The latest Aptian/earliest Albian age of the Kekura gold deposit, Western Chukotka, Russia: implications for mineralizat
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LETTER
The latest Aptian/earliest Albian age of the Kekura gold deposit, Western Chukotka, Russia: implications for mineralization associated with post-collisional magmatism Ekaterina V. Nagornaya 1,2
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Ivan A. Baksheev 2
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David Selby 3,4
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Petr L. Tikhomirov 2,5
Received: 25 October 2019 / Accepted: 26 February 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract The Kekura gold deposit (76.2 t Au at 8.1 g/t) is situated in Western Chukotka, a region that hosts several Au, Ag, Cu, and Mo deposits and prospects. The Kekura deposit is related to the eponymous granite intrusion that is cut by porphyry dikes. The U-Pb zircon age of one of these dikes is 112 ± 1 Ma (2σ) that corresponds to the latest Aptian/earliest Albian. Both intrusion and dikes are hydrothermally altered and are cut by gold-quartz and molybdenite-quartz veins and stringers. Two molybdenite samples yield Re-Os model ages of 112.5 ± 0.6 and 112.3 ± 0.6 Ma (2σ). These Re-Os ages indicate the close temporal relationship between the molybdenite mineralization and the porphyry dikes. The age of the Kekura mineral system is similar to that of the post-collisional granitic plutons of the Anyui zone spatially scattered, between 140 and 210 km northwest of Kekura. We suggest that this temporal relationship may increase the likelihood of further discoveries of economic gold mineralization related to the currently underexplored Aptian post-collisional magmatic complexes of the Western Chukotka area. Keywords Zircon . U-Pb geochronology . Molybdenite . Re-Os geochronology . Kekura deposit . Western Chukotka
Introduction The Western Chukotka region of Russia is host to several gold, silver, copper, and molybdenum deposits and prospects. Editorial handling: B. Lehmann Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00126-020-00969-7) contains supplementary material, which is available to authorized users. * Ekaterina V. Nagornaya [email protected] 1
Vernadsky Institute of Geochemistry and Analytical Chemistry RAS, 19 Kosygin Str., Moscow 119991, Russia
2
Faculty of Geology, Lomonosov Moscow State University, GSP-1, Leninskie Gory, Moscow 119991, Russia
3
Department of Earth Sciences, Durham University, Durham DH1 3LE, UK
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State Key Laboratory of Geological Processes and Mineral Resources, School of Earth Resources, China University of Geosciences, Wuhan 430074, China
5
North-East Interdisciplinary Scientific Research Institute, 16 Portovaya Str., Magadan 685000, Russia
Among them are the Kupol (55.3 t Au at 36.4 g/t, 752 t Ag at 485.7 g/t; Vasil’kova et al. 2018) and Dvoinoe (28.1 t Au at 2.3 g/t; Vasil’kova et al. 2018) epithermal gold-silver deposits, the Karalveem intrusion-related gold deposit (9.1 t Au at 14.1 g/t; Akimova et al. 2016), the Klen intermediate sulfidation epithermal gold deposit (18.6 t Au at 5 g/t; www. russdragmet.ru), and the Peschanka (3.7 Mt Cu at 0.83%, 98 kt Mo at 230 g/t, 234 t Au at 0.57 g/t, 2002 t Ag at 4.6 g/t; Vasil’kova et al. 2018) and Nakh
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