AGE AND GENESIS OF THE POKROVSKOE GOLD-SILVER DEPOSIT (Russian Far East)
A.A. Sorokin1, A.Yu. Kadashnikova1, A.V. Ponomarchuk2, A.V. Travin2, V.A. Ponomarchuk2,3
1Institute of Geology and Nature Management, Far Eastern Branch of the Russian Academy of Sciences, per. Relochnyi 1, Blagoveshchensk, 675000, Russia
2V.S. Sobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, pr. Akademika Koptyuga 3, Novosibirsk, 630090, Russia
3Novosibirsk State University, ul. Pirogova 1, Novosibirsk, 630090, Russia
Keywords: Pokrovskoe deposit, Argun continental massif, Ar-Ar geochronology, Mesozoic, magmatism
Abstract
We present results of geochronological studies of rocks from different igneous complexes and of hydrothermally altered volcanics with commercial Au-Ag mineralization from the Pokrovskoe deposit. The age of the ore-hosting granites of the Sergeevsky pluton of the Upper Amur complex is estimated at ~129 Ma. The primary age of dacites of a sill-like body is within 128-125 Ma and is close to the age of volcanics of the Taldan complex. Propylitization processes superposed on these dacites are dated at ~122-119 Ma. Taking into account the commercial contents of gold and silver in these rocks, we believe that the age of the hosted orebodies is in the same interval. The period 122-119 Ma is also the time of formation of the Gal’ka volcanic complex in the Umlekan volcanic zone, which was accompanied by granitoid magmatism. This suggests that the formation of the Pokrovskoe deposit was associated with the accumulation of the Gal’ka complex.
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