Liebrand, Diederik et al. (2011): Antarctic ice sheet and oceanographic response to eccentricity forcing during the early Miocene

Leg/Site/Hole:
ODP 208
ODP 208 1264
ODP 208 1265
Identifier:
2012-046923
georefid

Creator:
Liebrand, Diederik
Utrecht University, Department of Earth Sciences, Utrecht, Netherlands
author

Lourens, L. J.
University of Cambridge, United Kingdom
author

Hodell, D. A.
author

de Boer, B.
author

van de Wal, Roderik. S. W.
author

Palike, Heiko
author

Identification:
Antarctic ice sheet and oceanographic response to eccentricity forcing during the early Miocene
2011
Climate of the Past
Copernicus, Katlenburg-Lindau, International
7
3
869-880
Stable isotope records of benthic foraminifera from ODP Site 1264 in the southeastern Atlantic Ocean are presented which resolve the latest Oligocene to early Miocene ( approximately 24-19 Ma) climate changes at high temporal resolution (<3 kyr). Using an inverse modelling technique, we decomposed the oxygen isotope record into temperature and ice volume and found that the Antarctic ice sheet expanded episodically during the declining phase of the long-term ( approximately 400 kyr) eccentricity cycle and subsequent low short-term ( approximately 100 kyr) eccentricity cycle. The largest glaciations are separated by multiple long-term eccentricity cycles, indicating the involvement of a non-linear response mechanism. Our modelling results suggest that during the largest (Mi-1) event, Antarctic ice sheet volume expanded up to its present-day configuration. In addition, we found that distinct approximately 100 kyr variability occurs during the termination phases of the major Antarctic glaciations, suggesting that climate and ice-sheet response was more susceptible to short-term eccentricity forcing at these times. During two of these termination-phases, delta (super 18) O bottom water gradients in the Atlantic ceased to exist, indicating a direct link between global climate, enhanced ice-sheet instability and major oceanographic reorganisations.
English
Coverage:Geographic coordinates:
North:-28.3200
West:2.3800East: 2.5100
South:-28.5000

Stratigraphy; Antarctic ice sheet; Antarctica; Atlantic Ocean; benthic taxa; C-13/C-12; carbon; Cenozoic; climate change; climate forcing; Foraminifera; glacial environment; glacial geology; ice sheets; Invertebrata; isotope ratios; isotopes; Kerguelen Plateau; Leg 208; lower Miocene; magnetic properties; magnetic susceptibility; microfossils; Miocene; Neogene; O-18/O-16; Ocean Drilling Program; ODP Site 1264; ODP Site 1265; Oligocene; one-dimensional models; oxygen; paleo-oceanography; paleoclimatology; Paleogene; paleomagnetism; Protista; South Atlantic; Southeastern Atlantic; stable isotopes; Tertiary; upper Oligocene; Walvis Ridge;

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