Age and Geochemical Constraints on Formation of Fault-related Late Quaternary Carbonate Veins from Southern Turkey

2018-08-17
Ünal İmer, Ezgi
Uysal, Tonguç
Dirik, Ramazan Kadir
İmer, Ali
Ring, Uwe
Combined U-series dating and high-resolution geochemical analyses of co-seismic carbonate veins offer an invaluable opportunity to document young (<1 Ma) earthquake activity and for tracing origins of associated fluids. In this study, we analysed a total of 23 samples of fault-related carbonate veins and slickenfibered calcites collected from two separate SW– S-trending fault zones developed near Anamur and Gazipaşa areas in Southern Turkey. Microtexturally the carbonate veins mainly comprise medium- to coarse-grained, columnar calcite crystals elongated along growth direction. U-series dating indicated episodic fault-related carbonate mineralization between 132 ± 2 and 5.6 ± 0.4 ka and between 530 ± 63 and 30.0 ± 2.1 ka in Anamur and Gazipaşa areas, respectively. Carbon and oxygen isotope compositions of carbonates from both Anamur (δ13C = -12 to -6‰, δ18O = -7 to -4‰; relative to V-PDB) and Gazipaşa (δ13C = -12 to -7‰, δ18O = -7 to -3‰) areas are almost identical, whereas Anamur samples (0.7074–0.7080) have slightly lower 87Sr/86Sr ratios compared to Gazipaşa samples (0.7081–0.7096). The 87Sr/86Sr values correlate well with that of modern and Cenozoic seawater (~0.709) and Permian limestone host rocks (~0.707). PAAS-normalized rare earth element-Yttrium patterns of most samples are characterized by negative Ce and positive Y anomalies, confirming a predominantly seawater source for calcite precipitating fluids. Our acquired age and geochemical data not only has revealed young (<500 ka) seismic activity for these previously undocumented fault systems, but it also has implications for upper crustal fluid flow and palaeoclimatological conditions in the region.
Citation Formats
E. Ünal İmer, T. Uysal, R. K. Dirik, A. İmer, and U. Ring, “Age and Geochemical Constraints on Formation of Fault-related Late Quaternary Carbonate Veins from Southern Turkey,” presented at the Goldschmidt 2018 Conference (12 - 17 Ağustos 2018), Boston, Amerika Birleşik Devletleri, 2018, Accessed: 00, 2021. [Online]. Available: https://hdl.handle.net/11511/86095.