Lithospheric thermo-chemical heterogeneity and density structure of the Siberian craton

Abstract

<p>We present a new model for the density structure of the lithospheric upper mantle beneath the Siberian craton, based on a 3D tesseroid gravity modeling. Our model is based on a detailed crustal structural database SibCrust (Cherepanova et al., 2013) constrained by regional seismic data. The residual lithospheric mantle gravity anomalies are derived by removing the 3D gravitational effect of the crust. We next convert these anomalies 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. Density heterogeneities reflect a complex geodynamic evolution of the craton, which still preserves parts of the pristine cratonic lithosphere in areas where the lithosphere has not been modified by metasomatism associated with the Siberian LIP, several pulses of kimberlite-type magmatism, and rifting at the peripheral parts.</p>