Gravity anomalies and crustal structure of the western continental margin off Goa and Mulki, India

Abstract

Bathymetric and gravity data totalling 2000 line kilometres on the continental margin off Goa and Mulki, India, have been studied and prominent NNW-SSE and ENE-WSW trending free-air gravity anomalies varying between -60 + 25 mGal have been identified. Using constraints from seismic refraction and reflection and well log results the thicknesses of the layers are estimatEd. by computing two-dimensional crustal structure models for the free-air gravity anomalies. The study suggests that (1) there are three layers varying in thickness from 0.5 to 4.0 km, 0.5 to 12.0 km and from 14.0 to 26.0 km with densities of 2.3, 2.6 and 2.9 g/cm3 which are interpreted as sedimentary, granitic and mafic/basaltic layers respectively, (2) there is a maximum thickness of 4.0 km of sediment over the shelf margin basin, and (3) the Moho occurs at a depth of 24-30 km.