<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html> <head> <title>UTas ePrints - Geochemical Modeling of the Zoned Footwall Alteration Pipe, Hellyer Volcanic-Hosted Massive Sulfide Deposit, Western Tasmania, Australia</title> <script type="text/javascript" src="http://eprints.utas.edu.au/javascript/auto.js"><!-- padder --></script> <style type="text/css" media="screen">@import url(http://eprints.utas.edu.au/style/auto.css);</style> <style type="text/css" media="print">@import url(http://eprints.utas.edu.au/style/print.css);</style> <link rel="icon" href="/images/eprints/favicon.ico" type="image/x-icon" /> <link rel="shortcut icon" href="/images/eprints/favicon.ico" type="image/x-icon" /> <link rel="Top" href="http://eprints.utas.edu.au/" /> <link rel="Search" href="http://eprints.utas.edu.au/cgi/search" /> <meta content="Schardt, C." name="eprints.creators_name" /> <meta content="Cooke, D.R." name="eprints.creators_name" /> <meta content="Gemmell, J.B." name="eprints.creators_name" /> <meta content="Large, R.R." name="eprints.creators_name" /> <meta name="eprints.creators_id" /> <meta content="David.Cooke@utas.edu.au" name="eprints.creators_id" /> <meta content="Bruce.Gemmell@utas.edu.au" name="eprints.creators_id" /> <meta content="Ross.Large@utas.edu.au" name="eprints.creators_id" /> <meta content="article" name="eprints.type" /> <meta content="2007-09-27" name="eprints.datestamp" /> <meta content="2008-01-23T03:44:12Z" name="eprints.lastmod" /> <meta content="show" name="eprints.metadata_visibility" /> <meta content="Geochemical Modeling of the Zoned Footwall Alteration Pipe, Hellyer Volcanic-Hosted Massive Sulfide Deposit, Western Tasmania, Australia" name="eprints.title" /> <meta content="pub" name="eprints.ispublished" /> <meta content="260300" name="eprints.subjects" /> <meta content="restricted" name="eprints.full_text_status" /> <meta content="massive sulfide alteration halo numerical modelling" name="eprints.keywords" /> <meta content="The mineralogy of hydrothermal alteration assemblages (siliceous core, chlorite zone, sericite zone) in the footwall pipe of the Hellyer volcanic-hosted massive sulfide (VHMS) deposit is controlled mainly by the temperature, pH, and redox state of the hydrothermal fluids. Based on the results of our numerical modeling, the zoned alteration system could have formed by a combination of water-rock interaction and cooling, with a siliceous core predicted to form at the center of the conduit, passing outward to a chlorite-dominated zone, a sericite-rich zone, and finally grading out to unaltered andesite. These mineralogical changes relate to a gradual evolution of fluid chemistry, water/rock ratio, pH, and temperature from the core to the margin of the system. Initial temperatures were probably close to 350 degrees C, and the hydrothermal fluids were reduced (H2S dominated). At low temperatures (<200 degrees C) a peripheral alteration zone, consisting mostly of K feldspar, chlorite, sericite, and hematite, is predicted to form. This low-temperature zone has not been recognized at Hellyer, but elevated K2O contents and local K feldspar development have been noted at other VHMS deposits, suggesting that this zone might form at low temperatures and low water/rock ratios in the footwall of VHMS deposits. If the existence of barren outer K feldspar alteration zones is confirmed, the findings could have important implications for exploration, specifically with regards to distinguishing ore-related alteration zones from barren alteration systems." name="eprints.abstract" /> <meta content="2001-08" name="eprints.date" /> <meta