Geochemistry of Upper Eocene-Oligocene sandstones from Tuzgölü Basin (Central Anatolia)

Abstract

In this study, mineralogical and geochemical features of Upper Eocene-Oligocene sandstones exposed by the Tuzgölü Fault Zone (TFZ) at the eastern border of the Tuzgölü Basin were investigated. The absence of zircon enrichment in the Zr/Sc-Th/Sc diagram indicated no sedimentary recycling. This shows that the sandstones are first cycle sediments, that is, the material transported directly from the source. Critical element ratios for provenance such as La/Sc, La/Co, Th/Sc, Th/Co, Th/Cr, Zr/Sc, Zr/Co, Ba/Sc, and Ba/Co, Th/Sc-Eu/Eu* diagram and average Rare Earth Element (REE) pattern suggest a provenance in “intermediate magmatic” composition. The variation in the negative Ce anomaly effect observed between the lower and upper parts of the sequence indicates variation in the oxygen level of the water. In each of the La-Th-Sc, Th-Co-Zr/10, and Th-Sc-Zr/10 tectonic setting discrimination diagrams, the sandstone average fell onto the “Continental Island Arc” position. This tectonic setting defines the arc that developed along the continental margin of the subduction zone. The tectonic setting found for the basin, supported the evolution model that the Tuzgölü Basin developed as a fore-arc basin.