DOCSLIB.ORG

Andean Tectonics 7KLVSDJHLQWHQWLRQDOO\OHIWEODQN Andean Tectonics

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Andean Tectonics 7KLVSDJHLQWHQWLRQDOO\OHIWEODQN Andean Tectonics Andean Tectonics 7KLVSDJHLQWHQWLRQDOO\OHIWEODQN Andean Tectonics Edited by Brian K. Horton Andrés Folguera Elsevier Radarweg 29, PO Box 211, 1000 AE Amsterdam, Netherlands The Boulevard, Langford Lane, Kidlington, Oxford OX5 1GB, United Kingdom 50 Hampshire Street, 5th Floor, Cambridge, MA 02139, United States © 2019 Elsevier Inc. All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Details on how to seek permission, further information about the Publisher’s permissions policies and our arrangements with organizations such as the Copyright Clearance Center and the Copyright Licensing Agency, can be found at our website: www.elsevier.com/permissions. This book and the individual contributions contained in it are protected under copyright by the Publisher (other than as may be noted herein). Notices Knowledge and best practice in this field are constantly changing. As new research and experience broaden our understanding, changes in research methods, professional practices, or medical treatment may become necessary. Practitioners and researchers must always rely on their own experience and knowledge in evaluating and using any information, methods, compounds, or experiments described herein. In using such information or methods they should be mindful of their own safety and the safety of others, including parties for whom they have a professional responsibility. To the fullest extent of the law, neither the Publisher nor the authors, contributors, or editors, assume any liability for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions, or ideas contained in the material herein. Library of Congress Cataloging-in-Publication Data A catalog record for this book is available from the Library of Congress British Library Cataloguing-in-Publication Data A catalogue record for this book is available from the British Library ISBN: 978-0-12-816009-1 For information on all Elsevier publications visit our website at https://www.elsevier.com/books-and-journals Publisher: Candice Janco Acquisition Editor: Amy Shapiro Editorial Project Manager: Ruby Smith Production Project Manager: Nilesh Kumar Shah Cover Designer: Matthew Limbert Typeset by SPi Global, India Contents Contributors .........................................................................................................................................xix Preface and Acknowledgments .........................................................................................................xxvii Part I Overview CHAPTER 1 Seismic structure along the South American subduction zone using satellite gravity data ...............................................................3 Orlando Alvarez, Stefanie Pechuan, Mario Gimenez, Andrés Folguera 1 Introduction ..................................................................................................................3 2 Data and method ..........................................................................................................5 2.1 Satellite GOCE gravity data .................................................................................5 2.2 Reduction by topographic and sediments effect ...................................................5 2.3 Harmonic decomposition ......................................................................................5 3 Results and discussion .................................................................................................6 3.1 The Valdivia 1960 Mw=9.5 earthquake ................................................................6 3.2 The Maule segment ...............................................................................................8 3.3 The central Chile segment ....................................................................................8 3.4 Northern Chile-southern Peru .............................................................................11 3.5 Peru .....................................................................................................................13 3.6 Ecuador-Colombia ..............................................................................................15 4 Concluding remarks ...................................................................................................17 Acknowledgments .....................................................................................................18 References ..................................................................................................................18 CHAPTER 2 Control of subduction erosion and sediment accretion processes on the trench curvature of the central Chilean margin ....25 Eduardo Contreras-Reyes 1 Introduction ................................................................................................................25 2 Trench and margin curvature .....................................................................................27 3 Discussion ..................................................................................................................31 4 Summary ....................................................................................................................32 Acknowledgments .....................................................................................................32 References ..................................................................................................................32 CHAPTER 3 Measuring dynamic topography in South America ...............................35 Federico M. Dávila, Pilar Ávila, Federico