Where ρ0, α0, ∆T , η, κ are dimensional reference values of density of the background mantle, thermal expansivity, temperature difference between core-mantle boundary and surface, reference viscosity at temperature T = 0.5 (non-dimensional), and thermal diffusivity, respectively. g and h are dimensional gravitational acceleration and thickness of mantle, respectively. 1 Chemical complexity of h...

The effect of volatde exchange between surface reservoirs and the mantle on the evolution of proto-CO 2 atmosphere on the Earth is investigated using a global carbon cycle model coupled with thermal evolution of the mantle. Carbon is assumed to circulate among five reservoirs (atmosphere, ocean, continents, seafloor and mantle) and the carbon flux of each reservoir is calculated under varying c...

Subduction modifies the cycling of Earth’s volatile elements. Fluid-rich sediments and hydrated oceanic lithosphere enter the convecting mantle at subduction zones. Some of the sediments and volatile components are released from the subducting slab, promote mantle melting and are returned to the surface by volcanism. The remainder continue into the deeper mantle. Quantification of the fate of t...

Introduction: It has long been recognized that lunar mantle is chemically, isotopically, and lithologically heterogeneous. The heterogeneities are ancient and were formed during large-scale differentiation events, such as the solidification of a globally distributed lunar magma ocean (LMO) and subsequent lunar cumulate mantle overturn [1-3]. Mixing of distinct early and late LMO cumulates resul...

We have previously presented a model for the distribution and transport of rare gases within the Earth [1,2,3,4] which explains the available observational data for mantle He, Ne, Ar, and Xe isotope compositions and provides specific prdctions regarding the rare gas isotopic compositions of the lower mantle, interactions between rare gas reservoirs, and mantle rare gas concentrations. Here we d...

[1] The character of the mantle flow field in subduction zones remains poorly understood, despite its importance for our understanding of subduction dynamics. In particular, little attention has been paid to mantle flow beneath subducting slabs. In order to identify processes that make first-order contributions to the global pattern of subslab mantle flow, we have compiled shear wave splitting ...

The initial melting of mantle plumes produced unparalleled volumes of lava that formed large igneous provinces (LIPs). These events were sometimes so large that they triggered catastrophic mass extinctions and oceanic anoxic events. Global tomography and numerical models suggest that mantle plume occurrences are closely linked to the margins of the large low shear velocity provinces (LLSVPs) lo...

High-MgO (s 8.5 wt%), aphyric lavas erupted at various locations in the North Atlantic igneous province are utilized to characterize the nature of mantle melting during the formation of this province. Based on the observation that the Ni concentration in residual mantle olivine mostly falls in the range of 2000^3500 ppm, these high-MgO samples are corrected for olivine fractionation until the N...

S U M M A R Y Measurements of seismic anisotropy are commonly used to constrain deformation in the upper mantle. Observations of anisotropy at mid-mantle depths are, however, relatively sparse. In this study we probe the anisotropic structure of the mid-mantle (transition zone and uppermost lower mantle) beneath the Japan, Izu-Bonin, and South America subduction systems. We present source-side ...

[1] A formal inverse procedure is used to infer radial mantle viscosity profiles from several observations related to the glacial isostatic adjustment process. The data sets consist of Late Pleistocene and Holocene sea level data from Scandinavia, the Barents Sea, Central Europe, Canada, and the far field, as well as observations of changes in the Earth’s rotation and gravitational field, and p...