4 P. Einarsson4 and T. Sigurdsson5 1Nordic Volcanological Center, Institute of Earth Sciences, University of Iceland, IS-101 Reykjav´ık, Iceland. E-mail: [email protected] 2Department of Earth Sciences, Uppsala University, Villavagen¨ 16, 752 36 Uppsala, Sweden 3Physics Department, Icelandic Meteorological Office, Reykjav´ık, Iceland 4Institute of Earth Sciences, University of Iceland, IS-101 Reykjav´ık, Iceland 5National Land Survey of Iceland, Akranes, Iceland Downloaded from https://academic.oup.com/gji/article/177/2/691/2023257 by guest on 30 September 2021 Accepted 2008 December 10. Received 2008 December 5; in original form 2008 June 12 SUMMARY Iceland is one of the few places on Earth where a divergent plate boundary can be observed on land. Direct observations of crustal deformation for the whole country are available for the first time from nationwide Global Positioning System (GPS) campaigns in 1993 and 2004. The plate spreading across the island is imaged by the horizontal velocity field and high uplift rates (≥10 mm yr−1) are observed over a large part of central and southeastern Iceland. Several earthquakes, volcanic intrusions and eruptions occurred during the time spanned by the measurements, causing local disturbances of the deformation field. After correcting for the largest earthquakes during the observation period, we calculate the strain rate field and find that the main feature of the field is the extension across the rift zones, subparallel to the direction of plate motion. -
Iceland Is Cool: an Origin for the Iceland Volcanic Province in the Remelting of Subducted Iapetus Slabs at Normal Mantle Temperatures
Iceland is cool: An origin for the Iceland volcanic province in the remelting of subducted Iapetus slabs at normal mantle temperatures G. R. Foulger§1 & Don L. Anderson¶ §Department of Geological Sciences, University of Durham, Science Laboratories, South Rd., Durham, DH1 3LE, U.K. ¶California Institute of Technology, Seismological Laboratory, MC 252-21, Pasadena, CA 91125, U. S. A. Abstract The time-progressive volcanic track, high temperatures, and lower-mantle seismic anomaly predicted by the plume hypothesis are not observed in the Iceland region. A model that fits the observations better attributes the enhanced magmatism there to the extraction of melt from a region of upper mantle that is at relatively normal temperature but more fertile than average. The source of this fertility is subducted Iapetus oceanic crust trapped in the Caledonian suture where it is crossed by the mid-Atlantic ridge. The extraction of enhanced volumes of melt at this locality on the spreading ridge has built a zone of unusually thick crust that traverses the whole north Atlantic. Trace amounts of partial melt throughout the upper mantle are a consequence of the more fusible petrology and can explain the seismic anomaly beneath Iceland and the north Atlantic without the need to appeal to very high temperatures. The Iceland region has persistently been characterised by complex jigsaw tectonics involving migrating spreading ridges, microplates, oblique spreading and local variations in the spreading direction. This may result from residual structural complexities in the region, inherited from the Caledonian suture, coupled with the influence of the very thick crust that must rift in order to accommodate spreading-ridge extension. -
Paleoproterozoic Tectonic Evolution of the Trans-North China Orogen: Toward a Comprehensive Model
Paleoproterozoic tectonic evolution of the Trans-North China Orogen: toward a comprehensive model. Pierre Trap, Michel Faure, Wei Lin, Nicole Le Breton, Patrick Monié To cite this version: Pierre Trap, Michel Faure, Wei Lin, Nicole Le Breton, Patrick Monié. Paleoproterozoic tectonic evolution of the Trans-North China Orogen: toward a comprehensive model.. Precambrian Research, Elsevier, 2012, 222-223, pp.191-211. 