DOCSLIB.ORG

The Causes and Effect of Temporal Changes in Magma Generation Processes in Space and Time Along the Central Andes (13°S – 25°S)

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Causes and Effect of Temporal Changes in Magma Generation Processes in Space and Time Along the Central Andes (13°S – 25°S) The causes and effect of temporal changes in magma generation processes in space and time along the Central Andes (13°S – 25°S) Dissertation zur Erlangung des mathematisch-naturwissenschaftlichen Doktorgrades "Doctor rerum naturalium" der Georg-August-Universität Göttingen im Promotionsprogramm Geowissenschaften / Geographie der Georg-August University School of Science (GAUSS) vorgelegt von Rosanne Marjoleine Heistek aus Nederland/Niederlande Göttingen 2015 Betreuungsausschuss: Prof. Dr. Gerhard Wörner, Abteilung Geochemie, GZG Prof. Dr. Andreas Pack, Abteilung Isotopengeologie, GZG Referent: Prof. Dr. Gerhard Wörner Prof. Dr. Andreas Pack Weitere Mitglieder der Prüfungskommission: Prof. Dr. Sharon Webb Prof. Dr. Hilmar von Eynatten Prof. Dr. Jonas Kley Dr. John Hora Tag der mündlichen Prüfung: 25.06.2015 TABLE OF CONTENTS Acknowledgements .................................................................................................................................1 Abstracts .................................................................................................................................................2 Chapter 1: Introduction .........................................................................................................................7 1.1.The Andean volcanic belt .............................................................................................................................. 7 1.2. The Central volcanic zone ............................................................................................................................ 9 1.2.1. The basement....................................................................................................................................... 10 1.2.2. The onset of magmatic systems ........................................................................................................... 10 1.2.3. Subduction of the Nazca plate ............................................................................................................. 11 1.2.4. Movements of the Nazca and Juan Fernández Ridge ......................................................................... 12 1.2.5. Uplift ................................................................................................................................................... 14 1.3. Hypotheses and open questions .................................................................................................................. 15 References.......................................................................................................................................................... 17 Chapter 2: Constraints on P-T conditions of crystallization and rates of magma formation before and after crustal thickening in the Central Andes ................................................................24 Abstract .............................................................................................................................................................. 24 2.1. Introduction ................................................................................................................................................. 25 2.2. Methods ...................................................................................................................................................... 31 2.2.1. Sample selection .................................................................................................................................. 31 2.2.2. Single lava flow volume calculation ................................................................................................... 32 2.2.3. Major and trace elements .................................................................................................................... 33 2.2.4. Thermometry ...................................................................................................................................... 33 2.2.5. MELTS ............................................................................................................................................... 36 2.2.6. ABS .................................................................................................................................................... 37 2.2.7. Barometry ............................................................................................................................................ 38 2.2.8. Crystal Size Distribution (CSD) .......................................................................................................... 38 2.3. Results......................................................................................................................................................... 39 2.3.1. Petrography ......................................................................................................................................... 39 2.3.2. Geochemistry ...................................................................................................................................... 40 2.3.3. Volume estimates through time ........................................................................................................... 46 2.3.4. Conditions of the final stage of magmatic evolution .......................................................................... 50 2.3.4.1. Thermometry .................................................................................................................................... 50 2.3.4.2. Hygrometry and barometry .............................................................................................................. 