4th Biennial SGA Meeting on Mineral Deposits - Research and Exploration: Where do They Meet, Turku, Finland, 11 - 13 August 1997, pp.331-334
The gold occurrences in the eastern Pontides are associated with volcanic and sedimentary rocks of Liassic to Eocene age and are confined to NE-SW and NW-SE trending fracture zones. The gold mineralization is mainly restricted to zones containing quartz, adularia, sericite and illite. Ore minerals include base metal sulfides, fahlore group minerals, native gold, native silver, argentite, realgar, orpiment, stibnite, zincenite, and pyrite. Gold mainly occurs as free grains, 5 to 50 mu m in size, in the gangue, but is also included in some ore minerals such as zincenite. Deposition of Au and Ag took place in two to three stages mainly between 340 to 270 degrees C, 240 to 220 degrees C, and 200 to 120 degrees C from fluids with salinities between 2 to ii wt% NaCl eq. The mineralogic, alteration and fluid inclusion characteristics of these occurrences, except for the Kaletas gold occurrence, are similar to those of adularia-sericite type epithermal deposits. Gold deposition in these prospects is controlled mainly by boiling and associated cooling. However, gold deposition in the Kaletas occurrence which has the features of Carlin type deposits took place due to adsorption of gold on organic matter.