Petrochemical features of upper jurassic deposits in Southeastern Caucasus (Azerbaijan)

Background. This paper presents the results of complex lithological studies of the Upper Jurassic sediments in the southeastern part of Azerbaijan, the Greater Caucasus area. Aim. Determination of the formation characteristics of Upper Jurassic carbonate-terrigenous rock complexes in the Southeast Caucasus, including paleoclimate, the geochemical regime of the basin, and the petrophysical properties of adjacent erosion zones. Materials and methods. Materials were collected during fieldwork conducted over several years (2015–2023) in the Shahdag-Khyzy and Guton-Gonagkend facies zones of the Side range. The chemical composition of samples was analyzed using a S8-Tiger wavelength-dispersive X-ray fluorescence spectrometer. Mineralogical analysis was conducted using X-ray diffraction on a Miniflex 600 diffractometer. Quantitative assessment of mineral content in the samples was based on the intensity of diffraction peaks. For studying the structural and textural features of the rocks, a Carl ZEISS electron microscope was utilized. Results. The data obtained were used to determine the petrochemical properties of the Upper Jurassic sandstone and shale formations in the southeastern Caucasus. Using these parameters, a paleoclimatic and tectonic reconstruction of the formation process of these rocks was also conducted. Conclusion. For the first time, lithochemical modules were calculated and petrochemical characteristics of the Upper Jurassic sedimentary complex of the South-East Caucasus were carried out based on silicate analysis. The chemical composition of the Upper Jurassic rocks is generally uniform, and the distribution of trace elements in these rocks does not show noticeable deviations. Lithochemical parameters of sandstones show a moderate level of maturity, which indicates their formation as a result of mechanical destruction of rocks.