Postglacial sedimentation in the White Sea (northwestern Russia) reconstructed by integrated microfossil and geochemical data

Abstract

The White Sea being connected with the Arctic Ocean via the Barents Sea has an influence on its water temperature/salinity structures and biological processes and thus has an indirect impact on the Eurasian climate system. In this work, we have managed to find a correspondence between the climate fluctuation in the Holocene and changes in the geochemical and microfossil properties in the sediment core of the White Sea. For the first time, the element speciation in the sediment core covering about 10,000 cal yr BP period was investigated. The cooling periods (the early Holocene and the Subboreal stage) were characterized by a trend of increase in Si, Al, and Ti contents and Ti/Al ratios, which reflect lithogenous contribution, and decrease in geochemically labile forms of trace elements. A significant increase in the content of organic-bound trace elements and biogenic components (Сorg, BSi, and chlorin) was observed during periods of Holocene climatic optimums. The evident relationship between the metal speciation and indicators of the sedimentation paleoenvironment is observed at the stage of the active phase of early diagenesis after the slowing down of the biogeochemical processes. Down-core decrease in the Mn oxyhydroxide content exhibited a weakening of diagenesis processes at the ~130–150 cm depth.

Geochemical Signatures of Paleoclimate Changes in the Sediment Cores from the Gloria and Snorri Drifts (Northwest Atlantic) over the Holocene-Mid Pleistocene

“…In the western Arctic Ocean sediment cores, enriched in the Mn brown units were attributed to the glacial intervals, while the clear mechanisms of such correlation is still speculative [26]. In the subpolar White Sea (Northwestern Russia), a change in the Mn/Fe ratio in mobile forms (exchangeable and oxyhydroxides) reflects the rapid oxidation of Mn (II) in the uppermost layers of the cores, as well as a slowdown of diagenetic reduction of the oxidized forms of Fe and Mn at a depth of~130 cm [30,53].…”

Global Ocean Sediment Composition and Burial Flux in the Deep Sea

“…An important data gap in the Arctic Ocean was recently addressed by a surface sediment survey from the 68th expedition of RV Akademik Mstislav Keldysh (AMK68) to the Barents Sea (northwest Russian Arctic) in July–August 2017 (Kravchishina et al., 2019). Dried sediments from 27 stations from the upper 0.5 cm of multi‐cores were analyzed at the Shirshov Institute of Oceanology, Russian Academy of Sciences, by X‐ray fluorescence spectrometry for elemental composition using published methods (Budko et al., 2019; Demina et al., 2019). CaCO 3 and biogenic opal were analyzed at the University of Southern Mississippi by UIC coulometer for CaCO 3 and molybdate‐blue spectrophotometry after heated alkaline extraction for biogenic opal (Mortlock & Froelich, 1989).…”

Elemental and Mineral Composition of the Barents Sea Recent and Late Pleistocene−Holocene Sediments: A Correlation with Environmental Conditions

“…A slight increase of Si/Al and Zr/Ca ratios, recorded in the Early Holocene thickness of 210-255 cm (Figure 9), corresponds to elevated values (5.13-21.2%) of sand fraction with admixture of gravel; these evidently correlates with increased supply of terrigenous material caused by intensive bottom currents from the West-Southern shelf areas. In core AMK-5194, the average value of Si/Al ratio (2.96) is equal (3.0) to that in core PSh-6050 of terrigenous sediments from the subarctic White Sea, the Northwestern Russia [29], their downcore distribution are also similar. Ratios Al/Ca and Ti/Ca demonstrate a coherent rhythm down the core (Figure 9), their prominent peaks are detected at several depths, one of them, at a depth of 290 cm coincides with the density peak (1.75 g/cm 3 ).…”

“…In cores from the contourite drifts Snorri and Gloria (North Atlantic, 60 • N), the Al/Si, Ti/Al, and Fe/Al ratios varied synchronously to ice-rafted debris (IRD) counts; these downcore distributions showed an opposite trend with variation of Si/Fe, Mn/Fe, δ 18 O values and content of CaCO 3 , BioSiO 2 during MIS 1-6, thus distinguishing the glacial-interglacial periods [73]. Coincident with these tendencies, the cooling periods in the Early Holocene and Subboreal stage were characterized by the growth of Si/Al and Ti/Al ratios recorded in core PSh-6050 [29].…”

“…Taking the significant research results mentioned above into account, it should be noticed that less attention was paid to elemental geochemical and/or mineral indicators of the modern and paleo-sedimentation environment of the Barents Sea. Geochemical fractions (chemical element speciation) serve as an important tool to quantify different processes of elements' accumulation in sediments and assess the geochemical cycles of heavy metals in the different marine basins [22][23][24][25][26][27][28][29].…”