The study of distribution and forms of uranium occurrences in Lake Baikal sediments by the SSNTD method

Жмодик, С. М.; Верховцева, Н. В.; Soloboeva, E.V.; Mironov, A. G.; Nemirovskaya, N. A.; Ilić, R.; Khlystov, Oleg; Титов, А. Т.

doi:10.1016/j.radmeas.2005.04.025

Cited by 8 publications

(5 citation statements)

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“…concentrations down to the lake bottom and into the top sediment layer, it has been shown that sedimentary U contents can reach more than 20 µg g -1 (Petrov et al, 1999;Zhmodik et al, 2003Zhmodik et al, , 2005Chebykin et al, 2004Chebykin et al, , 2007Goldberg et al, 2005), i.e. about 5 times higher than the rocks of Lake Baikal's watershed (Jahn et al, 2009;Litvinovsky et al, 2011).…”

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confidence: 99%

Elevated uranium concentrations in Lake Baikal sediments: Burial and early diagenesis

et al. 2016

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The water column of Lake Baikal (Siberia) is pervasively oxic and O 2 penetrates several cm into the sediment, followed by distinct layers of Fe/Mn oxide that undergo reductive-dissolution/oxidativeprecipitation cycles. Uranium (U) contents of the oxic surface sediment layers were ~15 µg g-1 , which is unparalleled in oxygenated lakes. To understand the processes leading to this enrichment we investigated the geochemical composition of the particulate matter and pore water of four sediment cores from different locations in the lake and performed mass balance calculations based on sediment mass accumulation rates and published loads from major tributaries. The comparison of loads and export of U in Lake Baikal suggested that current estimates of loads are too low by a factor of about 3 compared to sediment mass accumulation rates. Peak loads during spring ice melt in tributaries that are difficult to monitor and quantify might be the main cause for the deviation. The high U concentrations in the lake sediments originated from the scavenging of U in the water column through association with settling organic particles and particulate Fe(III)-and, to a lesser extent, Mn(IV)-oxides. We outline the hypothesis that two distinct U phases, lithogenic and non-lithogenic U reach the lake sediment and that authigenic U is subsequently formed under reducing conditions within the sediment. In some cores we found that most U was remobilized during the degradation of organic matter, in particular within the top oxygenated layer of the sediment. Significant enrichments prevailed due to U adsorption to and/or co-precipitation with Fe-oxides. When Feoxides and, to a lesser extent, Mn-oxides were reductively dissolved, they released U to the pore water, leading to peak dissolved U concentrations in the anoxic sediment, which in turn, precipitated as authigenic U under predominantly sulphate-reducing conditions. The onset of the accumulation of authigenic U coincided with the formation of distinct Fe/Mn oxide layers above. We argue that the resilience of Fe-oxides (especially crystalline goethite and hematite), in association with phosphate, even within reducing (but non-sulfidic) sediments support the burial of substantial amounts of U.

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confidence: 99%

Elevated uranium concentrations in Lake Baikal sediments: Burial and early diagenesis

et al. 2016

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“…The diatomaceous deposits are also associated with U, S and Br. Variable U concentrations have been reported from diatomaceous sediments in Lake Baikal (Zhmodik et al, 2005) where they were related to phosphorite grains, organics, and diatomites. U and P correlate positively with biogenic silica (0.21), CaO (0.2) and P 2 O 5 (0.2) at Olorgesailie.…”

Section: Geochemistry and Sedimentary Faciesmentioning

confidence: 98%

Geochemical trends through time and lateral variability of diatom floras in the Pleistocene Olorgesailie Formation, southern Kenya Rift Valley

et al. 2011

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The Olorgesailie Formation (1.2–0.49 Ma) consists of fluvial and lacustrine rift sediments that have yielded abundant Acheulean artifacts and a fossil hominin (Homo cf. erectus). In testing prior understandings of the paleoenvironmental context, we define nine new geochemical zones. A Chemical Index of Alteration suggests increased catchment weathering during deposition of Members 1, 2, 7, 11, and 13. Biophile elements (Br, S) peak in M8–9 and lower M13 possibly reflecting increased input from soil erosion. REE data show that the Magadi Trachytes supplied most siliciclastic grains. Sixteen diatom stages indicate conductivities of 200–16,000 μS cm− 1 and pH of 7.5–9.5 for five deep-water lakes, ten shallow lakes and sixteen wetlands. These results are compared with diatom data from other sections in the basin and show aquatic spatial variability over km-scale distances. Similar floras are traceable over several kilometers for M2, M3 and M9, indicating broadly homogeneous lacustrine conditions during these times, but diatoms in other members imply variable conditions, some related to local tectonic controls. This lateral and temporal variability emphasizes the importance of carrying out stratigraphic sampling at multiple sites within a basin in efforts to define the environmental context relevant to human evolution.

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“…Suitable support materials are those with minimal content of U and Th, e.g., quartz glasses [73]. Among metals used as supports, Ti is characterized by the lowest content of fissile substance impurities [40].…”

Section: Solid Samples Without Pretreatment (In Situ)mentioning

confidence: 99%

“…Bottom sediments in the Black Sea before and after the Chernobyl accident were also studied with SSTDs [110]. The results of studying bottom sediments from Lake Baikal can be used for comparison [73].…”

Section: Studies Of Environment Pollution By Nuclear Weapons Tests Anmentioning

confidence: 99%

Solid-state track detectors in radiometry, isotope analysis, and radiography

Nikolaev¹

2012

Radiochemistry

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The study of distribution and forms of uranium occurrences in Lake Baikal sediments by the SSNTD method

Cited by 8 publications

References 3 publications

Elevated uranium concentrations in Lake Baikal sediments: Burial and early diagenesis

Elevated uranium concentrations in Lake Baikal sediments: Burial and early diagenesis

Geochemical trends through time and lateral variability of diatom floras in the Pleistocene Olorgesailie Formation, southern Kenya Rift Valley

Solid-state track detectors in radiometry, isotope analysis, and radiography

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