Abstract: Structural Framework and Distribution of Synrift Depocenters in Cambay Rift Basin, Western India

KUNDU, J., A. PRAKASH, B. PRASAD, KDMIPE

The Campay rift is a linear Cenozoic extensional basin located on western margin of Indian Precambrian shield. The Cenozoic sediments, floored by the Deccan basalts, typically show two-tier geometry corresponding to synrift and postrift sequences. In synrift succession, the geometries of extensional fault systems have been mapped.

The extensional architecture of the basin is defined by two types of faults, namely, listric normal faults striking north-south to north-northwest - south-southeast and transfer faults trending east-northeast - west-southwest to northeast - southwest. Multiple listric faults with frequent polarity changes is common in the rift zone subparallel to the rift border in north and at low angle to it in the southern part. Transfer faults offset the listric faults and also the rift-border faults. These fault systems compartmentalize the basin into 16 distinct structural domains bordered by major transfer faults. The geometry of synrift wedges reveals existence of numerous asymmetric half grabens forming discrete depocenters in early Paleocene. 88 half -grabens of varying dimensions have been recognized; of these 26 have formed major depocenters in the early stage of basin evolution. Hydrocarbon generation potential of the late synrift sequence (Late Paleocene - Early Eocene) is known only for 15 major half-grabens.

Based on the analysis of extensional fault systems, changes in polarities of major half-grabens, their disposition in eight tectonic blocks and distribution of transfer zones, an orthogonal rifting model is envisaged for the northern part and oblique rifting for the south.

AAPG Search and Discovery Article #90942©1997 AAPG International Conference and Exhibition, Vienna, Austria