DOCSLIB.ORG

Rapid Magma Ascent and Generation of Th Excesses in the Lower Crust At

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Rapid Magma Ascent and Generation of Th Excesses in the Lower Crust At Earth and Planetary Science Letters 255 (2007) 229–242 www.elsevier.com/locate/epsl Rapid magma ascent and generation of 230Th excesses in the lower crust at Puyehue–Cordón Caulle, Southern Volcanic Zone, Chile ⁎ Brian R. Jicha a, , Brad S. Singer a, Brian L. Beard a, Clark M. Johnson a, Hugo Moreno-Roa b,c, José Antonio Naranjo b a Department of Geology and Geophysics, University of Wisconsin—Madison, 1215 West Dayton Street, Madison WI 53706, USA b Servicio Nacional de Geología y Minería (SERNAGEOMIN), Avenida Santa María, 0104 Santiago, Chile c Observatorio Volcanologico de los Andes del Sur (OVDAS), Cerro Ñielol-Sector Antenas, Temuco, Chile Received 28 July 2006; received in revised form 7 December 2006; accepted 8 December 2006 Available online 30 January 2007 Editor: R.W. Carlson Abstract Basaltic to rhyolitic lavas and tephras erupted over the last 70 kyr at the Puyehue–Cordón Caulle volcanic complex in the Andean Southern Volcanic Zone (SVZ) were analyzed for major and trace element, Sr isotope, and U–Th isotope compositions to constrain the timescales of magmatic processes and identify the subducted and crustal components involved in magma genesis. Internal U–Th mineral isochrons from five lavas and three tephra fall deposits are indistinguishable from their eruption ages, indicating a short period (b1000 yr) of crystal residence in the magma prior to eruption. The (230Th/232Th) ratios define a narrow range (0.80–0.83) compared to that of all SVZ lavas (0.72–0.97), suggesting that Puyehue basalt was derived from a relatively uniform mantle source. Dacites and rhyolites have the largest U excesses and likely evolved via fractional crystallization of a plagioclase-dominated mineral assemblage. In contrast, basalts have 1 to 6% 230Th excesses, a characteristic not previously observed in frontal arc stratovolcanoes of the Andean SVZ. The 230Th excesses are interpreted to reflect a relatively small degree of fluid flux melting coupled with assimilation and melting of the lower crust. Lower crustal processes, therefore, have dampened the 238U excesses that were generated during fluid addition to the mantle wedge. Although prior 238U–230Th–226Ra studies of lavas from other southern SVZ stratovolcanoes (36 to 41° S) have inferred that slab additions and the extent of mantle melting were nearly constant along strike of the arc, our results suggest that MASH processes envisioned by Hildreth and Moorbath [W. Hildreth, S. Moorbath, Crustal contributions to arc magmatism in the Andes of central Chile, Contrib. Mineral. Petrol. 98 (1988) 455-489] in the northern SVZ also occur in the southern SVZ, where the crust is relatively thin. © 2006 Elsevier B.V. All rights reserved. Keywords: U–Th isotopes; Puyehue–Cordón Caulle; Southern Volcanic Zone; lower crust 1. Introduction between volcanic output and magma dynamics in the mantle and crust. Disequilibria among decay products of Determining the time involved for magma transport, U-series nuclides have been used to constrain these storage, and crystallization provides an important link processes (see reviews by [2,3]). In particular, along-arc surveys of historical lavas U–Th isotope compositions ⁎ Corresponding author. Tel.: +1 608 262 8960; fax: +1 608 262 0693. have been used to fingerprint the various subducted E-mail address: [email protected] (B.R. Jicha). components involved in magma genesis and to estimate 0012-821X/$ - see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.epsl.2006.12.017 230 B.R. Jicha et al. / Earth and Planetary Science Letters 255 (2007) 229–242 ascent rates [4–11]. Relatively few studies have focused Nd–Pb isotope characteristics of the erupted