Sedimentology, petrography and diagenesis of Eocene-Oligocene evaporites: the Tuzhisar Formation, SW Sivas Basin, Turkey

In the gypsum of the Yeniköy Member nodular, nodular-banded, laminated-banded lithofacies with enterolithic and chicken-wire structures are distinguished. These associations indicate a sabkha or shallow-water setting of deposition such as a lagoon. Secondary gypsum in the Tuzhisar Formation generally displays alabastrine and porphyroblastic textures with corroded anhydrite relics. Associated minerals are dolomite, calcite, celestite, and lutecite. The Küllü Member is composed of irregular thick-bedded, massive, locally brecciated secondary gypsum, probably formed by multiple synsedimentary collapse after the dissolution of pre-existing soluble minerals and/or by paleoslumping related to synsedimentary tectonism. However, most of the evidence for the origin of the breccia has been destroyed by intense karstification.