 | | Report (chapter) | | Ulster At Coleraine on May 14, 2015 Timing of geothermal activity in an active island-arc volcanic setting:...setting: First 40Ar/39Ar dating from Bouillante geothermal field (Guadeloupe, French West Indies) C. VERATI1*...breccias, newly discovered in the active Bouillante geothermal field (Guadeloupe archipelago), and investigated...geochronology in order to constrain the timing of geothermal activity in this part of the active Lesser Antilles...activity of the active Grande Découverte–Soufrière system (200 ka ago– present day). Our results demonstrate |  | Hannington, Mark D., Santaguida, Frank, Kjarsgaard, Ingrid M., Cathles, Larry M. (2003) Regional-scale hydrothermal alteration in the Central Blake River Group, western Abitibi subprovince, Canada: implications for VMS prospectivity. Mineralium Deposita, 38 (4) 393-422 doi:10.1007/s00126-002-0298-z | Journal (article/letter/editorial) | | positive encouragement for the existence of a fossil geothermal system of sufficient size or intensity to have...alteration volumes reflect the capacity of the geothermal system to produce large mineral deposits, in part...transitional tholeiitic to calc-alkaline basalt, andesite, dacite, and rhyolite. Slightly more calc-alkalic...Destor–Porcupine fault system in the north and Cadillac–Larder Lake fault system in the south. Volcanic...The Mine Sequence is a 3-km-thick succession of andesite, rhyolite, and minor volcaniclastic rocks erupted |  | | Journal (article/letter/editorial) | | I. metamorphic Geol., 1993, 11, 449454 Geothermal-type alteration in a burial metamorphosed volcanic...in a palaeogeothemal system with a high-T and a very low-P gradient. Geothermal alteration has also been...boundary of the graben. These expressions of geothermal alteration, together with the occurrence of caldera...central and northern Chile, suggest that fossil geothermal systems of this age are probably common features...Chilean Andes. Key words: Andes; Chile; geothermal system; Late Cretaceous to Tertiary; wairakite; yugawaralite; |  | | Journal (article/letter/editorial) | | deposition was proposed in a study of active geothermal systems in New Zealand (Henley and Ellis, 1983)...and the upper part of the magmatic hydrothermal system (e.g., Hayba and Ingebritsen, 1997). 2. Geological...A Middle Miocene marine sequence of dacite and andesite lavas, pyroclastic rocks, and sedimentary rocks...This has enabled observation of the wide fossil geothermal footprint in and around the vein. Because...hydrothermal fluids, reconstruction of a fossil geothermal system is a fundamental, essential step for clarifying |  | | Report (issue) | | (Rhodes, 1970; Krier, 1980; Seaman, 1988). The geothermal resources of the quadrangle have been the subject...basaltic lava flows of the Bearwallow Mountain Andesite (Tba), and volcaniclastic sedimentary rocks of...(ash-flow tuffs) of the Datil Group, and Last Chance Andesite (Cather and others, 1994), and by a thick sequence...Bearwallow Mountain (Tba) andesitic to basaltic-andesite lava flows from nearby shield volcanoes, and finally...Bloodgood Canyon Tuff (Tbt), Bearwallow Mountain Andesite (Tba), and Gila Conglomerate (QTg) can all be |  | | Journal (article/letter/editorial) | | shallow levels (<1 km) in a single paleogeothermal system. It is unclear if the Martha and Favona veins systems...above and on the margins of the paleogeothermal system, and during the eventual thermal collapse resulted...physical limits of hydrothermal alteration in a system in order to identify the limits of paleogeothermal...hydrothermal evolution of the paleohydrothermal system. Understanding the paleohydrologic structure of...example of a volcanichosted epithermal Au-Ag vein system that occurs less than 2 km east of the world-class |  | | Report (volume) | | chemistry at detachment faults, in calderas, in fossil geothermal sites, and in lacustrine environments in New...1965, 1973; Chapin and Lindley, 1986), and from fossil geothern1al activity (Nusbaum and Grant, 1987)...indicated a thermal event associated with detachment (Martin and others, 1980). On the basis of K-Ar studies...9ooac H 2o+ H2oK20:Na20 Picacho Peak PP-2K PP-9 Andesite Dacite 32°39'53"N. 32°32'57"N. 111 °23'24"W. 111...detachment mechanism affected the K-Ar isotopic system in both upper-plate and lower-plate rocks; the |  | | Journal (article/letter/editorial) | | of the dome acting as a heat source to drive a geothermal "cell". Circulating connate-hydrothermal fluids...cross-reference index, the Mineral Occurrence Documentation System (Anon, 1974). Many metalliferous showings are ...and agglomerates, mainly basaltic to basaltic-andesite in composition (Fig. i). These are succeeded westward...intersection lengths up to several metres, adjacent to an andesite dyke (Allcott, 1970). The widespread inated sulphides...common in geothermal fields in volcanic rocks, e.g. Wairaki, New Zealand. The spacing of geothermal c e n |  | Christie, A. B., Simpson, M. P., Brathwaite, R. L., Mauk, J. L., Simmons, S. F. (2007) Epithermal Au-Ag and Related