products on extended eruptive periods of individual volcanoes are relatively well-characterized [31], 3) its eruptive (i.e. 104 to 105 yr), and yet this approach is important for history is marked by numerous explosive sub-Plinian to understanding the tempo of magma storage, mixing, and Plinian eruptions, including the most recent eruption fractional crystallization over the lifetime of an arc which occurred on May 24, 1960, ∼38 h after the main volcano [12–15]. shock of the Mw 9.5 Great Chilean earthquake, whose The majority of U-series data from subduction zones epicenter was 240 km to the west [32,33], and 4) it is the are from island arc lavas that are typically enriched in target of a 40Ar/39Ar-based geochronological investiga- 238U over 230Th, which have been interpreted to reflect tion aimed at characterizing the eruptive and volumetric the addition of slab-derived, U-rich fluids to the mantle growth rate history during the past several hundred kyr wedge. Interpretation of U-series isotope data from [34,35]. This study combines new U-series, trace- continental arc lavas tends to be complicated by element, and Sr isotope data to examine magma sources magma–crust interaction [9–11,16–23]. Excess 226Ra and intracrustal magmatic processes over the last 70 kyr, over 230Th is a widespread characteristic in both island a period when the Puyehue stratocone grew rapidly to its and continental arc lavas, which requires rapid magma present form. ascent within 5 half-lives of 226Ra (b8 kyr). 226Ra excesses may be generated during fluid addition to the 2. Geologic setting and volcanological overview mantle wedge, melting and assimilation of crust, or during melt transport, all of which may relax the Puyehue–Cordón Caulle is located at 40.5° S in requirement of rapid magma ascent rates [24–26]. 230Th Southern Volcanic Zone of Chile, and comprises excesses in continental arc lavas, like 226Ra excesses, ∼140 km3 of Pleistocene to Holocene lavas and tephras may be due to variable amounts of fluid and melt that crop out over ∼800 km2 [31,34–36]. The complex addition to the mantle wedge [8,10,20–22] or assimi- includes the Puyehue stratovolcano and the Cordón lation–fractional crystallization processes [17,23]. Caulle fissural zone, which extends 20 km to the The Andean Southern and Austral Volcanic zones northwest of Puyehue (Fig. 1). Geologic mapping, (SVZ and AVZ, respectively; Fig. 1) are adjacent stratigraphy, and more than forty 40Ar/39Ar age continental arcs where petrologic and U-series studies determinations indicate that two broad shield volcanoes have revealed dramatic differences in magma sources dominated the Puyehue–Cordón Caulle region from 240 [10–12,18,27–30]. 230Th excesses and high Sr/Y and to 70 ka [34–36]. The modern Puyehue stratocone was La/Yb ratios in AVZ lavas may reflect partial melting of built on the remains of the southernmost shield from 69 subducted oceanic crust [10]. In contrast, most SVZ to 1 ka, and consists of ∼18 km3 of lava and tephra that lavas have 238Uand226Ra excesses that are well span a continuum from basalt (up to 10 wt.% MgO) to 10 9 correlated with Be/ Be [11,18]; this is interpreted to rhyolite with up to 72 wt.% SiO2 (Table A.1). The reflect addition of sediment-derived fluid to the mantle, basalts which contain 7–10 wt.