53 2.3.4.3. APT-11 ............................................................................................................................................. 55 2.3.5. Plagioclase CSD and compositions .................................................................................................... 57 2.4. Discussion ................................................................................................................................................... 61 2.4.1 Formation of homogeneous intermediate magmas ............................................................................... 61 2.4.2. Magma bodies ..................................................................................................................................... 63 2.4.3. A change in effusion rate..................................................................................................................... 66 2.4.4. Erosion patterns ................................................................................................................................... 67 2.5. Conclusions ................................................................................................................................................. 69 References.......................................................................................................................................................... 71 Chapter 3: Temporal changes in mantle wedge geometry and magma generation processes in the Central Andes: towards linking petrological data to thermomechanical models ....................................79 Abstract .............................................................................................................................................................. 79 3.1. Introduction ................................................................................................................................................. 80 3.2. Methods ...................................................................................................................................................... 83 3.2.1. Volume calculations ............................................................................................................................ 83 3.2.2. Magma differentiation and assimilation): MELTS.............................................................................. 84 3.2.3. Energy constrained model: EC-RAXFC ............................................................................................. 85 3.3. Areal extent, volumes and eruption rates: comparison of Miocene shields and Pliocene/Quaternary stratovolcanoes .................................................................................................................................................. 88 3.3.1. Quality of data ..................................................................................................................................... 88 3.3.2. Volumes and eruption rates for Miocene lava shields and Pliocene/Quaternary stratovolcanoes trough time............................................................................................................................................................... 90 3.3.3. Fractionation and/or assimilation ........................................................................................................ 91 3.4. EC-RAXFC ................................................................................................................................................. 93 3.4.1 geochemical trends ............................................................................................................................... 93 3.4.2. Source contamination – HREE depletion ............................................................................................ 97 3.5. Evaluation of Andean
Load more

Recommended publications
  • PUNTA ARENAS CAMPANA CAUTIN Colegio 0950 LONGAVI 700 600 CARAHUE 0700 VALDIVIA 8647 SANTA RAQUEL
    CANCILLER BRANDT CHAÑARCILLO G. ACOSTA PJE. EL TENIENTE POTRERILLOS FAMASOL SANTA ELENA Pasarela Peatonal 7750 EL BLANCO G. ACOSTA LOTA EL TOFO 300 7600 Sede Social ANDINA PJE 12 COLIPIT. PEREZ Restaurant Capilla R. TORO SAN JAIME 300 Villa GERONIMO DE ALDERETE 01200 PEÑUELAS Junta de NIEBLA DICHATO PJE. E03 Vecinos SURVEYOR Colegio LINARES GEMINIS Jardín 850 0700 GERONIMOInfantil DE ALDERETE 500 DON PEPE 300 1290 PJE PAIPOTE 7800 LUNIK HANGA-ROA MARINERS 1200 SPUTNIK RANQUIL Multicanchas LA SERENA Sede Social Pasarela AVDA. CORONEL 7900 Peatonal SOYUZ COSMOS Colegio MARINERS CORCOVADO 0800 Iglesia 400 1200 500 GRUMETE CORTÉS TELSTAR APOLO XI 850 Cancha PICHINMAVIDA 8000 0500 GERONIMO DE ALDERETE GRUMETE HERNANDEZ GRUMETE MACHADO GRUMETE VOLADOS Capilla G. BRICEÑO G. ESPINO 1200 G. VARGAS Capilla 0990 STA. JULIA VOSTOK 8000 Paso Club 850 Bajo GRUMETE SEPULVEDA Deportivo 0900 Multicanchas PIUQUENES PANGUIPULLI Nivel 7900 7900 0850 8000 7900 TELSTAR 7900 Cancha Junta de 0810 PJE 3 850 Vecinos 0700 7900 CRUCES 7900 Cancha GRUMETE PEREIRA G. QUINTEROS Capilla 7900 Hogar de Niños G. MIRANDA COMBARBALA ACONCAGUA y Ancianos G. PÉREZ 7900 DARWIN E10 MONTE 850 STOKES 100 8200 8200 PUERTO VARAS PJE LA PARVA CHOSHUENCO 8100 VILLARRICA CAÑETE INCA DE ORO SANTA RAQUEL AVDA. CORONEL 100 P. EL PEUMO P. EL QUILLAY LOS ALERCES PJE LA HIGUERILLA 01000 AV. AMERICO VESPUCIOOJOS DEL SALADO P. LA LUMA CALLE D LIRQUEN 8100 CALBUCO TRONADOR 100 ACONCAGUA 500 PJE EL PEUMO LOS CONDORES Iglesia ARICA EL QUILLAY COLBÚN SAUSALITO CALAFQUEN EL LINGUE Iglesia 0990 PASAJE 41 EL LITRANCURA TAMARUGO PJE TUCÁN 0905 PJE EL PEUMO 8000 PasarelaPasarela E10 LEONORA LATORRE CACHAPOAL PeatonalPeatonal 0800 TOME 8000 8300 8000 8000 PJE ALONDRA 0700 PELLÍN 8377 8377 8377 8377 9 ORIENTE LIMARI 8000 TOME 8 ORIENTE 0964 7 ORIENTE 5 NORTE 6 ORIENTE 8000 4 ORIENTE 5 ORIENTE LAUTARO 10 ORIENTE MIÑO Comercio 0700 0750 C.
