Geochemistry and origin of the manganese mineralization in the Yerköy Çiçekdağ (Yozgat) region

Eğerci village ferromanganese deposit is observed at 16km southwest of Yerköy (Yozgat) town with a basalt limestone contact and a banded and partly stockwork structure within the limestone. Pyrolusite, goethite, and ramsdellite were determined as the main minerals, and magnetite was determined to a lesser extent. Gang minerals are calcite and quartz. In the study, especially the geochemistry, petrography, and fluid inclusion data of the mineralization were evaluated. When the geochemical results of trace element, major oxide, and Rare Earth Elements (REE) data of the ore samples were interpreted and placed in various diagrams, it was determined that they were distributed in marine hydrothermal, terrestrial hydrothermal, marine hydrogenetic, and freshwater hydrogenetic areas. This indicates that Mn oxides may have been affected by diagenetic and supergene-associated fluids after hydrothermal formation. According to fluid inclusion studies, mineralization indicates three different solution phases. While the first one presents a distribution between 143-236 °C, the second phase varies between 269-317 °C and the third phase varies between 338-438 °C. While the calculated salinity amounts are partially high in Type I fluid inclusions (1.90-14.70 wt.% NaCl eq.), the salinities of Type II and III fluid inclusions are lower (1.90-5.10 wt.% NaCl eq.). Considering these values, it indicates that the mineralization consists of a mixture of magmatic and meteoric origin solutions.