Journal of Geological Society of India (Online archive from Vol 1 to Vol 78)

Indra Bir Singh ¹, Ajai Kumar Bhargava ¹, Vikram Rai ¹

Affiliations
1 Geology Department, Lucknow University, Lucknow-226 007, IN

Abstract

Study of sedimentary structures indicate that Krol succession of Mussoorie area represents deposits of a shallow tidal sea: Krol A-deposits of open sea tidal flats in intertidal-subtidal zone. Krol B - deposits of protected embayment Or lagoon, Krol C - open tidal flats to intertidal zone of restricted tidal flat, Krol D - algal mat facies of inner intertidal to supratidal zone with increased salinity, Krol E - intertidal zone. The algal mat facies of Krol E shows dominantly Loferite, fenestral dolomite or bird's eye dolomite, showing different types of shrinkage cracks e.g. sheet cracks, irregular fenestral fabric, shrinkage pores. The supratidal facies is quite abundant, represented by vuggy dolomite and bird's eye pisolitic dolomite.

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Vikram Rai ¹

Affiliations
1 Geological Survey of India, Jaipur, IN

Abstract

Pokaran Rann occupies an area of 12.0 sq. km in Jaisalmer District of Rajasthan, resting over the basement rocks of Marwar Supergroup. Five distinct litho-facies are recognized in a basin developed along E-W-trending linear stretch of palaeo-course after calcification. The base of the sequence consists of inter-laminated clay /gypsite unit. This unit grades into carbonate-rich clay showing pede-calcic pedogenesis. After a break in sedimentation, highly bio-turbated clays were deposited probably during a prominent humid phase. This was followed by present day semi-arid climatic conditions which resulted in the formation of silt to silty-clay deposits.

Keywords

Sedimentology, Facies, Pokaran, Jaisalmer, Rann, Rajasthan, Saline Jake.

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