HR: 1340h
AN: T23A-1199    [Abstracts]
TI: The Rapid Drift of the Indian Tectonic Plate
AU: Kumar, P
EM: prakashngri@rediffmail.com
AF: NGRI, Uppal Road, Hyderabad, 500007, India
AU: Yuan, X
EM: yuan@gfz-potsdam.de
AF: GFZ, Telegrafenberg, Potsdam, 14473, Germany
AU: Kumar, R
EM: mangalampallyravikumar@rediffmail.com
AF: NGRI, Uppal Road, Hyderabad, 500007, India
AU: * Kind, R
EM: kind@gfz-potsdam.de
AF: GFZ, Telegrafenberg, Potsdam, 14473, Germany
AU: Li, X
EM: li@gfz-potsdam.de
AF: GFZ, Telegrafenberg, Potsdam, 14473, Germany
AU: Chadha, R
EM: chadha@ngri.res.in
AF: NGRI, Uppal Road, Hyderabad, 500007, India
AB: The breakup of the supercontinent Gondwanaland into Africa, Antarctica, Australia and India about 140 million years ago and consequently the opening of the Indian Ocean was caused by heating of the lithosphere from below by a large plume whose relicts are the Marion, Kerguelen and Reunion plumes. Plate reconstructions based on paleomagnetic data suggest that the Indian plate attained a very high speed (18-20 cm/yr during late Cretaceous) subsequent to its breakup from the Gondwanaland and slowed down to ~5 cm/yr since the continental collision with Asia during the last ~50 Ma. The Australian and African plates moved comparatively lesser distances and at much lesser speed of 2-4 cm/yr. Antarctica remained almost stationary. This super mobility makes India unique compared to the other fragments of Gondwanaland. We propose that when the parts of Gondwanaland were separated by the plume, the penetration of their lithospheric roots into the asthenosphere played an important role in determining their speed. We estimated the thickness of the lithospheric plates of the different parts of Gondwanaland around the Indian Ocean using the S-receiver function technique. We found that the part of Gondwanaland with clearly the thinnest lithosphere has travelled with the highest speed - India. The lithospheric root in South Africa, Australia and Antarctica is between 180 and 300 km deep. The Indian lithosphere is in contrast only about 100 km thick. Our interpretation is that the plume that partitioned Gondwanaland has also melted the lower half of the Indian lithosphere thus permitting faster motion due to the ridge push or slab pull.
DE: 1236 Rheology of the lithosphere and mantle (7218, 8160)
DE: 8120 Dynamics of lithosphere and mantle: general (1213)
DE: 8155 Plate motions: general (3040)
SC: Tectonophysics [T]
MN: 2007 Fall Meeting