European and Siberian lithospheric thermo-chemical heterogeneity and density structure.

Abstract

We present a new combined model for the density structure of the lithospheric upper mantle beneath Europe and Siberia, based on a 3D tesseroid gravity modeling. Our results are based on the EuNaRho model (Shulgin & Artemieva, 2019) complimented by similar modeling approach for Siberia. For Siberia modeling is preformed based on a detailed crustal structural database SibCrust (Cherepanova et al., 2013) constrained by regional seismic data. The presented residual lithospheric mantle gravity anomalies are derived by removing the 3D gravitational effect of the crust. Later, these anomalies are converted to lithosphere mantle in situ densities. To evaluate chemical heterogeneities of the lithospheric mantle, thermal effects are removed based on the global continental thermal model TC1 (Artemieva, 2006). The resulting density model at SPT conditions shows a highly heterogeneous structure of the cratonic lithospheric mantle, and distinct change at the transition between different tectonic units. We speculate on the origin of these anomalies.