Paleopedogenesis and paleoclimatic changes recorded at the Khonako II loess section, Khovaling Loess Plateau, Southern Tajikistan

Loess-paleosol sequences from the Khovaling Loess Plateau serve as a complete sedimentary archive for understanding past climatic changes in Southern Tajikistan during the Pleistocene. To aid in paleoenvironmental interpretation in this region, we present mineralogical analysis, the micromorphological index of soil evolution (MISECA), and physicochemical properties (e.g., clay content, calcium carbonate equivalent, etc.) for the Khonako II loess-paleosol sequence. The Holocene soil and five representative pedocomplexes (PC1, PC2, PC3, PC4, and PC5), separated by loess units (L1, L2, L3, L4, L5, and L6), were selected to reconstruct Late Pleistocene to Holocene paleoclimate changes. Our results indicate that PC5 and PC3 are considered strongly developed pedocomplexes, as evidenced by high clay/silt ratios, intensive carbonate eluviation, and abundant clay coatings. The composition of clay minerals in the paleosols suggests a warmer and wetter paleoclimate during the formation of PC5 and PC3 compared to subsequent interglacials when the other pedocomplexes developed. The increased precipitation is indicated by the weathering of mica and chlorite minerals, as well as pedogenic transformation of smectite and mixed-layer minerals.