content="published" name="eprints.date_type" /> <meta content="Economic Geology" name="eprints.publication" /> <meta content="96" name="eprints.volume" /> <meta content="5" name="eprints.number" /> <meta content="1037-1054" name="eprints.pagerange" /> <meta content="10.2113/96.5.1037" name="eprints.id_number" /> <meta content="UNSPECIFIED" name="eprints.thesis_type" /> <meta content="TRUE" name="eprints.refereed" /> <meta content="0361-0128" name="eprints.issn" /> <meta content="http://dx.doi.org/10.2113/96.5.1037" name="eprints.official_url" /> <meta content="Alt, J.C., France-Lanord, C., Floyd, P.A., Castillo, P., and Galy, A., 1992, Lowtemperature hydrothermal alteration of Jurassic ocean crust, Site 801: Proceedings of the Ocean Drilling Program, Scientific Results, v. 129, p. 415-427. Akaku, K., Reed, M., Yagi, M., Kai, K., and Yasuda, Y., 1991, Chemical and physical processes occurring in the Fushime geothermal system, Kyushu, Japan: Geochemical Journal, v. 25, p. 315-333. Berman, R.G., 1988, Internally consistent thermodynamics for minerals in the system Na2O-K2O-CaO-MgO-FeO-Fe2O3-Al2O3-SiO2-TiO2-H2O-CO2: Journal of Petrology, v. 29, p. 445-522. Bischoff, J.L., and Dickson, F.W., 1975, Seawater-basalt interaction at 200°C and 500 bars: Implications for the origin of sea-floor heavy-metal deposits and regulation of seawater chemistry: Earth and Planetary Science Letters, v. 25, p. 385-397. Bowers, T., and Taylor, H.P., Jr., 1987, Some calculations pertaining to an integrated chemical and stable-isotope model of the origin of mid-ocean ridge hydrothermal systems, in Helgeson, H.C., ed., Chemical transport in metasomatic processes: Dortrecht, Reidel, p. 633-655. Bradley, A., 1997, Chlorite carbonate alteration at Hellyer: Unpublished M.Sc. thesis, Hobart, Tasmania, University of Tasmania, 101 p. Browne, P.R.L., and Ellis, A.J., 1970, The Ohaaki-Broadlands hydrothermal area, New Zealand: Mineralogy and related geochemistry: American Journal of Science, v. 269, p. 97-131. Corbett K.D., 1992, Stratigraphic-volcanic setting of massive sulfide deposits in the Cambrian Mount Read Volcanics, Tasmania: ECONOMIC GEOLOGY, v. 87, p. 564-586. Date, J., Watanabe, Y., and Saeki, Y., 1983, Zonal alteration around the Fukazawa Kuroko deposits, Akita Prefecture, northern Japan: ECONOMIC GEOLOGY MONOGRAPH 5, p. 365-386. Deer, W.A., Howie, R.A., and Zussman, J., 1989, An introduction to the rock forming minerals: New York, Longman, 528 p. Drummond, S.E., and Ohmoto, H., 1985, Chemical evolution and mineral deposition in boiling hydrothermal systems: ECONOMIC GEOLOGY, v. 80, p. 126-147. Eastoe, C.J., Solomon, M., and Walshe, J.L., 1987, District-scale alteration associated with massive sulfide deposits in the Mount Read Volcanics, western Tasmania: ECONOMIC GEOLOGY, v. 82, p. 1239-1258. Franklin, M.J., Lydon, J.W., and Sangster, D.F., 1981, Volcanic-associated massive sulfide deposits: ECONOMIC GEOLOGY 75TH ANNIVERSARY VOLUME, p. 485-627. Gemmell, J.B., and Fulton, R., 2001, Geological and geochemical characteristics of the footwall and hanging-wall alteration, Hellyer VHMS deposit, Economic Geology, v. 96, p. 1003-1035. Gemmell, J.B., and Large, R.R., 1992, Stringer system and alteration zones underlying the Hellyer volcanic-hosted massive sulfide deposit, Tasmania, Australia: ECONOMIC GEOLOGY, v. 87, p. 620-649. Green, G.R., 1990, Rock alteration, mineral and oxygen isotope zonation in the Rosebery district, Tasmania [abs.]: Geological Society of Australia Abstracts, v. 25, p. 15-16. Green, G.R., and Taheri, J., 1992, Stable isotopes and geochemistry as exploration indicators: Bulletin of the Geological Survey of