MAGNETIC STUDIES IN THE NORTHERN BAY OF BENGAL

Total magnetic intensity and bathymetric surveys were carried out in t he northern Bay of Bengal between 6-degrees to 11-degrees 45'N latitud es and east of 84-degrees to 93-degrees 30' E longitudes. The hitherto known 85-degrees-E Ridge is characterised as a subsurface feature by a large amplitude, positive magnetic anomaly surrounded by Mesozoic cr ust. A newly identified NE to NNE-SSW trending magnetic anomaly betwee n 7-degrees-N, 87-degrees-30' E and 10-degrees 30'N, 89-90-degrees-E m ay be one of the unidentified Mesozoic lineations in the northern Bay of Bengal. The Ninetyeast Ridge is not associated with any recognizabl e magnetic anomaly. The Sunda Trough to the east of the Ninetyeast Rid ge is characterised by a positive magnetic anomaly. A combined interpr etation, using Werner deconvolution and analytical signal methods, yie lds basement depths approximately 10 km below sea level. These depths are in agreement with the seismic results of Curray (1991).