Chenari, Afsaneh Dehghan , Feiznia, Sadat , Aleali, Mohsen , Ghorashi, Manouchehr
2025 IRANIAN JOURNAL OF EARTH SCIENCES 2025 17(卷), 3(期), (null页)
The present study conducted a geochemical analysis of the core sediments from the Jouybar and Zaghmarz areas located on the South Coast of the Caspian Sea in northern Iran. The aim of the study was to investigate the paleoclimate conditions and recycling effects of these sediments. The cores, named AZS (Azad University Shorsahra area) and AM (Amirabad), have depths of 9.3 m and 8.2 m, respectively. They consist of three lithological units, including sandy mud, mud, and silty sand. A total of 50 samples were collected from these units for X-ray diffraction (XRD), geochemistry (ICP-AES), and radiocarbon analyses. The X-ray diffraction analysis revealed that the samples predominantly composed of clay and non-clay minerals (e.g., Quartz, Feldspar, and Calcite). Various chemical indexes based on major and trace elements were used to assess the intensity of weathering. The results showed that sandy mud and muddy sediments experienced slightly higher weathering compared to silty sand sediments, indicating a weak to moderate degree of chemical weathering in the source region. Additionally, the A-CN-K and SiO2 vs. (Al2O3+K2O+Na2O) plots supported the conclusion of weak to moderate chemical weathering in arid and semi-arid paleoclimate conditions. Furthermore, the index of compositional variability (ICV) and the relationships between Zr/Sc and Th/Sc ratios suggested that sedimentary recycling in the core sediments was negligible. Binary plots of V/Cr vs. U/Th and Ni/Co vs. U/Th indicated that dysoxic/oxic conditions predominantly prevailed during the deposition of the two cores' sediments.