DOCSLIB.ORG

Notice Concerning Copyright Restrictions

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Notice Concerning Copyright Restrictions NOTICE CONCERNING COPYRIGHT RESTRICTIONS This document may contain copyrighted materials. These materials have been made available for use in research, teaching, and private study, but may not be used for any commercial purpose. Users may not otherwise copy, reproduce, retransmit, distribute, publish, commercially exploit or otherwise transfer any material. The copyright law of the United States (Title 17, United States Code) governs the making of photocopies or other reproductions of copyrighted material. Under certain conditions specified in the law, libraries and archives are authorized to furnish a photocopy or other reproduction. One of these specific conditions is that the photocopy or reproduction is not to be "used for any purpose other than private study, scholarship, or research." If a user makes a request for, or later uses, a photocopy or reproduction for purposes in excess of "fair use," that user may be liable for copyright infringement. This institution reserves the right to refuse to accept a copying order if, in its judgment, fulfillment of the order would involve violation of copyright law. Geothermal Resources Council Transactions,Vol. 22, September 20-23, 1998 The Chalupas and Chachimbiro Geothermal Fields in Ecuador Eduardo Aguilera Espe, Sangolqui-Ecuador ABSTRACT The geological setting as well as a preliminary geothermal geographic and physiographic zone corresponds to the core of model of two of the main geothermal areas of Ecuador are pre- the Ecuadorian Andes. It is characterized by two paralell moun- sented in this paper. The assessment is based only on surface tain ranges or Cordillera Occidental (to the west) and the exploration activities. It is likely that, because of the presence Cordillera Real (to the east) separated by a narrow valley, the of abundant highly differentiated volcanic products of recent Interandean Depression, which disappears towards the south. origin, both areas are good prospectors for hrther exploration. ‘The Ecuadorian Cordillera is mainly formed by basic and intermediate volcanic rocks emplaced in a submarine environ- Country Background ment (Macuchi Formation), which are covered by a discon- Ecuador covers an area of 284,000 km2 which is divided tinuous turbiditic deposits of Cretaceous to Eocene age. The into three distinct geographic zones (Figure 1). The western Cordillera Real consists of igneous and sedimentary rocks, coastal lowlands (Costa), which extend from the Pacific Ocean deeply modified by a Paleozoic to Cretaceous metamorphic to the Andes, corresponds to one-fourth of the country’s total event. The Interandean Depression is an important extensional area and has about one-half of its population. Guayaquil is structure bounded by active fault scarps and partly filled by Ecuador’s largest city and its most important port. The high volcanic and volcano-sedimentary deposits that locally reach Andean Mountains (Sierra), which run essentially north-south some thousands of meters in thickness. through the center of the country, have one-half of its popula- The Ecuadorian Volcanic Belt extends north-southalong the tion and includes Ecuador’s capital, Quito. The third geographic whole country, with an average width of about 80 km. The zone is the low-lying eastern region (Oriente) which is covered Quaternary activity, characterized by the building of a great by a tropical rainforest and is drained by tributaries of the number of huge stratovolcanoes, forming the highest peaks of Amazonas River, it holds nearly all of Ecuador’s proven oil the northern Andes, is restricted to the area north of 2”s. The reserves. The “Oriente” constitutes about one half of the products of stratovolcanoes cover a basal volcanic complex and country’s area, but has less than 4% of its population. form a thick lava pile with minor tuff intercalations and local Ecuador’s 1997 population was estimated in 11.46 million ignimbritic cover. A thickness of at least 1000 m has been ob- (52.9% urban), with a 2.5% growth rate for the 1982-1990 pe- served along the fault scarps of the Interandean Depression. riod. ’This roughly tabular volcanic sequence is faulted and tilted (Barberi F. et al., 1988). Regional Geological Framework Geothermal exploration studies in the areas of Chalupas and The Ecuadorian active continental margin is characterized Chachimbiro were carried out by the Ecuadorian Electrifica- by the subduction of the Nazca Plate beneath the South America tion Institute (INECEL)between 1983 ad 1986 using its own Plate under particular conditionsbecause of the presence of the resources. aseismic Carnegie Ridge, a structure generated by the move- ment of the Nazca plate over the Galapagos Hot Spot (Hey, The Chalupas Geothermal Field 1977). The Chalupas geothermal field is located in the Cordillera In Ecuador, the Andean Range was formed following