GEOPHYSICAL INVESTIGATIONS OVER A SEGMENT OF THE CENTRAL INDIAN RIDGE, INDIAN-OCEAN

Swath bathymetric, gravity, and magnetic studies were carried out over a 55 km long segment of the Central Indian Ridge. The ridge is charac terized by 12 to 15 km wide rift valley bounded by steep walls and pro minent volcanic constructional ridges on either side of the central ri ft valley. A transform fault at 7 degrees 45'S displaces the ridge axi s. A mantle Bouguer anomaly low of -14 mGals and shallowing of rift va lley over the middle of the ridge segment indicate along axis crustal thickness variations. A poorly developed neovolcanic zone on the inner rift valley floor indicate dominance of tectonic extension. The off-a xis volcanic ridgs suggest enhanced magmatic activity during the recen t past.