Dinocyst-derived sea-surface characteristics, palynomorph abundances, ice-rafted debris, and planktonic foraminifera abundances and δ¹⁸O of the 35-41 ka BP interval of core MD99-2285
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| Format: | Dataset Open Access |
| Language: | en |
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PANGAEA
2016
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| _version_ | 1867170993242374144 |
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| author | Wary, Mélanie Eynaud, Frédérique Rossignol, Linda Lapuyade, Joanna Gasparotto, Marie-Camille Londeix, Laurent Malaizé, Bruno Castera, Marie-Hélène Charlier, Karine |
| author_facet | Wary, Mélanie Eynaud, Frédérique Rossignol, Linda Lapuyade, Joanna Gasparotto, Marie-Camille Londeix, Laurent Malaizé, Bruno Castera, Marie-Hélène Charlier, Karine |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | The last glacial millennial climatic events (i.e. Dansgaard-Oeschger and Heinrich events) constitute outstanding case studies of coupled atmosphere-ocean-cryosphere interactions. Here, we investigate the evolution of sea-surface and subsurface conditions, in terms of temperature, salinity and sea ice cover, at very high-resolution (mean resolution between 55 and 155 years depending on proxies) during the 35-41 ka cal BP interval covering three Dansgaard-Oeschger cycles and including Heinrich event 4, in a new unpublished marine record, i.e. the MD99-2285 core (62.69°N; -3.57°E). We use a large panel of complementary tools, which notably includes dinocyst-derived sea-ice cover duration quantifications. The high temporal resolution and multiproxy approach of this work allows us to identify the sequence of processes and to assess ocean-cryosphere interactions occurring during these periodic ice-sheet collapse events. Our results evidence a paradoxical hydrological scheme where (i) Greenland interstadials are marked by a homogeneous and cold upper water column, with intensive winter sea ice formation and summer sea ice melting, and (ii) Greenland and Heinrich stadials are characterized by a very warm and low saline surface layer with iceberg calving and reduced sea ice formation, separated by a strong halocline from a less warm and saltier subsurface layer. Our work also suggests that this stadial surface/subsurface warming started before massive iceberg release, in relation with warm Atlantic water advection. These findings thus support the theory that upper ocean warming might have triggered European ice-sheet destabilization. Besides, previous paleoceanographic studies conducted along the Atlantic inflow pathways close to the edge of European ice-sheets suggest that such a feature might have occurred in this whole area. Nonetheless, additional high resolution paleoreconstructions are required to confirm such a regional scheme. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_864808 |
| institution | PANGAEA |
| language | en |
| publishDate | 2016 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | Dinocyst-derived sea-surface characteristics, palynomorph abundances, ice-rafted debris, and planktonic foraminifera abundances and δ¹⁸O of the 35-41 ka BP interval of core MD99-2285 Wary, Mélanie Eynaud, Frédérique Rossignol, Linda Lapuyade, Joanna Gasparotto, Marie-Camille Londeix, Laurent Malaizé, Bruno Castera, Marie-Hélène Charlier, Karine 2065N; AGE; Bitectatodinium tepikiense; CALYPSO; Calypso Corer; DEPTH, sediment/rock; Dinoflagellate cyst reworked per volume; Diversity; Dominance; Foraminifera, planktic; Halodinium spp.; Ice rafted debris; IMAGES V; Islandinium minutum var. minutum; Marion Dufresne (1995); MD114; MD99-2285; N.Faeroes; Neogloboquadrina pachyderma sinistral; Neogloboquadrina pachyderma sinistral, δ18O; Operculodinium centrocarpum; Pediastrum spp., coenobia; Primary production of carbon; Sea ice cover duration; Sea surface salinity, summer; Sea surface salinity, winter; Sea surface temperature, summer; Sea surface temperature, winter The last glacial millennial climatic events (i.e. Dansgaard-Oeschger and Heinrich events) constitute outstanding case studies of coupled atmosphere-ocean-cryosphere interactions. Here, we investigate the evolution of sea-surface and subsurface conditions, in terms of temperature, salinity and sea ice cover, at very high-resolution (mean resolution between 55 and 155 years depending on proxies) during the 35-41 ka cal BP interval covering three Dansgaard-Oeschger cycles and including Heinrich event 4, in a new unpublished marine record, i.e. the MD99-2285 core (62.69°N; -3.57°E). We use a large panel of complementary tools, which notably includes dinocyst-derived sea-ice cover duration quantifications. The high temporal resolution and multiproxy approach of this work allows us to identify the sequence of processes and to assess ocean-cryosphere interactions occurring during these periodic ice-sheet collapse events. Our results evidence a paradoxical hydrological scheme where (i) Greenland interstadials are marked by a homogeneous and cold upper water column, with intensive winter sea ice formation and summer sea ice melting, and (ii) Greenland and Heinrich stadials are characterized by a very warm and low saline surface layer with iceberg calving and reduced sea ice formation, separated by a strong halocline from a less warm and saltier subsurface layer. Our work also suggests that this stadial surface/subsurface warming started before massive iceberg release, in relation with warm Atlantic water advection. These findings thus support the theory that upper ocean warming might have triggered European ice-sheet destabilization. Besides, previous paleoceanographic studies conducted along the Atlantic inflow pathways close to the edge of European ice-sheets suggest that such a feature might have occurred in this whole area. Nonetheless, additional high resolution paleoreconstructions are required to confirm such a regional scheme. |
| title | Dinocyst-derived sea-surface characteristics, palynomorph abundances, ice-rafted debris, and planktonic foraminifera abundances and δ¹⁸O of the 35-41 ka BP interval of core MD99-2285 |
| topic | 2065N; AGE; Bitectatodinium tepikiense; CALYPSO; Calypso Corer; DEPTH, sediment/rock; Dinoflagellate cyst reworked per volume; Diversity; Dominance; Foraminifera, planktic; Halodinium spp.; Ice rafted debris; IMAGES V; Islandinium minutum var. minutum; Marion Dufresne (1995); MD114; MD99-2285; N.Faeroes; Neogloboquadrina pachyderma sinistral; Neogloboquadrina pachyderma sinistral, δ18O; Operculodinium centrocarpum; Pediastrum spp., coenobia; Primary production of carbon; Sea ice cover duration; Sea surface salinity, summer; Sea surface salinity, winter; Sea surface temperature, summer; Sea surface temperature, winter |
| url | https://doi.org/10.1594/PANGAEA.864808 |