% MgO are among the followed by rapid magma ascent (i.e., 102 to 103 yr) [11]. most Mg-rich lavas erupted from stratovolcanoes in The aim of this paper is to explore petrologic the entire southern SVZ [31,37]. Dacitic to rhyolitic processes and their timescales over an extended period activity is primarily restricted to the last 19 kyr during of several tens of kyr at the Puyehue–Cordón Caulle which a dome complex grew atop the volcano in volcanic complex through U–Th isotope compositions several effusive and explosive stages. A sub-Plinian to determined on lavas, tephra falls and their constituent phreatoplinian rhyodacitic eruption at ∼1kaobliter- minerals. We present the first U–Th isotope data ated these domes and formed the modern 2.5 km- available for minerals from SVZ lavas. In addition, we diameter summit crater. Along the Cordón Caulle fis- have analyzed several mafic lavas from small eruptive sural zone, ∼9km3 of rhyodacitic to rhyolitic domes, centers in the Puyehue–Cordón Caulle region in order to lava flows, pumice falls, and pyroclastic cones have compare the isotopic characteristics of basalts erupted at erupted from at least 27 vents during the past a mature stratovolcano to those of the surrounding ∼16.5 ka, including rhyodacitic to rhyolitic eruptions cinder cones (e.g., [18]). Puyehue–Cordón Caulle was in 1921–22 and 1960 [33–36]. chosen because: 1) it is unique among other predom- inantly mafic centers of the southern SVZ in that it has 3. Sample selection and analytical techniques produced a wide compositional spectrum of lavas ranging from high-MgO basalt to voluminous rhyoda- We have analyzed 26 lavas and tephra fall deposits cite and rhyolite, 2) the petrologic, geochemical, Sr– from Puyehue–Cordón Caulle erupted during the last B.R. Jicha et al. / Earth and Planetary Science Letters 255 (2007) 229–242 231 70 kyr, one coarse-grained, dioritic xenolith that was Puyehue lavas are known precisely from 40Ar/39Ar found in ∼1 ka pumice on the south rim of the Puyehue geochronology, AMS 14C ages ([34,35], Table A.2), or crater, nine late Holocene to historic basalts from nearby historical observations. Three of the five Puyehue small eruptive centers (e.g., Mirador, Carrán, and basalts (PU 02 39, PU 02 03, PU 05 29) have not Rininahue centers of Carrán-Los Venados; Antillanca, been dated directly, but their ages are constrained by Pajaritos, Cerro Mirador, Anticura, an unnamed cinder stratigraphic relations relative to lavas flows that erupted cone 3 km south of Puyehue), and one basaltic lava from between 14.9±2.9 and 11.5±1.1 ka based on 40Ar/39Ar the 1835 eruption of Osorno volcano, located ∼65 km geochronology (Fig.
Load more

Recommended publications
  • The Volcanic Ash Soils of Chile
    ' I EXPANDED PROGRAM OF TECHNICAL ASSISTANCE No. 2017 Report to the Government of CHILE THE VOLCANIC ASH SOILS OF CHILE FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS ROMEM965 -"'^ .Y--~ - -V^^-.. -r~ ' y Report No. 2017 Report CHT/TE/LA Scanned from original by ISRIC - World Soil Information, as ICSU World Data Centre for Soils. The purpose is to make a safe depository for endangered documents and to make the accrued information available for consultation, following Fair Use Guidelines. Every effort is taken to respect Copyright of the materials within the archives where the identification of the Copyright holder is clear and, where feasible, to contact the originators. For questions please contact [email protected] indicating the item reference number concerned. REPORT TO THE GOVERNMENT OP CHILE on THE VOLCANIC ASH SOILS OP CHILE Charles A. Wright POOL ANL AGRICULTURE ORGANIZATION OP THE UNITEL NATIONS ROME, 1965 266I7/C 51 iß - iii - TABLE OP CONTENTS Page INTRODUCTION 1 ACKNOWLEDGEMENTS 1 RECOMMENDATIONS 1 BACKGROUND INFORMATION 3 The nature and composition of volcanic landscapes 3 Vbloanio ash as a soil forming parent material 5 The distribution of voloanic ash soils in Chile 7 Nomenclature used in this report 11 A. ANDOSOLS OF CHILE» GENERAL CHARACTERISTICS, FORMATIVE ENVIRONMENT, AND MAIN KINDS OF SOIL 11 1. TRUMAO SOILS 11 General characteristics 11 The formative environment 13 ÈS (i) Climate 13 (ii) Topography 13 (iii) Parent materials 13 (iv) Natural plant cover 14 (o) The main kinds of trumao soils ' 14 2. NADI SOILS 16 General characteristics 16 The formative environment 16 tö (i) Climat* 16 (ii) Topograph? and parent materials 17 (iii) Natural plant cover 18 B.
