a r t i c l e i n f o a b s t r a c t Isostatic and dynamic models of Earth's surface topography can provide important insights into the driving processes of tectonic deformation. We analyze these two estimates for the tectonically-active western United States using refined structural models derived from EarthScope USArray. For the crust, use of recent Moho depth measurements and crustal densit...

The Re-Os isotope system is increasingly providing new insight into continental dynamics due to the fact that it is the only radiogenic isotope system that provides information on melt depletion events (hence lithosphere formation) in the uppermost mantle. Here we review application of the ReOs isotopic system to dating melt depletion in peridotites. In particular, we highlight examples of how ...

Elastic anisotropy is present where the speed of a seismic wave depends on its direction. In Earth's mantle, elastic anisotropy is induced by minerals that are preferentially oriented in a directional flow or deformation. Earthquakes generate two seismic wave types: compressional (P) and shear (S) waves, whose coupling in anisotropic rocks leads to scattering, birefringence, and waves with hybr...

The Earth is a wet planet, where water is recycled from the mantle to the surface and back again. The mantle is generally too hot for the stability of hydrous minerals and too cold to store water within significant melt sheets. Therefore, the current paradigm in geosciences is that water resides and moves only through point defects in nominally anhydrous minerals such as olivine, pyroxene and g...

[1] Phase equilibrium experiments on primitive Miocene olivine leucitite (Bb-107) from the Qiangtang terrane of the Tibetan Plateau were performed from 1.0 to 2.2 GPa and 1270 to 1440 C. The composition is multiply saturated with olivine and clinopyroxene from 1.2 to 2.2 GPa and 1340 C under nominally anhydrous conditions. Phase assemblages in the experiments have been used to model the effects...

[1] Broadband seismic experiments over the last two decades have produced dense data coverage across Tibet. Yet, the mechanism of the India-Asia lithospheric convergence beneath it remains a puzzle, with even its basic features debated and with very different end-member models advocated today. We measured highly accurate Rayleighand Love-wave phase-velocity curves in broad period ranges (up to ...

Seismic tomography models of the three-dimensional upper mantle velocity structure of the Mediterranean-Carpathian region provide a better understanding of the lithospheric processes governing its geodynamical evolution. Slab detachment, in particular lateral migration of this process along the plate boundary, is a key element in the lithospheric dynamics of the region during the last 20 to 30 ...

Bending of lithospheric plates at subduction zones is thought to be an important source of dissipation for convection in the Earth's mantle. However, the influence of bending on plate motion is uncertain. Here we use a variational description of mantle convection to show that bending strongly affects the direction of plate motion. Subduction of slabs and subsidence of oceanic lithosphere with a...

The rheology of Earth’s mantle is a complex function that depends on, at least, temperature, pressure, stress, grain size, and water content. Understanding this functionality is of fundamental importance in mantle dynamics, but constraints from laboratory experiments entail considerable extrapolation. Here we propose a new observational approach based on a unique tectonic setting of the Kaapvaa...

Findings of coesite and microdiamond in metamorphic rocks of supracrustal protolith led to the recognition of continental subduction to mantle depths. The crust-mantle interaction is expected to take place during subduction of the continental crust beneath the subcontinental lithospheric mantle wedge. This is recorded by postcollisional mafic igneous rocks in the Dabie-Sulu orogenic belt and it...