Tasmania, v. 70, p. 84-91. Green, G.R., Solomon, M., and Walshe, J.L., 1981, The formation of the volcanic- hosted massive sulfide ore deposit at Rosebery, Tasmania: ECONOMIC GEOLOGY, v. 76, p. 304-338. Hannington, M.D., and Scott S.D., 1988, Mineralogy and geochemistry of a hydrothermal silica-sulfide-sulfate spire in the caldera of axial seamount, Juan de Fuca Ridge: Canadian Mineralogist, v. 26, p. 603-625. Haynes, D.W., and Bloom, M.S., 1987, Stratiform copper deposits hosted by low-energy sediments: III. Aspects of metal transport: ECONOMIC GEOLOGY, v. 82, p. 635-648. Heinrich, C.A., 1990, The chemistry of hydrothermal tin(-tungsten) ore deposition: ECONOMIC GEOLOGY, v. 85, p. 457-481.1996, Chemical mass transfer modeling of ore-forming hydrothermal systems: Current practice and problems: Ore Geology Review, v. 10, p. 319-338. Heinrich, C.A., and Ryan, C.G., 1992, Mineral paragenesis and regional zonation of granite-related Sn-As-Cu-Pb-Zn deposits: A chemical model for the Mole granite district (Australia) based on PIXE fluid inclusion analysis, in Kharaka, Y.K., and Maest, A.S., eds., Fluid-rock interaction 7: Rotterdam, Balkema, p. 529-550. Herzig, P.M., and Hannington, M.D., 1995, Polymetallic massive sulfides at the modern seafloor: A review: Ore Geology Reviews, v. 10, p. 95-115. Huston, D.L., 1993, The effect of alteration and metamorphism on wall rock to the Balcooma and Dry River South volcanic-hosted massive sulfide deposits, Queensland, Australia: Journal of Geochemical Exploration, v. 48, p. 277-307. Jack, D.J., 1989, Hellyer host rock alteration: Unpublished M.Sc. thesis, Hobart, Tasmania, University of Tasmania, 182 p. Johnson, J.W., Oelkers, E.H., and Helgeson, H.C., 1992, SUPCRT 92: A software package for calculating the standard molal thermodynamic properties of minerals, gases, aqueous species and reactions from 1 to 5000 bars and 0ÃÂð to 1000ÃÂðC: Computers and Geosciences, v. 18, p. 899âÃÂÃÂ947. Khin Zaw, and Gemmell, J.B., 1996, Microthermometry and the compositional variation of fluid inclusions in the footwall stringer zone, Hellyer VHMS deposit, western Tasmania: Burnie, Tasmania, Aberfoyle Exploration Pty. Ltd., Unpublished report, 48 p. Khin Zaw, Gemmell, J.B., Large, R.R., Mernagh, T.P., and Ryan, C.G., 1996, Evolution and source of ore fluids in the stringer system, Hellyer VHMS deposit, Tasmania, Australia: Evidence from fluid inclusion microthermometry and geochemistry: Ore Geology Review, v. 10, p. 251âÃÂÃÂ278. Large, R.R., 1977, Chemical evolution and zonation of massive sulfide deposits in volcanic terrains: ECONOMIC GEOLOGY, v. 72, p. 549âÃÂÃÂ572. âÃÂÃÂâÃÂÃÂ1992, Australian volcanic-hosted massive sulfide deposits: Features, styles, and models: ECONOMIC GEOLOGY, v. 87, p. 471âÃÂÃÂ510. Larson, P.B., 1984, Geochemistry of the alteration pipe at the Bruce Cu-Zn volcanogenic massive sulfide deposit, Arizona: ECONOMIC GEOLOGY, v. 79, p.1880âÃÂÃÂ1896. Lydon, J.W. 1988, Volcanogenic massive sulfide deposits Part 2: Genetic models: Geoscience Canada Reprint Series 3, p. 155âÃÂÃÂ181. Lydon, J.W., and Galley, A., 1986, Chemical and mineralogical zonation of the Mathiati alteration pipe, Cyprus, and its genetic significance, in Gallagher, M.J., Ixer, R.A., Neary, C.R., and Prichard, H.M., eds., Metallogeny of basic and ultrabasic rocks: London, Institution of Mining and Metallurgy, p. 49âÃÂÃÂ68. Massoth, G.J., Butterfield, D.A., Lupton, J.E., McDuff, R.E., Lilley, M.D., and Jonasson, I.R., 1989, Submarine venting of phase-separated hydrothermal fluids at Axial Volcano, Juan de Fuca Ridge: Nature, v. 340, p. 702âÃÂÃÂ705. McArthur, G.J., 1986, The Hellyer massive