Noble Metal Minerals in Placers of the Fadeevka Ore Node (Primor'e Region): Evidence of the Formational Affiliation of Native Sources

摘要

Native metal placers have been developed for more than 150 years in the southern, northern, and central areas of the Laoelin-Grodekov structural-metallogenic zone (SMZ). The abundance of gold (in some places, platinoids) in alluvial sediments of the southwestern Primor'e region indicates the native metal specialization of the SMZ. The most well-known platinoid-gold placers of the central SMZ make up a nearly meridional band extending from the Fadeevka River (Razdol'naya River basin) in the south to the Zolotaya River (Nesterovka River drainage system) and its tributaries (Baikal, Malaya Nesterovka, Tolstokulachikha, and Polikarpikha creeks) in the north (see the figure). In some places, concentrations of platinum group elements (PGE) in placers of the Fadeevka ore node are locally comparable with placer gold contents. In gravity concentrate of some blocks in the Fadeevka placer, Pt and Pd contents are as high as 11.2 and 0.1 wt %, respectively. The identification of mineral forms of the occurrence of native metals in placers, the specific features of their areal distribution, and the formational affiliation of native sources, can promote an unbiased assessment of both the gold and platinoid potentials of the SMZ.