Rayleigh wave group velocity mapsRayleigh wave group velocity maps

At short periods, group velocities are slow because of the thick, slow crust

At long periods, group velocities are neutral to fast because the crust is compensated by fast material in the upper mantle

At short periods, group velocities are slow because of the thick, slow crust

At long periods, group velocities are neutral to fast because the crust is compensated by fast material in the upper mantle

Mantle structure: depth slicesMantle structure: depth slices

Low-velocity uppermost mantle beneath North-Central Tibet

Low-velocity uppermost mantle beneath North-Central Tibet

High-velocity material at 200 km beneath most of Tibet

High-velocity material at 200 km beneath most of Tibet

Mantle structure:slice across Western Tibet

Mantle structure:slice across Western Tibet

Subduction of Indian lithosphereSubduction of Indian lithosphere

Mantle structure:slice across Central Tibet

Mantle structure:slice across Central Tibet

Detached lithosphereDetached lithosphere

Mantle structure:slice across Eastern Tibet

Mantle structure:slice across Eastern Tibet

Subduction of Asian lithosphere ???Subduction of Asian lithosphere ???

Main Belt Thrust

Yarlung-Zangbo Suture

Bangong-Nujiang Suture

Jinsha River Suture Kunlun Fault

Altyn Tagh Fault

Interpretation of the tomographic model for Tibetan region

Interpretation of the tomographic model for Tibetan region

Western Tibet1. Subduction of the Indian lithosphere2. Penetration of hot asthenospheric material

from the North3. Strong mid-crustal anisotropy is probably

caused by the extended ductile deformation of the crust

Western Tibet1. Subduction of the Indian lithosphere2. Penetration of hot asthenospheric material

from the North3. Strong mid-crustal anisotropy is probably

caused by the extended ductile deformation of the crust

0

300

dept

h (k

m)

Central Tibet1. Lithospheric detachment2. Penetration of hot asthenospheric material

from the North3. Strong mid-crustal anisotropy is probably

caused by the extended ductile deformation of the crust

Central Tibet1. Lithospheric detachment2. Penetration of hot asthenospheric material

from the North3. Strong mid-crustal anisotropy is probably

caused by the extended ductile deformation of the crust

0

300

dept

h (k

m)

Eastern Tibet1. Possible subduction of the Asian lithosphere2. Possible penetration of hot asthenospheric

material from the South3. Mid-crustal anisotropy is weaker than in

Western and Central Tibet

Eastern Tibet1. Possible subduction of the Asian lithosphere2. Possible penetration of hot asthenospheric

material from the South3. Mid-crustal anisotropy is weaker than in

Western and Central Tibet

0

300

dept

h (k

m)