sulphide deposit: Mount Read Volcanics and Associated Ore Deposits Symposium, Geological Society of Australia, Tasmanian Division, Burnie, Tasmania, November 20âÃÂÃÂ21, 1986, Proceedings, 96 p. âÃÂÃÂâÃÂÃÂ1996, Textural evolution of the Hellyer massive sulfide deposit: Unpublished Ph.D. thesis, Hobart, Tasmania, University of Tasmania, 272 p. McArthur, G. J., and Dronseika, E.V., 1990, Que River and Hellyer zinc-leadsilver deposits, in Hughes, F.E., ed., Geology of the mineral deposits of Australia and Papua New Guinea: Melbourne, Australasian Institute of Mining and Metallurgy, v. 2, p. 1257âÃÂÃÂ1266. McGoldrick, P.J., and Large, R.R., 1992, Geologic and geochemical controls on gold-rich stringer mineralization in the Que River deposit, Tasmania: ECONOMIC GEOLOGY, v. 87, p. 667âÃÂÃÂ685. McLeod, R.L., and Stanton, R.L., 1984, Phyllosilicates and associated minerals in some Paleozoic stratiform sulfide deposits of southern Australia: ECONOMIC GEOLOGY, v. 79, p. 1âÃÂÃÂ22. McPhie, J., and Allen, R.L., 1992, Facies architecture of mineralized submarine volcanic sequences: Cambrian Mount Read Volcanics, western Tasmania: ECONOMIC GEOLOGY, v. 87, p. 587âÃÂÃÂ596. Offler, R., and Whitford, D.J., 1992, Wall-rock alteration and metamorphism of a volcanic-hosted massive sulfide deposit at Que River, Tasmania: Petrology and mineralogy: ECONOMIC GEOLOGY, v. 87, p. 686-705. Ohmoto, H., and Skinner, B.J., 1983, The kuroko and related volcanogenic massive sulfide deposits: Introduction and summary of new findings: ECONOMIC GEOLOGY MONOGRAPH 5, p. 1âÃÂÃÂ8. Petersen, S., Herzig, P.M., Foertsch, P., and Hannington, M.D., 1996, Fluid temperature history of the TAG hydrothermal mound, Mid-Atlantic Ridge, 26 degrees N.: EOS, v. 77, no. 46, p. 763. Reed, M.H., 1982, Calculation of multicomponent chemical equilibria and reaction processes in systems involving minerals, gases and an aqueous phase: Geochimica et Cosmochimica Acta, v. 43, p. 513âÃÂÃÂ528. âÃÂÃÂâÃÂÃÂ1983, Seawater-basalt interaction and the origin of greenstone and related ore deposits: ECONOMIC GEOLOGY, v. 78, p. 466âÃÂÃÂ485. âÃÂÃÂâÃÂÃÂ1998, Calculation of simultaneous chemical equilibrium in aqueousmineral- gas systems and its application to modeling hydrothermal processes: Reviews in Economic Geology, v. 10, p. 109âÃÂÃÂ124. Reed, M.H., and Spycher, N., 1984, Calculation of pH and mineral equilibria in hydrothermal waters with application to geothermometry and studies of boiling and dilution: Geochimica et Cosmochimica Acta, v. 48, p. 1479âÃÂÃÂ1492. Rimstidt, J.D., 1997, Gangue mineral transport and deposition, in Barnes, H.L., ed., Geochemistry of hydrothermal ore deposits: Toronto, Wiley and Sons, p. 487âÃÂÃÂ516. Riverin, G., and Hodgson, C.J., 1980, Wall-rock alteration at the Millenbach Cu-Zn mine, Noranda, Quebec: ECONOMIC GEOLOGY, v. 75, p. 424âÃÂÃÂ444. Saccocia, P.J., and Seyfried, W.E., Jr., 1993, A resolution of discrepant thermodynamic properties for chamosite retrieved from experimental and empirical techniques: American Mineralogist, v. 78, p. 607âÃÂÃÂ611. Sangster, D.F., 1972, Precambrian volcanogenic massive sulfide deposits in Canada. A review: Canada Geological Survey Paper 72-77, 44 p. Seward, T.M., 1989, The hydrothermal chemistry of gold and its implications for ore forming: Boiling and conductive cooling as examples: ECONOMIC GEOLOGY MONOGRAPH 6, p. 398âÃÂÃÂ404. Seyfried, W.E., Jr., and Bishop, J.L., 1977, Hydrothermal transport of heavy metals by seawater: The role of seawater/basalt ratio: Earth and Planetary Science Letters, v. 34, p. 71âÃÂÃÂ77. âÃÂÃÂâÃÂÃÂ1981, Experimental basalt-seawater interaction at 350ÃÂðC, 500 