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Borly |
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Kazakhstan |
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Cu Mo 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 Borly porphyry copper deposit is located in the Lake Balkhash region of Kazakhstan, 60 km north of Balkhash City and 45 km to the northwest of the major Kounrad mine. It lies within the 'Balkhash-Ili' zone of the Upper Palaeozoic Kazakh-Mongol magmatic arc (#Location: 47° 31' 22"N, 73° 57' 16"E).
Borly is centred on the Carboniferous Borlinksy intrusive body which is an apophysis of the larger Kyzylzhalsky pluton. The intruded sequence includes a suite of rhyolitic to dacitic tuffs, litho-crystalline tuffs, lavas and subvolcanic rocks of the Lower Carboniferous Karkaralinskaya Formation, overlain by the Middle to Upper Carboniferous Keregetass Formation, a sequence of dacitic and sometimes trachy-dacitic or andesitic to dacitic ignimbrites, vitric-tuffs, tuffaceous lavas, lavas and sub-volcanic rocks.
The Borlinksy intrusive/apophysis contains three petrofacies, the first being quartz diorite. The second and dominant facies is a biotite-amphibole granodiorite, while the third is a light-coloured granite-porphyry. These petrofacies are cut by a granodiorite pluton with a complex dendritic texture. The intrusion of the latter was accompanied by intense cryptoexplosive brecciation, hydrothermal alteration, and formation of quartz-sulphide stockworks. The youngest magmatic assemblage comprises alkaline granite porphyry dykes and subvolcanic rocks of the Early Permian Zhaksitagalinsky complex (Abdulin et al., 1998).
Two separate, elongated ore zones have been delineated, both striking north to northwesterly and dipping steeply to the northeast. The central orebody is 800 m long, 15 to 340 m wide and has been traced to a depth of between 200 and 460 m, while the eastern zone is 260 x 50 to 150 m at surface and persists to a depth of 120 m. The principal alteration style accompanying mineralisation is quartz-sericite with associated chlorite and carbonates. The sulphide assemblage comprises pyrite, chalcopyrite and molybdenite with minor sphalerite, tetrahedrite, tennantite, galena, magnetite, bornite, chalcocite and pyrrhotite.
The deposit comprises ~175 Mt @ 0.34% Cu, 0.011% Mo, 0.03 g/t Au, 3.4 g/t Ag.
Note: these figures are based on a contained copper tonnage and grade consistent with 175 Mt of ore (Chen et al., 2010), although earlier sources Seltmann et al. (2004) and Singer et al. (2008), both quote figures that require of ~94 Mt of ore. The grades of Cu and Mo are consistent in all three sources, while the Au grade, which Seltmann et al. (2004) quote from MMAJ, 1997; Mineral Resources of Kazakhstan, Copper deposits of Kazakhstan, Almaty, 1998 is independently verified. The Ag grade is from Singer et al. (2008).
The most recent source geological information used to prepare this decription was dated: 2010.
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.
Borly
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Chen X H, Qu W J, Han S Q, Seitmuratova E, Yang N, Chen Z L, Zeng F G, Du A D and Wang Z H, 2010 - Re-Os geochronology of Cu and W-Mo deposits in the Balkhash metallogenic belt, Kazakhstan and its geological significance: in Geoscience Frontiers v.1 pp. 115-124
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Gao, J., Klemd, R., Zhu, M., Wang, X., Li, J., Wan, B., Xiao, W., Zeng, Q., Shen, PO., Sun J., Qin, K. and Campos, E., 2017 - Large-scale porphyry-type mineralization in the Central Asian metallogenic domain: A review: in J. of Asian Earth Sciences Available on-line from October 18, 2017, 30p.
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Li, G.-M., Cao, M.-J., Qin, K.-Z., Hollings, P., Evans N.J. and Seitmuratova, E.Y., 2016 - Petrogenesis of ore-forming and pre/post-ore granitoids from the Kounrad, Borly and Sayak porphyry/skarn Cu deposits, Central Kazakhstan: in Gondwana Research v.37, pp. 408-425.
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Shen, P., Pan, H.D. and Seitmuratova, E., 2017 - Petrogenesis of the mineralized granitoids from the Kounrad and Borly porphyry Cu deposits and the East Kounrad porphyry Mo deposit in Kazakhstan: Implication for tectonic evolution and mineralization of western part of Central Asian Orogenic Belt: in Lithos v.286-287 pp. 53-74.
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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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