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This paper describes the occurrence of dolomite and the mechanism of dolomitization of the Upper Triassic-Lower Jurassic Kiziloren Formation in the autochthonous Bolkardagi unit of the middle Taurus Mountains in south western Turkey. Dolomites were analyzed for geochemical, isotopic and crystallographic variation. Dolomites occur as a replacement of precursor carbonate and cement. The dolomite crystals range from <10 to ~1000 μm existing as both replacements and cements. Sr concentrations range between 84 and 156 ppm, and the molar Sr/Ca ratios of dolomitizing fluids are estimated to range between 0.0066 to 0.013 ratios. Dolomites are Ca-rich (with average CaCO3 and MgCO3 equal to 56.43 and 43.57 mol%, respectively) and they are non-stoichiometric, with an average Sr=116 ppm, Na=286 ppm, Mn=81 ppm, Fe=1329 ppm, and δ18O and δ13C ranges from -0.6‰ to -6.1‰ Pee Dee Belemnite [PDB], and +1.2 to +3.9‰ PDB. The North American Shale Composition [NASC]-normalized rare earth element (REE) values of the both limestone and dolomite sample groups show very similar REE patterns characterized by small positive Eu (mean=1.32 and mean=1.42, respectively) and slightly or considerably negative Ce (mean=0.61 and mean=0.72, respectively) anomalies and a clear depletion in all REE species. The Kiziloren Formation dolomites have been formed as early diagenetic from mixing zone fluids at the tidal-subtidal environment and at the late diagenetic from basinal brines at the shallow-deep burial depths.
This paper describes the occurrence of dolomite and the mechanism of dolomitization of the Upper Triassic-Lower Jurassic Kiziloren Formation in the autochthonous Bolkardagi unit of the middle Taurus Mountains in south western Turkey. Dolomites occur as a replacement of precursor carbonate and cement. The dolomite crystals range from <10 to ~ 1000 μm existing as both replacements and cements. Sr concentrations range between 84 and 156 ppm, and the molar Sr / Ca ratios of dolomitizing fluids are estimated to range between 0.0066 to 0.013 ratios. Dolomites are Ca-rich (with average CaCO3 and MgCO3 equal to 56.43 and 43.57 mol%, respectively) and they are non-stoichiometric, with an average Sr = 116 ppm, Na = 286 ppm, Mn = 81 ppm , Fe = 1329 ppm, and δ18O and δ13C ranges from -0.6 ‰ to -6.1 ‰ Pee Dee Belemnite [PDB], and +1.2 to + 3.9 ‰ PDB. The North American Shale Composition [NASC] -normalized rare earth element (REE) values of the both limestone and dolomite sample groups show very similar REE patterns characterized by small positive Eu (mean = 1.32 and mean = 1.42, respectively) and slightly or considerably less negative Ce (mean = 0.61 and mean = 0.72, respectively) anomalies and a clear depletion in all REE species. The Kiziloren Formation dolomites have been formed as early diagenetic from mixing zone fluids at the tidal-subtidal environment and at the late diagenetic from basinal brines at the shallow-deep burial depths.