Status and Age of the Red Beds in Krishna - Godavari Basin (India) and their Relationship with Hydrocarbon Occurrences

Palynological studies carried out on the "red beds" encountered in the subsurface sections of Krishna-Godavari Basin establish the occurrence of two distinct red beds; the older of Triassic age, deposited in fluvial intracratonic Pranhita-Godavari Graben and equated with the Maleri rocks of Central India and an younger one of Early Cretaceous (Neocomian - Barremian) age, deposited during synrift stage of the Krishna-Godavari Basin in marginal to shallow marine environment, corresponding to the red claystones of Gollapali Formation. A major hiatus of about 80 Ma is present between the two red beds involving the absence of latest Triassic and major part of Jurassic sediments.

The gaseous pay-sand zones in Mandapeta and Ramchandrapuram structures which lie just below the Cretaceous red beds, belong to the Gollapali Sandstone and indicate Early Cretaceous (Neocomian-Barremian) age. The Cretacous red beds are considered to serve as caprocks for hydrocarbon accumulation in these pay-sands.