bars, chemical exchange, secondary mineral formation and implications for the transport of heavy metals: Geochimica et Cosmochimica Acta, v. 45, p. 135âÃÂÃÂ149. Seyfried, W.E., Jr., and Mottl, M.J., 1982, Hydrothermal alteration of basalt by seawater under seawater-dominated conditions: Geochimica et Cosmochimica Acta, v. 46, p. 985âÃÂÃÂ1002. Sharpe, R., 1991, Geology and geochemistry of the barite and siliceous caps, Hellyer mine, Tasmania: Unpublished B.Sc. (Honours) thesis, Hobart, Tasmania, University of Tasmania, 114 p. Shirozu, H., 1974, Clay minerals in altered wall rocks of the Kuroko-type deposits: Society of Mining Geologists of Japan Special Issue 6, p. 303âÃÂÃÂ311. Solomon, M., and Groves, D.I., 1994, The geology and origin of AustraliaâÃÂÃÂs mineral deposits: Oxford, Clarendon Press, 951 p. Solomon, M., and Khin Zaw, 1997, Formation on the sea floor of the Hellyer volcanogenic massive sulfide deposit: ECONOMIC GEOLOGY, v. 92, p. 686âÃÂà695. Spycher, N.F., and Reed, M.H., 1990a, UserâÃÂÃÂs guide for CHILLER: A program for computing water-rock reactions, boiling, mixing and other reaction processes in aqueous-mineral-gas systems: Pullman, OR, University of Oregon, User Guide, 64 p. âÃÂÃÂâÃÂÃÂ1990b, UserâÃÂÃÂs guide for SOLVEQ: A computer program for computing aqueous-mineral-gas equilibria: Pullman, OR, University of Oregon, User Guide, 37 p. âÃÂÃÂâÃÂÃÂ1990c, UserâÃÂÃÂs Guide for the SOLTHERM database: Pullman, OR, University of Oregon, User Guide, 47 p. âÃÂÃÂâÃÂÃÂ1998, UserâÃÂÃÂs guide for CHILLER: A program for computing water-rock reactions, boiling, mixing and other reaction processes in aqueous-mineralgas systems and Minplot guide: Pullman, OR, University of Oregon, User Guide, 67 p. Steefel, C.I., and Lasaga, A.C., 1994, A coupled model for transport of multiple chemical species and kinetic precipitation/dissolution reactions with application to reactive flow in single-phase hydrothermal systems: American Journal of Science, v. 294, p. 529âÃÂÃÂ592. Sverjensky, D.A., 1987, The role of migrating oil field brines in the formation of sediment-hosted Cu-rich deposits: ECONOMIC GEOLOGY, v. 82, p. 1130âÃÂÃÂ1141. Udata, M., Minato, H., Isikawa, T., and Yoshizaki, Y., 1974, The alteration zones surrounding kuroko-type deposits in Nishi-Aizu district, Fukashima Prefecture, with emphasis on the analcime zone as an indicator in exploration for ore deposits: Society of Mining Geologists Japan Special Issue 6, p. 291âÃÂÃÂ303. Urabe, T., Scott, S.D., and Hattori, K., 1983, A comparison of footwall-rock alteration and geothermal systems beneath some Japanese and Canadian volcanogenic massive sulfide deposits: ECONOMIC GEOLOGY MONOGRAPH 5, p. 345âÃÂÃÂ364. Vance, R.K., and Condi, K.C., 1987, Geochemistry of footwall alteration associated with the early Proterozoic United Verde massive sulfide deposit, Jerome, Arizona: ECONOMIC GEOLOGY, v. 82, p. 571âÃÂÃÂ586. Walther, J.V., and Wood, B.J., 1984, Rate and mechanism in prograde metamorphism: Contributions to Mineralogy and Petrology, v. 88, p. 246âÃÂÃÂ259. Waters, J.C., and Wallace, D.B., 1992, Volcanology and sedimentology of the host succession to the Hellyer and Que River volcanic-hosted massive sulfide deposits, northwestern Tasmania: ECONOMIC GEOLOGY, v. 87, p. 650âÃÂÃÂ666. Zierenberg, R.A., Shanks, III, W.C., and Bischoff, J.L., 1984, Massive sulfide deposits at 21ÃÂðN, East Pacific Rise: Chemical composition, stable isotopes, and phase equilibria: Geological Society of America Bulletin, v. 95, p. 922âÃÂÃÂ929." name="eprints.referencetext" /> <meta content="Schardt, C. and Cooke, D.R. and Gemmell, J.B. and Large, R.R. (2001) Geochemical