Heterogeneity of the Uppermost Eurasian Mantle along the DSS Profile “Quartz”, Russia

Abstract

The ultra-long Deep Seismic Sounding (DSS) profile “Quartz’ crosses 6 major geologic provinces in Eurasia and is sourced by 3 nuclear (PNE) and 48 chemical explosions. Our interpretation shows a 42-kin thick, high-velocity crust under the Baltic Shield, a 29-km thick crust and high-velocity upper mantle under the Mezenskaya depression, 52-km thick crust with high-velocity lower crust and uppermost mantle under the Urals, and 40-km thick crust under the West Siberian Basin deepening to 45 km under the Altay-Sayan fold belt. High velocity (8.4 km/sec) uppermost mantle is found under the Mezenskaya depression and under the east flank of the Urals. One almost continuous upper mantle boundary occurs at 65 to 80 km depth, and another with an approximately 40-km thick LVZ occurs at 120–140 km depth. The shallow upper mantle blocks and the two extensive interfaces indicate strong upper mantle heterogeneity imaged by this unique profile.