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| Format: | Dataset Open Access |
| Language: | en |
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PANGAEA
2019
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| Online Access: | https://doi.org/10.1594/PANGAEA.904398 |
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| _version_ | 1867168199453179904 |
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| author | Barker, Stephen Knorr, Gregor Conn, Stephen Lordsmith, Sian Newman, Dhobasheni Thornalley, David J R |
| author_facet | Barker, Stephen Knorr, Gregor Conn, Stephen Lordsmith, Sian Newman, Dhobasheni Thornalley, David J R |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | Throughout the last glacial cycle millennial timescale variations in atmospheric CO2 occurred in parallel with perturbations in deep ocean circulation, which were themselves reflected by observable changes in surface conditions across the North Atlantic region. Here we use continuous proxy records to argue that an equivalent relationship has held throughout the last 800kyr i.e. since before the first occurrence of Heinrich events sensu stricto. Our results highlight the importance of internal climate dynamics in amplifying external (insolation) forcing on the climate system to produce the large amplitude of glacial terminations (deglaciations) during the mid to late Pleistocene. We show that terminations are characterized by an interval of intense ice rafting followed by a subsequent and abrupt shift to anomalously warm surface conditions (with respect to the more gradually evolving background state), which we interpret to reflect an abrupt recovery of deep ocean circulation in the Atlantic. According to our synthesis, this is followed by a period of enhanced (or at least anomalous) overturning lasting thousands of years until equilibrium interglacial conditions are attained and during which atmospheric CO2 is likely to decrease. Our results therefore suggest that deglacial oscillations in ocean circulation can have a lasting influence on early interglacial climate and highlight the transient nature of atmospheric CO2 overshoots associated with the onset of some previous interglacials. Accordingly we suggest that these intervals should be considered as a part of the deglacial process. This has implications for studies concerned with the evolution of atmospheric CO2 during interglacial periods including the Holocene. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_904398 |
| institution | PANGAEA |
| language | en |
| publishDate | 2019 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | Foraminifer and IRD counts from ODP Site 162-983 Barker, Stephen Knorr, Gregor Conn, Stephen Lordsmith, Sian Newman, Dhobasheni Thornalley, David J R %NPS; 162-983; 162-983A; 162-983B; 162-983C; Accumulation rate, ice rafted debris by number; Accumulation rate, mass; AGE; Calculated; COMPCORE; Composite Core; Counting >150 µm fraction; Density, dry bulk; DEPTH, sediment/rock; DRILL; Drilling/drill rig; Event label; Foraminifera, planktic, whole test; Ice rafted debris; IRD; Joides Resolution; Leg162; Mass spectrometer VG Prism Series II; Neogloboquadrina pachyderma sinistral; North Atlantic Ocean; Ocean Drilling Program; ODP; ODP 983; pachyderma; Sample code/label; Sedimentation rate; Size fraction < 0.063 mm, mud, silt+clay; Size fraction > 0.063 mm, sand; Split; Total counts Throughout the last glacial cycle millennial timescale variations in atmospheric CO2 occurred in parallel with perturbations in deep ocean circulation, which were themselves reflected by observable changes in surface conditions across the North Atlantic region. Here we use continuous proxy records to argue that an equivalent relationship has held throughout the last 800kyr i.e. since before the first occurrence of Heinrich events sensu stricto. Our results highlight the importance of internal climate dynamics in amplifying external (insolation) forcing on the climate system to produce the large amplitude of glacial terminations (deglaciations) during the mid to late Pleistocene. We show that terminations are characterized by an interval of intense ice rafting followed by a subsequent and abrupt shift to anomalously warm surface conditions (with respect to the more gradually evolving background state), which we interpret to reflect an abrupt recovery of deep ocean circulation in the Atlantic. According to our synthesis, this is followed by a period of enhanced (or at least anomalous) overturning lasting thousands of years until equilibrium interglacial conditions are attained and during which atmospheric CO2 is likely to decrease. Our results therefore suggest that deglacial oscillations in ocean circulation can have a lasting influence on early interglacial climate and highlight the transient nature of atmospheric CO2 overshoots associated with the onset of some previous interglacials. Accordingly we suggest that these intervals should be considered as a part of the deglacial process. This has implications for studies concerned with the evolution of atmospheric CO2 during interglacial periods including the Holocene. |
| title | Foraminifer and IRD counts from ODP Site 162-983 |
| topic | %NPS; 162-983; 162-983A; 162-983B; 162-983C; Accumulation rate, ice rafted debris by number; Accumulation rate, mass; AGE; Calculated; COMPCORE; Composite Core; Counting >150 µm fraction; Density, dry bulk; DEPTH, sediment/rock; DRILL; Drilling/drill rig; Event label; Foraminifera, planktic, whole test; Ice rafted debris; IRD; Joides Resolution; Leg162; Mass spectrometer VG Prism Series II; Neogloboquadrina pachyderma sinistral; North Atlantic Ocean; Ocean Drilling Program; ODP; ODP 983; pachyderma; Sample code/label; Sedimentation rate; Size fraction < 0.063 mm, mud, silt+clay; Size fraction > 0.063 mm, sand; Split; Total counts |
| url | https://doi.org/10.1594/PANGAEA.904398 |