Modeling of the Zoned Footwall Alteration Pipe, Hellyer Volcanic-Hosted Massive Sulfide Deposit, Western Tasmania, Australia. Economic Geology, 96 (5). pp. 1037-1054. ISSN 0361-0128" name="eprints.citation" /> <meta content="http://eprints.utas.edu.au/2008/1/Schardt_Cooke_Gemmell_Large_ECON_GEOL_2001.pdf" name="eprints.document_url" /> <link rel="schema.DC" href="http://purl.org/DC/elements/1.0/" /> <meta content="Geochemical Modeling of the Zoned Footwall Alteration Pipe, Hellyer Volcanic-Hosted Massive Sulfide Deposit, Western Tasmania, Australia" name="DC.title" /> <meta content="Schardt, C." name="DC.creator" /> <meta content="Cooke, D.R." name="DC.creator" /> <meta content="Gemmell, J.B." name="DC.creator" /> <meta content="Large, R.R." name="DC.creator" /> <meta content="260300 Geochemistry" name="DC.subject" /> <meta content="The mineralogy of hydrothermal alteration assemblages (siliceous core, chlorite zone, sericite zone) in the footwall pipe of the Hellyer volcanic-hosted massive sulfide (VHMS) deposit is controlled mainly by the temperature, pH, and redox state of the hydrothermal fluids. Based on the results of our numerical modeling, the zoned alteration system could have formed by a combination of water-rock interaction and cooling, with a siliceous core predicted to form at the center of the conduit, passing outward to a chlorite-dominated zone, a sericite-rich zone, and finally grading out to unaltered andesite. These mineralogical changes relate to a gradual evolution of fluid chemistry, water/rock ratio, pH, and temperature from the core to the margin of the system. Initial temperatures were probably close to 350 degrees C, and the hydrothermal fluids were reduced (H2S dominated). At low temperatures (<200 degrees C) a peripheral alteration zone, consisting mostly of K feldspar, chlorite, sericite, and hematite, is predicted to form. This low-temperature zone has not been recognized at Hellyer, but elevated K2O contents and local K feldspar development have been noted at other VHMS deposits, suggesting that this zone might form at low temperatures and low water/rock ratios in the footwall of VHMS deposits. If the existence of barren outer K feldspar alteration zones is confirmed, the findings could have important implications for exploration, specifically with regards to distinguishing ore-related alteration zones from barren alteration systems." name="DC.description" /> <meta content="2001-08" name="DC.date" /> <meta content="Article" name="DC.type" /> <meta content="PeerReviewed" name="DC.type" /> <meta content="application/pdf" name="DC.format" /> <meta content="http://eprints.utas.edu.au/2008/1/Schardt_Cooke_Gemmell_Large_ECON_GEOL_2001.pdf" name="DC.identifier" /> <meta content="http://dx.doi.org/10.2113/96.5.1037" name="DC.relation" /> <meta content="Schardt, C. and Cooke, D.R. and Gemmell, J.B. and Large, R.R. (2001) Geochemical Modeling of the Zoned Footwall Alteration Pipe, Hellyer Volcanic-Hosted Massive Sulfide Deposit, Western Tasmania, Australia. Economic Geology, 96 (5). pp. 1037-1054. 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border: solid 1px #ccc; padding: 3px"><tr> <td align="left"><a href="http://eprints.utas.edu.au/cgi/users/home">Login</a> | <a href="http://eprints.utas.edu.au/cgi/register">Create Account</a></td> <td align="right" style="white-space: nowrap"> <form method="get" accept-charset="utf-8" action="http://eprints.utas.edu.au/cgi/search" style="display:inline"> <input class="ep_tm_searchbarbox" size="20" type="text" name="q" /> <input class="ep_tm_searchbarbutton" value="Search" type="submit" name="_action_search" /> <input type="hidden" name="_order" value="bytitle" /> <input type="hidden" name="basic_srchtype" value="ALL" /> <input type="hidden" name="_satisfyall" value="ALL" /> </form> </td> </tr></table></td></tr> <tr> <td class="toplinks"><!