    [Show full text]
  • Multiple Sources for Tephra from AD 1259 Volcanic Signal in Antarctic Ice
    Multiple sources for tephra from AD 1259 volcanic signal in Antarctic ice cores Biancamaria Narcisi, Jean Robert Petit, Barbara Delmonte, Valentina Batanova, Joel Savarino To cite this version: Biancamaria Narcisi, Jean Robert Petit, Barbara Delmonte, Valentina Batanova, Joel Savarino. Mul- tiple sources for tephra from AD 1259 volcanic signal in Antarctic ice cores. Quaternary Science Reviews, Elsevier, 2019, 210, pp.164-174. 10.1016/j.quascirev.2019.03.005. hal-02350371 HAL Id: hal-02350371 https://hal.archives-ouvertes.fr/hal-02350371 Submitted on 25 Nov 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. Manuscript Details Manuscript number JQSR_2019_21 Title MULTIPLE SOURCES FOR TEPHRA FROM AD 1259 VOLCANIC SIGNAL IN ANTARCTIC ICE CORES Abstract Strong volcanic signals simultaneously recorded in polar ice sheets are commonly assigned to major low-latitude eruptions that dispersed large quantities of aerosols in the global atmosphere with the potential of inducing climate perturbations. Parent eruptions responsible for specific events are typically deduced from matching to a known volcanic eruption having coincidental date. However, more robust source linkage can be achieved only through geochemical characterisation of the airborne volcanic glass products (tephra) sometimes preserved in the polar strata.
    [Show full text]
  • Lesson Plans Villarrica Volcano Eruption
    My NASA Data - Lesson Plans Villarrica Volcano Eruption Purpose Students use scale to determine the area of volcanic deposits following the March 3, 2015 eruption of Chile's Mount Villarrica stratovolcano, one of the country's most active volcanoes. Learning Objectives Students use a scale to calculate a map area. Students determine the area of volcanic deposits. Students explain the time scale involved in the measured change. Why Does NASA Study This Phenomenon? Landsat 8 Launched on February 11, 2013, Landsat 8 (formerly the Landsat Data Continuity Mission, LDCM) is the most recently launched Landsat satellite. It is collecting valuable data and imagery used in 1 / 8 agriculture, education, business, science, and government. The Landsat Program provides repetitive acquisition of high resolution multispectral data of the Earth’s surface on a global basis. The data from Landsat spacecraft constitute the longest record of the Earth’s continental surfaces as seen from space. It is a record unmatched in quality, detail, coverage, and value. Essential Questions How quickly did volcanic debris from Mount Villarricia's eruption cover the area? How much of thea area was covered? Materials Required Rulers Colored printouts of images Technology Requirements Standalone Lesson (no technology required) Teacher Background Information Glacier-clad Villarrica is one of Chile's most active volcanoes. It rises above the lake and town of the same name. It is the westernmost of three large stratovolcanoes that trend perpendicular to the Andean chain. A 6-km-wide caldera formed during the late Pleistocene. A 2-km-wide caldera that formed about 3500 years ago is located at the base of the presently active, dominantly basaltic to basaltic-andesitic cone at the NW margin of the Pleistocene caldera.
