Geochemical features of the MenteAYe Formation dolostones (Rhaetian) in the Karacahisar-KasA±mlar area (Isparta-Turkey)

The purpose of this study is to determine the geochemical characteristics of the MenteAYe dolostones (Rhaetian) in the west Taurus Mountains, Turkey. The isotope characteristics of the MenteAYe dolostones show a variation in the delta O-18 values of the dolomites between + 1.35 and - 2.72aEuro degrees (VPDB) and a variation in the delta C-13 values of the dolomites between + 1.6 and + 3.33aEuro degrees (VPDB). Most of the MenteAYe dolostone samples have positive oxygen isotope values; others have weak negative isotope values, which indicate early diagenetic development. In addition, oxygen, carbon, and strontium isotopes and trace element analyses suggest that these dolostones were probably resulted from insignificant recrystallizaion process than chemically similar fluids. Furthermore, Mn/Sr values of the MenteAYe dolostones indicate that there is no significant diagenetic alteration. The total REE contents of the MenteAYe Formation dolostones display a strong positive correlation with Si, Al, Fe, K, Ti, Ba, Rb and negative correlation with Mg, hence REE content is associated with in the first degree titanium-bearing minerals (probably sphene, rutile, anatase), second degree phosphate (apatite), and barium and rubidium-bearing minerals (probably barite). Ce anomalies versus Nd concentrations of the MenteAYe dolostone samples indicate that these dolostones are formed in an anoxic environment. In addition, the K/Rb ratios of the MenteAYe dolostones are not exposed to any metamorphism and indicate some diagenetic alteration. Calculated temperature values using delta O-18 values of the MenteAYe dolostones yield precipitation temperatures of 17 to 42 A degrees C, and suggest burial depths of 67 to 900 m. Sources of magnesium for dolomitization of the MenteAYe Formation carbonates were most likely fluids from seawater and/or diagenetic brines (slightly modified seawater). The MenteAYe dolostones formed as early diagenetic (Rhaetian to Cenomanian) in shallow burial areas at lower temperatures than seawater and/or diagenetic brines (slightly modified seawater).