    [Show full text]
  • Actas III Seminario Un Encuentro Con Nuestra Historia 1
    Actas III Seminario Un Encuentro con Nuestra Historia 1 ACTAS III SEMINARIO UN ENCUENTRO CON NUESTRA HISTORIA SOCIEDAD DE HISTORIA Y GEOGRAFÍA DE AISÉN COYHAIQUE CHILE Sociedad de Historia y Geografía de Aisén 2 Actas III Seminario Un Encuentro con Nuestra Historia. © Sociedad de Historia y Geografía de Aisén Registro de Propiedad Intelectual Nº 173.977 ISBN Nº 978-956-8647-02-5 Representante legal: Mauricio Osorio Pefaur Producción, compilación y correcciones: Leonel Galindo Oyarzo & Mauricio Osorio Pefaur Corrección de estilo y diagramación final: Ediciones Ñire Negro, [email protected] Diseño de portada: Paulina Lobos Echaveguren, [email protected] Fotografías portada: don Baldo Araya Uribe en dos épocas de su vida. En 1950 y con 26 años, trabajaba en el Consulado chileno en Bariloche y en la radio L.U.8 de dicha ciudad. En 2001, a los 77 años, viviendo en Coyhaique. Gentileza de su hija, Inés Araya Echaveguren. Fotografía contraportada: Paisaje sector Escuela Vieja Cerro Castillo. Archivo Mauricio Osorio P. Fotografías interiores: págs 29, 59, 88, 95 y 103 aportadas por los autores. Págs 22, 40 y 56 aportadas por editor. Fono : (56) (67) 246151 Correo electrónico: [email protected] Impresión: Lom Ediciones, Santiago de Chile Tiraje: 500 ejemplares Edición financiada con el aporte del Gobierno Regional de Aisén Coyhaique, 2008 Actas III Seminario Un Encuentro con Nuestra Historia 3 ÍNDICE CONTENIDOS PÁGINA DON BALDO ARAYA URIBE 5 PRESENTACIÓN 7 PONENCIAS: ARCHIVOS: EL PAPEL DE LA MEMORIA. LA EXISTENCIA ESTABLECIDA 9 Carmen Gloria Parés Fuentes UTTI POSIDETTIS ‘LO QUE POSEÉIS’. LA LARGA CONTROVERSIA DE LÍMITES DE CHILE Y ARGENTINA 15 Danka Ivanoff Wellmann LA CONSTRUCCIÓN DEL PASO SAN CARLOS FRENTE AL SALTÓN DEL RÍO BAKER: APORTES PARA EL RECONOCIMIENTO DEL TRABAJO DE LAS COMISIONES DE LÍMITES CHILENAS EN LA PATAGONIA OCCIDENTAL, INICIOS DEL S.
    [Show full text]
  • Appendix A. Supplementary Material to the Manuscript
    Appendix A. Supplementary material to the manuscript: The role of crustal and eruptive processes versus source variations in controlling the oxidation state of iron in Central Andean magmas 1. Continental crust beneath the CVZ Country Rock The basement beneath the sampled portion of the CVZ belongs to the Paleozoic Arequipa- Antofalla terrain – a high temperature metamorphic terrain with abundant granitoid intrusions that formed in response to Paleozoic subduction (Lucassen et al., 2000; Ramos et al., 1986). In Northern Chile and Northwestern Argentina this Paleozoic metamorphic-magmatic basement is largely homogeneous and felsic in composition, consistent with the thick, weak, and felsic properties of the crust beneath the CVZ (Beck et al., 1996; Fig. A.1). Neodymium model ages of exposed Paleozoic metamorphic-magmatic basement and sediments suggest a uniform Proterozoic protolith, itself derived from intrusions and sedimentary rock (Lucassen et al., 2001). AFC Model Parameters Pervasive assimilation of continental crust in the Central Andean ignimbrite magmas is well established (Hildreth and Moorbath, 1988; Klerkx et al., 1977; Fig. A.1) and has been verified by detailed analysis of radiogenic isotopes (e.g. 87Sr/86Sr and 143Nd/144Nd) on specific systems within the CVZ (Kay et al., 2011; Lindsay et al., 2001; Schmitt et al., 2001; Soler et al., 2007). Isotopic results indicate that the CVZ magmas are the result of mixing between a crustal endmember, mainly gneisses and plutonics that have a characteristic crustal signature of high 87Sr/86Sr and low 145Nd/144Nd, and the asthenospheric mantle (low 87Sr/86Sr and high 145Nd/144Nd; Fig. 2). In Figure 2, we model the amount of crustal assimilation required to produce the CVZ magmas that are targeted in this study.
