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Shalkiya |
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Kazakhstan |
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Zn Pb Ag
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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 Shalkiya carbonate hosted lead-zinc deposit is located ~108 km NW of Kentau, and 780 km west of Almaty in southern Kazakhstan (#Location: 44° 0' 42"N, 67° 24' 39"E).
The deposit lies within the Neoproterozoic to Palaeozoic Karatau intracratonic rift basin, filled by sedimentary rocks, and intercalated lesser alkaline bimodal volcanic rocks.
The host rocks to ore are a 700 m thick sequence of Upper Devonian (Famennian) argillic carbonaceous dolomite, chert, cherty dolomite, dolomitic breccia and dolomitic limestone. These overlie a >800 m thick suite of Upper Devonian (Frasnian) variegated clastic sediments.
The basement to all of these rocks, commenced with a thick succession (6 to 7 km) of Meso- to Neoproterozoic clastic shale, carbonate and flysch sequences that were folded and intruded by granites. The unconformably overlying late Neoproterozoic commenced with a sub-aerial basalt-rhyolite and dacite-rhyolite red-rock volcanic series, followed by variegated continental and marine tuffs and clastic rocks with jasper and basalt, then sandstones and conglomerates with bands of dolomite. These are overlain by a few hundred metres of Cambrian and Ordovician siliceous-carbonate rocks, passing up into a thick succession (2 to 2.5 km) of flyschoid clastic rocks with andesite-basalt. During the late Ordovician and Silurian, these rocks were folded, with the intrusion of granitoids, to the Middle Devonian, when a stable platform had developed which was subsequently rifted to form the basin in which the mineralised carbonate sequence was deposited (Gorzhevskiy et al., 1989).
The hosts are overlain by ~2000 m of Upper Devonian to Lower Carboniferous (upper Famennian to Tournaisian) dolomite, limestone, mudstone, variegated sandstone and siltstone. The host sequence is cut by a 220 to 210 Ma lamprophyre dyke.
Gorzhevskiy et al. (1989) interpret the deposit to be the result of prolonged reaction between ore-bearing brines with Famennian to early Tournaisian carbonate rocks. They suggest that metals were leached from the basement shelf-rift sequences, transported as chlorides and organometallic compounds, and deposited at a carbonate geochemical barrier.
The principal sulphide minerals include sphalerite and galena, with marcasite, pyrite, arsenopyrite, boulangerite, bournonite and tetrahedrite in a gangue that includes anhydrite, dolomite, epidote, chlorite, fluorite and K-feldspar. The upper, oxidised zone contains goethite, hematite, cerussite, anglesite and other oxides.
Unattributed geological and mineralogical data is taken from the USGS Mineral Resources On-Line Spatial Database.
JORC compliant mineral resources and ore reserves in 2012 (Shalkiya Zinc website, 2013, after AMC Consultants [UK] Ltd), at a 3% ZnEq. cutoff, were:
Measured resource - 59 Mt @ 3.2% Zn, 1.0% Pb;
Indicated resource - 206 Mt @ 3.1% Zn, 0.7% Pb;
TOTAL measured + indicated resource - 265 Mt @ 3.1% Zn, 0.8% Pb, 2 g/t Ag;
Inferred resource - 9 Mt @ 4.6% Zn, 2.2% Pb;
Proved reserves - 44 Mt @ 3.3% Zn, 1.1% Pb;
Inferred reserves - 158 Mt @ 3.2% Zn, 0.8% Pb;
TOTAL proved + probable reserves - 202 Mt @ 3.2% Zn, 0.8% Pb
The most recent source geological information used to prepare this decription was dated: 1990.
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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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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