Grain size distribution, carbon content and wet bulk density of sediment cores in the equatorial Atlantic and the Norwegian Sea
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| Format: | Dataset Open Access |
| Language: | en |
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PANGAEA
1989
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| _version_ | 1867170454231318528 |
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| author | Kassens, Heidemarie Sarnthein, Michael |
| author_facet | Kassens, Heidemarie Sarnthein, Michael |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | Near-surface sediments from the equatorial east Atlantic and the Norwegian Sea exhibit pronounced shear strength maxima in profiles from the peak Holocene and Pleistocene. These semi-indurated layers start to occur at 8-102 cm below the sediment surface and can be explained neither by the modal composition nor by the effective overburden pressure of the sediments. However, scanning electron microscope and microprobe data exhibit micritic crusts and crystal carpets, which are clearly restricted to (undisturbed) samples from indurated layers and form a manifest explanation for their origin. The minerals precipitated comprise calcite, aragonite, and in samples more proximal to the African continent SiO2 needles, and needles of as yet unidentified K-Mg-Fe-Al silicates, crusts of which dominate the indurated layers in the Norwegian Sea. By their stratigraphic position in deep-sea sediments the carbonate-based shear strength maxima are tentatively ascribed to dissolved adjacent pteropod layers from the early Holocene and hence to short-lived no-analogue events of early diagenesis. Possibly, they have been controlled by a reduced organic carbon flux, leading to increased aragonite preservation in the deep sea. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_696097 |
| institution | PANGAEA |
| language | en |
| publishDate | 1989 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | Grain size distribution, carbon content and wet bulk density of sediment cores in the equatorial Atlantic and the Norwegian Sea Kassens, Heidemarie Sarnthein, Michael 377; ANT-IV/1c; Atlantic Ocean; BC; Box corer; Equatorial Atlantic; GC; GEOTROPEX 83, NOAMP I; Giant box corer; GIK/IfG; GIK16402-1; GIK16403-1; GIK16404-1; GIK16405-1; GIK16407-1; GIK16408-1; GIK16410-1; GIK16413-1; GIK16415-1; GIK16416-1; GIK16417-1; GIK16426-1; GIK16453-2; GIK16455-1; GIK16457-1; GIK16458-2; GIK23055-2; GIK23056-2; GIK23057-1; GIK23059-2; GIK23062-3; GIK23063-2; GIK23064-2; GIK23065-2; GIK23068-3; GIK23070-2; GIK23071-3; GIK23072-2; GIK23074-1; GKG; Gravity corer; Institute for Geosciences, Christian Albrechts University, Kiel; KAL; Kasten corer; M2/2; M65; Meteor (1964); Meteor (1986); Norwegian Sea; Polarstern; PS08; Quaternary Environment of the Eurasian North; QUEEN Near-surface sediments from the equatorial east Atlantic and the Norwegian Sea exhibit pronounced shear strength maxima in profiles from the peak Holocene and Pleistocene. These semi-indurated layers start to occur at 8-102 cm below the sediment surface and can be explained neither by the modal composition nor by the effective overburden pressure of the sediments. However, scanning electron microscope and microprobe data exhibit micritic crusts and crystal carpets, which are clearly restricted to (undisturbed) samples from indurated layers and form a manifest explanation for their origin. The minerals precipitated comprise calcite, aragonite, and in samples more proximal to the African continent SiO2 needles, and needles of as yet unidentified K-Mg-Fe-Al silicates, crusts of which dominate the indurated layers in the Norwegian Sea. By their stratigraphic position in deep-sea sediments the carbonate-based shear strength maxima are tentatively ascribed to dissolved adjacent pteropod layers from the early Holocene and hence to short-lived no-analogue events of early diagenesis. Possibly, they have been controlled by a reduced organic carbon flux, leading to increased aragonite preservation in the deep sea. |
| title | Grain size distribution, carbon content and wet bulk density of sediment cores in the equatorial Atlantic and the Norwegian Sea |
| topic | 377; ANT-IV/1c; Atlantic Ocean; BC; Box corer; Equatorial Atlantic; GC; GEOTROPEX 83, NOAMP I; Giant box corer; GIK/IfG; GIK16402-1; GIK16403-1; GIK16404-1; GIK16405-1; GIK16407-1; GIK16408-1; GIK16410-1; GIK16413-1; GIK16415-1; GIK16416-1; GIK16417-1; GIK16426-1; GIK16453-2; GIK16455-1; GIK16457-1; GIK16458-2; GIK23055-2; GIK23056-2; GIK23057-1; GIK23059-2; GIK23062-3; GIK23063-2; GIK23064-2; GIK23065-2; GIK23068-3; GIK23070-2; GIK23071-3; GIK23072-2; GIK23074-1; GKG; Gravity corer; Institute for Geosciences, Christian Albrechts University, Kiel; KAL; Kasten corer; M2/2; M65; Meteor (1964); Meteor (1986); Norwegian Sea; Polarstern; PS08; Quaternary Environment of the Eurasian North; QUEEN |
| url | https://doi.org/10.1594/PANGAEA.696097 |