10.1016/j.precamres.2011.09.008. insu-00628119 HAL Id: insu-00628119 https://hal-insu.archives-ouvertes.fr/insu-00628119 Submitted on 2 Jan 2012 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Paleoproterozoic tectonic evolution of the Trans-North China Orogen: Toward a comprehensive model Pierre Trapa, Michel Faureb, Wei Linc, Nicole Le Bretonb, Patrick Moniéd UMR-CNRS 6249 Chrono-Environnement, Université de Franche-Comté, 16 route de Gray a 25030 Besançon Cedex, France Institut des Sciences de la Terre d‟Orléans, CNRS, Université d‟Orléans (UMR 6113), b 45071 Orléans Cedex 2, France State Key Laboratory of Lithosphere Evolution, Institute of Geology and Geophysics, c Chinese Academy of Sciences, Beijing 100029, China Géosciences Montpellier, UMR CNRS 5243, Université Montpellier II, 34095 Montpellier d Cedex 5, France Abstract In this contribution we present a reconstruction of the overall lithotectonic architecture, from inner zones to external ones, of the Paleoproterozoic Trans-North China Orogen, within the North China Craton. -
Plate Tectonics Review from Valerie Nulisch Some Questions (C) 2017 by TEKS Resource System
Plate Tectonics Review from Valerie Nulisch Some questions (c) 2017 by TEKS Resource System. Some questions (c) 2017 by Region 10 Educational Service Center. Some questions (c) 2017 by Progress Testing. Page 2 GO ON A student wanted to make a model of the Earth. The student decided to cut a giant Styrofoam ball in half and paint the layers on it to show their thickness. 1 Which model below best represents the layers of the Earth? A B C D Page 3 GO ON 2 A student is building a model of the layers of the Earth. Which material would best represent the crust? F Grouping of magnetic balls G Styrofoam packing pellets H Bag of shredded paper J Thin layer of graham crackers 3 Your teacher has asked you to make a model of the interior of the Earth. In your model, how do the thicknesses of the lithosphere and crust compare? A The lithosphere is thinner than the crust. B The lithosphere is exactly the same thickness as the crust. C The lithosphere is thicker than the crust. D The lithosphere is thicker than the oceanic crust, but thinner than the continental crust. 4 Sequence the layers of the Earth in order from the exterior surface to the interior center. F Lithosphere, mantle, inner core, outer core, crust, asthenosphere G Inner core, outer core, mantle, asthenosphere, lithosphere, crust H Crust, mantle, outer core, inner core, asthenosphere, lithosphere J Crust, lithosphere, asthenosphere, mantle, outer core, inner core Page 4 GO ON 5 The tectonic plate labeled A in the diagram is the A Eurasian Plate B Indo-Australian Plate C Pacific Plate D African Plate Page 5 GO ON 6 The tectonic plate labeled B in the diagram is the — F Eurasian Plate G Indo-Australian Plate H Pacific Plate J North American Plate Page 6 GO ON Directions: The map below shows Earth's tectonic plates; six of them are numbered. -
The Timing and Location of Major Ore Deposits in an Evolving Orogen" the Geodynamic Context
Downloaded from http://sp.lyellcollection.org/ by guest on September 26, 2021 The timing and location of major ore deposits in an evolving orogen" the geodynamic context DEREK J. BLUNDELL Department of Geology, Royal Holloway, University of London, Egham, Surrey TW20 OEX, UK (e-mail: d. blundell@gl, rhul.ac, uk) Abstract: Although it is possible to identify the potential controls on mineralization, the problem remains to identify the critical factors. Very large mineral deposits are rare occurrences in the geological record and are likely to have resulted from the combination of an unusual set of circumstances. When attempting to understand the mineralization processes that occurred to form a major ore deposit in the geological past, especially the reasons why the deposit formed at a particular time and location within an evolving orogenic system, it is instructive to look at mineralization in modern, active subduction complexes. There it is possible to measure and quantify the rates at which both tectonic and mineralizing processes occur. In a complex subduction system, regions of extension develop. For example, subduction hinge retreat is a process that creates extension and generates heat from the upwelling of hot asthenosphere ahead of the retreating slab, producing partial melting, magmatism and associated mineraliza- tion. Seismic tomography not only images mantle as it is now, but subduction slab anomalies can be interpreted in terms of the past histo12¢ of subduction. This can be used to test tectonic plate reconstructions. Tectonic and magmatic events occur rapidly and are of short duration so that many are ephemeral and will not be preserved. -