-- InstanceBeginEditable name="content" --> <div align="center"> <table width="720" class="ep_tm_main"><tr><td align="left"> <h1 class="ep_tm_pagetitle">Geochemical Modeling of the Zoned Footwall Alteration Pipe, Hellyer Volcanic-Hosted Massive Sulfide Deposit, Western Tasmania, Australia</h1> <p style="margin-bottom: 1em" class="not_ep_block"><span class="person_name">Schardt, C.</span> and <span class="person_name">Cooke, D.R.</span> and <span class="person_name">Gemmell, J.B.</span> and <span class="person_name">Large, R.R.</span> (2001) <xhtml:em>Geochemical Modeling of the Zoned Footwall Alteration Pipe, Hellyer Volcanic-Hosted Massive Sulfide Deposit, Western Tasmania, Australia.</xhtml:em> Economic Geology, 96 (5). pp. 1037-1054. ISSN 0361-0128</p><p style="margin-bottom: 1em" class="not_ep_block"></p><table style="margin-bottom: 1em" class="not_ep_block"><tr><td valign="top" style="text-align:center"><a href="http://eprints.utas.edu.au/2008/1/Schardt_Cooke_Gemmell_Large_ECON_GEOL_2001.pdf"><img alt="[img]" src="http://eprints.utas.edu.au/style/images/fileicons/application_pdf.png" border="0" class="ep_doc_icon" /></a></td><td valign="top"><a href="http://eprints.utas.edu.au/2008/1/Schardt_Cooke_Gemmell_Large_ECON_GEOL_2001.pdf"><span class="ep_document_citation">PDF</span></a> - Full text restricted - Requires a PDF viewer<br />269Kb</td><td><form method="get" accept-charset="utf-8" action="http://eprints.utas.edu.au/cgi/request_doc"><input value="2483" name="docid" accept-charset="utf-8" type="hidden" /><div class=""><input value="Request a copy" name="_action_null" class="ep_form_action_button" onclick="return EPJS_button_pushed( '_action_null' )" type="submit" /> </div></form></td></tr></table><p style="margin-bottom: 1em" class="not_ep_block">Official URL: <a href="http://dx.doi.org/10.2113/96.5.1037">http://dx.doi.org/10.2113/96.5.1037</a></p><div class="not_ep_block"><h2>Abstract</h2><p style="padding-bottom: 16px; text-align: left; margin: 1em auto 0em auto">The mineralogy of hydrothermal alteration assemblages (siliceous core, chlorite zone, sericite zone) in the footwall pipe of the Hellyer volcanic-hosted massive sulfide (VHMS) deposit is controlled mainly by the temperature, pH, and redox state of the hydrothermal fluids. Based on the results of our numerical modeling, the zoned alteration system could have formed by a combination of water-rock interaction and cooling, with a siliceous core predicted to form at the center of the conduit, passing outward to a chlorite-dominated zone, a sericite-rich zone, and finally grading out to unaltered andesite. These mineralogical changes relate to a gradual evolution of fluid chemistry, water/rock ratio, pH, and temperature from the core to the margin of the system. Initial temperatures were probably close to 350 degrees C, and the hydrothermal fluids were reduced (H2S dominated). At low temperatures (<200 degrees C) a peripheral alteration zone, consisting mostly of K feldspar, chlorite, sericite, and hematite, is predicted to form. This low-temperature zone has not been recognized at Hellyer, but elevated K2O contents and local K feldspar development have been noted at other VHMS deposits, suggesting that this zone might form at low temperatures and low water/rock ratios in the footwall of VHMS deposits. If the existence of barren outer K feldspar alteration zones is confirmed, the findings could have important implications for exploration, specifically with regards to distinguishing ore-related alteration zones from barren alteration systems.