Noble Metals in Graphitized Rocks of the Khanka Terrain (Primorye): Evidence from Analytical Results Based on Decomposition by the Fluoroxidizing Method

摘要

Development of the geology, geochemistry, and analytical chemistry of noble metals (NM) in the past 30 years has provided new insights into the nature of unconventional complex gold and platinum group metal (PGM) deposits. In particular, such deposits confined to black shales were discovered in Caledonides of the Central Asian orogenic belt, such as the well-known Muruntau, Kumtor, Zun-Kholba, Irokinda, Sukhoi Log, Nezhdaninskoe, Natalka, and others. In the past 10-15 years, commercial PGM concentrations were detected in ores of these deposits [1-4 and others]. The PGMs in these deposits are traditionally assigned to the carbonaceous matter (CM) of rocks. However, it turned out that they are likely (and primarily) associated with sulfides. Geochemical aspects of PGM concentration in rocks (and ores) and issues of their reliable determination have attracted the main attention in discussions devoted to the problem of PGM occurrence in black shales in the recent period of more than 20 years [4, 5, and others].