Deposits of the Hauraki Goldfield, Coromandel Volcanic Zone, New Zealand. Economic Geology, 102 (5) 785-816 doi:10.2113/gsecongeo.102.5.785 | Journal (article/letter/editorial) | | production was from deposits hosted in Miocene andesite and dacite of the Coromandel Group, although this...steeply dipping planar veins occur in the oldest andesite and dacite in the northern portion of the goldfield...well-developed crustiform textures, formed in andesite and dacite in the southern goldfield at 7 to 6...flows and tuffs Andesite 2.3 Quartz veins py, el, (hes, sl, gn) Propylitic Andesite Kuaotunu 3.3...veins el Propylitic Andesite breccias and flows Andesite breccias and flows Andesite 1.5 Quartz veins |  | | Journal (article/letter/editorial) | | deposits type is presented. The silver-gold vein system occurs in the southeastern portion of the Sierra...in a continental basin. These sediments contain fossil vertebrate faunas with ages between late Clarendonian...Clarendonian and Blancan. Southeast of El Bajío fault system sand and gravel deposits, partially covered by...Ag-Au hydrothermal veins deposits associated with andesite-rhyolite continental volcanic activity of the...for the prospection of ore deposits, which are fossil hydrothermal systems where at the time of the formation |  | | Report (issue) | | districts are calc-alkaline volcanics, consisting of andesite rhyodacites and rhyodacites. However, at Guanajuato...Valenciana mines; Veta Madre vein system, Sierra vein system and La Luz vein system. COMMODITIES MINED: AJ, Ag...air-fall and ash flows of rhyolite (Bufa Fm), andesite tuff with basal volcaniclastic shale and sandstone...sandstone (Calderones Fm), porphyritic andesite flows interbedded with andesitic tuff (Cedro Fm) and welded...sulfide deposition. In time, a self-sealing of the system occurs both above the level of boiling (due to |  | | Journal (article/letter/editorial) | | British Columbia— Raymond M. Caron, Claire Samson, Martin Bates, and Michel Chouteau Applying laterally varying...Zhi-Hui Dai CANADIAN MINERALOGIST New data on the system Na2CO3-CaCO3-MgCO3 at 6 GPa with implications to...Thomas Wagner, Erik Jonsson, Tobias Fusswinkel, and Martin J. Whitehouse Hydrothermal oxidation of Os—Dionysis...GONDWANA RESEARCH Early Palaeozoic high-Mg basalt-andesite suite in the Duobaoshan porphyry Cu deposit, NE...fluorite-mica-feldspar veins: Evidences of a fossil geothermal system in the São Gabriel terrane and consequences |  | Ortega, L., Millward, D., Luque, F.J., Barrenechea, J.F., Beyssac, O., Huizenga, J.-M., Rodas, M., Clarke, S.M. (2010) The graphite deposit at Borrowdale (UK): A catastrophic mineralizing event associated with Ordovician magmatism. Geochimica et Cosmochimica Acta, 74 (8) 2429-2449 doi:10.1016/j.gca.2010.01.020 | Journal (article/letter/editorial) | | carbonaceous metapelites of the Skiddaw Group by andesite magmas of the Borrowdale Volcanic Group. The graphite...mixtures. Coevally with graphite deposition, the andesite and dioritic wall rocks adjacent to the veins...the carbon isotope evolution of the fluid–graphite system in granulites. 2430 L. Ortega et al. / Geochimica...Borrowdale graphite deposit (Cumbria, UK) is hosted by andesite lavas and sills belonging to the Upper Ordovician...sulphur isotope data from sulphides within the andesite rocks of the BVG also support this contention |  | | Report (issue) | | test remaining near-surface parts of the main vein system. Blackhawk Mines Corporation, the designated operator...amount of ore in the deepest parts of the vein system formed in argillite of the Palmetto Formation of...probably derived from the caldera-forming magma system. The Oligocene rocks were extensively eroded before...latite and basalt (all included in the Milltown Andesite of Ransome, 1909). Rhyolite and rhyodacite intrude...presumably because faults of the ring-fracture system Epithermal Gold Deposits-Part I H3 EXPLANATION |  | | Journal (article/letter/editorial) | | Formation and Ore Deposition in the Purisima-Colon Vein System, Pachuca Real del Monte District, Hidalgo, Mexico*...of the north-south–trending Purisima-Colon vein system of the Pachuca Real del Monte district where field...deposits are located in a high-angle normal fault system where vertical offset varies systematically from...center to nil at the north and south ends. The fault system is blind and its top describes a concave downward...to a bottom determined by silver grade. The vein system is vertically zoned, from the top down, with respect |  | | Report (issue) | | DEPARTMENT OF THE INTERIOR GEOLOGICAL SURVEY The Geothermal Research Program of the U.S. Geological Survey.................................1 Birth of the Geothermal Research Program.........................1 Organization.............................................15 Geothermal Development............................................................. 