Martina, Horacio N. Canelo, Julieta C. Nóbile, Gilda Collo, Francisco Sánchez Nassif, Miguel Ezpeleta 1 Introduction ................................................................................................................35 2 Geodynamic and tectonic setting ...............................................................................37 v vi Contents 3 Theory, methods, and data .........................................................................................44 3.1 Global to continental residual topography ..........................................................44 3.2 Local to regional residual topographic analysis .................................................46 3.3 Dynamic topography ..........................................................................................48 4 Results ........................................................................................................................48 4.1 Continental lithospheric scale analysis. Modern and ancient .............................48 4.2 Local residual estimations ..................................................................................51 5 Discussion, ongoing studies, and future perspectives ................................................54 6 Conclusions ................................................................................................................59 Acknowledgments .....................................................................................................60 References ..................................................................................................................60 Further reading ...........................................................................................................66 Part II Northern Andes CHAPTER 4 Cenozoic tectonic evolution of the North Andes with constraints from volcanic ages, seismic reflection, and satellite geodesy ................................................................................69 James N. Kellogg, Gabriela Beatriz Franco Camelio, Héctor Mora-Páez 1 Introduction ................................................................................................................69 1.1 Flat subduction ....................................................................................................69 1.2 Slab geometry .....................................................................................................70 1.3 Arc-continent accretion and "escape" .................................................................70 2 Present tectonics of the North Andes (GPS vectors and profiles) .............................71 2.1 Nazca subduction and volcanic arc .....................................................................71 2.2 Amagmatic Caribbean subduction and accretionary prism formation ...............74 2.3 Arc-continent collision .......................................................................................76 2.4 Margin-parallel "escape" ....................................................................................77 2.5 Margin-normal mountain building ......................................................................78 3 Data sources and methodology ..................................................................................80 3.1 Radiometric ages for arc volcanics .....................................................................80 3.2 Revised plate tectonic model ..............................................................................80 3.3 Earthquake hypocentral locations .......................................................................84 4 Plate tectonic evolution of the North Andes ..............................................................85
Load more

Recommended publications
  • New Hypothesis for the Formation of the Catalina Schist
    Medial Cretaceous Subduction Erosion of Southwestern North America: New Hypothesis for the Formation of the Catalina Schist M. Grove1 Department of Earth & Space Sciences, University of California, Los Angeles, 3806 Geology, Los Angeles, CA 90095, Tel. (310) 794-5457; FAX: (310) 825-2779 [email protected] G.E. Bebout Department of Earth & Environmental Sciences, Lehigh University, 31 Williams Dr, Bethlehem, PA 18015. C.E. Jacobson Department of Geological and Atmospheric Sciences, 253 Science I, Iowa State University, Ames, IA 50011-3212 D.L. Kimbrough Department of Geological Sciences, San Diego State University, 5500 Campanile Drive, San Diego CA 92182-1020 R.L. King Department of Earth & Environmental Sciences, Lehigh University, 31 Williams Dr, Bethlehem, PA 18015. O.M. Lovera Department of Earth & Space Sciences, University of California, Los Angeles, 3806 Geology, Los Angeles, CA 90095. 1Corresponding author Submitted August 4, 2006 to GSA Special Paper Formation and applications of the sedimentary record in arc collision zones Edited by Amy E. Draut, Peter D. Clift, and David W. Scholl Abstract The high P/T Catalina Schist underlies the inner southern California borderland outboard of southwestern North America and records amphibolite facies recrystallization and partial melting at ca. 115 Ma and 40 km depth. While inverted metamorphism down to lawsonite albite facies across low-angle faults has most commonly been regarded as a product of nascent subduction, new detrital zircon U-Pb ages (33 samples; N = 645) demonstrate that the Catalina Schist was derived from successively accreted sediment shed from the evolving northern Peninsular Ranges batholith. Zircons from high-grade metasediments represent early Aptian, craton-enriched detritus shed predominantly from the batholith’s pre-Cretaceous flysch wallrocks and the Late Jurassic to Early Cretaceous volcanic cover.
