M. A. Levitan

History of sedimentation rates in the sea-ice sedimentation zone during the last 130 ka

Based on literature and our data, analysis of sedimentation rates during the last glacial/interglacial cycle (during the last 130 ka) is given for the Norwegian-Greenland Basin, the Arctic Ocean, Bering and Okhotsk seas, as well as a number of seas in the Southern Ocean. Sedimentation rates in the studied zone are controlled by the development of continental ice sheets, sea ice covers, and biogenic sedimentation, which, in turn, depends on climate variations.

Facies structure and quantitative parameters of pleistocene pelagic sedimentation in the Indian Ocean

We compiled lithofacies maps for the early and middle-late Pleistocene (Eopleistocene and Neopleistocene, respectively) pelagic sedimentation of the Indian Ocean and a database for sediment thicknesses in the respective stratigraphic subdivisions. Using these data, we calculated areas, volumes, masses, and intensities of accumulation of main sediment types for both Pleistocene subdivisions. A comparison of the results confirmed a strong increase in the rate of terrigenous sedimentation. Special attention was given to the evolution of siliceous and carbonate sedimentation of the biogenic type.

Quantitative Parameters of Pleistocene Pelagic Sedimentation in the Pacific Ocean

Using the methodology of A.B. Ronov, we compiled lithofacies maps for the Early and Middle-Late Pleistocene pelagic sedimentation of the Pacific Ocean, accounting for sediment thicknesses. We calculated areas, volumes, masses, and accumulation rates of main sediment types for both Pleistocene subdivisions. A comparison of the results confirmed a strong increase in the rates of terrigenous and biogenic sedimentation. Special emphasis was laid on intensification of sea-ice and eolian sedimentation for the terrigenous types of sediments and on the evolution of siliceous and carbonate sedimentation for the biogenic types of sediments.

Quantitative parameters of Pleistocene pelagic sedimentation in the World Ocean: Global trends and regional features

A comparative analysis of Pleistocene pelagic sedimentation in the Pacific, Indian, and Atlantic oceans revealed the predominance of terrigenous sediments, while carbonate and siliceous sediments are second and third in abundance. During Pleistocene, the mass of terrigenous and siliceous sediments increased, while that of carbonates slightly decreased. The latter is related to the fact that the bottom waters aggressive to carbonates became increasingly generated at high latitudes, thus exceeding an increase in the productivity of plankton carbonate organisms. The peculiarities of accumulation of the main types of bottom sediments in the Pleistocene are considered. It is concluded that the Pleistocene geological history of continents, especially neotectonic uplift and continental glaciations, played an important role in pelagic sedimentation.

Comparative analysis of pelagic Pleistocene silica accumulation in the Pacific and Indian Oceans

The methodical principles of the analysis of biogenic silica accumulation in the pelagic zones of the Pacific and Indian oceans are considered. Two quantitative approaches of lithological analysis are compared: method of absolute mass by A.D. Arkhangel’skii and volumetric method by A.B. Ronov. It is established that the concept of “two oceans” (“ice” and “non-ice”) may be applied to both the oceans. Differences in the evolution of the silica accumulation rate in the Pleistocene between high- and low-latitude oceans are revealed.

Mesozoic-cenozoic sedimentation in the circum-arctic belt. 1. Triassic-Jurassic

Data from the literature were used to revise a set of lithofacies maps for the Triassic-Jurassic epochs published by V.E. Khain, A.B. Ronov, and A.N. Balukhovskii in 1983. The study area is the Circum-Arctic belt, whose present-day northern boundary lies along the shelf break, and the southern boundary, at a latitude of 60° N. For the purpose of our study we used a simplified legend, which does not show climatic and tectonic features and emphasizes lithofacies zones. For each map, we calculated areas and volumes of sediments of the identified lithofacies zones and particular types of sediments. Using these data, we estimated the masses of dry sediment and rates of sediment accumulation. Trends in the distribution of the quantitative parameters of the Circum-Arctic belt were compared with global trends driven by tectonic and climatic changes. The contributions of regional-scale characteristics of sediment accumulation were identified. The results of this study indicate that global trends played a dominant role in regional sedimentation history. Two stages, Triassic and Jurassic, were distinguished in the history of sedimentation.

History of sedimentation in Isfjord (Western Spitsbergen)

Lithology, heavy mineral associations, and chemical composition of sediments studied in two gravity cores from Isfjord, Western Spitsbergen, accompanied by high-frequency seismic records, provide a new insight on the provenance and glaciomarine sedimentation in the fjord from the last deglaciation through the Holocene.

Lithological and geochemical typification of surface bottom sediments in the Kara Sea

The Kara Sea is part of the Western Arctic shelf of Eurasia. The deposition of sediments in this shallow sea is largely determined by solid runoff from two great Siberian rivers (the Yenisei and Ob) and the glacial periods when the sea area repeatedly (during the Quaternary) dried up and was covered by continental glaciers. The rise of the World Ocean due to Holocene warming resulted in a significant expansion of the sea area to the south and complete degradation of the ice sheet. In this article, new data on the geochemical composition of the surface (0- to 2-cm) layer of sea-bottom sediments are considered, which reflects the spatial distribution of marine sediments during the maximum sea level. Cluster analysis of the variance for 24 chemical elements reveals sediment chemotypes, and critical analysis of their relationship with lithotypes is performed. The presented data have been collected on cruises of the R/V Akademik Boris Petrov in 2000, 2001, and 2003 and the R/V Akademik Mstislav Keldysh in 2015.

Techniques for identification of the fine structure of the Polyarnaya sequence and sediments of the marine isotope stage 6 in the central part of Arctic Ocean

New techniques were recently developed to provide insight into sedimentation, paleoclimatic, and paleooceanological evolution of the Arctic Ocean. For instance, neodymium isotopes are widely applied to study the paleocirculation and evolution of provenances (Chen et al., 2012, Fagel et al., 2013), while changes in the ice regime are analyzed using diverse modifications of IP25 parameter (Stein et al., 2012). At the same time, old methods, for instance, mathematical statistics, also have not lost their significance. These methods have been repeatedly applied to the bottom cores from the Arctic ocean and Subarctic seas in order to reveal factors controlling the evolution of sedimentary process and to distinguish chemolithostratigraphic units in a sequences (Gurvich et al., 2001; Rusakov et al., 2010; Levitan et al., 2012, 2013; Andrews and Eberl, 2012). It is obvious that obtained results, which, in particular, made it possible to correlate the distinguished chemolithostratigraphic units with marine isotope stages, represent the beginning of the considerable work yet to be done. For instance, in order to provide the deeper insight into sedimentation history in the framework of highresolution stratigraphy and paleooceanology, it is essential to study the fine (inner) structure of regionally distributed revealed sequences. For this purpose, we focused on investigation of two objects located in the Central Arctic zone: near-polar segment of the submarine Lomonosov Ridge and the continental slope of the Kara sea (Table 1).

Evolution of sedimentation on the continental slope of the Kronotskii Peninsula (Eastern Kamchatka) over the last 20 ka

Different genetic types of marine sediments that were deposited on the continental slope of the Kronotskii Peninsula with the rate of several tens of centimeters per thousand years during the last 20 ka have been investigated. It is established that their lithological, mineral, and chemical compositions were determined by climate changes.