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The Gondwanaland assembly rifted dominantly during Late Carboniferous-Early Permian forming several intracratonic rift basins. These rifts were subsequently filled with a thick sequence of continental clastic sediments with minor marine intercalations in early phase. In western part of India, these sediments are recorded in enclaves of Bikaner-Nagaur and Jaisalmer basins in Rajasthan. Facies correlatives of these sediments are observed in a number of basins that were earlier thought to be associated with the western part of India. The present work is a GIS based approach to reconnect those basins to their position during rifting and reconstruct the tectono-sedimentary environment at that time range. The study indicates a rift system spanning from Arabian plate in the north and extending to southern part of Africa that passes through Indus basin, western part of India and Madagascar, and existed from Late Carboniferous to Early Jurassic. Extensions related to the opening of Neo-Tethys led to the formation of a number of cross trends in the rift systems that acted as barriers to marine transgressions from the north as well as disrupted the earlier continuous longitudinal drainage systems. The axis of this rift system is envisaged to pass through present day offshore Kutch and Saurashtra and implies a thick deposit of Late Carboniferous to Early Jurassic sediments in these areas. Based on analogy with other basins associated with this rift system, these sediments may be targeted for hydrocarbon exploration.

In the West Bengal part of the Bengal Basin, even after five decades of seismic-based hydrocarbon exploration no commercial finds have been identified. Deep drilling revealed the presence of hydrocarbon within the thick sedimentary sequence ranging from Gondwana to Recent. However, well-defined structures suitable for hydrocarbon pool in shallower sediments are apparently not visible in seismic data. In this article, a parallel approach to seismic exploration has been attempted to delineate shallow and subtle structures in the shelf area based on analysis of surface geomorphic data. The study identifies subtle structures in shallow sediments that entrap the remigrated hydrocarbons as well as envisages a multistoried, stacked model of hydrocarbon accumulations in the area. These areas are considered as promising targets and recommended for high-resolution seismic and close grid micro-gravity exploration survey for further detailing.

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