Mapping Absolute Migration of the Indian Triple Junction Since 75 Ma and Implication for its Evolution

ABSTRACT

The absolute migration of the Indian Triple Junction (ITJ) or also known as the Rodriguez Triple Junction (RTJ) has been mapped using published data. The ITJ is made of the Southwest Indian Ridge (SWIR), the Central Indian Ridge (CIR) and the Southeast Indian Ridge (SEIR). The traces of the ITJ on the three plates (Africa, Antarctica, and Australia) were reconstructed to their former positions in the hotspot reference frame to map its absolute migration for the past 75 million years. The ITJ migrated northeasterly at a speed of 10 cm/yr at 70 Ma that declined gradually to 2.6 cm/yr at 43 Ma and thereafter remaining almost constant about 3.6-3.8 cm/yr, in a fairly straight trajectory suggesting a stable configuration of the ITJ since its formation. Because the most stable configuration known is the Ridge-Ridge-Ridge (RRR) triple junction, it is suggested that the configuration of the ITJ has been largely an RRR triple junction since its formation.