Günyüzü-Kavuncu (Eskişehir) Yöresi Üst Miyosen-Pliyosen Yaşlı Sedimanter Birimlerin Mineralojik ve Jeokimyasal İncelenmesi

Abstract

In this study, mineralogical, petrographic and geochemical characteristics of the Neogene formations in the Eskişehir Günyüzü Basin have been investigated. The units in the study area consist of Pre-Neogene Basement Rock (Kertek Formation, Eryiğit Formation and Beldede Formation), uncomformably overlying Neogene units (Mercan Formation, Çakmak Formation, Ballıhisar Formation-Acıkır Member), Pleistocene Kepen Formation and recent alluvial deposits that uncomformably cover all units.

During fieldwork, a total of 18 samples were collected from lithostratigraphic units from each formation and a total of 53 samples were obtained from cores taken at two different drilling locations. Results have been evaluated after mineralogical, petrographic and geochemical analyses were conducted on the collected samples in line with the purpose of the study.

According to petrographical and XRD analysis, Çakmak Formation and Ballıhisar Formation Acıkır Member are composed of evaporite minerals while the Mercan Formation which is located in the southern part of the study area contains carbonate units and sepiolite mineral. Geochemical analysis results of the gypsum samples taken from the SG-4 drilling cores and the Çakmak Formation indicate that the Sr values range between 1125 and 2875 ppm. Geochemical analysis of the water sample taken from the lake in the Kavuncu Plain within the study area revealed the following concentrations: Na: 5540 ppm, Mg: 1852 ppm, SO4²⁻: 12516 ppm, and Cl⁻: 4401 ppm. Additionally, XRD analysis was performed on a sample taken from the recent sediment in the dry parts of the lake. This region, the paragenesis of bloedite (Na2Mg(SO4)2.4H2O), thenardite (Na2SO4), löweite (Na12Mg7(SO4)13.15H2O) and hydroglauberite (Na10Ca3(SO4)8.6H2O) was identified through this study.

Based on these results of this study, SG-3 drilling cores were examined near the lake to investigate the presence of buried sulfate salts. Moreover, a 26-meter-thick glauberite (Na2Ca(SO4)2) ore deposit was identified in Gunyuzu Neogene Basin.