Late Pleistocene stratigraphy and micropaleontology of a part of the Eurasian Basin (=Fram Basin), central Arctic Ocean

Abstract

During the 1979 Lomonosov Ridge Experiment ( lorex), 12 short gravity cores were collected from the Fram Basin part of the Eurasian Basin on the eastern flank of the Lomonosov Ridge. Sediments of these cores are organized into 11 lithologic units that constitute the first stratigraphy for any part of the deeper Eurasian Basin. Foraminifera are the same species that have been described elsewhere in the central Arctic Ocean, but are abundant only in the uppermost part of the cores. Neogloboquadrina pachyderma is the most abundant species, but the presence of Eponides tumidulus horvathi and Stetsonia arctica in core SSK-2 provide a general chronologic framework for interpreting the Fram Basin sediment. The stratigraphy ( a-k) is unique and is only partially correlated with other sediments of the North Polar region including that of the adjacent Lomonosov Ridge and Makarov Basin (=Amerasian Basin). Differences in stratigraphies of the Lomonosov area are interpreted to be at least in part the result of winnowing by turbidity currents and by currents crossing the Ridge from the Fram Basin toward the Makarov Basin. The sediment consists of silty lutites and sandy lutites, as well as laminated lutites interpreted to have been deposited as a result of glacial-marine and turbidite sedimentation. These short cores document the same sedimentary processes in part of the Arctic Ocean east of the Lomonosov Ridge as have been previously reported for the western Amerasian Basin.