XRF-scan (Si, K, Ca, Ti, Mn, Fe, Sr) and 14C-age of sediment core MD96-2094
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| Formato: | Dataset Open Access |
| Lenguaje: | en |
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PANGAEA
2002
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| _version_ | 1867167798471426048 |
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| author | Stuut, Jan-Berend W Prins, Maarten Arnoud Jansen, J H Fred |
| author_facet | Stuut, Jan-Berend W Prins, Maarten Arnoud Jansen, J H Fred |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | We present a new index of carbonate fragmentation based on the size distribution of bulk sediments in core MD962094 from Walvis Ridge (SE Atlantic Ocean). The carbonate fragmentation index is constructed by taking a ratio of the two coarsest fractions in the grain size distributions of the bulk calcareous ooze. The coarsest two fractions (25–90 µm and >90 µm) of the bulk sediments consist primarily of complete shells and fragments of adult foraminifera shells, and juvenile foraminifera shells and fragments, respectively. The ratio of the proportions of the two fractions is interpreted as a measure of fragmentation of the foraminifera shells caused by carbonate dissolution. Downcore changes in our carbonate fragmentation index compare very well with those in the coarse-carbonate fragmentation index in sediments from a nearby core on Walvis Ridge. The latter commonly used fragmentation index is defined as a ratio of foraminifera fragments over whole foraminifera in the >150-µm fraction as seen with a light microscope. Fragmentation is relatively high during glacial stages and relatively low during interglacial stages during the last 300 kyr, caused by the combined effect of wind-driven upwelling of corrosive water and increased production of organic matter, decreasing the preservation potential of carbonates both during and after deposition. The carbonate fragmentation index we present here provides a precise and fast method to establish a downcore fragmentation record. It can be applied to bulk sediments that are carbonate-rich (CaCO3>68%) and to all other deep-marine sediments of which the grain size distribution of the carbonate-free fraction is available. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_230295 |
| institution | PANGAEA |
| language | en |
| publishDate | 2002 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | XRF-scan (Si, K, Ca, Ti, Mn, Fe, Sr) and 14C-age of sediment core MD96-2094 Stuut, Jan-Berend W Prins, Maarten Arnoud Jansen, J H Fred AGE; Calcium; CALYPSO; Calypso Corer; DEPTH, sediment/rock; IMAGES; IMAGES II; International Marine Global Change Study; Iron; Manganese; Marion Dufresne (1995); MD105; MD962094; MD96-2094; Outer Walvis Ridge; Potassium; Silicon; Strontium; Titanium; X-ray fluorescence core scanner (XRF) We present a new index of carbonate fragmentation based on the size distribution of bulk sediments in core MD962094 from Walvis Ridge (SE Atlantic Ocean). The carbonate fragmentation index is constructed by taking a ratio of the two coarsest fractions in the grain size distributions of the bulk calcareous ooze. The coarsest two fractions (25–90 µm and >90 µm) of the bulk sediments consist primarily of complete shells and fragments of adult foraminifera shells, and juvenile foraminifera shells and fragments, respectively. The ratio of the proportions of the two fractions is interpreted as a measure of fragmentation of the foraminifera shells caused by carbonate dissolution. Downcore changes in our carbonate fragmentation index compare very well with those in the coarse-carbonate fragmentation index in sediments from a nearby core on Walvis Ridge. The latter commonly used fragmentation index is defined as a ratio of foraminifera fragments over whole foraminifera in the >150-µm fraction as seen with a light microscope. Fragmentation is relatively high during glacial stages and relatively low during interglacial stages during the last 300 kyr, caused by the combined effect of wind-driven upwelling of corrosive water and increased production of organic matter, decreasing the preservation potential of carbonates both during and after deposition. The carbonate fragmentation index we present here provides a precise and fast method to establish a downcore fragmentation record. It can be applied to bulk sediments that are carbonate-rich (CaCO3>68%) and to all other deep-marine sediments of which the grain size distribution of the carbonate-free fraction is available. |
| title | XRF-scan (Si, K, Ca, Ti, Mn, Fe, Sr) and 14C-age of sediment core MD96-2094 |
| topic | AGE; Calcium; CALYPSO; Calypso Corer; DEPTH, sediment/rock; IMAGES; IMAGES II; International Marine Global Change Study; Iron; Manganese; Marion Dufresne (1995); MD105; MD962094; MD96-2094; Outer Walvis Ridge; Potassium; Silicon; Strontium; Titanium; X-ray fluorescence core scanner (XRF) |
| url | https://doi.org/10.1594/PANGAEA.230295 |