Geomorphic evolution of Talchappar salt lake, Churu District, Rajasthan

Talchappar salt lake (4-5 km in length and 3 km in breadth) is near Devani, Churu District, Rajasthan. This saline lake is bounded on its south south-west direction by obstructed stabilized sand sheets and dunes against the Gopalpura quartzitic monadknocks. Well sections dug out in this saline lake revealed the lithological sequence of fluvio-aeolian and lacustral organic rich clays overlying the chlorite hornblende gneisses and the hardpan calcretes. The deposit at depth of 1•7m in the organic rich clays has been dated by 14 C method to 6620 ± 170 B.P. (PRL 915). The fluvio-aeolian sediments and the clastic lacustral organic-rich clays could have been deposited since the Late Middle Pleistocene period when the climate fluctuated between semi-arid to sub-humid conditions. Geomorphological, structural, sedimentological and micromorphological studies of the different lithological units of this salt lake reveal that the evolution of the lake is an early Quaternary phenomenon. Palaeoclimate and neotectonic activity in the catchment area of the basin has played a vital role in the initial phase of lake basin development.