    [Show full text]
  • Full-Text PDF (Final Published Version)
    Pritchard, M. E., de Silva, S. L., Michelfelder, G., Zandt, G., McNutt, S. R., Gottsmann, J., West, M. E., Blundy, J., Christensen, D. H., Finnegan, N. J., Minaya, E., Sparks, R. S. J., Sunagua, M., Unsworth, M. J., Alvizuri, C., Comeau, M. J., del Potro, R., Díaz, D., Diez, M., ... Ward, K. M. (2018). Synthesis: PLUTONS: Investigating the relationship between pluton growth and volcanism in the Central Andes. Geosphere, 14(3), 954-982. https://doi.org/10.1130/GES01578.1 Publisher's PDF, also known as Version of record License (if available): CC BY-NC Link to published version (if available): 10.1130/GES01578.1 Link to publication record in Explore Bristol Research PDF-document This is the final published version of the article (version of record). It first appeared online via Geo Science World at https://doi.org/10.1130/GES01578.1 . Please refer to any applicable terms of use of the publisher. University of Bristol - Explore Bristol Research General rights This document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: http://www.bristol.ac.uk/red/research-policy/pure/user-guides/ebr-terms/ Research Paper THEMED ISSUE: PLUTONS: Investigating the Relationship between Pluton Growth and Volcanism in the Central Andes GEOSPHERE Synthesis: PLUTONS: Investigating the relationship between pluton growth and volcanism in the Central Andes GEOSPHERE; v. 14, no. 3 M.E. Pritchard1,2, S.L. de Silva3, G. Michelfelder4, G. Zandt5, S.R. McNutt6, J. Gottsmann2, M.E. West7, J. Blundy2, D.H.
    [Show full text]
  • [email protected].: Tacora/Rev
    [email protected].: Tacora/rev: 18 de noviembre, 2009/24 de abril, 2011/19 de mayo, 2011/05 de mayo, 2013/10 de marzo, 2014/07 de mayo, 014/l28 de diciembre, 2015/26 de junio, 2016 [email protected].: Tacora/rev: 18 de noviembre, 2009/24 de abril, 2011/19 de mayo, 2011/05 de mayo, 2013/10 de marzo, 2014/07 de mayo, 014/l28 de diciembre, 2015/26 de junio, 2016 LA INDUSTRIA AZUFRERA, EL ANDARIVEL Y EL FERROCARRIL DE TACORA por: Ian Thomson N. ÍNDICE 1. Introducción y conclusiones. 2. Los inicios de la explotación del azufre en Chile. 3. La importancia crítica de los costos de transporte. 4. La explotación del azufre del Tacora y los orígenes del Ferrocarril. 5. El tráfico del Ferrocarril, el personal y la rentabilidad. 6. El trazado y la infraestructura del Ferrocarril. 7. El Ferrocarril de Tacora después de su cierre. 8. La red de andariveles. 9. El material rodante ferroviario. Recuadro 1: El de Aucanquilcha: otro ferrocarril azufrero en altura Recuadro 2: La Asociación para la Conservación de las ex-azufreras y del Ferrocarril de Tacora Referencias seleccionadas El autor es, por profesión, un economista dedicado a temas de transporte. Además, durante largos años, ha sido activo en las áreas de la conservación y del estudio de la historia de sistemas de transporte, especialmente los ferroviarios. Promovió, a principios de la década de 1980, la formación de la Asociación Chilena de Conservación del Patrimonio Ferroviario, sirviendo como su presidente durante unos diez años, con breves intervalos.