Azores and Iceland
13th World Conference on Earthquake Engineering Vancouver, B.C., Canada August 1-6, 2004 Paper No. 2369 A COMPARATIVE STUDY ON STRONG GROUND MOTION IN TWO VOLCANIC ENVIRONMENTS: AZORES AND ICELAND Carlos S. OLIVEIRA1, Ragnar SIGBJÖRNSSON2, Simon ÓLAFSSON3 SUMMARY The objective of this paper is to present the main results of a comparative study of strong ground motion on the Azores and Iceland. These islands are a super-structural part of the Mid Atlantic Ridge, which marks the boundary between the North-American Plate and the Eurasian Plate and creates a north-south oriented belt of seismic and volcanic activity. The tectonic environments are described and compared emphasising the similarities in the geological structure, including surface geology and its effects on strong ground motion. Furthermore, the seismicity of the Azores and Iceland is compared based on earthquake catalogues using statistical analysis. The strong-motion networks on the islands are described along with the strong-motion data used in the subsequent analysis. The strong-motion data are compared using statistical analysis. The main emphasis is put on attenuation of strong-motion data, characterised by root mean square acceleration and peak ground acceleration. The attenuation is also compared to some of the common attenuation relationships, used by the engineering community in Europe and America. The main findings are that there are significant similarities between the tectonic environments of the Azores and Iceland. Furthermore, the similarities found in seismicity are statistically significant. The attenuation is characterised by rapid decay with increasing distance and high acceleration in the near source area. It is found that the same ground motion estimation models can be applied on the Azores and in Iceland. -
Plate Tectonics Passport
What is plate tectonics? The Earth is made up of four layers: inner core, outer core, mantle and crust (the outermost layer where we are!). The Earth’s crust is made up of oceanic crust and continental crust. The crust and uppermost part of the mantle are broken up into pieces called plates, which slowly move around on top of the rest of the mantle. The meeting points between the plates are called plate boundaries and there are three main types: Divergent boundaries (constructive) are where plates are moving away from each other. New crust is created between the two plates. Convergent boundaries (destructive) are where plates are moving towards each other. Old crust is either dragged down into the mantle at a subduction zone or pushed upwards to form mountain ranges. Transform boundaries (conservative) are where are plates are moving past each other. Can you find an example of each type of tectonic plate boundary on the map? Divergent boundary: Convergent boundary: Transform boundary: What do you notice about the location of most of the Earth’s volcanoes? P.1 Iceland Iceland lies on the Mid Atlantic Ridge, a divergent plate boundary where the North American Plate and the Eurasian Plate are moving away from each other. As the plates pull apart, molten rock or magma rises up and erupts as lava creating new ocean crust. Volcanic activity formed the island about 16 million years ago and volcanoes continue to form, erupt and shape Iceland’s landscape today. The island is covered with more than 100 volcanoes - some are extinct, but about 30 are currently active. -
Earthquake Risk Transfer for Greece
Earthquake Risk Transfer for Greece Overview Figure 59. Hash circles represent current Earling undercover regions. Greece is located at the complex boundary zone in the eastern Mediterranean between the African Plate and the Eurasian Plate. The northern part of Greece lies on the Eurasian Plate while the southern part lies on the Aegean Sea Plate. The Aegean Sea Plate is moving southwestward with respect to the Eurasian Plate at about 30 mm/yr while the African Plate is subducting northwards beneath the Aegean Sea Plate at a rate of about 40 mm/yr. The northern plate boundary is a relatively 64 Earling Natural Risk Transfer Platform More; https://acircularworld.com diffuse divergent boundary