The Plio-Pleistocene development of Atlantic deep-water circulation and its influence on climate trends

Bell, David B.; Jung, Simon; Kroon, Dick

doi:10.1016/j.quascirev.2015.06.026

Cited by 45 publications

(60 citation statements)

References 115 publications

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“…In this regard, and Lisiecki (2014) suggested the lack of increased overturning circulation in the deep water during this time interval. At a first glance this stands in contrast to the proposed increased overturning circulation postulated by Bell et al (2015) in relation to changes in the North Atlantic surface water mass trajectory. We argue that the changes in the surface water masses potentially relate to an intensification in the intermediate not the deep-water branch of the overturning cell stimulated by the increased northward protrusion of MOW.…”

Section: Did Mow Contribute To the Early Pleistocene Climate Transition?contrasting

confidence: 58%

“…This northward protrusion of warm and saline MOW towards high-latitude deep-water convection hotspots is considered an important modulator of the North Atlantic salt budget Rogerson et al, 2006;Voelker et al, 2006). We suggest that steady contributions of MOW throughout Interval I continuously supplied salt into the North Atlantic and potentially preconditioned the strong AMOC activity phase starting at ∼ 2.4 Ma (Bell et al, 2015), when a tipping point was reached (Fig. 4a).…”

Section: Did Mow Contribute To the Early Pleistocene Climate Transition?mentioning

confidence: 81%

“…4b), confirming a more southern delineation of transitional and subpolar water masses during glacial periods of the Early Pleistocene than in recent setting . This latitudinal shift might have occurred in concert with a more sluggish AMOC at least during the glacial periods, if not throughout the whole time interval (Bell et al, 2015). Colder and more arid background conditions in the Mediterranean Sea could foster a stronger MOW analogous to cold spells related to Heinrich events throughout the last climatic cycle (Bahr et al, 2014Kaboth et al, 2016).…”

Section: Did Mow Contribute To the Early Pleistocene Climate Transition?mentioning

confidence: 99%

“…The Early Pleistocene period spans the transition from the preceding Pliocene climate optimum with limited ice sheets in the Northern Hemisphere to the cooler Middle and Late Pleistocene climate with rapidly developing continental ice growth in both hemispheres (Raymo et al, 1992;Shackleton and Hall, 1984). Throughout the Early Pleistocene, however, an interruption of the long-term Northern Hemisphere ice volume increase can be observed in concert with a seasurface temperature stabilization in the high-latitude North Atlantic cooling trend (Bell et al, 2015). It was suggested that these changes relate to an increase in AMOC strength and, by extension, an increase in northward heat transport (Bell et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

“…Throughout the Early Pleistocene, however, an interruption of the long-term Northern Hemisphere ice volume increase can be observed in concert with a seasurface temperature stabilization in the high-latitude North Atlantic cooling trend (Bell et al, 2015). It was suggested that these changes relate to an increase in AMOC strength and, by extension, an increase in northward heat transport (Bell et al, 2015). Here we elaborate on the possible role of MOW on North Atlantic palaeoceanographic changes during the Early Pleistocene climate transition by investigating the benthic foraminifera stable oxygen and carbon isotopes and grain sizes from IODP 339 Site U1389, located on the upper slope of the Gulf of Cadiz (see Fig.…”

Section: Introductionmentioning

confidence: 99%

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Mediterranean Outflow Water variability during the Early Pleistocene

2017

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Abstract. Gaining insights into the evolution of Mediterranean Outflow Water (MOW) during the Early Pleistocene has been so far hampered by the lack of available palaeoclimatic archives. Here we present the first benthic foraminifera stable oxygen and carbon isotope records and grain-size data from IODP Expedition 339 Site U1389 presently located within the upper core of the MOW in the Gulf of Cadiz for the time interval between 2.6 and 1.8 Ma. A comparison with an intermediate water mass record from the Mediterranean Sea strongly suggest an active MOW supplying Site U1389 on glacial-interglacial timescales during the Early Pleistocene. We also find indication that the increasing presence of MOW in the Gulf of Cadiz during the investigated time interval aligns with the progressive northward protrusion of Mediterranean sourced intermediate water masses into the North Atlantic, possibly modulating the intensification of the North Atlantic Meridional Overturning Circulation at the same time. Additionally, our results suggest that MOW flow strength was already governed by precession and semi-precession cyclicity during the Early Pleistocene against the background of glacial-interglacial variability.