    [Show full text]
  • Glacial-Interglacial Trench Supply Variation, Spreading-Ridge
    Glacial-interglacial trench supply variation, spreading-ridge subduction, and feedback controls on the Andean margin development at the Chile triple junction area (45-48°S) Jacques Bourgois, Christèle Guivel, Yves Lagabrielle, Thierry Calmus, Jacques Boulègue, Valérie Daux To cite this version: Jacques Bourgois, Christèle Guivel, Yves Lagabrielle, Thierry Calmus, Jacques Boulègue, et al.. Glacial-interglacial trench supply variation, spreading-ridge subduction, and feedback controls on the Andean margin development at the Chile triple junction area (45-48°S). Journal of Geo- physical Research : Solid Earth, American Geophysical Union, 2000, 105 (B4), pp.8355-8386. 10.1029/1999JB900400. hal-02497069 HAL Id: hal-02497069 https://hal.archives-ouvertes.fr/hal-02497069 Submitted on 17 Sep 2020 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. JOURNALOF GEOPHYSICALRESEARCH, VOL. 105,NO. B4,PAGES 8355-8386, APRIL 10,2000 Glacial-interglacial trench supply variation, spreading-ridge subduction, and feedback controls on the Andean margin developmentat the Chile triple junction area (45-48øS) JacquesBourgois,• Christhie Guivel,2 Yves Lagabrielle,3Thierry Calmus,4 JacquesBoulbgue,S and Valerie Daux6 Abstract. Duringthe Chile triple junction (CTJ) cruise (March-April 1997), EM12 bathymetry andseismic reflection data were collected in thevicinity of theChile triple junction (45-48øS), wherean activespreading ridge is beingsubducted beneath the Andean continental margin.
    [Show full text]
  • Andean Flat-Slab Subduction Through Time
    Andean flat-slab subduction through time VICTOR A. RAMOS & ANDRE´ S FOLGUERA* Laboratorio de Tecto´nica Andina, Universidad de Buenos Aires – CONICET *Corresponding author (e-mail: [email protected]) Abstract: The analysis of magmatic distribution, basin formation, tectonic evolution and structural styles of different segments of the Andes shows that most of the Andes have experienced a stage of flat subduction. Evidence is presented here for a wide range of regions throughout the Andes, including the three present flat-slab segments (Pampean, Peruvian, Bucaramanga), three incipient flat-slab segments (‘Carnegie’, Guan˜acos, ‘Tehuantepec’), three older and no longer active Cenozoic flat-slab segments (Altiplano, Puna, Payenia), and an inferred Palaeozoic flat- slab segment (Early Permian ‘San Rafael’). Based on the present characteristics of the Pampean flat slab, combined with the Peruvian and Bucaramanga segments, a pattern of geological processes can be attributed to slab shallowing and steepening. This pattern permits recognition of other older Cenozoic subhorizontal subduction zones throughout the Andes. Based on crustal thickness, two different settings of slab steepening are proposed. Slab steepening under thick crust leads to dela- mination, basaltic underplating, lower crustal melting, extension and widespread rhyolitic volcan- ism, as seen in the caldera formation and huge ignimbritic fields of the Altiplano and Puna segments. On the other hand, when steepening affects thin crust, extension and extensive within-plate basaltic flows reach the surface, forming large volcanic provinces, such as Payenia in the southern Andes. This last case has very limited crustal melt along the axial part of the Andean roots, which shows incipient delamination.