    [Show full text]
  • Geología De La Cadena Volcánica Paniri-Toconce, Zona Volcánica Central, Altiplano De La Región De Antofagasta, Chile
    Geología de la cadena volcánica Paniri-Toconce, Zona Volcánica Central, Altiplano de la Región de Antofagasta, Chile Edmundo Polanco 1*, Jorge Clavero 1 y Aldo Giavelli 1 1 Energía Andina S.A. Darío Urzúa 2165, Providencia, Santiago, Chile *E-mail: [email protected] conformado por los volcanes del León (5.753 m s.n.m.) y Resumen. La cadena volcánica del Paniri-Toconce (NW- Lagunita (5.404 m s.n.m.) que se ubican al W del volcán SE) localizada en el Altiplano de la Región de Antofagasta Toconce. El Volcán Lagunita corresponde a un se caracteriza por un fuerte control estructural a través de estratovolcán más antiguo fuertemente erosionado, de más su evolución durante el Pleistoceno. Esta cadena volcánica de 7 km de diámetro en dirección E-W que presenta de más de 30 km de longitud es dominada por dacitas de anfíbola y biotita y subordinadamente por andesita de importantes zonas afectadas por procesos de alteración piroxeno±anfíbola±biotita e incluye al domo torta más hidrotermal y está constituido por coladas de lava voluminoso del planeta, el Domo Chao, donde nuevas andesíticas y dacíticas (59 y 65-66% en peso de SiO2) y dataciones Ar/Ar señalan su actividad culminaría en el depósitos piroclásticos de bloques y ceniza. El Volcán del Pleistoceno Superior. Evidencias de terreno, petrográficas León es un estratovolcán de más de 6 km de diámetro y geoquímicas indican la cristalización fraccionada como conformado principalmente por coladas de lava andesíticas proceso dominante durante la evolución de los magmas y dacíticas de piroxeno y anfíbola aunque también tiene que dieron origen a las rocas a los distintos centros depósitos piroclásticos de bloques y ceniza asociados.
    [Show full text]
  • The Water Resources of Latin America and the Caribbean and Their Utilization
    ^Cjlr. 1 LsiuDroa t:- wormes fa CEPAL THE WATER RESOURCES OF LATIN AMERICA AND THE CARIBBEAN AND THEIR UTILIZATION UNITED NATIONS ESTUDIOS e INFORMES de la CEPAL THE WATER RESOURCES OF LATIN AMERICA AND THE CARIBBEAN AND THEIR UTILIZATION A report on progress in the application of the Mar del Piata Action Pian UNITED NATIONS Santiago Chile, 1985 LC/G.1358 October 1985 This study was prepared by the ECLAC Natural Resources and Energy Division, with contributions from several countries of the region. A preliminary version was distributed at the twentieth session of the Economic Commission for Latin America and the Caribbean under the symbol E/CEPAL/G.1298, dated 5 March 1984. UNITED NATIONS PUBLICATION Sales No.: E.85.II.G.16 ISSN 0256-9795 ISBN 92-1-121125-5 CONTENTS Page INTRODUCTION 9 Chapter 1 ASSESSMENT OF WATER RESOURCES II A. Characteristics of the physical supply 11 1. The hydrologic systems of Latin America and the Caribbean 12 2. Groundwater 15 B. A review of the state of assessment of the water resource in Latin America and the Caribbean 17 1. Recent advances in international co-operation in water resources assessment 18 Chapter 2 WATER USE AND EFFICIENCY 23 A. Overall patterns of water use 23 B. The extractive use of water 27 C. Instream water use 34 1. Hydroelectric power generation 38 2. River transport 40 3. Recreation 43 4. Commercial fishing 43 Chapter 3 ENVIRONMENT, HEALTH AND POLLUTION CONTROL 47 A. Environmental aspects of water use management 47 B. Water and health 49 C. Pollution control 52 Page Chapter 4 THE INSTITUTIONAL AND LEGAL STRUCTURE FOR WATER RESOURCE PLANNING AND MANAGEMENT 57 A.
