Darıca epitermal cevherleşmesinin mineralojik ve jeokimyasal özellikleri (Bayburt, Doğu Pontidler)

Abstract

Darıca epithermal mineralization is located about the 38 km northwest of Bayburt in the South Zone of the Eastern Pontides. The Middle-Late Eocene volcanic rocks that host the mineralization have basalt, basaltic andesite and andesite composition. Late Eocene Kaçkar II cutting the volcanic rocks have quartz-monzonite and monzonite composition. Mineralization and alteration zones are developed along of the NW-SE and NE-SW trending fractures in the Middle-Late Eocene andesite and pyroclastic rocks. As a result of the functions of hydrothermal solutions in the region, propylitic (chlorite, epidote, calcite, pyrite), sericitic (sericite, quartz, pyrite) and argillic alteration (quartz, illite, kaolinite) are developed in the wall rock. Mineral paragenesis of mineralization consists of sphalerite, galena, pyrite and tennantite. Quartz and barite are gangue minerals. Different textures have been identified in quartz, such as microcrystalline mosaic, a cavity lined crystallized quartz and colloform banded.

As a result of the geochemical analysis of the samples taken along the traverse in the silicified zone, Pb, Zn, Cu, Ag, As and Sb abundances were determined to be high. Fluid inclusion studies have shown that mineralization developed low-temperature (193−235 °C) and salinity (2.1−4.8 wt% NaCl eq.) fluids. Eutectic temperature (-57.7 to -54.3 °C) values indicate that the fluids contain NaCl and CaCl2 salts. All these data indicate activity of near-neutral pH thermal waters. It can be said that these data characterize a low sulfidation epithermal system.