    [Show full text]
  • Plate Tectonic Setting of the Andean Cordillera
    183 by Victor A. Ramos Plate tectonic setting of the Andean Cordillera Laboratorio de Tectónica Andina, Universidad de Buenos Aires, Argentina. E-mail: [email protected] The Andes are a natural laboratory for the study of the acterize the different segments are widely variable. The present interaction between subduction of the oceanic plate and overview will focus on the major geological differences among these segments, based on today’s plate-tectonic knowledge of this moun- active geological processes. Inter- and intraplate seis- tain chain. micity, volcanic activity, thick- and thin-skinned fold and thrust belts, and foreland basin subsidence, in con- junction with space geodetic observations, contribute to Major geological provinces characterize the present plate tectonic setting of discrete The Andes north of the Golfo de Guayaquil are unique, as estab- segments of the Andes. The inherited geological history, lished by Gansser (1973). The Northern Andes record an important as well as the present tectonic setting, is responsible for accretion of oceanic crust during Jurassic, late Cretaceous, and Pale- the unique geology of the Northern, Central, and South- ogene times. As a result, the Western Cordillera of Colombia and Ecuador is mainly constituted of an oceanic basement that during ern Andes. The Northern Andes are the result of Meso- accretion was related to ophiolite obduction, important penetrative zoic and Cenozoic collisions of oceanic terranes, prior deformation and metamorphism, in cases up to blue schist facies. to the present Andean-type setting. The Central Andes Further north, the emplacement of the Caribbean nappes was related to the collision of an island arc system, the Bonaire block, during have a long history of subduction and volcanic arc Paleogene times (Bosch and Rodríguez, 1992, Kellogg and Bonini, activity, while the Southern Andes record the closing of 1982).
    [Show full text]
  • Transient Stripping of Subducting Slabs Controls Periodic Forearc Uplift
    ARTICLE https://doi.org/10.1038/s41467-020-15580-7 OPEN Transient stripping of subducting slabs controls periodic forearc uplift ✉ Armel Menant 1,3 , Samuel Angiboust 1, Taras Gerya 2, Robin Lacassin 1, Martine Simoes1 & Raphael Grandin1 Topography in forearc regions reflects tectonic processes along the subduction interface, from seismic cycle-related transients to long-term competition between accretion and ero- 1234567890():,; sion. Yet, no consensus exists about the topography drivers, especially as the contribution of deep accretion remains poorly constrained. Here, we use thermo-mechanical simulations to show that transient slab-top stripping events at the base of the forearc crust control uplift- then-subsidence sequences. This 100s-m-high topographic signal with a Myr-long periodi- city, mostly inaccessible to geodetic and geomorphological records, reflects the nature and influx rate of material involved in the accretion process. The protracted succession of stripping events eventually results in the pulsing rise of a large, positive coastal topography. Trench-parallel alternation of forearc highs and depressions along active margins worldwide may reflect temporal snapshots of different stages of these surface oscillations, implying that the 3D shape of topography enables tracking deep accretion and associated plate-interface frictional properties in space and time. 1 CNRS, Institut de physique du globe de Paris, Université de Paris, 75005 Paris, France. 2 Institute of Geophysics, Swiss Federal Institute of Technology (ETH), Zürich, Switzerland. 3Present address: GFZ Helmholtz Centre Potsdam, German Research Centre for Geosciences, Telegrafenberg, 14473 ✉ Potsdam, Germany. email: [email protected] NATURE COMMUNICATIONS | (2020) 11:1823 | https://doi.org/10.1038/s41467-020-15580-7 | www.nature.com/naturecommunications 1 ARTICLE NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-020-15580-7 plift and subsidence of the forearc domain have been long critical lack of constraints on the long-term (i.e.
    [Show full text]
  • Constraints from U-Pb and Hf Isotopic Data of Detrital Zi
    Magmatic History and Crustal Genesis of South America: Constraints from U-Pb Ages and Hf Isotopes of Detrital Zircons in Modern Rivers Item Type text; Electronic Dissertation Authors Pepper, Martin Bailey Publisher The University of Arizona. Rights Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. Download date 23/09/2021 09:38:39 Link to Item http://hdl.handle.net/10150/347220 MAGMATIC HISTORY AND CRUSTAL GENESIS OF SOUTH AMERICA: CONSTRAINTS FROM U-Pb AGES AND Hf ISOTOPES OF DETRITAL ZIRCONS IN MODERN RIVERS by Martin Pepper __________________________ Copyright © Martin Pepper 2014 A Dissertation Submitted to the Faculty of the DEPARTMENT OF GEOSCIENCES In Partial Fulfillment of the Requirements For the Degree of DOCTOR OF PHILOSOPHY In the Graduate College THE UNIVERSITY OF ARIZONA 2014 1 THE UNIVERSITY OF ARIZONA GRADUATE COLLEGE As members of the Dissertation Committee, we certify that we have read the dissertation prepared by Martin Pepper, titled Magmatic History and Crustal Genesis of South America: Constraints from U-Pb ages and Hf isotopes of detrital zircons in modern rivers and recommend that it be accepted as fulfilling the dissertation requirement for the Degree of Doctor of Philosophy. _______________________________________________________________________ Date: (11/17/2014) Peter Reiners _______________________________________________________________________ Date: (11/17/2014) Paul Kapp _______________________________________________________________________ Date: (11/17/2014) George Zandt Final approval and acceptance of this dissertation is contingent upon the candidate’s submission of the final copies of the dissertation to the Graduate College.
