Mineralogical and geochemical characteristics of the upper cretaceous and lower Paleocene parts of the Germav Formation: southeastern Türkiye.

The mineralogical and chemical characteristics of Upper Cretaceous-Lower Paleocene claystone sediment samples taken from Mardin and Batman, located in southeastern Türkiye, were analyzed in the present study. The clay mineral paragenesis in the Upper Cretaceous units consisted of chlorite-smectite (C-S) and illite, whereas the Lower Paleocene unit consisted of chlorite-vermiculite (C-V) and vermiculite minerals. Analyses conducted on clay samples indicated high levels of Al, Mg, Fe, Cr, V, Ni, and Zr. Low levels of alkali and alkaline earth elements (Mg, Na, Ca, K) in the clay-rich sediments suggest relatively high-grade weathering in the source area. The mineralogical compositions, major elemental ratios, and trace and rare earth element (REE) contents of the sediments indicate that the Upper Cretaceous unit consists of materials with predominantly felsic lithology, whereas relatively detrital contributions from basic sources are found in the Lower Paleocene unit. A comparison of the major and trace element contents of phyllosilicate/clay minerals with the members revealed that the patterns of the clays were distinct from each other. However, the enrichments/depletions varied depending on the origin (basement rocks or detrital) of the derived rocks, minerals, and elements. The major and trace element geochemistry of Upper Cretaceous-Lower Paleocene rocks was associated with a passive margin setting. Sedimentation processes and differences in provenance among members of the Germav Formation during the Cretaceous-Tertiary periods were largely influenced by local or regional geodynamic and diagenetic events. [ABSTRACT FROM AUTHOR]