Petorgraphic and geochemical properties of Bayıralan formation (Denizli-GB Türkiye) sandstones

The Bayıralan Formation, which has extensive exposures in the eastern and northeastern parts of the Denizli basin (southwestern Turkey), consists of thin- to medium-bedded sedimentary rocks containing conglomerate, claystone, and organic-rich rock layers. Sandstones observed in greenish-gray and light brown colors consist of quartz, chlorite, clay + mica, plagioclase, opaque minerals, pyroxene, calcite, and rock fragments (quartzite, serpentinite, gabbro, chert, marble, limestone). These mineralogical findings were also supported by XRD and SEM-EDS analyses. In chemical classification diagrams based on sandstone's major oxide element contents, it was determined that they fall into litharenite and Fe-rich sand areas. Geochemical diagrams such as SiO2-Al2O3/TiO2, Rb-K2O, and Hf-La/Th show that the sandstone components are mainly derived from felsic-intermediate rocks. Still, some samples are close to mafic-ultramafic compositions. Trace element ratios such as Ni/Co, Cr/V, Cr/Th, Co/Th, Sc/Th, La/Th, La/Sc, Ba/Nb, and Y/Ni indicate that the lithologies in the source area vary between felsic rocks such as shale/schist, granite and mafic rocks such as gabbro and basalt. In the NASC and PAAS normalized multi-element variation diagrams, significant enrichments in Al, Ca, Cr, Co, and Ni elements and depletions in Si, Ti, Na, K, Mn, Rb, Ba, Th, Nb, Sc, and V elements are observed. In the PAAS normalized REE diagrams, sandstone samples display similar and flat patterns, with REE concentrations ranging from 22.11 to 178.67 ppm. Sandstones show moderate to slightly high LOI, K/Cs, and Al/Ti index values while exhibiting low to moderate ICV, CIA, PIA, and IOL values. This indicates weak to moderate weathering in the source area. Tectonic discrimination diagrams demonstrate that the sandstone components are derived from rocks formed in an active continental margin (continental island arc) environment. Geological, palynological, and geochemical data indicate that the Bayıralan Formation sandstones were deposited under a hot and humid climate, in a shallow marine-coastal (transitional) environment, and under oxidizing conditions.