Deep Structure of the East Barents Megabasin: Evidence from Wide-Angle Deep Seismic Profiling

摘要

In 1991-1995, the WACDP-WARRP (ShGSP in the Russian abbreviation) inter-branch scientific group of specialists from the Arctic Offshore Geophysical Expedition (MAGE), Sevmorgeologiya and Yuzh-morgeologiya Scientific and Industrial Associations, Polar Offshore Geological Exploration Expedition (PMGRE), Sevmorgeo State Geological Enterprise, Institute of Oceanology of the Russian Academy of Sciences and its Southern Division, Institute of Physics of the Earth of the Russian Academy of Sciences, and Soyuzmorgeo State Scientific and Industrial Association shot wide-angle deep seismic profiling to study the deep structure of the consolidated crust and sedimentary cover of the East Barents Megabasin and acquired 5300 line-km of seismic profiles, 10 Musgrave's soundings from two vessels, and 124 soundings with standalone bottom seismographs. Data obtained shed light on the structural framework of the whole Cenozoic to Pro-terozoic sedimentary sequence from top to bottom (20-23 km) as well as the crystalline basement and upper mantle to a depth of 50-60 km. Interpreted wide-angle seismic data attest to the ancient (Early Proterozoic) age of the East Barents Megabasin and the prevalence of crustal subsidence throughout its geologic history as a result of the eclogitization of the basaltic layer, which eventually gave rise to an extremely deep sag following the destruction of the ancient West Arctic metaplatform. The interest to this region is particularly high considering that up to 30-35% of the potential hydrocarbon resources of Russia's continental shelf are concentrated beneath the Barents Sea. The East Barents Megabasin apparently falls within the category of oil and gas prolific pelagic basins.