Seismic signature of the collision between the east Tibetan escape flow and the Sichuan Basin

Physics

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

7

Scientific paper

GPS displacement vectors show that the crust in east Tibet is being squeezed in an easterly direction by the northward motion of the Indian plate, and the Sichuan Basin is resisting this stream and redirecting it mainly towards Indochina. The Longmen Shan, containing the steepest rise to the high plateau anywhere in Tibet, results from the strong interaction between the east Tibetan escape flow and the rigid Yangtze block (Sichuan Basin), but the kinematics and dynamics of this interaction are still the subject of some debates. We herein present results from a dense passive-source seismic profile from the Sichuan Basin into eastern Tibet in order to study the deep structure of this collision zone. Using P and S receiver function images we observe a sudden rise of the Lithosphere-Asthenosphere Boundary (LAB) from 120 to 150 km beneath the Sichuan Basin and from 70 to 80 km beneath eastern Tibet. In contrast, the depth of the crust-mantle boundary (Moho) increases from 36 to 40 km beneath the Sichuan Basin and from 55 to 60 km beneath eastern Tibet. The 410 km discontinuity is depressed below eastern Tibet by about 30 km, although the 660 remains at nearly the same depth throughout the LMS. From these observations, we conclude that the mode of collision that occurs between Tibet and the Sichuan Basin is very different to that found between India and Tibet. In southern Tibet, we observe in essence the subduction of the Indian plate, which penetrates northwards for several hundred kilometers under central Tibet. The very thin mantle part of the lithosphere beneath eastern Tibet may indicate delamination or removal of the bottom of the lithosphere by hot asthenospheric escape flow. This process leads to the exceptionally steep topography at the eastern Tibetan margin as a result of gravitational buoyancy. This view is supported by the very unusual depression of the 410 km discontinuity beneath eastern Tibet, which could be caused by the dynamics of the sub-vertical downward asthenospheric flow.

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

Seismic signature of the collision between the east Tibetan escape flow and the Sichuan Basin does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Seismic signature of the collision between the east Tibetan escape flow and the Sichuan Basin, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Seismic signature of the collision between the east Tibetan escape flow and the Sichuan Basin will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-1314524

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.