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Reefton Goldfield - Blackwater, Globe-Progress |
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South Island, New Zealand |
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Au
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Super Porphyry Cu and Au
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IOCG Deposits - 70 papers
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All papers now Open Access.
Available as Full Text for direct download or on request. |
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The Reefton goldfield incorporates a group of mesothermal orogenic gold-quartz lode deposits which lie within metasediments of the Buller Terrane in the north-western part of the South Island of New Zealand. Significant mines include Blackwater and Globe-Progress.
The Buller Terrane comprises is an up to 100 km wide belt of turbidite sediments that are largely found on the west coast of the South Island of New Zealand, to the west of the major Alpine transcurrent fault that runs the length of the country. The Reefton goldfield covers an area of some 34 x 10 km of Cambro-Ordovician metasediments known as the Greenland Group, made up of a monotonous succession of tightly folded alternating sandstones (feldspathic litharenites) and mudstones that have been metamorphosed to greenschist facies prior to the introduction of hydrothermal veining and associated alteration. The Greenland Group sediments in the goldfield are bounded to the north and east by plutons of Devono-Carboniferous and Cretaceous granitoids, and have been intruded by a series of mafic dykes (both pre- and post-mineralisation). In-faulted blocks of early Devonian, Triassic, Jurassic and Cretaceous sediments are also present.
The ore lodes are lensoid 0.6 to 3.2 m thick quartz shoots in north to NNE striking shear zones that dip steeply. The shoots are generally of limited lateral extent, usually no more than 150 m (although at Blackwater the main lode is 1070 m long), but may persist down plunge for considerable depths (Blackwater continues for 1200 m). The veins are characterised by ribbon crack-seal textures defined by phyllosilicate laminae. Gangue includes carbonate, sericite and chlorite also. Gold occurs as free grains and in association with arsenopyrite and pyrite which are ubiquitous minor constituents of the lodes. Stibnite is also recorded, as well as minor chalcopyrite, galena, sphalerite and sulphosalts, bournonite, zinkenite and tetrahedrite/tennantite. Disseminated gold-arsenopyrite-pyrite(-stibnite) may occur between and adjacent to the lodes as disseminations in poorly veined altered sandstones or mudstones and in clay rich fault breccias.
Historic production prior to 1951 was: 91 tonnes of gold.
For more detail consult the reference(s) listed below.
The most recent source geological information used to prepare this decription was dated: 2003.
This description is a summary from published sources, the chief of which are listed below.
© Copyright Porter GeoConsultancy Pty Ltd. Unauthorised copying, reproduction, storage or dissemination prohibited.
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Allibone, A., Blakemore, H., Gane, J., Moore, J., MacKenzie, D. and Craw, D., 2018 - Contrasting Structural Styles of Orogenic Gold Deposits, Reefton Goldfield, New Zealand: in Econ. Geol. v.113, pp. 1479-1497.
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Bierlein F P, Christie A B, Smith P K, 2004 - A comparison of orogenic gold mineralisation in central Victoria (AUS), western South Island (NZ) and Nova Scotia (CAN): implications for variations in the endowment of Palaeozoic metamorphic terrains: in Ore Geology Reviews v25 pp 125-168
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Christie A B, Brathwaite R L 2003 - Hydrothermal alteration in metasedimentary rock-hosted orogenic Gold deposits, Reefton Goldfield, South Island, New Zealand: in Mineralium Deposita v38 pp 87-107
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Porter GeoConsultancy Pty Ltd (PorterGeo) provides access to this database at no charge. It is largely based on scientific papers and reports in the public domain, and was current when the sources consulted were published. While PorterGeo endeavour to ensure the information was accurate at the time of compilation and subsequent updating, PorterGeo, its employees and servants: i). do not warrant, or make any representation regarding the use, or results of the use of the information contained herein as to its correctness, accuracy, currency, or otherwise; and ii). expressly disclaim all liability or responsibility to any person using the information or conclusions contained herein.
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