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Section: Did Mow Contribute To the Early Pleistocene Climate Transition?contrasting

confidence: 58%

Section: Did Mow Contribute To the Early Pleistocene Climate Transition?mentioning

confidence: 81%

Section: Did Mow Contribute To the Early Pleistocene Climate Transition?mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Mediterranean Outflow Water variability during the Early Pleistocene

2017

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Plio-Pleistocene evolution of water mass exchange and erosional input at the Atlantic-Arctic gateway

2016

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Water mass exchange between the Arctic Ocean and the Norwegian-Greenland Seas has played an important role for the Atlantic thermohaline circulation and Northern Hemisphere climate. We reconstruct past water mass mixing and erosional inputs from the radiogenic isotope compositions of neodymium (Nd), lead (Pb), and strontium (Sr) at Ocean Drilling Program site 911 (leg 151) from 906 m water depth on Yermak Plateau in the Fram Strait over the past 5.2 Myr. The isotopic compositions of past bottom waters were extracted from authigenic oxyhydroxide coatings of the bulk sediments. Neodymium isotope signatures obtained from surface sediments agree well with present-day deepwater ε Nd signature of À11.0 ± 0.2. Prior to 2.7 Ma the Nd and Pb isotope compositions of the bottom waters only show small variations indicative of a consistent influence of Atlantic waters. Since the major intensification of the Northern Hemisphere Glaciation at 2.7 Ma the seawater Nd isotope composition has varied more pronouncedly due to changes in weathering inputs related to the waxing and waning of the ice sheets on Svalbard, the Barents Sea, and the Eurasian shelf, due to changes in water mass exchange and due to the increasing supply of ice-rafted debris (IRD) originating from the Arctic Ocean. The seawater Pb isotope record also exhibits a higher short-term variability after 2.7 Ma, but there is also a trend toward more radiogenic values, which reflects a combination of changes in input sources and enhanced incongruent weathering inputs of Pb released from freshly eroded old continental rocks.

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Global deepwater circulation between 2.4 and 1.7 Ma and its connection to the onset of Northern Hemisphere Glaciation

Huang

Zhou

2016

Paleoceanography

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We have generated an early Pleistocene benthic isotopic record for the Ocean Drilling Program Site 807 (2804 m) from the western equatorial Pacific. Between 2.4 and 1.7 Ma, the benthic δ 13 C of this site and a few other deep Pacific sites was consistently higher than the Southern Ocean Site MV0502-4JC (4286 m), pointing to a reversal relative to the current gradient and hence implying a different circulation regime. We reconstructed the deepwater mass distribution of this interval by using a collection of benthic isotope records from 15 Pacific and 10 Atlantic sites and a δ 13 C-δ 18 O mixing model. A two-end-member mixing regime between the North Atlantic Deep Water (NADW) and the Antarctic Bottom Water (AABW), with properties very different from today, was identified. The Southern Ocean showed strong signs of stratification and AABW with low benthic δ 13 C, but high δ 18 O values reached out to other basins only below~4000 m. In contrast, NADW ventilated most of the ocean interior, contributing~70% to the Pacific Deep Water volumetrically. Our model results also reveal a strong remineralization effect at the bottom sites of the Pacific and the Atlantic, suggesting significant accumulation of respired carbon in the bottom water between 2.4 and 1.7 Ma. We propose that such a circulation pattern was initiated by the reversal of salinity gradient between AABW and NADW from 3.0 to 2.4 Ma, possibly linked to Antarctic sea ice expansion and reduced southward heat transport during the onset of Northern Hemisphere Glaciation.

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The Plio-Pleistocene development of Atlantic deep-water circulation and its influence on climate trends

Cited by 45 publications

References 115 publications

Mediterranean Outflow Water variability during the Early Pleistocene

Mediterranean Outflow Water variability during the Early Pleistocene

Plio-Pleistocene evolution of water mass exchange and erosional input at the Atlantic-Arctic gateway

Global deepwater circulation between 2.4 and 1.7 Ma and its connection to the onset of Northern Hemisphere Glaciation

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