    [Show full text]
  • Subduction Erosion: Rates, Mechanisms, and Its Role in Arc Magmatism and the Evolution of the Continental Crust and Mantle
    GR-00621; No of Pages 25 Gondwana Research xxx (2011) xxx–xxx Contents lists available at ScienceDirect Gondwana Research journal homepage: www.elsevier.com/locate/gr GR focus review Subduction erosion: Rates, mechanisms, and its role in arc magmatism and the evolution of the continental crust and mantle Charles R. Stern ⁎ Department of Geological Sciences, University of Colorado, Boulder, CO, 80309-0399, USA article info abstract Article history: Subduction erosion occurs at all convergent plate boundaries, even if they are also accretionary margins. Received 30 November 2010 Frontal subduction erosion results from a combination of erosion and structural collapse of the forearc wedge Received in revised form 23 March 2011 into the trench, and basal subduction erosion by abrasion and hydrofracturing above the subduction channel. Accepted 27 March 2011 High rates of subduction erosion are associated with relatively high convergence rates (N60 mm/yr) and low Available online xxxx rates of sediment supply to the trench (b40 km2/yr), implying a narrow and topographically rough fi Handling Editor: M. Santosh subduction channel which is neither smoothed out nor lubricated by ne-grained water-rich turbidites such as are transported into the mantle below accreting plate boundaries. Rates of subduction erosion, which range 3 Keywords: up to N440 km /km/my, vary temporally as a function of these same factors, as well as the subduction of Subduction erosion buoyant features such as seamount chains, submarine volcanic plateaus, island arcs and oceanic spreading Arc magmatism ridge, due to weakening of the forearc wedge. Revised estimates of long-term rates of subduction erosion Crustal recycling appropriate for selected margins, including SW Japan (≥30 km3/km/my since 400 Ma), SW USA (≥30 km3/ Mantle evolution km/my since 150 Ma), Peru and northern Chile (50–70 km3/km/my since N150 Ma), and central (115 km3/ Supercontinent cycle km/my since 30 Ma) and southernmost Chile (30–35 km3/km/my since 15 Ma), are higher than in previous compilations.
    [Show full text]
  • How Do Subduction Processes Contribute to Forearc Andean Uplift?
    How do subduction processes contribute to forearc Andean uplift? Insights from numerical models Joseph Martinod, Vincent Regard, Yoann Letourmy, Hadrien Henry, Riad Hassani, Sébastien Baratchart, Sébastien Carretier To cite this version: Joseph Martinod, Vincent Regard, Yoann Letourmy, Hadrien Henry, Riad Hassani, et al.. How do subduction processes contribute to forearc Andean uplift? Insights from numerical models. Journal of Geodynamics, Elsevier, 2015, 96, pp.10.1016/j.jog.2015.04.001. 10.1016/j.jog.2015.04.001. hal- 01147947 HAL Id: hal-01147947 https://hal.archives-ouvertes.fr/hal-01147947 Submitted on 3 May 2015 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. How do subduction processes contribute to forearc Andean uplift? Insights from numerical models Joseph Martinod(1), Vincent Regard(2), Yoann Letourmy(2,3), Hadrien Henry(2,4), Riad Hassani(5), Sébastien Baratchart(2) and Sébastien Carretier(2) (1) Corresponding author; ISTerre, UMR CNRS-IRD-Université de Savoie, 73376 Le Bourget du Lac cedex, France ([email protected]). Tel (+33) 4 75 79 87 10 (2) GET, UMR CNRS-IRD-Université de Toulouse, 14 avenue Edouard Belin, 31400 Toulouse, France (3) Department of Geology, Baylor University, One Bear Place #97354, Waco, TX 76798, USA (4) ARC CCFS & GEMOC, Department of Earth and Planetary Sciences, Macquarie University, Sydney, NSW 2109, Australia (5) Géoazur, UMR CNRS-IRD-Université de Nice Sophia-Antipolis, 250 rue A.
