Element enrichment and provenance of the detrital component in Holocene sediments from the western Black Sea
Summary: Concentrations of a large set of major and trace elements, and Sr, Nd and Pb isotope ratios were measured in Holocene sediments cored in the western deep Black Sea in order to unravel: (1) the controls of element enrichment, and (2) sources of the detrital component. The transition of the b...
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Institute of Oceanology of the Polish Academy of Sciences
2020-04-01
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| Series: | Oceanologia |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S0078323419300764 |
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| author | Vesselin M. Dekov Valentina Y. Darakchieva Kjell Billström C. Dieter Garbe-Schönberg George D. Kamenov Morgane Gallinari Lyubomir Dimitrov Olivier Ragueneau Ellen Kooijman |
| author_facet | Vesselin M. Dekov Valentina Y. Darakchieva Kjell Billström C. Dieter Garbe-Schönberg George D. Kamenov Morgane Gallinari Lyubomir Dimitrov Olivier Ragueneau Ellen Kooijman |
| author_sort | Vesselin M. Dekov |
| collection | DOAJ |
| description | Summary: Concentrations of a large set of major and trace elements, and Sr, Nd and Pb isotope ratios were measured in Holocene sediments cored in the western deep Black Sea in order to unravel: (1) the controls of element enrichment, and (2) sources of the detrital component. The transition of the basin from oxic to euxinic resulted in enrichment or depletion in a number of elements in the deep-sea sediments. Authigenic Fe enrichment appears to depend on the amount of Fe mobilized from the sediment through the benthic redox shuttle mechanism and free H2S in the water column (degree of “euxinization”). Manganese enrichment is controlled by diagenetic reactions within the sediment: the dissolution of Mn minerals, Mn2+ diffusion upward and reprecipitation. Barium enrichment is also controlled by diagenetic reactions, sulfate reduction and methanogenesis, that take place above and below the sulfate-methane transition, respectively. The major part of V, Co, Ni, Cu, Zn, Cr, Mo, Cd and Sb is inferred to have co-precipitated with Fe in the euxinic deep waters and to have been incorporated into authigenic Fe-sulfides. Basin reservoir effect additionally influences the Mo enrichment. The U enrichment is interpreted to have a different origin in the two organic-rich stratigraphic units (II and I). It is inferred to be: (i) at the expense of the U inventory of the deepwater pool and a result of inorganic reduction of U at euxinic conditions in the lower Unit II; and (ii) at the expense of the U inventory of the surface water pool and a result of biogenic uptake and transfer to the sediment by the plankton in the upper Unit I. The high field strength elements are closely linked to the detrital component and their depletion in the organic-rich sediments reflects a dilution of the detrital component by the biogenic one. The enrichments of REE, Sn and Th are likely controlled by adsorption on clay minerals. Sr-Nd-Pb isotope compositions of the alumino-silicate component of the studied sediments are relatively uniform. They are most likely controlled by riverine suspended matter supplied mainly in the NW Black Sea (Danube Delta) and transported southward by marine currents, and to a lesser degree by suspended matter from the small rivers draining SE Bulgaria and NW Turkey. Wind-blown dust from the Sahara Desert appears to have a minor contribution to the alumino-silicate component of the sediments. The slight shift in the Pb isotopes in Unit I upper layers is possibly caused by the addition of anthropogenic Pb. Keywords: Anoxic, Black Sea, Element enrichment, Sr-Nd-Pb-isotopes, Holocene |
| format | Article |
| id | doaj-art-3185d83eee57497ebd4ad1a17099ecec |
| institution | Kabale University |
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| language | English |
| publishDate | 2020-04-01 |
| publisher | Institute of Oceanology of the Polish Academy of Sciences |