sev- Real about 60 km southeast of Quito and 35 km northeast of eral orogenic pulses since at least Cretaceous times. The Sierra Latacunga (Figure 1). The most important clement is a caldera, 247 Aguiera at the center of which there is the Quilindafia volcano (at 0'74's and Chalupas rivers run through the eastern rim, toward the and 78"20'W). lower lands at about 400 masl. The caldera rim is about 5 km from the southeast flank of The area is covered by clouds and subjected to constant rain Cotopaxi volcano. In its immediate vicinity there are only a most of the time. The daily temperatures varies from 0 to 16" C few scattered houses of workers from some large cattle ranches with a mean of 4' C. Mean annual rainfall is about 1,200 mm. (haciendas). The Cotopaxi National Park is the closest neigh- The period July-September is considered to be the dry season, bor of the Chalupas field. with sunny but cold and windy days. The field can be reached by an about 50 km long gravel road which runs along the northern and eastern flanks of the Cotopaxi volcano and is connected to the Pan American highway near Summary of Performed Research the town of Lasso. The 130 kV Pisayambo-Santa Rosa trans- The Chalupas Caldera has an approximate elliptical shape mission line of the National Interconnected System, is about (13 km x 16 km) and is defined morphologically by a series of 25 km from the center of the field. periclinal lavas, clearly recognizable on the northern, western The topography of the area is irregular and it is influenced and southern caldera rims, covering the core of the Cordillera by the Quillindafia stratovolcano (Elev. 4,878 m). The bottom Real. The bottom is filled with fractured lavas and fragmentary of the caldera is relatively flat, at an average elevation of 3,600 materials from the paroxismical eruption and subsequent col- m. The lowest areas inside the caldera (Elev. 3,500 m.) are lo- lapse of the Chalupas stratovolcano. Surface deposits are prod- cated at its northeastern and southeastern ends where the Tambo uct of glacial, lacustrine and fluvial erosion. Figure 1. Location of the geothermal fields. 248 Aguiera The evolution of volcanism in this area, has generated a se- The geochemical studies included 45 surface and subsur- ries of differentiated volcanic caldera rocks that include basic, face water sampling points outside and inside the caldera. Of intermediate and acid products. these, 26 are thermal with temperatures ranging from 37" to Three main faults systems have been identified. One is par- 26°C. The most frequent chemical types are alkaline-earth and allel to the dominant direction to the Andean Range ("E- alkaline bicarbonate, within which subgroups based on their SSW) the other two are transversal to it (NW-SE and NE-SW) salinity and temperature have been defined. and displace the previous one. Apparently the NE-SW faults Alkaline-earth bicarbonate waters are characteristicof shal- are the most recent ones. lower waters which interact with gases rich in CO,. The alka- The metamorphic core of the Cordillera Real forms an im- line bicarbonate waters indicate deeper flow regimes and inter- pervious basement on which a pile of Pliocene lavas have ac- action processes with acid rocks despite the fact that they al- cumulated; it may reach very high values of secondary perme- ways show a high grade of dilution due to the mixture with ability by fracturing, as well as the lavas that formed the meteoric waters. Values of pH are generally between 6.1 and Chalupas stratovolcano, buried by the caldera collapse. 6.8. The pyroclastic products, morraine and lagunar deposits that The ratio between CO, partial pressure and the temperature fill the caldera, have low or zero primary permeability, and a obtained for the manifestations could indicate a regional ther- plastic behavior that prevents them from acquiring secondary mal anomaly. There are also traces of hot gases that contami- permeability by fracturing. nate the surface waters. .. 4' 150 km OU Figure 2. Schematic map of the Chachimbiro area. 249 Aguiera North of the caldera, in a transversal fault zone sulfate water nomenon, caused by the precipitation of minerals when hot flu- with ammonia and boron anomalies have been found. The lat- ids get in contact with cold recharge fluids. ter might be manifestations of ascending fluids stemming from a convective steam system; their deep temperatures should ex- Chachimbiro Geothermal Field ceed 180°C. The geothermal area of Chachimbiro is located in the West As for the isotopic composition, all the samples fall on the Andean Range (Cordillera Occidental) about 70 kxn north-north- straight meteoric water line in a wide composition interval, east of Quito and at 17 km northwest of Ibarra (Fig. 1). The which assumes extensive near surface circulation and confirms center of the area of interest is at the 0'25" and 78*17'W, the impervious condition of the surface deposits filling the inside the Cayapas-CotacachiNational Park.
