GRANITOIDS OF THE NETPNEYVEEM TIN-TUNGSTEN-GOLD ORE DISTRICT, WESTERN CHUKOTKA

In this paper, we report new data on the age (U-Pb SIMS), petrogeochemical, isotopic composition, and geodynamic settings for the emplacement of Cretaceous granitoid complexes of the Netpneyveem ore district in western Chukotka. The ages obtained for biotite granites of the Konevaam stock (114 ± 1 Ma) and leucogranites of the Elvenei massif (107 ± 1 Ma) are comparable with Aptian and Albian stages of intrusive magmatism associated with extension upon completion of the collision between the Chukchi microcontinent and the Siberian (North Asian) continent. Sr-Nd isotopic characteristics of the studied granitoids indicate a significant contribution of mature continental crust to the magma source. This is supported by Mesoproterozoic model ages of granitoids and the presence of Neoproterozoic inherited cores in zircons. Geochemical characteristics of rocks from the Konevaam stock are compared with those from the reduced intrusions with which gold mineralization may be associated. The data on the age and composition of intrusive rocks of the Netpneyveem district increase expectations for the identification of new targets within its boundaries and increase prospectivity of this cluster.