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| spelling | doaj-art-3185d83eee57497ebd4ad1a17099ecec2025-08-20T03:52:28ZengInstitute of Oceanology of the Polish Academy of SciencesOceanologia0078-32342020-04-0162213916310.1016/j.oceano.2019.10.001Element enrichment and provenance of the detrital component in Holocene sediments from the western Black SeaVesselin M. Dekov0Valentina Y. Darakchieva1Kjell Billström2C. Dieter Garbe-Schönberg3George D. Kamenov4Morgane Gallinari5Lyubomir Dimitrov6Olivier Ragueneau7Ellen Kooijman8Tokyo University of Marine Science and Technology, Konan, Minato-ku, Tokyo, Japan; Department of Marine Geosciences, IFREMER, Plouzané, France; Corresponding author at: Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo 108-8477, Japan; Department of Marine Geosciences, IFREMER, 29280 Plouzané, France; Tel.: +81 03-5463-0642; fax: +81 03-5463-0642.Institute of Mineralogy and Crystallography, Bulgarian Academy of Sciences, Sofia, BulgariaDepartment of Geosciences, Swedish Museum of Natural History, Stockholm, SwedenInstitute of Geosciences, Marine Climate Research, University of Kiel, Kiel, GermanyDepartment of Geological Sciences, University of Florida, Gainesville, FL, USAUMR CNRS/UBO 6539 LEMAR, European Institute for Marine Studies, Technopôle Brest-Iroise, Plouzané, FranceInstitute of Oceanology, Bulgarian Academy of Sciences, Varna, BulgariaUMR CNRS/UBO 6539 LEMAR, European Institute for Marine Studies, Technopôle Brest-Iroise, Plouzané, FranceDepartment of Geosciences, Swedish Museum of Natural History, Stockholm, SwedenSummary: Concentrations of a large set of major and trace elements, and Sr, Nd and Pb isotope ratios were measured in Holocene sediments cored in the western deep Black Sea in order to unravel: (1) the controls of element enrichment, and (2) sources of the detrital component. The transition of the basin from oxic to euxinic resulted in enrichment or depletion in a number of elements in the deep-sea sediments. Authigenic Fe enrichment appears to depend on the amount of Fe mobilized from the sediment through the benthic redox shuttle mechanism and free H2S in the water column (degree of “euxinization”). Manganese enrichment is controlled by diagenetic reactions within the sediment: the dissolution of Mn minerals, Mn2+ diffusion upward and reprecipitation. Barium enrichment is also controlled by diagenetic reactions, sulfate reduction and methanogenesis, that take place above and below the sulfate-methane transition, respectively. The major part of V, Co, Ni, Cu, Zn, Cr, Mo, Cd and Sb is inferred to have co-precipitated with Fe in the euxinic deep waters and to have been incorporated into authigenic Fe-sulfides. Basin reservoir effect additionally influences the Mo enrichment. The U enrichment is interpreted to have a different origin in the two organic-rich stratigraphic units (II and I). It is inferred to be: (i) at the expense of the U inventory of the deepwater pool and a result of inorganic reduction of U at euxinic conditions in the lower Unit II; and (ii) at the expense of the U inventory of the surface water pool and a result of biogenic uptake and transfer to the sediment by the plankton in the upper Unit I. The high field strength elements are closely linked to the detrital component and their depletion in the organic-rich sediments reflects a dilution of the detrital component by the biogenic one. The enrichments of REE, Sn and Th are likely controlled by adsorption on clay minerals. Sr-Nd-Pb isotope compositions of the alumino-silicate component of the studied sediments are relatively uniform. They are most likely controlled by riverine suspended matter supplied mainly in the NW Black Sea (Danube Delta) and transported southward by marine currents, and to a lesser degree by suspended matter from the small rivers draining SE Bulgaria and NW Turkey. Wind-blown dust from the Sahara Desert appears to have a minor contribution to the alumino-silicate component of the sediments. The slight shift in the Pb isotopes in Unit I upper layers is possibly caused by the addition of anthropogenic Pb. Keywords: Anoxic, Black Sea, Element enrichment, Sr-Nd-Pb-isotopes, Holocenehttp://www.sciencedirect.com/science/article/pii/S0078323419300764 |
| spellingShingle | Vesselin M. Dekov Valentina Y. Darakchieva Kjell Billström C. Dieter Garbe-Schönberg George D. Kamenov Morgane Gallinari Lyubomir Dimitrov Olivier Ragueneau Ellen Kooijman Element enrichment and provenance of the detrital component in Holocene sediments from the western Black Sea Oceanologia |
| title | Element enrichment and provenance of the detrital component in Holocene sediments from the western Black Sea |
| title_full | Element enrichment and provenance of the detrital component in Holocene sediments from the western Black Sea |
| title_fullStr | Element enrichment and provenance of the detrital component in Holocene sediments from the western Black Sea |
| title_full_unstemmed | Element enrichment and provenance of the detrital component in Holocene sediments from the western Black Sea |
| title_short | Element enrichment and provenance of the detrital component in Holocene sediments from the western Black Sea |
| title_sort | element enrichment and provenance of the detrital component in holocene sediments from the western black sea |
| url | http://www.sciencedirect.com/science/article/pii/S0078323419300764 |
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