Summary of Abstract Submission

Abstract Submission No. IO50-11-0031PresentationPoster

MARINE GEOPHYSICAL STUDIES FOR IDENTIFICATION OF MEGAMULLIONS OVER THE SLOW SPREADING RIDGES IN THE INDIAN OCEAN

Kiranmai Samudrala*1, K.A. Kamesh Raju1

1 National Institute of Oceanography, India

ABSTRACT :

Indian Ocean is the third largest of the world┐s oceanic divisions, covering about 20% of the water on the earth┐s surface. Indian Ocean was formed as a result of fragmentation of Gondwanaland and the spreading among the African, Indian and Antarctic plates. In this context, the Carlsberg and the Central Indian Ridges represent the boundary between Indian and African plates. Detailed high resolution marine geophysical investigations consisting of magnetics and multibeam bathymetry have been carried out over the Carlsberg Ridge and Central Indian Ridge, which are located between Owen fracture zone and Indian Ocean triple junction (Rodriguez Triple Junction) under the Indian Ridge program. We analyzed the data to study magmatic and less magmatic segments of the Carlsberg and Central Indian Ridges. The ridge segments have been classified into magmatic and amagmatic ridge segments based on the rift valley configuration and off axis morphology. Several ridges are associated with megamullion structures (Oceanic Core Complex), which are seabed geologic features that forms a long ridge perpendicular to the mid-ocean ridge. Compared to Carlsberg Ridge segments, well defined megamullions are confined only at Central Indian Ridge segments. Combinations of magmatic and less magmatic segments characterize both Carlsberg and Central Indian ridges sections. Magmatic segments are associated with well defined transform faults while the less magmatic sections are often associated with Non-transform Discontinuities .The identified megamullion structures are associated with amagmatic ridge segments. Discovery of megamullion structures over the CIR is an important finding of the present study.