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A. F. Morozov, O. V. Petrov, S. P. Shokalsky, S. N. Kashubin, A. A. Kremenetsky, M. Yu. Shkatov, V. D. Kaminsky, E. A. Gusev, G. E. Grikurov, P. V. Rekant, S. S. Shevchenko, S. A. Sergeev, V. V. Shatov

New geological data confirming the continental nature of the Central Arctic uplifts area

Results of the Russian and foreign studies of rocks collected from the seafloor in the central part of the Arctic Ocean during the expeditions of ”Academic Fedorov“ RV (”Arctic-2000“, ”Arctic-2005“, ”Arctic-2007“), USGS ”Healy“ (2008, 2009) and German ”Polarstern-2008 “ icebreakers are presented. New data on the submarine Mendeleev Ridge were obtained during the Russian high-latitude expedition ”Arctic-2012“. Conducted studies have shown that sedimentary rocks: irregularly metamorphosed dolomite and quartz sandstone, limestone sometimes with the Devonian-Permian fossils predominate in the composition of rock fragments, and only 5–15% fall at magmatic rocks (Archean and Paleoproterozoic gneiss-granite, Neoproterozoic gabbro-dolerite) and metamorphic formations (green schist, metabasite, quartzite, gneiss). Apparently, these rocks are a part of the acoustic basement underlying layered unconsolidated sediments of the Late Mesozoic – Cenozoic. Along with ancient mafic rocks dredged as a result of deep-water drilling in the northern and southern parts of the Mendeleev Ridge during ”Arctic-2012“ expedition, core of cenotypal basalts occurring after the seismic data at the boundary of the Late Mesozoic – Cenozoic sedimentary cover and the acoustic basement, similar in composition to the Early-Late Cretaceous basalts from seamounts north of the Chukchi Plateau, from the Alpha Ridge, Franz Josef Land islands, De Long and other areas of the High Arctic large igneous province (HALIP). Video images of the seabed at the Mendeleev Ridge scarps indicate bedrock exposures and local origin or small transfer of most rock fragments in the sampling areas. Continental type of basement crust at deepwater rises in the Central Arctic is proved by bottom rock material study, the processing and analysis of which will be used in the preparation of the updated Russian submission to delineate the outer limits of the continental shelf.
Key words: acoustic basement, Mendeleev Ridge, dredging, deepwater drilling, HALIP basalts, bottom rock material.