Integrated petrographic and XRD characterization of carboniferous-aged sandstones from the Zonguldak basin (NW Turkey): insights into tectonic provenance and sedimentary processes

This study presents an integrated petrographic and mineralogical evaluation of Carboniferous-aged sandstone units from the Zonguldak Basin, located in northwestern Turkey. A total of four representative samples from the Kozlu, Armutçuk, Üzülmez, and Karadon formations were analyzed through thin-section petrography and X-ray Diffraction (XRD) techniques to investigate their compositional characteristics, provenance signatures, and depositional environments. Petrographic analysis revealed that the majority of the samples fall into Feldspathic Litharenite, Arkose and Lithic Arkose categories, based on Folk’s sandstone classification scheme. The dominance of quartz and feldspar, alongside lithic fragments derived from felsic igneous and high-grade metamorphic sources, suggests deposition under tectonically active conditions with limited chemical weathering and short sediment transport distances. XRD analyses confirmed the presence of quartz, feldspar, clay minerals (illite, muscovite), and minor calcite. The diffraction patterns exhibit sharp peaks for quartz and feldspar, indicating well-crystallized detrital grains, whereas broader peaks for clay minerals imply diagenetic alteration during burial. Grain size assessments indicate a wide spectrum ranging from fine- to coarse-grained textures, which points to fluctuating depositional energies—likely controlled by fluvio-deltaic processes in an actively uplifting basin margin. The presence of angular lithic fragments and feldspar-rich assemblages supports a provenance associated with nearby orogenic highlands. These findings are consistent with previous tectonic reconstructions that associate the Zonguldak Basin with the closure of the Intrapontide Ocean and collisional events during the Paleozoic–Mesozoic transition. Overall, this study provides significant insights into the sedimentary and tectonic evolution of the Zonguldak Basin and contributes to a better understanding of the basin's geodynamic history and sedimentary processes.

کلیدواژه ها:

Zonguldak Basin ، tectonic provenance ، sandstone petrography ، Mineralogical analysis ، X-ray diffraction (XRD)