[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...

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...

S U M M A R Y We compare 3-D upper mantle anisotropic structures beneath the North American continent obtained using standard and improved crustal corrections in the framework of Non-linear Asymptotic Coupling Theory (NACT) applied to long period three component fundamental and higher mode surface waveform data. Our improved approach to correct for crustal structure in high-resolution regional ...

Chromitite lenses rich in the platinum-group elements (PGE) have recently been discovered in the deeper part of the mantle section of the northern part of the Oman ophiolite. In terms of stratigraphic level, there are two types of chromitite: Moho transition zone (MTZ) and mantle types. The mantle type can be further classified into two subtypes: PGE-poor and PGE-rich. Platinum-group minerals (...

We investigate the role that upper mantle buoyancy anomalies play in determining behavior of crust. Recently, Castellanos et al. (2020; https://doi.org/10.1126/sciadv.abb0476) observed anisotropy Pacific Northwest (PNW) crust correlates with upper-mantle velocity structure and suggested vertical loads can displace Moho drive crustal flow on a regional scale. To provide further insight into this...

[1] We utilize seismic converted phases on more than 700 receiver functions calculated for 42 stations in the South Island, New Zealand, to infer crustal and uppermost mantle structure. We determine the crustal thickness from direct observations of conversion from the Moho interface and infer zone of the maximum thickness being located along the axis of the Southern Alps, just east from the Alp...

[1] Between June 2003 and September 2005, 20 broadband, three-component seismometers were deployed along the MacKenzie-Liard Highway in Canada’s Northwest Territories as part of the joint Lithoprobe-IRIS Canada Northwest Experiment (CANOE). These stations traverse a paleo-Proterozoic suture and subduction zone that has been previously documented to mantle depths using seismic reflection profili...

[1] Arc volcanism is intimately linked to mineral dehydration reactions in the subducting oceanic mantle, crust, and sediments. The location of slab dehydration reactions depends strongly on the temperature and pressure conditions at the top of the subducting plate and hence on the detailed thermal structure of subduction zones. A particularly important physical property of subduction zone ther...

Abstract Lithospheric deformation is a fundamental process in plate tectonics. It is, therefore, critical to determine how the lithosphere responds geological loads better understand tectonic processes. The can be modelled as flexure of thin, elastic over long-term (> 10 5 yr) timescales. partial differential equation for an orthotropic used indirectly calculate theoretical admittance and co...

[1] Residual mantle exposures in the accreted Talkeetna arc, Alaska, provide the first rock analog for the arc-parallel flow that is inferred from seismic anisotropy at several modern arcs. The peridotites exposed at the base of the Jurassic Talkeetna arc have a Moho-parallel foliation and indicate dislocation creep of olivine at temperatures of 1000 to >1100 C. Slip occurred chiefly on the (00...