Geology, mineralogy and geochemistry of manganese mineralization in Gumushane, Turkey

Abstract

In the scope of this study, geochemical and genetic characteristics of manganese mineralization of the Gümüşhane were investigated. The mineralizations area is located in near Gümüşhane city, the Eastern Black Sea Tectonic Unit. Different from other manganese occurrences in the Black Sea region, this mineralization occurred in massif limestone of Late Jurassic–Early Cretaceous Berdiga formation. The ore mineralization exhibits mainly lens shaped stacks and stockwork-form structures and is characterized with late filling of open cavities and replacement of limestone by manganese oxides. Manganese oxides are in relation with the nortwest-southeast oriented feeder cracks and fault zones and often associated with jasper and iron oxide minerals like hematite and goethite. The ore mineralization exhibits mainly lens shaped stacks and stockwork-form structures and is characterized with late filling of open cavities and replacement of limestone by manganese oxides. Element analysis such as major, minor and trace elements, and XRD and ore microscopy studies were carried out to investigate the geochemical and genetic properties and mineralogical association of manganese mineralizations. As a result of mineralogical studies, pyrolusite, braunite, manganite, psilomelane and stiplomelane are defined as manganese minerals, and also quartz, calcite, dolomite and smectite are found as gangue minerals. According to geochemical data such as, major oxides, trace and rare earth elements, the mineralizations are determined as hydrothermal in origin, supported with hydrogenic contributions.