Volcanogenic Deposits of Non-ferrous Metals in the Lesser Caucasus and Eastern Pontides

摘要

The paper presents brief characteristics of geological environments of ore deposit occurrences in Turkey,Georgia and Armenia.They can be attributed to Kuroko-type deposits,being distinguished by the character of ore accumulation.To the west,in Turkey,there are epigenetic and hydrothermal-sedimentary copper-zinc deposits that were formed in deep restricted basinal settings.An example of the latter is the Chayeli deposit.To the east,in the Caucasus,we have predominantly only epigenetic deposits.Besides,in the Bolnisi mining district(Georgia)there is the Madneuli deposit which represents an example of polyformational deposit.Here,within the restricted territory,have been concentrated:barite,barite-polymetallic,gold-bearing secondary quartzite,large-scale stockworks of copper ores.Judged by the 87Sr/86Sr ratios,some volcanites which are spatially associated with ores,might have been products of the“differentiation”of undepleted mantle,or other magmas that were generated in the lower part of the earth crust.In the Alaverdi ore district in Armenia,there are Jurassic volcano-depressions that host copper,copper-zinc and barite-sulfide ores.All the deposits of the Alaverdi district,porphyry copper including,contain economic reserves of ores.On the basis of available literature material and our own data,there has been created a mental-logical geological-genetic model of volcanogenic deposits.