    [Show full text]
  • Andean Adakites from Slab Melting, Crustal Thickening, and Forearc Subduction Erosion
    ANDEAN ADAKITES FROM SLAB MELTING, CRUSTAL THICKENING, AND FOREARC SUBDUCTION EROSION Suzanne MAHLBURG KAY (1) (1) Snee Hall, Cornell University, Ithaca, NY, 14853, USA, [email protected] KEYWORDS: Andes, adakites, magmatism, slab melting, subduction erosion, crustal thickening Neogene Andean magmas with chemical characteristics of adakitic magmas as defined by Defont and Drummond (1990) are common in the Central Andes. Their high-pressure source mineralogy as signaled by trace element characteristics (steep REE patterns, low heavy REE and high Sr contents, etc.) can be produced in at least three ways. In order of descending importance, these are subduction of young oceanic crust, subduction- erosion of forearc crust, and tectonic thickening of the Andean crust. Melting of old subducting oceanic crust in shallow subduction zones (Gutcher et al. 2000) is not required. The origins of adakitic magmas are best deciphered by matching them with specific tectonic conditions and events along the evolving Andean margin (Fig. 1). Some of the most convincing Phanerozoic slabmelts on Earth are found among the Neogene to Recent adakitic magmas in the southernmost Andes. The two most convincing cases are lavas erupted at the Recent Mt. Cook center in the southernmost Austral Volcanic Zone (see Stern and Kilian 1996) and at the ~ 12 Ma Cerro Pampa center, which is located east of where the Chilean Rise collided with the Chile trench at ~ 12 Ma (see Kay et al., 1993). The combination of low 87Sr/86Sr ratios (~ 0.7028; Fig. 2), extreme Sr concentrations (>1000 ppm; Fig. 3), and steep REE patterns (La/Yb ~ 30; Fig. 4) in these adakites is difficult to explain in other contexts as is the case for the first proposed Neogene slabmelt at Adak Island in the Aleutian arc in Alaska (Kay, 1878).
    [Show full text]
  • 1 Horizontal Subduction Zones, Convergence Velocity And
    1 Horizontal subduction zones, convergence velocity and the building of the Andes. J. Martinod(1), L. Husson(2,3), P. Roperch(1,2), B. Guillaume(4) and N. Espurt(5) (1) Corresponding author ; LMTG, UMR CNRS-IRD-Université de Toulouse, 14 avenue Edouard Belin, 31400 Toulouse, France ([email protected]). Tel (+33) 5 61 33 26 52 ; fax (+33) 5 61 33 25 60 (2) Géosciences Rennes, UMR-CNRS 6118, Université Rennes 1, 35042 Rennes cedex, France (3) Laboratoire de Planétologie et Géodynamique, UMR CNRS 6112, université de Nantes, BP 92208, 44322 Nantes cedex, France (4) Università Roma TRE, Dipartimento Scienze Geologiche, Largo S. L. Murialdo 1, 00146 Roma, Italy (5) CEREGE, UMR-CNRS, Aix-Marseille Université, Europôle Méditerranéen de l’Arbois, BP 80, 13545 Aix en Provence cedex 04, France Abstract : We discuss the relationships between Andean shortening, plate velocities at the trench, and slab geometry beneath South America. Although some correlation exists between the convergence velocity and the westward motion of South America on the one hand, and the shortening of the continental plate on the other hand, plate kinematics neither gives a satisfactory explanation to the Andean segmentation in general, nor explains the development of the Bolivian orocline in Paleogene times. We discuss the Cenozoic history of horizontal slab segments below South America, arguing that they result from the subduction of oceanic plateaus whose effect is to switch the buoyancy of the young subducting plate to positive. We argue that the existence of horizontal slab segments, below the Central Andes during Eocene-Oligocene times, and below Peru and North-Central Chile since Pliocene, resulted (1) in the shortening of the continental plate interiors at a large distance from the trench, (2) in stronger interplate coupling and ultimately, (3) in a decrease of the trenchward velocity of the oceanic plate.
