Noble Metals in Coals of the Amur-Zeya and Bureya Depressions of the Middle Amur Region

摘要

The Amur region, a unique region (in terms of the structural-tectonic setting) is located in eastern Asia within the Mongol-Okhotsk branch of the Pacific ore belt. It consists of three major structural units: the Stanovoi area of Proterozoic folding in the north, the Bureya median mass of Proterozoic folding in the south, and the Mongol-Okhotsk area of Paleozoic folding that separates the first two areas. The studied region bounded by the Amur district covers an area of 363700 km~2 [1]. The study region incorporates gold placer and primary deposits confined to ancient faults separating structural elements of the Earth's crust [1]. Gold deposits, as well as gold- and platinum-bearing areas are concentrated in 46 gold-bearing and 7 potential platinum-bearing, ore-placer nodes occupying 45% of the region territory. The main gold placer areas, which are located within orogenic areas and along the periphery of the Amur-Zeya Plain, embrace landscapes of different altitudes [2]. Direct indicators of platinum mineralization were established incidentally when studying and exploiting gold deposits and placers. The authors of [3] distinguish the Upper Amur platinum province, the boundaries of which overlap the study region. Platinum mineralization is mainly encountered in basic and ultra-basic rocks and is 3-7 times greater than analogous ore occurrences in granite rocks. It includes the following minerals: sperrylite, native platinum, isoferroplatinum, iridosmines, osmirides, rutheniridosmines, laurite, erli-chmanite, and less common sulfides and sulfoars-enides. In general, the study region includes two mineral associations: sperrylite and rutheniridosmine. New sources of platinoid mineralization are mentioned in [4] and reported from black shale sequences and metaso-matites of the metamorphic and hydrothermal rock classes.