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| Bachem, Paul E.; Risebrobakken, Bjorg; De Schepper, Stijn; Mcclymont, Erin L.. |
| The Pliocene was a time of global warmth with small sporadic glaciations, which transitioned towards the larger-scale Pleistocene glacial-interglacial variability. Here, we present high-resolution records of sea surface temperature (SST) and ice-rafted debris (IRD) in the Norwegian Sea from 5.32 to 3.14 Ma, providing evidence that the Pliocene surface conditions of the Norwegian Sea underwent a series of transitions in response to orbital forcing and gateway changes. Average SSTs are 2 degrees C above the regional Holocene mean, with notable variability on millennial to orbital timescales. Both gradual changes and threshold effects are proposed for the progression of regional climate towards the Late Pliocene intensification of Northern Hemisphere... |
| Tipo: Text |
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| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00495/60710/65332.pdf |
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| Bachem, Paul E.; Risebrobakken, Bjorg; Mcclymont, Erin L.. |
| The mid-Piacenzian warm period (3.264-3.025 Ma) of the Pliocene epoch has been proposed as a possible reference for future warm climate states. However, there is significant disagreement over the magnitude of high latitude warming between data and models for this period of time, raising questions about the driving mechanisms and responsible feedbacks. We have developed a new set of orbital-resolution alkenone-based sea surface temperature (SST) and ice rafted debris (IRD) records from the Norwegian Sea spanning 3.264-3.14 Ma. The SSTs in the Norwegian Sea were 2-3 degrees C warmer than the Holocene average, likely caused by the radiative effect of higher atmospheric CO2 concentrations. There is notable obliquity-driven SST variability with a range of 4... |
| Tipo: Text |
Palavras-chave: Pliocene; Norwegian Sea; ODP Site 642; Alkenones; SST; Subpolar gyre. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00421/53230/83372.pdf |
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| Panitz, Sina; De Schepper, Stijn; Salzmann, Ulrich; Bachem, Paul E.; Risebrobakken, Bjorg; Clotten, Caroline; Hocking, Emma P.. |
| During the mid-Piacenzian, Nordic Seas sea surface temperatures (SSTs) were higher than today. While SSTs provide crucial climatic information, on their own they do not allow a reconstruction of potential underlying changes in water masses and currents. A new dinoflagellate cyst record for Ocean Drilling Program (ODP) Site 642 is presented to evaluate changes in northward heat transport via the Norwegian Atlantic Current (NwAC) between 3.320 and 3.137Ma. The record is compared with vegetation and SST reconstructions from Site 642 and SSTs from Iceland Sea ODP Site 907 to identify links between SSTs, ocean currents, and vegetation changes. The dinocyst record shows that strong Atlantic water influence via the NwAC corresponds to higher-than-present SSTs and... |
| Tipo: Text |
Palavras-chave: Dinoflagellate cysts; Norwegian Atlantic Current; Arctic Front; Northward heat transport; Obliquity forcing; Late Pliocene. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00504/61595/65879.pdf |
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