Geochemistry of organic matter of bottom sediments in the rises of the central Arctic Ocean

Abstract

Abstract Based on geomorphological, lithological, and facial characteristics of the East Arctic continental margin, we studied the main factors controlling the Late Cenozoic supply of organic matter (OM) to the bottom sediments of the Central Arctic rises of the Arctic Ocean. Complex analysis of dispersed OM in the samples taken during the expeditions of the R/V “Akademik Fedorov” in 2000 and 2005 showed a significant difference between the sediments of the Lomonosov Ridge and Mendeleev Rise. The bottom sediments of the latter are strongly transformed and lack terrigenous components, as evidenced results from the main geochemical characteristics (contents of Corg, Ccarb, Norg, bitumens, and humic acids) and the composition and distribution of hydrocarbon molecular markers (alkanes, saturated and aromatic cyclanes). The obtained data evidence that ancient sedimentary rocks containing genetically uniform deeply transformed (up to mesocatagenesis) OM played a significant role in the formation of the Pleistocene–Holocene sediments of the axial part of the Mendeleev Rise.