Load more

Recommended publications
  • Li in Plagioclase: Investigating Its Rapid Diffusion and Potential As
    Goldschmidt Conference Abstracts 2009 A181 Li in plagioclase: Investigating its Uranium minerals from a Portuguese rapid diffusion and potential as Variscan granite and its geospeedometer hydrothermal alteration 1,2 1 M.E.J.A. CABATO*, R. ALTHERR AND T. LUDWIG M.M.S. CABRAL PINTO , M.M.V.G. SILVA , 1 3 3 A.M.R. NEIVA , F. GUIMARÃES AND P.B. SILVA Mineralogie, Institut für Geowissenschaften, Universität- Heidelberg, Im Neuenheimer Feld 236, 69120 Heidelberg, 1Center of Geosciences, Department of Earth Sciences, Germany University of Coimbra, Portugal ([email protected]) (*correspondence: [email protected]) 2Department of Geosciences, University of Aveiro, Portugal 3LNEG–National Laboratory of Energy and Geology, 4466- Elemental and isotopic studies with Li as a geochemical 956 S. Mamede de Infesta, Portugal tracer for source components and potential tool for geospeedometry have proliferated in recent years. Indeed, the Electron microscopy images, X-ray maps and electron abundance and isotopic fractionation of Li, alongside its rather microprobe analyses were carried out on uraninite, coffinite, (meta)saleeite, thorite, xenotime, monazite and apatite from rapid diffusivity especially in plagioclase, remain topics of unaltered and altered Variscan peraluminous granite and interest and importance. In volcanic systems, such Li data may related hydrothermal brecciated uranium-quartz veins. demonstrate processes and timescales that lead up to the Uraninite occurs mainly in the unaltered granite [1], is rare in extrusion of magma. the altered granite and was not found in the mineralized quartz To further understand Li diffusion in (and out of) veins. Uraninite from the altered granite is fractured and plagioclase, we analyse exceptionally large crystals using the hydrated, has the radioactive damage halos filled with late SIMS, to be confirmed by other methods.
    [Show full text]
  • (REFC) Magma Chambers: Implications for Differ
    Available online at www.sciencedirect.com ScienceDirect Geochimica et Cosmochimica Acta 143 (2014) 8–22 www.elsevier.com/locate/gca Modeling the compositional evolution of recharging, evacuating, and fractionating (REFC) magma chambers: Implications for differentiation of arc magmas Cin-Ty A. Lee a,⇑, Tien Chang Lee b, Chi-Tang Wu a a Dept. of Earth Science, MS-126 Rice University, 6100 Main St., Houston, TX 77005, United States b Dept. of Earth Sciences, University of California, Riverside, CA 92521, United States Available online 25 August 2013 Abstract Equations are presented to describe the compositional evolution of magma chambers undergoing simultaneous recharge (R), evacuation (E), and fractional crystallization (FC). Constant mass magma chambers undergoing REFC will eventually approach a steady state composition due to the “buffering” effect of recharging magma. Steady state composition is attained after 3/(Dax + ae) overturns of the magma chamber, where D is the bulk solid/melt partition coefficient for the element of interest and ax and ae are the proportions of crystallization and eruption/evacuation relative to the recharge rate. Steady state composition is given by Cre/(Dax + ae). For low evacuation rates, steady state concentration and the time to reach steady state scale inversely with D. Compatible (D > 1) elements reach steady state faster than incompatible (D < 1) elements. Thus, mag- ma chambers undergoing REFC will eventually evolve towards high incompatible element enrichments for a given depletion in a compatible element compared to magma chambers undergoing pure fractional crystallization. For example, REFC mag- ma chambers will evolve to high incompatible element concentrations for a given MgO content compared to fractional crys- tallization.
