Dinocyst assemblages of site HM52-43
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| Format: | Dataset Open Access |
| Sprache: | en |
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PANGAEA
2000
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| _version_ | 1867169536299499520 |
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| author | de Vernal, Anne Hillaire-Marcel, Claude Turon, Jean-Louis Matthiessen, Jens |
| author_facet | de Vernal, Anne Hillaire-Marcel, Claude Turon, Jean-Louis Matthiessen, Jens |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | Past sea-surface conditions over the northern North Atlantic during the last glacial maximum were examined from the study of 61 deep-sea cores. The last glacial maximum time slice studied here corresponds to an interval between Heinrich layers H2 and H1, and spanning about 20-16 ka on a 14C time scale. Transfer functions based on dinocyst assemblages were used to reconstruct sea-surface temperature, salinity, and sea-ice cover. The results illustrate extensive sea-ice cover along the eastern Canadian margins and sea-ice spreading, only during winter, over most of the northern North Atlantic. On the whole, much colder winter prevailed, despite relatively mild conditions in August (10-15°C at most offshore sites), thus suggesting a larger seasonal contrast of temperatures than today. Lower salinity than at present is reconstructed, especially along the eastern Canadian and Scandinavian margins, likely because of meltwater supply from the surrounding ice sheets. These reconstructions contrast with those established by CLIMAP on the basis of planktonic foraminifera. These differences are discussed with reference to the stratigraphical frame of the last glacial maximum, which was not the coldest phase of the last glacial stage. The respective significance of dinocyst and foraminifer records is also examined in terms of the thermohaline characteristics of surface waters and the vertical structure of upper water masses, which was apparently much more stratified than at present in the northern North Atlantic, thus preventing deep-water formation. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_79362 |
| institution | PANGAEA |
| language | en |
| publishDate | 2000 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | Dinocyst assemblages of site HM52-43 de Vernal, Anne Hillaire-Marcel, Claude Turon, Jean-Louis Matthiessen, Jens 52-43; Alexandrium excavatum; Algidasphaeridium minutum; Algidasphaeridium minutum var. cesare; Ataxiodinium choane; Bitectatodinium tepikiense; Brigantedinium spp.; Counting, dinoflagellate cysts; DEPTH, sediment/rock; GC; Gravity corer; HM52-43; Impagidinium aculeatum; Impagidinium pallidum; Impagidinium paradoxum; Impagidinium patulum; Impagidinium sphaericum; Lingulodinium machaerophorum; MARGO; Multiproxy Approach for the Reconstruction of the Glacial Ocean surface; Multispinula quanta; Nematosphaeropsis labyrinthus; northern North Atlantic; Operculodinium centrocarpum; Peridinium faeroense; Peridinoid type; Polykrikos schwarzii; Pyxidinopsis reticulata; Spiniferites bentori; Spiniferites elongatus; Spiniferites membranaceus; Spiniferites mirabilis; Spiniferites ramosus; Spiniferites spp.; Trinovantedinium capitatum Past sea-surface conditions over the northern North Atlantic during the last glacial maximum were examined from the study of 61 deep-sea cores. The last glacial maximum time slice studied here corresponds to an interval between Heinrich layers H2 and H1, and spanning about 20-16 ka on a 14C time scale. Transfer functions based on dinocyst assemblages were used to reconstruct sea-surface temperature, salinity, and sea-ice cover. The results illustrate extensive sea-ice cover along the eastern Canadian margins and sea-ice spreading, only during winter, over most of the northern North Atlantic. On the whole, much colder winter prevailed, despite relatively mild conditions in August (10-15°C at most offshore sites), thus suggesting a larger seasonal contrast of temperatures than today. Lower salinity than at present is reconstructed, especially along the eastern Canadian and Scandinavian margins, likely because of meltwater supply from the surrounding ice sheets. These reconstructions contrast with those established by CLIMAP on the basis of planktonic foraminifera. These differences are discussed with reference to the stratigraphical frame of the last glacial maximum, which was not the coldest phase of the last glacial stage. The respective significance of dinocyst and foraminifer records is also examined in terms of the thermohaline characteristics of surface waters and the vertical structure of upper water masses, which was apparently much more stratified than at present in the northern North Atlantic, thus preventing deep-water formation. |
| title | Dinocyst assemblages of site HM52-43 |
| topic | 52-43; Alexandrium excavatum; Algidasphaeridium minutum; Algidasphaeridium minutum var. cesare; Ataxiodinium choane; Bitectatodinium tepikiense; Brigantedinium spp.; Counting, dinoflagellate cysts; DEPTH, sediment/rock; GC; Gravity corer; HM52-43; Impagidinium aculeatum; Impagidinium pallidum; Impagidinium paradoxum; Impagidinium patulum; Impagidinium sphaericum; Lingulodinium machaerophorum; MARGO; Multiproxy Approach for the Reconstruction of the Glacial Ocean surface; Multispinula quanta; Nematosphaeropsis labyrinthus; northern North Atlantic; Operculodinium centrocarpum; Peridinium faeroense; Peridinoid type; Polykrikos schwarzii; Pyxidinopsis reticulata; Spiniferites bentori; Spiniferites elongatus; Spiniferites membranaceus; Spiniferites mirabilis; Spiniferites ramosus; Spiniferites spp.; Trinovantedinium capitatum |
| url | https://doi.org/10.1594/PANGAEA.79362 |