    [Show full text]
  • La Catástrofe Del Nevado Del Ruiz, ¿Una Enseñanza Para El Ecuador? El Caso Del Cotopaxi
    La catástrofe del Nevado del Ruiz, ¿Una enseñanza para el Ecuador? El caso del Cotopaxi. Robert d’Ercole To cite this version: Robert d’Ercole. La catástrofe del Nevado del Ruiz, ¿Una enseñanza para el Ecuador? El caso del Cotopaxi.. Estudios de Geograf’ia, Corporación Editora Nacional, 1989, Riesgos Naturales en Quito, 2, pp.5-32. hal-01184809 HAL Id: hal-01184809 https://hal.archives-ouvertes.fr/hal-01184809 Submitted on 25 Aug 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. LA CATASTROFE DEL NEVADO DEL RUIZ l UNA ENSENANZA- PARA EL ECUADOR ? EL CASO DEL COTOPAXI Robert D'Ercole* El 13 de noviembre de 1985, el volcân colombiano, el Nevado deI Ruiz, erupciono provocando la muerte de unas 25.000 personas. Esta es la mayor catâstrofe causada por un volcan desde la que produjo 29.000 victimas, en 1902 en la isla Martinica, luego de la erupci6n de la Montafla Pelée. La magnitud de las consecuencias y el hecho de que el Ruiz haya dado signos de reactivaci6n mucho tiempo antes, plantean el problema deI fenomeno natural pero también de los factores humanos que originaron la tragedia.
    [Show full text]
  • Possible Causes for the Seismic Activity Observed in Cotopaxi Volcano, Ecuador
    GEOPHYSICALRESEARCH LETTERS, VOL. 25, NO.13, PAGES2305-2308, JULY 1, 1998 Possible causes for the seismic activity observed in Cotopaxi volcano, Ecuador MarioRuiz 1, Bertrand Guillierl, 2, Jean-LucChatelain l, 2, 3, HugoYepes l Minard Hall •, and PatricioRamon 4 Abstract. Continuous monitoring of Cotopaxi volcano probability of having an explosive eruption similar or greater from January 1989 to September 1997 shows that it is subject than that of 1877 in 50, 100 and 200 years is respectivelyof to a steady shallow Long Period (LP) activity. LP events are 0.35, 0.57 and 0.82. concentrated in a column with a diameter of about 3 km and a Given this very active eruptive history and associated height of about 12 km, between an elevation of 4 km and 8 km volcanic hazards (pyroclastic flows, lahars, tephra falls, lava depth. They do not occur in swarms, nor have there been flows) that could affect populatedareas, the Instituto Geofisico periods of complete calm. High frequency volcano-tectonic (IG) of Quito start6d continuous monitoring of the seismic (VT) events are mostly located on the northeasternside of the activity of Cotopaxi in 1989. The goal of this paper is to LP column, with the maximum activity of both types of events describe the characteristicsof the Cotopaxi seismic activity, coinciding in depth. LP activity cannot be related to unrest of usingthe recordingsof the IG array from January1989 up to the volcano. The most likely explanation for the continuous September 1997. occurrence of LP events beneath Cotopaxi is that they are produced by the interaction of glacier thaw water and hot material at shallow depths.
    [Show full text]
  • Field Measurements of Active Volcanoes in the Southern Chilean Andes
    Field Measurements of Active Volcanoes in the Southern Chilean Andes February – March 2012 Kelby Hicks Kayla Iacovino Tehnuka Ilanko Yves Moussallam Nial Peters Department of Geography, University of Cambridge, Downing Place, Cambridge CB2 3EN, UK _____________________________________________________________________ Funding provided by the Royal Geopgraphical Society with IBG facilitated a month- long volcano monitoring campaign on three active volcanoes in Chile: Villarrica, a steadily active and constantly degassing stratovolcano; Puyehue-Cordon Caulle, a recently active, explosive volcano; and Lascar, a periodically active volcano in the Atacama region, which showed signs of unrest prior to this field campaign. This funding combined with additional monies from Antofagasta, The Jeremy Willson Charitable Trust and the Cambridge University Department of Geography was used principally for equipment costs, transportation, and guide hire at the fieldwork sites. From February 1st to March 6th 2012 our group of five PhD students, through collaboration with the local volcanic observatory OVDAS (Observatorio Volcanologico de los Andes del Sur), deployed a series of remote and direct sensing instruments previously unavailable to local observatory at Villarrica, Puyehue-Cordon Caulle, and Láscar, three active volcanoes that present a real and significant risk to surrounding populations. Here we present an overview of the work conducted and preliminary high-resolution data on the volcanic emissions at these three sites, an essential component of volcanic hazard assessment and eruption forecasting. _____________________________________________________________________ Cover Image: The team sets up equipment near the active vent of Puyehue-Cordon Caulle. Fieldwork Overview After a few days spent organising logistics in Santiago the team headed south to Temuco where we had scheduled a meeting with the head of OVDAS.
