Obliquity-paced Pliocene West Antarctic ice sheet oscillations

Naish, T.; Powell, Ross D.; Levy, R. H.; Wilson, Gary; Scherer, Reed P.; Talarico, F.; Krissek, L. A.; Niessen, Frank; Pompilio, M.; Wilson, T. J.; Carter, L.; DeConto, Robert M.; Huybers, Peter; McKay, Robert; Pollard, David; Ross, Jake; Winter, D.; Barrett, P. J.; Browne, Greg H.; Cody, Rosemary; Cowan, Ellen A.; Crampton, James S.; Dunbar, Gavin B.; Dunbar, Nelia W.; Florindo, Fabio; Gebhardt, Catalina; Graham, Ian; Hannah, Michael; Hansaraj, Dhiresh; Harwood, David M.; Helling, D.; Henrys, S. A.; Hinnov, Linda A.; Kuhn, Gerhard; Kyle, Philip R.; Läufer, Andreas; Maffioli, P.; Magens, Diana; Mandernack, Kevin W.; McIntosh, William C.; Millan, C.; Morin, Roger H.; Ohneiser, Christian; Paulsen, Timothy; Persico, Davide; Raine, J. Ian; Reed, J.; Riesselman, C. R.; Sagnotti, Leonardo; Schmitt, D. R.; Sjunneskog, Charlotte; Strong, P.; Taviani, Marco; Vogel, S. W.; Wilch, T. I.; Williams, T.

doi:10.1038/nature07867

Cited by 615 publications

(606 citation statements)

References 46 publications

(73 reference statements)

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“…On the contrary, the ε Nd values at deepest site 900 gradually followed the shift towards more negative values indicating the dominant presence of northern source waters in the abyssal North Atlantic. Consequently, we infer that the entire meridional overturning circulation in the northern North Atlantic decreased at least during 1.68-1.40 Ma and SOW did not reach as far North, for example, as during the last glacial period (e.g., Crocket et al, 2011;Piotrowski et al, 2012), potentially as a consequence of the smaller size of West Antarctic ice sheet and thus reduced deep-water production during that time (e.g., Naish et al, 2009).…”

Section: Resultsmentioning

confidence: 93%

“…Apparently, the expansion of the West Antarctic ice sheet across the mid-Pleistocene transition promoted the production and export of AABW from the Southern Ocean (e.g., Naish et al, 2009;Lawrence et al, 2010). This major change suggests that after the mid-Pleistocene transition both northern and southern hemispheric ice sheets started to exert more far-field influence on ocean circulation and climate linked to the onset of the more pronounced 100 kyr late Quaternary style cyclicity of glacial-interglacial climates that still prevails today.…”

Section: Resultsmentioning

confidence: 99%

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A major change in North Atlantic deep water circulation 1.6 million years ago

Khélifi

2014

Clim. Past

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Abstract. The global ocean-climate system has been highly sensitive to the formation and advection of deep overflow water from the Nordic Seas as integral part of the Atlantic Meridional Overturning Circulation (AMOC) but its evolution over the Pliocene-Pleistocene global cooling is not fully understood. In particular, changes in the sources and mixing of prevailing deep waters that were involved in driving overturning throughout the Pliocene-Pleistocene climate transitions are not well constrained. Here we investigate the evolution of a substantial deep southward return overflow of the AMOC over the last 4 million years. We present new records of the bottom-water radiogenic neodymium isotope (ε Nd ) variability obtained from three sediment cores (DSDP site 610 and ODP sites 980/981 and 900) at water depths between 2170 and 5050 m in the northeast Atlantic. We find that prior to the onset of major Northern Hemisphere glaciation (NHG) ∼ 3 million years ago (Ma), ε Nd values primarily oscillated between −9 and −11 at all sites, consistent with enhanced vertical mixing and weak stratification of the water masses during the warmer-than-today Pliocene period. From 2.7 Ma to ∼ 2.0 Ma, the ε Nd signatures of the water masses gradually became more distinct, which documents a significant advection of Nordic Seas overflow deep water coincident with the intensification of NHG. Most markedly, however, at ∼ 1.6 Ma the interglacial ε Nd signatures at sites 610 (2420 m water depth (w.d.)) and 980/981 (2170 m w.d.) synchronously and permanently shifted by 2 to 3 ε Nd units to less radiogenic values, respectively. Since then the difference between glacial and interglacial ε Nd values has been similar to the Late Quaternary at each site. A decrease of ∼ 2 ε Nd units at 1.6 Ma was also recorded for the deepest water masses by site 900 (∼ 5 050 m w.d.), which thereafter, however, evolved to more radiogenic values again until the present. This major ε Nd change across the 1.6 Ma transition reflects a significant reorganization of the overturning circulation in the northeast Atlantic paving the way for the more stratified water column with distinct water masses prevailing thereafter.

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Section: Resultsmentioning

confidence: 93%

Section: Resultsmentioning

confidence: 99%

A major change in North Atlantic deep water circulation 1.6 million years ago

Khélifi

2014

Clim. Past

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“…It is unlikely that wind patterns were markedly different at the time of deposition of all the localities because (1) the ITCZ (whose seasonal movement drives the formation of wind-jets) reached it's modern position around 4.4 Ma (Billups et al, 1999), and (2) the obliquity of the earth away from the sun, although less in the Pliocene than it is today (Naish et al, 2009), would have been enough to ensure that the ITCZ passed seasonally over the Burica region. We also reject that mountains were high enough to have blocked wind-jet formation because Cocos Ridge subduction (Corrigan et al, 1990) did not begin until the Pleistocene (Collins et al, 1995;Leon-Rodriguez, 2007).…”

Section: Paleogeographic Implicationsmentioning

confidence: 99%

History of upwelling in the Tropical Eastern Pacific and the paleogeography of the Isthmus of Panama

O’Dea

Hoyos

Rodriguez

et al. 2012

Palaeogeography, Palaeoclimatology, Palaeoecology

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“…Thus our study provides a calibration for palaeoclimate reconstructions of warm intervals of the Pliocene world (e.g. Dowsett et al 2010), and potentially for comparing with the Antarctic climate records that span key intervals of West Antarctic ice sheet collapse and regrowth (Naish et al 2009). …”

Section: Introductionmentioning

confidence: 94%

“…Lisiecki and Raymo 2005;Naish et al 2009). During warmer intervals, for example the mid-Piacenzian warm period (defined by PRISM as 3.246 to 3.025 Ma; Dowsett et al 2010), the average global surface temperature was 2 C° to 3 C° (Jansen et al 2007) warmer than pre-industrial.…”

Section: Possible Explanations Of Warmer Antarctic Coastal Conditionsmentioning

confidence: 99%