</p></div><table style="margin-bottom: 1em" border="0" cellpadding="3" class="not_ep_block"><tr><th valign="top" class="ep_row">Item Type:</th><td valign="top" class="ep_row">Article</td></tr><tr><th valign="top" class="ep_row">Keywords:</th><td valign="top" class="ep_row">massive sulfide alteration halo numerical modelling</td></tr><tr><th valign="top" class="ep_row">Subjects:</th><td valign="top" class="ep_row"><a href="http://eprints.utas.edu.au/view/subjects/260300.html">260000 Earth Sciences > 260300 Geochemistry</a></td></tr><tr><th valign="top" class="ep_row">Collections:</th><td valign="top" class="ep_row">UNSPECIFIED</td></tr><tr><th valign="top" class="ep_row">ID Code:</th><td valign="top" class="ep_row">2008</td></tr><tr><th valign="top" class="ep_row">Deposited By:</th><td valign="top" class="ep_row"><span class="ep_name_citation"><span class="person_name">Mrs Katrina Keep</span></span></td></tr><tr><th valign="top" class="ep_row">Deposited On:</th><td valign="top" class="ep_row">27 Sep 2007</td></tr><tr><th valign="top" class="ep_row">Last Modified:</th><td valign="top" class="ep_row">23 Jan 2008 14:44</td></tr><tr><th valign="top" class="ep_row">ePrint Statistics:</th><td valign="top" class="ep_row"><a target="ePrintStats" href="/es/index.php?action=show_detail_eprint;id=2008;">View statistics for this ePrint</a></td></tr></table><p align="right">Repository Staff Only: <a href="http://eprints.utas.edu.au/cgi/users/home?screen=EPrint::View&eprintid=2008">item control page</a></p> </td></tr></table> </div> <!-- InstanceEndEditable --></td> </tr> <tr> <td><!-- #BeginLibraryItem "/Library/footer_eprints.lbi" --> <table width="795" border="0" align="left" cellpadding="0" class="footer"> <tr valign="top"> <td colspan="2"><div align="center"><a href="http://www.utas.edu.au">UTAS home</a> | <a href="http://www.utas.edu.au/library/">Library home</a> | <a href="/">ePrints home</a> | <a href="/contact.html">contact</a> | <a href="/information.html">about</a> | <a href="/view/">browse</a> | <a href="/perl/search/simple">search</a> | <a href="/perl/register">register</a> | <a href="/perl/users/home">user area</a> | <a href="/help/">help</a></div><br /></td> </tr> <tr><td colspan="2"><p><img src="/images/eprints/footerline.gif" width="100%" height="4" /></p></td></tr> <tr valign="top"> <td width="68%" class="footer">Authorised by the University Librarian<br /> © University of Tasmania ABN 30 764 374 782<br /> <a href="http://www.utas.edu.au/cricos/">CRICOS Provider Code 00586B</a> | <a href="http://www.utas.edu.au/copyright/copyright_disclaimers.html">Copyright & Disclaimers</a> | <a href="http://www.utas.edu.au/accessibility/index.html">Accessibility</a> | <a href="http://eprints.utas.edu.au/feedback/">Site Feedback</a> </td> <td width="32%"><div align="right"> <p align="right" class="NoPrint"><a href="http://www.utas.edu.au/"><img src="http://www.utas.edu.au/shared/logos/unioftasstrip.gif" alt="University of Tasmania Home Page" width="260" height="16" border="0" align="right" /></a></p> <p align="right" class="NoPrint"><a href="http://www.utas.edu.au/"><br /> </a></p> </div></td> </tr> <tr valign="top"> <td><p> </p></td> <td><div align="right"><span class="NoPrint"><a href="http://www.eprints.org/software/"><img src="/images/eprintslogo.gif" alt="ePrints logo" width="77" height="29" border="0" align="bottom" /></a></span></div></td> </tr> </table> <!-- #EndLibraryItem --> <div align="center"></div></td> </tr> </table> </body> </html>