    [Show full text]
  • Geothermal Country Update for Ecuador, 2005 -2010
    Proceedings World Geothermal Congress 2010 Bali, Indonesia, 25-29 April 2010 Geothermal Country Update for Ecuador, 2005 -2010 Bernardo Beate, Rodney Salgado Escuela Politécnica Nacional, Dpto. de Geología, PO Box 17-01-2759, Quito/Ecuador [email protected] Keywords: Ecuador, geothermal exploration, heat sources, already completed the first geothermal gradient exploration hot springs of Ecuador, assessment of geothermal hole, ever, in Ecuador, on the Tufiño prospect, to a depth of prospects, use of geothermal energy. 554 m and final diameter NQ (76 mm). Chachimbiro has been allocated 1 MUSD for geophysical exploration ABSTRACT starting 2009 and reconnaissance geological and geochemical surveys are underway in Chacana-Papallacta Ecuador is located on the active convergent plate margin of prospect. This and several other high and low-medium Southamerica, which is characterized by a broad continental temperature geothermal prospects in Ecuador await state volcanic arc with abundant active volcanoes and intense and private investment to be developed in order to lessen seismicity. Earlier geothermal exploration, carried out from the dependance on fossil fuel use. Finally, in Ecuador, the mid 1970’s to the earlier 1990’s by government geothermal energy is challenged to be cost-efficient in front institutions with the aid of foreign technical assistance of an abundant hydro resource, as well as to be programs, defined a combined theoretical potential of about environmentally safe. 500 MWe for the three most promising geothermal prospects, namely: Tufiño-Chiles, Chalupas and Chachimbiro, located in the highlands of central-north 1. INTRODUCTION Ecuador. A dozen of other geothermal prospects, related to This paper is a follow up of the previous country update for silicic calderas, or to evolved stratovolcanoes, or even to the interval 2000-2005, published in the Proceedings of evolved basaltic shields, like Alcedo in Galapagos, will WGC2005 in Antalya, Turkey (Beate & Salgado, 2005).
    [Show full text]
  • The Central Atlantic Magmatic Province (CAMP) in Morocco
    The Central Atlantic Magmatic Province (CAMP) in Morocco Andrea Marzoli, Hervé Bertrand, Nasrrddine Youbi, Sara Callegaro, Renaud Merle, Laurie Reisberg, Massimo Chiaradia, Sarah Brownlee, Fred Jourdan, Alberto Zanetti, et al. To cite this version: Andrea Marzoli, Hervé Bertrand, Nasrrddine Youbi, Sara Callegaro, Renaud Merle, et al.. The Central Atlantic Magmatic Province (CAMP) in Morocco. Journal of Petrology, Oxford University Press (OUP), 2019, 60 (5), pp.945-996. 10.1093/petrology/egz021. hal-02405965 HAL Id: hal-02405965 https://hal.univ-lorraine.fr/hal-02405965 Submitted on 12 Dec 2019 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. J OURNAL OF Journal of Petrology, 2019, Vol. 60, No. 5, 945–996 doi: 10.1093/petrology/egz021 P ETROLOGY Advance Access Publication Date: 19 April 2019 Original Article The Central Atlantic Magmatic Province (CAMP) in Morocco Andrea Marzoli 1*, Herve´ Bertrand2, Nasrrddine Youbi3,4, Downloaded from https://academic.oup.com/petrology/article-abstract/60/5/945/5475177 by guest on 13 December 2019 Sara Callegaro 5, Renaud Merle6, Laurie Reisberg7, Massimo Chiaradia8, Sarah I. Brownlee9, Fred Jourdan10, Alberto Zanetti11, Joshua H.F.L. Davies8†, Tiberio Cuppone1, Abdelkader Mahmoudi12, Fida Medina13, Paul R.
