Deep Structure of the Mendeleev Rise on the Basis of Multicomponent Wide-angle Studies ('Arctic-2012' project)

Sergey Kashubin

Integrated geological and geophysical studies were conducted in 2012 in the central Arctic Basin (joint efforts of different organizations under the leadership of JSC 'Sevmorgeo'). Wide-angle studies were carried out to determine the type of crust on the Mendeleev Rise. Seismic line crosses the Mendeleev Rise in the south, showing its relationship to the framing structures - the Siberian Shelf in the west and the Chukchi Abyssal Plain and the Chukchi Plateau in the east. A high-power air-gun source (120 l) and self-floating bottom recording systems with multicomponent data acquisition were used during wide-angle surveying. The line was worked out by a dense observation network: spacing between the bottom stations is generally 20 km (in individual parts of the line - 10 km); shooting interval (seismic traces) is 315 m. Observations were obtained in 27 points on the 480-km line. Refracted and reflected waves associated with the interfaces in the sedimentary cover, in the consolidated crust, and with Moho boundary. Wide-angle seismic line coincides with reflection MCS line worked out with the 4,500 km long streamer; this enabled a considerable specification of the upper section and taking it into account when constructing a deep Earth's crust model. Construction of a deep velocity model was made using P, S, and converted waves ray tracing modeling with SeisWide software. The estimates of Vp/Vs ratio playing an important role in determining the Earth’s crust type were obtained. Structure of the Mendeleev Rise corresponds to the sections of thin continental crust in shelf seas and thinned continental crust on submarine ridges and rises