A 25 ky BP record of Himalayan aridity using muscovite and clays as proxy climate indicators
Abstract
Based upon the temporal variations in the grain size parameters, characteristic clay minerals, their ratios and detrital muscovite content in a isotopically dated turbidity free core from hemipelagic environment. (2713 m water depth), the climatic variability in the Himalayas for the past 25 ky, and the utility of detrital muscovite as a proxy climatic indicator are evaluated. The muscovite content at 0-35 cm level is low, but thereafter three prominent maxima at 35-45 cm (10-11.5 ky BP), 55-60 cm (approx. 13 ky BP), and 78-100 cm (18-22 ky, BP) levels have been observed. The characteristic clay mineral illite has a positive spurt at 40-45 cm and chlorite at 35-40 (11.5 ky BP), 55-60 (approx. 13 ky BP) and 78-85 (18 ky BP) cm levels. The silt content and C/l ratio at these times are increased. The observed temporal variations are attributed to changes in the paleoclimatic conditions in the Himalayas, shifting of fluvial source and supply of coarse silt as a result of sea level fluctuations
Collections
- Scholarly literature [8765]