    [Show full text]
  • Crustal Thickness Control on Sr/Y Signatures of Recent Arc Magmas
    OPEN Crustal thickness control on Sr/Y SUBJECT AREAS: signatures of recent arc magmas: an PETROLOGY GEOCHEMISTRY Earth scale perspective Massimo Chiaradia Received 4 November 2014 Section of Earth and Environmental Sciences, University of Geneva, Rue des Maraıˆchers 13, 1205 Geneva, Switzerland. Accepted 7 January 2015 Arc magmas originate in subduction zones as partial melts of the mantle, induced by aqueous fluids/melts Published liberated by the subducted slab. Subsequently, they rise through and evolve within the overriding plate crust. 29 January 2015 Aside from broadly similar features that distinguish them from magmas of other geodynamic settings (e.g., mid-ocean ridges, intraplate), arc magmas display variably high Sr/Y values. Elucidating the debated origin of high Sr/Y signatures in arc magmas, whether due to mantle-source, slab melting or intracrustal processes, is instrumental for models of crustal growth and ore genesis. Here, using a statistical treatment of .23000 Correspondence and whole rock geochemical data, I show that average Sr/Y values and degree of maturation (MgO depletion at requests for materials peak Sr/Y values) of 19 out of 22 Pliocene-Quaternary arcs correlate positively with arc thickness. This should be addressed to suggests that crustal thickness exerts a first order control on the Sr/Y variability of arc magmas through the M.C. (Massimo. stabilization or destabilization of mineral phases that fractionate Sr (plagioclase) and Y (amphibole 6 garnet). In fact, the stability of these mineral phases is function of the pressure at which magma evolves, [email protected]) which depends on crustal thickness. The data presented show also that high Sr/Y Pliocene-Quaternary intermediate-felsic arc rocks have a distinct origin from their Archean counterparts.
    [Show full text]
  • Seyed Amir Mohammad Razavi Khosroshahi
    Geology, geochemistry, geochronology, and economic potential of the Taftan volcanic complex, southeastern Iran by Seyed Amir Mohammad Razavi Khosroshahi A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science Department of Earth and Atmospheric Sciences University of Alberta © Seyed Amir Mohammad Razavi Khosroshahi, 2015 Abstract The late Miocene-Quaternary Taftan volcanic complex is located above the Makran subduction zone in Sistan and Baluchestan province of southeastern Iran. The earliest volcanic eruptions at Taftan started in the late Miocene (~8 Ma) by explosive eruption of andesitic to dacitic lava on the Cretaceous to Eocene volcanic and sedimentary paleosurface ~20 km to the northwest of the current edifice. Later Plio-Pleistocene volcanism consisted of voluminous andesitic and dacitic lavas and pyroclastic flows (~3.1-0.4 Ma). The major and trace element compositions of the Taftan volcanic rocks show calc-alkaline to high-K calc-alkaline affinity with depletions of Nb, Ta, and Ti and relative enrichment of large-ion lithophile elements (LILE) and Th and U; these are typical signatures of subduction-related arc magmas. From the late Miocene to the late Pleistocene La/Yb and Sr/Y ratios of the Taftan volcanic rocks increase, which likely reflects fractional crystallization of pyroxene and amphibole. Electron microprobe analysis of amphibole phenocrysts from the Taftan volcanic rocks show that amphibole chemistry changed from high-Al pargasite to low-Al magnesio-amphibole from the late Miocene to the Pleistocene. Detailed modelling of amphibole chemistry indicates that the host magmas were water saturated (>5 wt.% H2O) and underwent partial crystallization at various depths between ~20 to ~5 km in the upper crust prior to eruption.
