A tomographic image of the upper mantle beneath central Tibet from INDEPTH data has revealed a subvertical high-velocity zone from approximately 100- to approximately 400-kilometers depth, located approximately south of the Bangong-Nujiang Suture. We interpret this zone to be downwelling Indian mantle lithosphere. This additional lithosphere would account for the total amount of shortening in t...

[1] Satellite gravity inversion incorporating a lithosphere thermal gravity correction has been used to map crustal thickness and lithosphere thinning factor for the NE Atlantic. Predicted oceanic crustal thicknesses in the Norwegian Basin are between 4 and 7 km on the extinct Aegir Ridge, increasing to 9 – 14 km at the margins, consistent with volcanic margin continental breakup at the end of ...

[1] We present evidence for the existence of an Australian-Antarctic Mantle Anomaly (AAMA), which trends northwest-southeast (NW-SE) through the Australian-Antarctic Discordance (AAD) on the Southeast Indian Ridge (SEIR), is confined to the upper 120 km of the mantle beneath the AAD, and dips shallowly to the west so that it extends to a depth of about 150 km west of the AAD. Average temperatur...

To improve the understanding of formation and evolution sub-continental lithospheric mantle (SCLM) underlying South Australian Craton we have conducted a detailed petrological study on >3,000 xenocrysts from 13 kimberlites emplaced across craton. Pressure (P) temperature (T) estimates Cr diopside garnet been coupled with their chemical concentrations to constrain thickness chemo-lithostratigrap...

On Earth, the velocity at which subducting plates are consumed their trenches (termed “subduction rate” herein) is typically 3 times higher than trench migration velocities. The subduction rate also 5 estimated lower mantle slab sinking rates. Using simple kinematic analyses, we show that if this present-day “kinematic state” operated into past, lithosphere should have accumulated and folded be...

We use two-plane-wave tomography with a dense network of seismic stations across Sabah, northern Borneo, to image the shear wave velocity structure crust and upper mantle. Our model is used estimate crustal thickness depth lithosphere-asthenosphere boundary (LAB) beneath region. Calculated ranges between 25 55 km suggests extension in NW-SE direction, presumably due back-arc processes associate...

The fate of the colliding Indian and Asian tectonic plates below the Tibetan high plateau may be visualized by, in addition to seismic tomography, mapping the deep seismic discontinuities, like the crust-mantle boundary (Moho), the lithosphere-asthenosphere boundary (LAB), or the discontinuities at 410 and 660 km depth. We herein present observations of seismic discontinuities with the P and S ...

Cold mantle lithosphere is gravitationally unstable with respect to the hotter buoyant asthenosphere beneath it, leading to the possibility that the lower part of the mantle lithosphere could sink into the mantle in convective downwelling. Such instabilities are driven by the negative thermal buoyancy of the cold lithosphere and retarded largely by viscous stress in the lithosphere. Because of ...