    [Show full text]
  • Late Mesozoic to Paleogene Stratigraphy of the Salar De Atacama Basin, Antofagasta, Northern Chile: Implications for the Tectonic Evolution of the Central Andes
    Late Mesozoic to Paleogene stratigraphy of the Salar de Atacama Basin, Antofagasta, Northern Chile: Implications for the tectonic evolution of the Central Andes Constantino Mpodozisa,T,Ce´sar Arriagadab, Matilde Bassoc, Pierrick Roperchd, Peter Cobbolde, Martin Reichf aServicio Nacional de Geologı´a y Minerı´a, now at Sipetrol. SA, Santiago, Chile bDepartamento de Geologı´a, Universidad de Chile, Santiago, Chile cServicio Nacional de Geologı´a y Minerı´a, Santiago, Chile dIRD/Dep. de Geologı´a, Universidad de Chile, Santiago, Chile eGe´osciences-Rennes (UMR6118 du CNRS), France fDepartment of Geological Sciences University of Michigan, United States Abstract The Salar de Atacama basin, the largest bpre-AndeanQ basin in Northern Chile, was formed in the early Late Cretaceous as a consequence of the tectonic closure and inversion of the Jurassic–Early Cretaceous Tarapaca´ back arc basin. Inversion led to uplift of the Cordillera de Domeyko (CD), a thick-skinned basement range bounded by a system of reverse faults and blind thrusts with alternating vergence along strike. The almost 6000-m-thick, upper Cretaceous to lower Paleocene sequences (Purilactis Group) infilling the Salar de Atacama basin reflects rapid local subsidence to the east of the CD. Its oldest outcropping unit (Tonel Formation) comprises more than 1000 m of continental red sandstones and evaporites, which began to accumulate as syntectonic growth strata during the initial stages of CD uplift. Tonel strata are capped by almost 3000 m of sandstones and conglomerates of western provenance, representing the sedimentary response to renewed pulses of tectonic shortening, which were deposited in alluvial fan, fluvial and eolian settings together with minor lacustrine mudstone (Purilactis Formation).
    [Show full text]
  • Alkalic-Type Epithermal Gold Deposit Model
    Alkalic-Type Epithermal Gold Deposit Model Chapter R of Mineral Deposit Models for Resource Assessment Scientific Investigations Report 2010–5070–R U.S. Department of the Interior U.S. Geological Survey Cover. Photographs of alkalic-type epithermal gold deposits and ores. Upper left: Cripple Creek, Colorado—One of the largest alkalic-type epithermal gold deposits in the world showing the Cresson open pit looking southwest. Note the green funnel-shaped area along the pit wall is lamprophyre of the Cresson Pipe, a common alkaline rock type in these deposits. The Cresson Pipe was mined by historic underground methods and produced some of the richest ores in the district. The holes that are visible along several benches in the pit (bottom portion of photograph) are historic underground mine levels. (Photograph by Karen Kelley, USGS, April, 2002). Upper right: High-grade gold ore from the Porgera deposit in Papua New Guinea showing native gold intergrown with gold-silver telluride minerals (silvery) and pyrite. (Photograph by Jeremy Richards, University of Alberta, Canada, 2013, used with permission). Lower left: Mayflower Mine, Montana—High-grade hessite, petzite, benleonardite, and coloradoite in limestone. (Photograph by Paul Spry, Iowa State University, 1995, used with permission). Lower right: View of north rim of Navilawa Caldera, which hosts the Banana Creek prospect, Fiji, from the portal of the Tuvatu prospect. (Photograph by Paul Spry, Iowa State University, 2007, used with permission). Alkalic-Type Epithermal Gold Deposit Model By Karen D. Kelley, Paul G. Spry, Virginia T. McLemore, David L. Fey, and Eric D. Anderson Chapter R of Mineral Deposit Models for Resource Assessment Scientific Investigations Report 2010–5070–R U.S.
    [Show full text]
  • The South American Indian As a Pioneer Alpinist
    TI-lE SOUTH AMERICAN INDIAN AS A PIONEER ALPINIST 81 THE SOUTH AMERICAN INDIAN AS A PIONEER ALPINIST BY EVELIO ECHEVARRfA C. ECENTL Y it has become kno\vn that a number of very high Andean mountain tops had not only been ascended but also permanently occupied by the Indians, possibly as much as three centuries before de Saussure's ascent of Mont Blanc. They climbed peaks of up to 22,ooo ft., they constructed shelters on or near their tops, and they used the high places as watch-towers or as sacrificial shrines. Some authorities believe that this activity took place as early as the late four­ teenth century, though we cannot prove that some of it did not take place long after, possibly as late as the nineteenth century. These Indian accomplishments have been left unmentioned in practi­ cally all mountaineering history books. In this article, which may be the first to attempt a comprehensive survey,1 my purpose is to review briefly the location and the nature of each discovery. The area in which these Indian mountain ascents took place is what in physical geography is known as the Atacama desert (although this name is nowadays used in political and cultural geography for a much more restricted area). It is a treeless, sandy and volcanic waste-land seldom visited by mountaineers. It stretches from the neighbourhood of Arequipa, in Peru, as far south as Elqui in Chile; to the east it reaches the Andean slopes that face the jungles of Argentina and Bolivia, and to the west, the Pacific Ocean.
