Abstract

Aeromagnetic data over the Cauvery basin in south-eastern India was examined in the light of known basement structure inferred from gravity and seismic data. Although the major tectonic elements of the basin could be delineated from aeromagnetics, the basement trends inferred from gravity and aeromagnetics differ in their orientations. The gravity trends oriented in NNE-SSW direction appear to be dominated by the Eastern Ghat trend while those shown from aeromagnetic data are mainly NE-SW and ENE-WSW. The gravity anomalies also reveal that the basement beneath the basin might belong to the Eastern Ghat group than the expected peninsular gneissic complex. The unusual increase of gravity anomaly from about -100 mGal to the west of the basin to about 10 mGal within the basin might be attributed to collision tectonics and suturing, the suture zone roughly located along the western margin of the basin. Further interpretation of gravity and aeromagnetic anomalies by means of residual and pseudo-gravity maps reveal that the sedimentary thickness is maximum in the Ariyalur