23 Projects of the Geothermal Research Program for 1980............28 Illustrations... Illustrations Figure 1. Page Graph of funding of the Geothermal Research Program since 1972................. |  | | Journal (article/letter/editorial) | | central Veta Madre, the La Luz system to the northwest, and the Sierra system to the east. Mineralization...gold-rich portions of the eastern Sierra system; this part of the system is interpreted as the least eroded...deposits are thought to be the analog of modern geothermal systems distal to magmatic centers, thereby relying...circulating groundwater; the heat source for this system was a thermal remnant of middle Oligocene volcanism...distribution. With this information, he formulated a geothermal model depicting a “typical” volcanic-hosted, |  | | Book | | this work may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic...to the present time, and many subaerial active geothermal systems occur. Some of them are associated with...subaerial geothermal areas in the Japanese Islands have been explored considerably and geothermal energy...developed. It was recognized that some active geothermal systems are accompanied by present-day basemetal...above-fossil and active subaerial and submarine hydrothermal systems are compared with fossil hydrothermal |  | | Book (volume) | | Gold Deposits and Geothermal Fields in Kyushu 3. Kuroko Deposits and Geothermal Fields in Northern Honshu...Quaternary of Japan, Volume 4: Volcanoes and Geothermal Fields of Japan, Volume 5: Metamorphic Belts...Masaaki Shimizu Gold Mineralization in Volcano-Geothermal Areas of Kyushu (C33). 143 Eiji IZAWA, Sachihiro...volcanic rocks of Hokkaido are grouped into a basalt-andesite-dacite-rhyolite suite, of which andesites and...stage-1 are a little dissected and consist of andesite lava. During stage-2, major explosive activity |  | | Journal (article/letter/editorial) | | Z489-2%x2 Printed in U.S.A. Germanium in Icelandic geothermal systems STEF~ ARN~RSSON Science Institute, University...form August 29, 1984) A~~~~~~urn ~~~nt~~o~s in geothermal waters in Iceland lie mostly in the range 2-30...The germanium content GERMANIUMIS enriched in geothermal waters and uf all minerals increases from basic...significant variation is in rivers and sea-water. Geothermal waters in Japan observed in the total germanium...Comparable concenrocks. trations have been observed in geothermal waters in In hydrothermal deposits germanium |  | | Journal (article/letter/editorial) | | very fine, and pyrite is disseminated. Quartz andesite in the western hill of Eoupo underwent propylitic...2 1.5 0.9 1.1 1.2 2 2.1 7.4 Al, alunite; An, andesite; AT, altered tuff; n.d, not detected; Pyr, pyrophyllite;...formed in a steam-heated environment of a fossil geothermal system. Clay minerals associated with alunite...N. (1979) Oxygen isotopic fractionation in the system quartz-albite-anorthitewater. Geochim. Cosmochim...York, 509–567. Reyes, A. G. (1990) Petrology geothermal systems and the application of alteration mineralogy |  | | Report (volume) | | contains several areas of dense phenocryst-poor andesite breccia (unit Tab, fig. 4). Morris and Kopf (1970a)...fragments of fine-grained, dark-reddish-brown andesite; monzonite porphyry; quartzite; and carbonate...sparse matrix of hematite-stained, pulverized andesite. Where seen by the author, this unit consists...appear to have formed by brecciation of a massive andesite and may be flow breccia or agglomerate, or they...have been brecciated subsequent to cooling. The andesite breccia was interpreted by Morris and Kopf (1970a) |  | | Report (issue) | | volumes of silicic ash-flow tuffs and basaltic andesite lavas. The later phase of extension (primarily...constant as denudation occurs (i.e. constant geothermal gradient); (3) uplift equals erosion (Parrish...denudation rates, assuming reasonable estimates of geothermal gradient during denudation can be established...lens, a drawing tube, and a digitizing tablet. The system allows the track lengths to be measured to approximately...order-ofmagnitude estimates. Furthermore, since the geothermal gradient is unlikely to have remained constant |  | | Report (issue) | | U.S. Geological Survey's Mineral Resource Data System (MRDS) as of September, 1985. Two 1:250,000 scale...monzogranite as well as subvolcanic intrusions of andesite to rhyoj.ite. Permissive Structure; Commonly areas...and self-sealing of the silica cap of the geothermal system. This brecciated, silicified zone may be of...Sb, Hg, Tl, and Ag; Ag increases with depth of system and As, Sb, Tl, and Hg decrease with depth. For...Associated Volcanic/Intrusive Rocks: andesite. Rhyolite, andesite, basaltic Alteration: Silicification |  | | Book | | this work may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic...purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work... Foreword The Earth is a complex and dynamic system that over 4.5 billion years has evolved to form...mineral resources that have developed in this dynamic system, and where appropriate their links with the development...hydrosphere and biosphere (Chapter 3), the major mineral system types including intrusion-related (Chapter 4), |
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