    [Show full text]
  • The Role of Subduction Erosion in the Generation of Andean and Other Convergent Plate Boundary Arc Magmas, the Continental Crust and Mantle
    Gondwana Research 88 (2020) 220–249 Contents lists available at ScienceDirect Gondwana Research journal homepage: www.elsevier.com/locate/gr GR Focus Review The role of subduction erosion in the generation of Andean and other convergent plate boundary arc magmas, the continental crust and mantle Charles R. Stern Department of Geological Sciences, University of Colorado, Boulder, CO 80309-0399, USA article info abstract Article history: Subduction erosion, which occurs at all convergent plate boundaries associated with magmatic arcs formed on Received 2 March 2020 crystalline forearc basement, is an important process for chemical recycling, responsible globally for the transport Received in revised form 2 August 2020 of ~1.7 Armstrong Units (1 AU = 1 km3/yr) of continental crust back into the mantle. Along the central Andean Accepted 4 August 2020 convergent plate margin, where there is very little terrigenous sediment being supplied to the trench as a result Available online 17 September 2020 of the arid conditions, the occurrence of mantle-derived olivine basalts with distinctive crustal isotopic character- 87 86 ≥ ε ≤− ε ≤ Handing Editor: M. Santosh istics ( Sr/ Sr 0.7050; Nd 2; Hf +2) correlates spatially and/or temporally with regions and/or episodes of high rates of subduction erosion, and a strong case can be made for the formation of these basalts to be due to Keywords: incorporation into the subarc mantle wedge of tectonically eroded and subducted forearc continental crust. In Subduction erosion other convergent plate boundary
    [Show full text]
  • Tectonic Evolution of the North Patagonian Andes (41–44 S) Through Recogni- Tion of Syntectonic Strata
    ÔØ ÅÒÙ×Ö ÔØ Tectonic evolution of the North Patagonian Andes (41–44 S) through recogni- tion of syntectonic strata A. Echaurren, A. Folguera, G. Gianni, D. Orts, A. Tassara, A. Encinas, M. Gim´enez, V. Valencia PII: S0040-1951(16)30049-X DOI: doi: 10.1016/j.tecto.2016.04.009 Reference: TECTO 127045 To appear in: Tectonophysics Received date: 22 November 2014 Revised date: 10 March 2016 Accepted date: 3 April 2016 Please cite this article as: Echaurren, A., Folguera, A., Gianni, G., Orts, D., Tassara, A., Encinas, A., Gim´enez, M., Valencia, V., Tectonic evolution of the North Patagonian Andes (41–44 S) through recognition of syntectonic strata, Tectonophysics (2016), doi: 10.1016/j.tecto.2016.04.009 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. ACCEPTED MANUSCRIPT Tectonic evolution of the North Patagonian Andes (41°-44° S) through recognition of syntectonic strata Echaurren, A.1, Folguera, A.1, Gianni, G.1, Orts, D.1, Tassara, A.2, Encinas, A.2, Giménez, M.3, Valencia, V.4 1. Instituto de Estudios Andinos. Conicet-Universidad de Buenos Aires, Argentina [email protected] 2. Departamento de Ciencias de la Tierra, Universidad de Concepción, Concepción, Chile.
    [Show full text]