Diagenetic Evolution of Upper Jurassic-Lower Cretaceous Berdiga Formation, NE Turkey: Petrographic and Geochemical Evidence
Upper Jurassic-lower Cretaceous Berdiga Formation crops out extensively in NE Turkey. The host carbonates at Eski Gümüşhane section are pervasively dolomitized by fabric-destructive and fabric-preserving replacive dolomites (RD). These dolomites are Ca-rich and non-stoichiometric (Ca56-58Mg42-44). They have highly variable but low δ18O (−11.38 to −4.05‰ V-PDB) and δ13C (0.69 to 3.13‰V-PDB) values, radiogenic 87Sr/86Sr ratios (0.70753 to 0.70884), extremely high Fe (2727–21053 ppm) and Mn (1548–27726 ppm) contents. Microcrystalline quartz cement, dolomite cement and the scattered euhedral pyrite minerals (average 5 μm) are also observed in the dissolution porosity of replacive dolomites. This study demonstrates that these carbonates have undergone a complex diagenetic history from shallow to deep burial associated with syn-sedimentary extensional tectonic activity during the Albian–Aptian and later with the hydrothermal emplacement of the polymetallic mineralization during the Eocene.
KeywordsDiagenesis Carbonates Berdiga Formation NE turkey
The authors thank Karadeniz Technical University (Project no: FBA-2015-5160) and TUBİTAK (Project no: 115Y005, ÇAYDAG and International PhD Research Scholarship Program-2214-A-BIDEP) for their financial support. ISA acknowledge the support from NSERC.
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