    [Show full text]
  • Area Changes of Glaciers on Active Volcanoes in Latin America Between 1986 and 2015 Observed from Multi-Temporal Satellite Imagery
    Journal of Glaciology (2019), 65(252) 542–556 doi: 10.1017/jog.2019.30 © The Author(s) 2019. This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons. org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited. Area changes of glaciers on active volcanoes in Latin America between 1986 and 2015 observed from multi-temporal satellite imagery JOHANNES REINTHALER,1,2 FRANK PAUL,1 HUGO DELGADO GRANADOS,3 ANDRÉS RIVERA,2,4 CHRISTIAN HUGGEL1 1Department of Geography, University of Zurich, Zurich, Switzerland 2Centro de Estudios Científicos, Valdivia, Chile 3Instituto de Geofisica, Universidad Nacional Autónoma de México, Mexico City, Mexico 4Departamento de Geografía, Universidad de Chile, Chile Correspondence: Johannes Reinthaler <[email protected]> ABSTRACT. Glaciers on active volcanoes are subject to changes in both climate fluctuations and vol- canic activity. Whereas many studies analysed changes on individual volcanoes, this study presents for the first time a comparison of glacier changes on active volcanoes on a continental scale. Glacier areas were mapped for 59 volcanoes across Latin America around 1986, 1999 and 2015 using a semi- automated band ratio method combined with manual editing using satellite images from Landsat 4/5/ 7/8 and Sentinel-2. Area changes were compared with the Smithsonian volcano database to analyse pos- sible glacier–volcano interactions. Over the full period, the mapped area changed from 1399.3 ± 80 km2 − to 1016.1 ± 34 km2 (−383.2 km2)or−27.4% (−0.92% a 1) in relative terms.
    [Show full text]
  • United States-Chile Binational Exchange for Volcanic Risk Reduction, 2015—Activities and Benefits
    Prepared in cooperation with Red Nacional de Vigilancia Volcánica del Servicio Nacional de Geología y Minería de Chile United States-Chile Binational Exchange for Volcanic Risk Reduction, 2015—Activities and Benefits Circular 1432 U.S. Department of the Interior U.S. Geological Survey Cover. Chilean and American delegates on caldera rim of Chaitén Volcano, Chile, March 28, 2015. The steaming lava dome is in the background. (Photograph by Christopher Wills, California Geological Survey.) United States-Chile Binational Exchange for Volcanic Risk Reduction, 2015— Activities and Benefits By Thomas C. Pierson, Margaret T. Mangan, Luis E. Lara Pulgar, and Álvaro Amigo Ramos Prepared in cooperation with Red Nacional de Vigilancia Volcánica del Servicio Nacional de Geología y Minería de Chile Circular 1432 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior RYAN K. ZINKE, Secretary U.S. Geological Survey William H. Werkheiser, Acting Director U.S. Geological Survey, Reston, Virginia: 2017 For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment—visit https://www.usgs.gov/ or call 1–888–ASK–USGS. For an overview of USGS information products, including maps, imagery, and publications, visit https://store.usgs.gov. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner.