    [Show full text]
  • Three-Dimensional Resistivity Image of the Magmatic System Beneath
    PUBLICATIONS Geophysical Research Letters RESEARCH LETTER Three-dimensional resistivity image of the magmatic system 10.1002/2015GL064426 beneath Lastarria volcano and evidence for magmatic Key Points: intrusion in the back arc (northern Chile) • Electrical resistivity images of the Lastrarria volcano Daniel Díaz1,2, Wiebke Heise3, and Fernando Zamudio1 • The magmatic source is located to the south of Lastarria volcano 1Departamento de Geofísica, Universidad de Chile, Santiago, Chile, 2Centro de Excelencia en Geotermia de Los Andes, • Deep conductor in the back arc 3 suggests magmatic intrusion Santiago, Chile, GNS Science, Lower Hutt, New Zealand Supporting Information: Abstract Lazufre volcanic center, located in the central Andes, is recently undergoing an episode of uplift, • Readme conforming one of the most extensive deforming volcanic systems worldwide, but its magmatic system and • Text S1 • Figure S1 its connection with the observed uplift are still poorly studied. Here we image the electrical resistivity structure • Figure S2 using the magnetotelluric method in the surroundings of the Lastarria volcano, one of the most important • Figure S3 features in the Lazufre area, to understand the nature of the magmatic plumbing, the associated fumarolic • Figure S4 activity, and the large-scale surface deformation. Results from 3-D modeling show a conductive zone at 6 km Correspondence to: depth south of the Lastarria volcano interpreted as the magmatic heat source which is connected to a shallower D. Díaz, conductor beneath the volcano, showing the pathways of volcanic gasses and heated fluid. A large-scale [email protected] conductive area coinciding with the area of uplift points at a magma intrusion at midcrustal depth.
    [Show full text]
  • Hoyas Hidrográficas De Chile: Segunda Región
    HOYAS HIDROGRÁFICAS DE CHILE: SEGUNDA REGIÓN REALIZADO POR: HANS NIEMEYER F. HOVA DEL RlO LOA La hoya hidrográfica del río Loa~ con una superf! cie tota~'de 33 570 km2 , se desarrolla en el tercio norte de la IIa R~ gión de Chile, entre latitudes extremas 20Q52' y 22Q57' L.S. ylongit~ des 68QOO' y 7oQ02' L.o. El río Loa nace en la falda norte del Vn. Mi­ ño~ en los Ojos del Hiño, casi en los límites entre la la y IIa Regio­ nes de Chile, en 21Q15' L.S. y 70Q L.O~ Su longitud total se acerca a 440 km. A pesar de su extensa hoya, los recursos h!dricos provienen de la cuenca alta que comprende alrededor del 20% de la su~ perficie total. Con curso aproximadamente norte-sur~ el Loa reco­ rre casi 150 km en un profundo cañón de altura variable, desde su nací miento hasta el oasis de Chiu ~hiu, pueblo que se levanta en su margen izquierda. En este trayecto recibe sus dos tributarios más importantes que le caen del este: el río San Pedro o Inacaliri y el río Salado. En Chiu Chiu dobla su curso sensiblemente hacia el oeste para alcanzar en un recorrido de 115 km el punto denominado Chacance. En él se le reúne por la derecha el río San Salvador. En Chacance,el Loa toma franca di= recci6n sur-norte hasta fertilizar el oasis de Quillagua, despu~s de una trayectoria de 80 km. A partir de Quillagua el Loa describe un gran arco y luego desemboca en el Pacífico~ en Caleta Huel~n, despu~8 de trasponer el macizo costero en un tajo profundo~ de más de 500 m de al­ tura.
    [Show full text]