while the southern convergent boundary forms the Hellenic arc. These two plate boundaries give rise to two contrasting tectonic styles, extension on east-west trending fault zones with strike-slip tectonics on SW-NE trending fault zones throughout west and central Greece, Peloponnese and the northern Aegean and contractional in the southern Aegean, continuing around to the Ionian islands. The south Aegean is the location of the volcanic arc and is characterized by extension. To the east of Crete along the Hellenic Arc, strike-slip tectonics with some extension become important. Earling can issue accurate earthquake preparedness alert especially for North of Greece. EPA Effect on Greece Insurance Loss Longterm Loss Millions $3,500 $1,300 $130 $600 Total Loss Insured Loss EPA Effect Figure 60. EPA effect on Sep 7, 1999, Greece earthquake (Higgins, 2016). 65 Earling Natural Risk Transfer Platform More; https://acircularworld.com EPA Effect on Greece Insurance Penetration Rate 38% 36% 33% 30% 28% 25% 23% 21% 17% 18% 15% 13% 2020 2021 2022 2023 2024 Figure 61. -
Earthquake Risk in Bangladesh
STUDENT VERSION Earthquake Risk in Bangladesh PASSAGE ONE Background A major earthquake can destroy any town. Imagine the damage it could do to a huge city, where millions of people live in poorly made buildings. Now imagine this city is also threatened by natural hazards like flooding and rising sea levels. These are the dangers that face Dhaka, the capital of Bangladesh. Scientists predict a major earthquake in the region. It’s been more than 100 years since the last one so Dhaka is not prepared. Today, a team of scientists is investigating the active geology behind earthquakes in Bangladesh. The project is led by Michael Steckler and Leonardo Seeber from Columbia University’s Lamont-Doherty Earth Observatory, and includes international and local scientists. These scientists represent a range of specialties, such as seismology (earthquakes), structural geology (rocks and tectonic forces), and the center sedimentology (sediments and past environments). Together, they of the action Bangladesh is a country in South Asia are studying the country’s past and present geological events — bordered by India, Bhutan, and Myanmar. It sits on the Bay of Bengal and its capital from shifting faults to changing river patterns — to help people in city, Dhaka, is located in the Bengal Delta. ©AMNH / Google Earth Bangladesh prepare for the next major earthquake. nepal bhutan bangladesh china dhaka myanmar india thailand laos cambodia amnh.org/education/bangladesh © 2013 American Museum of Natural History. All Rights Reserved. Page 1 Earthquake Risk STUDENT VERSION in Bangladesh CONTINUED Background Bangladesh: A Land of Extremes Bangladesh is a small country in south Asia. -
Post-Collisional Mantle Delamination in the Dinarides Implied
www.nature.com/scientificreports OPEN Post‑collisional mantle delamination in the Dinarides implied from staircases of Oligo‑Miocene uplifted marine terraces Philipp Balling1*, Christoph Grützner1, Bruno Tomljenović2, Wim Spakman3 & Kamil Ustaszewski1 The Dinarides fold‑thrust belt on the Balkan Peninsula resulted from convergence between the Adriatic and Eurasian plates since Mid‑Jurassic times. Under the Dinarides, S‑wave receiver functions, P‑wave tomographic models, and shear‑wave splitting data show anomalously thin lithosphere overlying a short down‑fexed slab geometry. This geometry suggests a delamination of Adriatic lithosphere. Here, we link the evolution of this continental convergence system to hitherto unreported sets of extensively uplifted Oligocene–Miocene (28–17 Ma) marine terraces preserved at elevations of up to 600 m along the Dinaric coastal range. River incision on either side of the Mediterranean‑Black Sea drainage divide is comparable to the amounts of terrace uplift. The preservation of the uplifted terraces implies that the most External Dinarides did not experience substantial deformation other than surface uplift in the Neogene. These observations and the contemporaneous emplacement of igneous rocks (33–22 Ma) in the internal Dinarides suggest that the Oligo‑Miocene orogen‑wide uplift was driven by post‑break‑of delamination of the Adriatic lithospheric mantle, this was followed by isostatic readjustment of the remaining crust. Our study details how lithospheric delamination exerts an important control on crustal deformation and that its crustal signature and geomorphic imprint can be preserved for millions of years. Te infuence of deep-seated processes on deformation patterns and rates in collisional orogens is unequivo- cally accepted, yet challenging to quantify. -