    [Show full text]
  • Outlook on Climate Change Adaptation in the Tropical Andes Mountains
    MOUNTAIN ADAPTATION OUTLOOK SERIES Outlook on climate change adaptation in the Tropical Andes mountains 1 Southern Bogota, Colombia photo: cover Front DISCLAIMER The development of this publication has been supported by the United Nations Environment Programme (UNEP) in the context of its inter-regional project “Climate change action in developing countries with fragile mountainous ecosystems from a sub-regional perspective”, which is financially co-supported by the Government Production Team of Austria (Austrian Federal Ministry of Agriculture, Forestry, Tina Schoolmeester, GRID-Arendal Environment and Water Management). Miguel Saravia, CONDESAN Magnus Andresen, GRID-Arendal Julio Postigo, CONDESAN, Universidad del Pacífico Alejandra Valverde, CONDESAN, Pontificia Universidad Católica del Perú Matthias Jurek, GRID-Arendal Björn Alfthan, GRID-Arendal Silvia Giada, UNEP This synthesis publication builds on the main findings and results available on projects and activities that have been conducted. Contributors It is based on available information, such as respective national Angela Soriano, CONDESAN communications by countries to the United Nations Framework Bert de Bievre, CONDESAN Convention on Climate Change (UNFCCC) and peer-reviewed Boris Orlowsky, University of Zurich, Switzerland literature. It is based on review of existing literature and not on new Clever Mafuta, GRID-Arendal scientific results generated through the project. Dirk Hoffmann, Instituto Boliviano de la Montana - BMI Edith Fernandez-Baca, UNDP The contents of this publication do not necessarily reflect the Eva Costas, Ministry of Environment, Ecuador views or policies of UNEP, contributory organizations or any Gabriela Maldonado, CONDESAN governmental authority or institution with which its authors or Harald Egerer, UNEP contributors are affiliated, nor do they imply any endorsement.
    [Show full text]
  • Boron and Other Trace Element Constraints on the Slab-Derived Component in Quaternary Volcanic Rocks from the Southern Volcanic Zone of the Andes
    Geochemical Journal, Vol. 47, pp. 185 to 199, 2013 Boron and other trace element constraints on the slab-derived component in Quaternary volcanic rocks from the Southern Volcanic Zone of the Andes HIRONAO SHINJOE,1* YUJI ORIHASHI,2 JOSÉ A. NARANJO,3 DAIJI HIRATA,4 TOSHIAKI HASENAKA,5 TAKAAKI FUKUOKA,6 TAKASHI SANO7 and RYO ANMA8 1Tokyo Keizai University, Japan 2Earthquake Research Institute, The University of Tokyo, Japan 3Servicio Nacional de Geología y Minería, Chile 4Kanagawa Prefectural Museum of Natural History, Japan 5Department of Earth and Environmental Sciences, Graduate School of Science and Technology, Kumamoto University, Japan 6Department of Environment Systems, Faculty of Geo-environmental Science, Rissho University, Japan 7Department of Geology and Paleontology, National Museum of Nature and Science, Japan 8Integrative Environmental Sciences, Graduate School of Life and Environmental Sciences, Tsukuba University, Japan (Received April 18, 2012; Accepted December 25, 2012) We present a dataset for boron and other trace element contents obtained from samples from 13 volcanoes distributed along the Quaternary volcanic front of the Southern Volcanic Zone (SVZ) of the Chilean Andes. The dataset shows con- straints on the nature of slab-derived component to mantle source. Analyzed samples show large negative Nb and Ta anomalies, and enrichment of alkaline earth elements and Pb, which are features of typical island arc volcanic rocks. Boron contents of SVZ volcanic rocks range 2.3–125.5 ppm, exhibiting marked enrichment relative to N-MORB and OIB. Both the boron contents and B/Nb ratios of the volcanic rocks increase from the southern SVZ (SSVZ) to central SVZ (CSVZ). Fluid mobile/immobile element ratios (B/Nb, Ba/Nb, Pb/Nb, and K/Nb) are used to examine slab-derived com- ponent to mantle source.