    [Show full text]
  • Geothermal Country Update for Ecuador, 2000-2005
    Proceedings World Geothermal Congress 2005 Antalya, Turkey, 24-29 April 2005 Geothermal Country Update for Ecuador, 2000-2005 Bernardo Beate, Rodney Salgado Escuela Politecnica Nacional, Dept de Recursos Minerales, PO Box 17-01-2759, Quito/Ecuador [email protected] Keywords: Ecuador, geothermal exploration, heat source, The energy market is dominated by Hydro (50.6 %) and hot springs of Ecuador, assessment of geothermal prospects, Fossil Fuel (49.4 %) generation, with a total installed use of geothermal energy. capacity of 3451 Mwe, yielding a gross electricity production of 12357 GWh/yr (as of Dec 2002). ABSTRACT Production from renewable energy sources in Ecuador, Due mainly to its favorable geodynamic setting along the including geothermal, solar and wind, is still neglegible, but active convergent plate margin of Southamerica, is planned to increase in the future. The Tufiño-Chiles characterized by a broad continental volcanic arc with geothermal prospect owns the especial status of Bi-National numerous active volcanoes and intense seismicity, and to Project, due to its location on the Ecuador-Colombia border. the elevated oil prices of the time, Ecuador started the This and several other high and low-medium temperature exploration of its geothermal resources about 30 years ago, geothermal prospects in Ecuador await state and private aiming on high enthalpy prospects, suitable for electricity investment to be developed in order to lessen the production. dependence on fossil fuel use. Finally, in Ecuador, geothermal energy is challenged to be cost-efficient in front Exploration for geothermal resources was carried out from of an abundant hydro resource, as well as to be the mid 1970´s through the early 1990´s by ecuadorean environmentally safe.
    [Show full text]
  • Article Reference
    Article Why large porphyry Cu deposits like high Sr/Y magmas? CHIARADIA, Massimo, et al. Reference CHIARADIA, Massimo, et al. Why large porphyry Cu deposits like high Sr/Y magmas? Scientific Reports, 2012, vol. 2 DOI : 10.1038/srep00685 Available at: http://archive-ouverte.unige.ch/unige:27594 Disclaimer: layout of this document may differ from the published version. 1 / 1 Why large porphyry Cu deposits like high Sr/Y magmas? SUBJECT AREAS: Massimo Chiaradia1, Alexey Ulianov2, Kalin Kouzmanov1 & Bernardo Beate3 PETROLOGY EARTH SCIENCES 1Section of Earth and Environmental Sciences, University of Geneva, 1205 Geneva, Switzerland, 2Institute of Mineralogy and GEOCHEMISTRY Geochemistry, University of Lausanne, 1015 Lausanne, Switzerland, 3Escuela Polite´cnica Nacional, Dep.to de Geologı´a, Ladro´nde MINERALOGY Guevara E11-253, Quito, Ecuador. Received Porphyry systems supply most copper and significant gold to our economy. Recent studies indicate that they 19 March 2012 are frequently associated with high Sr/Y magmatic rocks, but the meaning of this association remains elusive. Understanding the association between high Sr/Y magmatic rocks and porphyry-type deposits is Accepted essential to develop genetic models that can be used for exploration purposes. Here we present results on a 10 September 2012 Pleistocene volcano of Ecuador that highlight the behaviour of copper in magmas with variable (but generally high) Sr/Y values. We provide indirect evidence for Cu partitioning into a fluid phase exsolved at Published depths of ,15 km from high Sr/Y (.70) andesitic magmas before sulphide saturation. This lends support to 24 September 2012 the hypothesis that large amounts of Cu- and S-bearing fluids can be accumulated into and released from a long-lived high Sr/Y deep andesitic reservoir to a shallower magmatic-hydrothermal system with the potential of generating large porphyry-type deposits.
    [Show full text]
  • Why Large Porphyry Cu Deposits Like High Sr/Y Magmas?
