Micropaleontological investigation of sediment core Kronsmoor
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| Natura: | Dataset Open Access |
| Lingua: | en |
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PANGAEA
2005
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| _version_ | 1867169500814639104 |
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| author | Friedrich, Oliver Herrle, Jens O Hemleben, Christoph |
| author_facet | Friedrich, Oliver Herrle, Jens O Hemleben, Christoph |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | Benthic foraminiferal and calcareous nannofossil assemblages, as well as stable isotope data from the Campanian/Maastrichtian boundary interval (~71.4 to ~70.7 Ma) of the Kronsmoor section (North German Basin), were investigated in order to characterize changes in surface-water productivity and oxygen content at the seafloor and their link to climatic and paleoceanographic changes. A nutrient index based on calcareous nannofossils is derived for the high-latitude, epicontinental North German Basin, reflecting changes in surface-water productivity. Oxygen isotopes of well-preserved planktic foraminiferal specimens of Heterohelix globulosa reflect warmer surface-water temperatures in the lower part of the studied succession and a cooling of up to 2°C (0.5 per mil) in the upper part (after 71.1 Ma). For the lower and warmer part of the investigated succession, benthic foraminiferal assemblages and the calcareous nannofossils indicate well-oxygenated bottom waters and low-surface water productivity. In contrast, the upper part of the succession is characterized by cooler conditions, lower oxygen content at the seafloor and increasing surface-water productivity. It is proposed that the cooling phase starting at 71.1 Ma was accompanied by increasing surface-water mixing caused by westerly winds. As a consequence of mixing, nutrients were advected from sub-surface waters into the mixed layer, resulting in increased surface-water productivity and enhanced organic matter flux to the seafloor. We hypothesize that global sea-level fall during the earliest Maastrichtian (~71.3 Ma), indicated by decreasing carbon isotope values, may have led to a weaker water mass exchange through narrower gateways between the Boreal Realm and the open North Atlantic and Tethys oceans. Both the weaker water mass exchange and enhanced surface-water productivity may have led to slightly less ventilated bottom waters of the upper part of the studied section. Our micro-paleontological and stable isotopic approach indicates short-term (<100 kyr) changes in oxygen consumption at the seafloor and surface-water productivity across the homogeneous Boreal White Chalk succession of the North German Basin. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_736977 |
| institution | PANGAEA |
| language | en |
| publishDate | 2005 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | Micropaleontological investigation of sediment core Kronsmoor Friedrich, Oliver Herrle, Jens O Hemleben, Christoph Germany, North; Kronsmoor; MULT; Multiple investigations Benthic foraminiferal and calcareous nannofossil assemblages, as well as stable isotope data from the Campanian/Maastrichtian boundary interval (~71.4 to ~70.7 Ma) of the Kronsmoor section (North German Basin), were investigated in order to characterize changes in surface-water productivity and oxygen content at the seafloor and their link to climatic and paleoceanographic changes. A nutrient index based on calcareous nannofossils is derived for the high-latitude, epicontinental North German Basin, reflecting changes in surface-water productivity. Oxygen isotopes of well-preserved planktic foraminiferal specimens of Heterohelix globulosa reflect warmer surface-water temperatures in the lower part of the studied succession and a cooling of up to 2°C (0.5 per mil) in the upper part (after 71.1 Ma). For the lower and warmer part of the investigated succession, benthic foraminiferal assemblages and the calcareous nannofossils indicate well-oxygenated bottom waters and low-surface water productivity. In contrast, the upper part of the succession is characterized by cooler conditions, lower oxygen content at the seafloor and increasing surface-water productivity. It is proposed that the cooling phase starting at 71.1 Ma was accompanied by increasing surface-water mixing caused by westerly winds. As a consequence of mixing, nutrients were advected from sub-surface waters into the mixed layer, resulting in increased surface-water productivity and enhanced organic matter flux to the seafloor. We hypothesize that global sea-level fall during the earliest Maastrichtian (~71.3 Ma), indicated by decreasing carbon isotope values, may have led to a weaker water mass exchange through narrower gateways between the Boreal Realm and the open North Atlantic and Tethys oceans. Both the weaker water mass exchange and enhanced surface-water productivity may have led to slightly less ventilated bottom waters of the upper part of the studied section. Our micro-paleontological and stable isotopic approach indicates short-term (<100 kyr) changes in oxygen consumption at the seafloor and surface-water productivity across the homogeneous Boreal White Chalk succession of the North German Basin. |
| title | Micropaleontological investigation of sediment core Kronsmoor |
| topic | Germany, North; Kronsmoor; MULT; Multiple investigations |
| url | https://doi.org/10.1594/PANGAEA.736977 |