CALCRETE AND GYPSUM CRUSTS OF THE THAR DESERT, RAJASTHAN, THEIR GEOMORPHIC LOCALES AND USE AS PALEOCLIMATIC INDICATORS

Calcrete and gypsum crusts in Churu-Bikaner areas of the Thar desert, are presently found buried under a cover of aeolian sediments. Non-ped ogenic and pedogenic calcrete types occur in various geomorphic locale s like, channels, flood plains, pediments etc. Also, different non-ped ogenic 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 se diments indicate climatic vicissitudes in the Late Quaternary from hum id to arid and vice versa.