Luminescence Chronology of Loess, Kashmir Valley, India: Implications to Palaeoclimate Studies

Borde, Harshwardhan Sukhadeo (2022) Luminescence Chronology of Loess, Kashmir Valley, India: Implications to Palaeoclimate Studies. Masters thesis, Indian Institute of Science Education and Research Kolkata.

Text (MS dissertation of Harshwardhan Sukhadeo Borde (17 MS 141)) 17MS141_Thesis_file.pdf - Submitted Version Restricted to Repository staff only Download (10MB)

Abstract

Loess Paleosol sequence (LPS) are very important terrestrial paleoclimate indicators, documenting records of Glacial and interglacial phases of Cold/Dry and Warm/Wet climatic conditions. LPS sequence also contains major paleovegetation archives, tectonics, geochemical activity and past sedimentary processes. Kashmir valley has extensive Loess deposits distributed over 500 Km². Using these LPS deposits, paleoclimate reconstruction is possible. The optically Stimulated Luminescence (OSL) dating technique is used to date samples from a thick LPS section. OSL is currently a worldwide dating method and has been proven to give a more accurate age of such suspected old deposits of LPS from Kashmir Valley. Here we provide a paleoclimatic implication of the 20 m thick Loess Paleosol section by studying 8 samples from this section. Loess paleosol layers of variable thickness intercalated with carbonate nodule horizon provide detailed paleoclimate information. ~301 Ka marks the start of major glaciation and influx of loess sediments deposited overlying Karewa. Around ~ 199 Ka and above 123 Ka carbonate nodules are observed, suggesting an interstadial climate of warm period and high precipitation, which matches Holocene interstadial. These records of major climate change after every 100 Ka seem to follow the Milankovitch cycle. Alternate Loess and Paleosol horizons suggest glacial and interglacial cycles. This study is the first reporting start of loess deposition in Kashmir valley, India.

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