Gold in the Pontide magmatic arc
Karadeniz Technical University, Department of Geological Engineering, Trabzon, Turkey
Eastern Black Sea region known as the Pontide magmatic arc embraces favorable properties such as intensive and widespread magmatic activities and fracture systems developed due to north-south compression of the Pontides since Late Mesozoic and therefore host several well known massive sulfide and epithermal gold deposits, yet some still to be discovered. The gold occurrences are mainly associated with NE-SW and NW-SE trending fracture and fault zones which served as channelways for hydrothermal solutions to circulate and hence loci for gold deposition.
Gold deposition in these occurrences is mainly caused by boiling and mixing processes. Hydrothermal waters enriched in gold- bearing complexes are mainly derived from granitic intrusions emplaced between 47-42 million years. However, Incursion of a considerable amount of meteoric waters into magmatic waters played an important role in destabilization of gold complexes. Depositional temperatures of gold indicate mainly epithermal and less mesothermal conditions for mineralizations.
The mineral chemistry, nature of fluid inclusions together with isotopic data and alteration products suggest intermediate to low-sulfidation epithermal types of gold deposition in the region. Exception might be the Kaletaş gold occurence which is hosted by limestone enriched with organic material. Hence, it might be classified as one of the Carline types.