Regional Subduction Zone Models
Subduction III Regional subduction zone modeling Thorsten W Becker University of Southern California Short course at Universita di Roma TRE April 18 – 20, 2011 Reading • King, S. (Elsevier Treatise, 2007) • Billen, M. (Ann Rev, 2009) • Becker & Faccenna (2009) Jarrard (1986) King (2007) Pre - Plate Tectonics Internal deformation of subducted lithosphere. - Isacks & Molnar, 1969 Deep planar fault zone - Elsasser, 1968 Lithospheric thrusting - Plafker, 1965 Mantle Convection Mega-shear to 700 km Crustal-scale thrusting - Holmes, 1944 - Benioff, 1954 - Hess, 1962 1940s 1950s 1960s • Subduction into the mantle was one of the last pieces of the plate tectonics puzzle. Slide courtesy of M. Billen Plate Tectonics: in the SZ Steady-state slab dip: * Newtonian - Stevenson & Turner,1977 * Non-Newtonian Linking slab temp. to - Tovish et al., 1978 mineralogy & petrology * Layered mantle visc. - Peacock, 1990 - Yokokura, 1981 Dynamic topography Corner-flow model. from corner-flow Slab thermal structure - McKenzie, 1969 - Sleep, 1975 -Toksov, 1971; 1973 1960s 1970s 1980s 1970s 1990s • Early analytic models capture major processes. – Force balance on slab. – Slab thermal structure. Slide courtesy of M. Billen Kinematic Slab - Dynamic Wedge 3D, anisotropy implication - Kneller & van Keken, 2007 Non-linear viscosity - Kneller et al., 2007 Compositional & phase: density & viscosity - Gerya & Yuen, 2003 Low viscosity wedge - Honda & Saito, 2003 Wedge/back arc flow Convection in the wedge - Bodri & Bodri, 1978 - Ida, 1983 Temperature-dep. visc. - Toksov & Hsui, 1978 - Honda, 1985 - Eberle, 2001 1970s 1980s 1990s 2000s • Slab & mantle wedge thermal/min./pet. structure. • Fluid transport • Seismic anisotropy. Slide courtesy of M. Billen Observations Plate kinematics & characteristics - Mueller et al., 1997 - Lallemand et al., 2005 Seismic anisotropy - Russo & Silver, 1994 - Fischer et al., 1998 - Long & Silver, 2008 Plate kinematics & characteristics - Jarrard, 1986 Seismic tomography - e.g., van der Hilst, 1997 Arc curvature, slab dip, subduction velocity. -
Tectonics and Magmatism in Turkey and the Surrounding Area Geological Society Special Publications Series Editors
Tectonics and Magmatism in Turkey and the Surrounding Area Geological Society Special Publications Series Editors A. J. HARTLEY R. E. HOLDSWORTH A. C. MORTON M. S. STOKER Special Publication reviewing procedures The Society makes every effort to ensure that the scientific and production quality of its books matches that of its journals. Since 1997, all book proposals have been refereed by specialist reviewers as well as by the Society's Publications Committee. If the referees identify weaknesses in the proposal, these must be addressed before the proposal is accepted. Once the book is accepted, the Society has a team of series editors (listed above) who ensure that the volume editors follow strict guidelines on refereeing and quality control. We insist that individual papers can only be accepted after satisfactory review by two independent referees. The questions on the review forms are similar to those for Journal of the Geological Society. The referees' forms and comments must be available to the Society's series editors on request. Although many of the books result from meetings, the editors are expected to commission papers that were not presented at the meeting to ensure that the book provides a balanced coverage of the subject. Being accepted for presentation at the meeting does not guarantee inclusion in the book. Geological Society Special Publications are included in the ISI Science Citation Index, but they do not have an impact factor, the latter being applicable only to journals. More information about submitting a proposal and producing a Special Publication can be found on the Society's web site: www.geolsoc.org.uk.