    [Show full text]
  • Processes Culminating in the 2015 Phreatic Explosion at Lascar Volcano, Chile, Evidenced by Multiparametric Data
    Nat. Hazards Earth Syst. Sci., 20, 377–397, 2020 https://doi.org/10.5194/nhess-20-377-2020 © Author(s) 2020. This work is distributed under the Creative Commons Attribution 4.0 License. Processes culminating in the 2015 phreatic explosion at Lascar volcano, Chile, evidenced by multiparametric data Ayleen Gaete1, Thomas R. Walter1, Stefan Bredemeyer1,2, Martin Zimmer1, Christian Kujawa1, Luis Franco Marin3, Juan San Martin4, and Claudia Bucarey Parra3 1GFZ German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany 2GEOMAR Helmholtz Centre for Ocean Research Kiel, 24148 Kiel, Germany 3Observatorio Volcanológico de Los Andes del Sur (OVDAS), Servicio Nacional de Geología y Minería (SERNAGEOMIN), Temuco, Chile 4Physics Science Department, Universidad de la Frontera, Casilla 54-D, Temuco, Chile Correspondence: Ayleen Gaete ([email protected]) Received: 13 June 2019 – Discussion started: 25 June 2019 Accepted: 5 December 2019 – Published: 4 February 2020 Abstract. Small steam-driven volcanic explosions are com- marole on the southern rim of the Lascar crater revealed a mon at volcanoes worldwide but are rarely documented or pronounced change in the trend of the relationship between monitored; therefore, these events still put residents and the CO2 mixing ratio and the gas outlet temperature; we tourists at risk every year. Steam-driven explosions also oc- speculate that this change was associated with the prior pre- cur frequently (once every 2–5 years on average) at Lascar cipitation event. An increased thermal anomaly inside the ac- volcano, Chile, where they are often spontaneous and lack tive crater as observed in Sentinel-2 images and drone over- any identifiable precursor activity.
    [Show full text]
  • Along Arc Petrochemical Variations in the Southernmost Andean SVZ (43.5-46°S): Implications for Magma Genesis
    O EOL GIC G A D D A E D C E I H C I L E O S F u n 2 d 6 la serena octubre 2015 ada en 19 Along Arc Petrochemical Variations in the Southernmost Andean SVZ (43.5-46°S): Implications for Magma Genesis Charles R Stern* Department of Geological Sciences, University of Colorado, Boulder, Colorado 80309-0399, USA José Antonio Naranjo SERNAGEOMIN, Av. Santa María 0104, Santiago, Chile *Contact email: [email protected] Abstract. The southernmost Andean SVZ (43.5-46°S) (Sellés et al., 2004) further to the north. Among the smaller consists of six stratovolcanoes (Yanteles, Melimoyu, MEC, the Puyuhuapi group are HA type basalts (Fig. 2; Mentolat, Macá, Cay, Hudson). Hudson and Melimoyu are Lopéz et al. 1995a). In contrast, the Palena group just to high-K (K2O>1 wt% at 50 wt% SiO2), high incompatible the north of are LA type basalts (Fig. 2; Watt et al., 2013), element abundance (HA) types. Macá and Cay are low-K, as are all other MEC cones further to the south in the low incompatible element abundance (LA) centers, while Mentolat has very low K, Rb and other incompatible SSVZ. This paper addresses these regional variations in element contents (VLA), similar to Huequi, Calbuco and magma types along and across the SSVZ arc. Nevados de Longaví further north. Such differences have been attributed to differences in degree of mantle partial melting due to variability in the extent of contamination of the mantle source region by hydrous fluids and/or melts derived from subducted oceanic lithosphere, possibly as a result in down-dip temperature changes at the top of the subducted slab.
    [Show full text]