MESOZOIC ANOMALIES IN THE BAY OF BENGAL

The analysis of 8200 line km of total magnetic intensity data in the B ay of Bengal, northeastern Indian Ocean, revealed the presence of appr oximately N30-degrees-E-trending seafloor spreading type magnetic anom alies. These anomalies resemble the Mesozoic anomaly series (M11-M0) r eported elsewhere. The oldest anomaly (M11, 132.5 Ma) identified close to the east coast of India is followed by the younger series of Mesoz oic anomalies towards the offshore. Some of the anomalies are offset b y 60-80 km. The configuration of the offsets of the isochrons allowed us to propose approximately N120-degrees-E-trending oceanic fracture z ones. The Mesozoic crust of 132.5-118 Ma is estimated to evolve with a n average half-spreading rate of 3.5 cm/yr, except for the ocean floor between the M9 and M4 magnetic isochrons. This part of the crust appe ars to be affected by the buried subsurface 85-degrees-E Ridge.