    Why large porphyry Cu deposits like high Sr/Y magmas? SUBJECT AREAS: Massimo Chiaradia1, Alexey Ulianov2, Kalin Kouzmanov1 & Bernardo Beate3 PETROLOGY EARTH SCIENCES 1Section of Earth and Environmental Sciences, University of Geneva, 1205 Geneva, Switzerland, 2Institute of Mineralogy and GEOCHEMISTRY Geochemistry, University of Lausanne, 1015 Lausanne, Switzerland, 3Escuela Polite´cnica Nacional, Dep.to de Geologı´a, Ladro´nde MINERALOGY Guevara E11-253, Quito, Ecuador. Received Porphyry systems supply most copper and significant gold to our economy. Recent studies indicate that they 19 March 2012 are frequently associated with high Sr/Y magmatic rocks, but the meaning of this association remains elusive. Understanding the association between high Sr/Y magmatic rocks and porphyry-type deposits is Accepted essential to develop genetic models that can be used for exploration purposes. Here we present results on a 10 September 2012 Pleistocene volcano of Ecuador that highlight the behaviour of copper in magmas with variable (but generally high) Sr/Y values. We provide indirect evidence for Cu partitioning into a fluid phase exsolved at Published depths of ,15 km from high Sr/Y (.70) andesitic magmas before sulphide saturation. This lends support to 24 September 2012 the hypothesis that large amounts of Cu- and S-bearing fluids can be accumulated into and released from a long-lived high Sr/Y deep andesitic reservoir to a shallower magmatic-hydrothermal system with the potential of generating large porphyry-type deposits. Correspondence and requests for materials hree-quarters of the world’s Cu and one-fifth of the world’s Au are currently supplied by porphyry should be addressed to systems1.
    [Show full text]
  • Universite Blaise Pascal Ecole Doctorale Des
    No d’Ordre : D.U. 2593 UNIVERSITE BLAISE PASCAL U.F.R. Sciences et Technologies ECOLE DOCTORALE DES SCIENCES FONDAMENTALES No 830 THESE présentée pour obtenir le grade de DOCTEUR D’UNIVERSITE Spécialité : Géochimie - Volcanologie Par : KÜLAHCI DOĞAN G. Deniz Master Le volcanisme basaltique post-collisionnel d’Anatolie Centrale Etude chronologique, magmatologique et géochimique Evolution spatio-temporelle Soutenue publiquement le 1 Septembre 2015, devant le commission d’examen President : LE PENNEC Jean-Luc Université Blaise Pascal Clermont-Ferrand Rapporteur : GUILLOU Hervé LSCE CEA-CNRS- Gif-Sur-Yvette Rapporteur : SEYİTOĞLU Gürol Université d'Ankara - Ankara Examinateur : KÜRKÇÜOĞLU Biltan Université Hacettepe- Ankara Examinateur : MURATÇAY VAROL Elif Université Hacettepe- Ankara Directeur de thèse : TEMEL Abidin Université Hacettepe- Ankara Co-directeur de thèse : GOURGAUD Alain Université Blaise Pascal Clermont-Ferrand Le volcanisme basaltique post-collisionnel d’Anatolie Centrale Etude chronologique, magmatologique et géochimique Evolution spatio-temporelle Résumé Cette thèse est consacrée à la caractérisation pétrologique et géochimique des basaltes quaternaires post-collisionnels d’Anatolie centrale (strato-volcans Erciyes et Hasandağ et volcanisme dispersé d'Obruk-Zengen et de Karapınar), en se focalisant sur l’évolution spatio-temporelle de ce magmatisme de la Cappadoce (Turquie). Par la géochronologie K-Ar, la coexistence de basaltes alcalins et calco-alcalins a été démontrée, parfois dans un même lieu et à la même époque. Par ailleurs, nos résultats montrent aussi que ces basaltes peuvent être très jeunes (quelques milliers d’années seulement). La minéralogie des basaltes quaternaires de la Cappadoce est la suivante : plagioclase, olivine, clinopyroxène, orthopyroxène et oxydes (magnétite, ilménite). Pourtant, seuls les basaltes de l’Erciyes contiennent de l’orthopyroxène, alors que ceux du Hasandağ et du volcanisme dispersé d’Obruk-Zengen et de Karapınar en sont dépourvus.
