Location of the Africa-Australia-India Triple Junction and Motion Between the Australian and Indian Plates: Results From an Aeromagnetic Investigation of the Central Indian and Carlsberg Ridges

Abstract

Accepted 1994 June 7. Received 1994 May 23; in original form 1993 May 24 SUMMARY Prior studies have proposed and examined the hypothesis that India and Australia are separate rigid plates separated by a wide, near-equatorial, E-W striking, plate boundary. Attempts to place narrow limits on the location of the Africa-AustraliaIndia triple junction have been hindered, however, by the lack of useful magnetic profiles crossing the eastern Carlsberg Ridge and northern Central Indian Ridge. Herein we present near-ridge portions of new profiles from an aeromagnetic survey of the Carlsberg Ridge east of 66E and of the Central Indian Ridge north of 19s. These new data are used to estimate 35 new spreading rates averaged from the middle of chron 2A (3.03 Ma) to the present. All other plate motion data along the Central Indian and Carlsberg ridges are also analysed to investigate the present kinematics of the Indian Ocean, especially the motion and boundary between the Indian and Australian plates. Unlike prior efforts, we objectively estimate uncertainties in the strikes of transform faults along the Carlsberg and Central Indian ridges.