In this study, chlorite is used to investigate the diagenetic-metamorphic evolution and accurate geological history of the different units belonging to the Karakaya complex, Turkey. Primary and secondary chlorite minerals in the very low-grade metamorphic rocks display interference colors of blue and brown and an appearance of optical isotropy. Chlorites are present in the matrix, pores, and/or rocks units as platy/flaky and partly radial forms. X-ray diffraction (XRD) data indicate that Mg-Fe chlorites with entirely IIb polytype (trioctahedral) exhibit a variety of compositions, such as brunsvigite-diabantite-chamosite. The major element contents and structural formulas of chlorite also suggest these were derived from both felsic and metabasic source rocks. Trace and rare earth element (REE) concentrations of chlorites increase with increasing grade of metamorphism, and these geochemical changes can be related to the tectonic structures, formational mechanics, and environments present during their generation.

The hydrocarbon potentials of the carbonates and siliciclastic rocks forming the continuous Paleozoic successions in Southeast Turkey are well understood. In this study, every aspect of the sequence stratigraphy was investigated and the erosional unconformity surfaces of different origin and transgressive surfaces were defined. In this way, the Paleozoic successions of Southeast Turkey were correlated with the hydrocarbon-producing Paleozoic successions of Saudi Arabia. Based on fieldwork, new formations and members were defined and formation boundaries were slightly modified. The stratigraphic sequence extending between the Neoproterozoic igneous basement (Telbesmi Formation) and the Early Ordovician (Konur Formation) is best represented along Zabuk Valley (Derik town). Middle-Late Ordovician successions are exposed between Bedinan (Gurmese) and Yurteri villages, west of Kiziltepe town. The stratigraphic sequence between the Early Silurian (Dadas Formation) and Late Permian-Early Triassic (Gomanibrik Formation) is represented northwest of Hazro town. In these areas, many stratigraphic and sedimentologic sections were measured, and shale and sandstone samples were collected for palynological and petrographic examination to evaluate their reservoir quality. The outcrops and subsurface indicated that the thick Middle Cambrian stromatolitic algal limestone (Koruk Formation) has both source rock and reservoir rock potentials. The glaciogenic Yurteri Formation has deeply incised into the Bedinan Formation. The well-sorted and porous glaciofluvial sandstones produce oil and gas in southeast Turkey and other countries located on the Gondwana continent. The organic rich shale deposited at the base of the Silurian Dadas Formation forms a very productive source rock for the entire Paleozoic successions. Crude oil has been produced from the Late Silurian Hazro sandstone. In order to locate exploration wells in the right place, depositional environment models of all the formations, their lithofacies, isopach maps and hydrocarbon migration pathways were prepared. This is crucial for geological exploration and oil and gas production.

ŞANLIURFA-HACI YADİGÂR CAMİİ RESTORASYON AMAÇLI YAPI MALZEMELERİNİN ARKEOMETRİK ÖZELLİKLERİNİN İNCELENMESİ

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 (CV) 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.