The Rodriguez Triple Junction (Indian Ocean): Structure and evolution for the past one million years

The Rodriguez Triple Junction (RTJ) corresponds to the junction of the 3 Indian Ocean spreading ridges. A detailed survey of an area of 90 km by 85 km, centered at 25 degree 30 degree S and 70 degree E, allows detailed mapping (at a scale of 1/100,000) of the bathymetry (Seabeam) and the magnetic anomalies. The Southeast Indian Ridge, close to the triple junction, is a typical intermediate spreading rate ridge (2.99 cm/a half rate) trending N140 degree . The Central Indian Ridge rift valley prolongs the Southeast Indian Ridge rift valley with a slight change of orientation (12 degree ). The half spreading rate and trend of this ridge are 2.73 cm/a and N152 degree respectively. A model is proposed to explain the evolution of the unstable RRF Rodriguez Triple Junction