Calcrete and Gypsum Crusts of the Thar Desert, Rajasthan, their Geomorphic Locales and Use as Palaeoclimatic Indicators

Calcrete and gypsum crusts in Churu-Bikaner areas of the Thar desert, are presently found buried under a cover of aeolian sediments. Non-pedogenic and pedogenic calcrete types occur in various geomorphic locales like, channels, flood plains, pediments etc. Also, different non-pedogenic channel and lacustrine basin-fill gypsum crusts are noted. The occurrences of surface and near surface calcrete, gypsum crusts, their presence in representative sub-surface sequences of fluvio-aeolian sediments indicate climatic vicissitudes in the Late Quaternary from humid to arid and vice versa.