Constraining the timing and deposition pattern of loess-palaeosol sequences in Kashmir Valley, Western Himalaya: Implications to paleoenvironment studies

Abstract

Terrestrial loess palaeosol sequences (LPS) are the most extensive paleoclimate archives documenting dynamic sedimentary processes in response to glacial (cold-dry) and interglacial (warm-wet) phases. In the present study, we provide chrono-stratigraphy and paleoenvironmental implications of a 600 cm LPS outcrop from the Kashmir Valley, Western Himalaya. The Optically Stimulated Luminescence (OSL) dating revealed development of polycyclic palaeosol units with variable thickness, a parent loess horizon and pedogenically modified loess during the last ~65.8 ± 7.2 ka to ~14.7 ± 5.4 ka. The multiproxy analysis revealed four major climate phases that prevailed between 65.8 ± 7.2 ka to 14.7 ± 5.4 ka. Sediment deposition from ~800 to ~640 cm suggests moderate climate, followed by development of an unaltered loess horizon (~640 to ~600 cm depth; C horizon) suggesting arid/dry climatic conditions with relatively higher wind velocity. Occurrence of a well-developed palaeosol (600 to 450 cm) suggests prevalence of warm/wetter climatic conditions. Cambisol deposited with high CaCO 3 content followed by a weakly developed palaeosol (450 to 200 cm) suggests dominance of cold/dry climate conditions and progression of the climate during the latter phase. Subsequently, the accumulation of parent loess ceased at ~14.7 ± 5.4 ka and the sedimentary environment was overtaken by the fluvial activity probably caused by widespread precipitation and/or glacial melting.