    [Show full text]
  • Quaternary Sanukitoid-Like Andesites Generated by Intracrustal Processes (Chacana Caldera Complex, Ecuador): Implications for Archean Sanukitoids
    JOURNAL OF PETROLOGY VOLUME 55 NUMBER 4 PAGES 769^802 2014 doi:10.1093/petrology/egu006 Quaternary Sanukitoid-like Andesites Generated by Intracrustal Processes (Chacana Caldera Complex, Ecuador): Implications for Archean Sanukitoids MASSIMO CHIARADIA1*, OTHMAR MU«NTENER2 AND BERNARDO BEATE3 1SECTION OF EARTH AND ENVIRONMENTAL SCIENCES, UNIVERSITY OF GENEVA, RUE DES MARAI“ CHERS 13, 1205 GENEVA, SWITZERLAND 2INSTITUTE OF EARTH SCIENCES, UNIVERSITY OF LAUSANNE, GE¤OPOLIS, 1015 LAUSANNE, SWITZERLAND 3DEPARTMENT OF GEOLOGY, ESCUELA POLITECNICA NACIO¤NAL, QUITO, ECUADOR RECEIVED MAY 27, 2013; ACCEPTED JANUARY 21, 2014 High-Mg diorites enriched in incompatible elements and their extru- associated with predominant silica-rich (adakite-like) andesites, sive equivalents are rare subduction-related rock types that have been which are widespread throughout the Quaternary arc of Ecuador. found in modern arc settings and in Late Archean sequences, where This makes the Quaternary Ecuadorian magmatic province a close they are associated with trondhjemite^tonalite^granodiorite equivalent of the Archean TTG^sanukitoid association. The bulk- (TTG) suites. Archean rocks with these geochemical features are rock geochemistry, petrography and mineral chemistry data indicate known as sanukitoids and, despite their limited abundance, are con- that the sanukitoid-like features of the andesites of the Yuyos flow sidered to be the indicators of the onset of modern plate tectonics derive from intracrustal recycling of the felsic^intermediate to because of their similarities to modern subduction-related high-Mg mafic^ultramafic roots of the Quaternary volcanic arc of Ecuador andesites and diorites. Understanding the genesis of sanukitoid by ‘normal’ mantle-derived basaltic magmas with the geochemical rocks is thus an essential step towards understanding crustal growth characteristics of continental arc basalts or high-alumina basalts.
    [Show full text]
  • CCVG-Workshop-Second-Circular.Pdf
    INVITATION On behalf of the Instituto Geofísico de la Escuela Politécnica Nacional (IG- EPN), the Parque Nacional Galápagos, the Commission on the Chemistry of Volcanic Gases (CCVG) and the International Association of Volcanology and Chemistry of the Earth Interior, we are glad to invite you to the 13th Gas Field Workshop to be held in Ecuador, from September 24 to October 3, 2017. The main objectives of the workshop are to discuss and share new and exis- ting direct sampling, in situ sampling and remote sensing results, collect complementary volcanic gas measurements from local volcanoes, and to discuss the latest theories and observations related to volcanic degassing. The workshop will include four days of conference meetings and presenta- tions, five days of field measurement and sample collection at Tungurahua, Guagua Pichincha, Pululahua and Cotopaxi volcanoes and two optional four and five days field excursion to Reventador volcano and to the Galápa- gos Islands. CCVG-IAVCEI 13th GAS WORKSHOP Scientific Programme The program will include a 4-day scientific meeting focused on geochemistry of magmatic gases and fluxes from volcanoes, followed by a 5-day field excursion to allow participants to acquire plume measurements, diffuse soil flux measurements and direct fumarole and water samples from local volcanoes. Details of the scientific program and field campaign are outlined below. Conference: 1. New developments in direct, in situ, remote, and diffuse volcanic gas and aerosol sampling/measurement tech- niques, including but not limited to advancements related to measurement accuracy and precision, acquisition, automation and analysis. 2. Geochemical observations and interpretations of volcanic and hydrothermal systems.
    [Show full text]