Enhanced weathering and CO2 drawdown caused by latest Eocene strengthening of the Atlantic meridional overturning circulation

Elsworth, Geneviève; Galbraith, Eric D.; Halverson, Galen P.; Yang, Simon X.

doi:10.1038/ngeo2888

Cited by 81 publications

(83 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, the gateway 10 change may explain ~3°C of deep ocean cooling (Sijp et al, 2014), in agreement with late Eocene cooling found in deep sea foraminifera (Bohaty et al, 2012). Part of the CO 2 decline at the EOT may have been caused by the opening of Southern Ocean gateways (Elsworth et al, 2017), due to feedbacks in silicate weathering. This presents a possible way to reconcile the CO 2 forcing and gateway…”

mentioning

confidence: 63%

“…Many studies investigating gateway effects have used modern topography for their control simulation (Elsworth et al, 2017;England et al, 2017;Fyke et al, 2015;Sijp et al, 2009;Yang et al, 2014) and created EOT-like 20 perturbations by closing Drake Passage and/or opening the Panama Seaway. While this method of changing basin geometry is appealing in that it illuminates specific gateway effects, it implicitly ignores several features of the late Eocene or early Oligocene paleogeography that are potentially crucial to the ocean circulation.…”

Section: Hypotheses 15mentioning

confidence: 99%

See 1 more Smart Citation

Climate sensitivity and meridional overturning circulation in the late Eocene using GFDL CM2.1

Hutchinson¹,

Boer²,

Coxall³

et al. 2018

Preprint

View full text Add to dashboard Cite

show abstract

mentioning

confidence: 63%

Section: Hypotheses 15mentioning

confidence: 99%

Climate sensitivity and meridional overturning circulation in the late Eocene using GFDL CM2.1

Hutchinson¹,

Boer²,

Coxall³

et al. 2018

Preprint

View full text Add to dashboard Cite

show abstract

“…Comparison of benthic foraminiferal δ 18 O records suggests the inception of NCW formation around the middle to late Eocene (~38.5 Ma) in the Labrador Sea (Borrelli et al, ), strengthening around 35 Ma (Langton et al, ). The presence of NCW in the deep Atlantic by the earliest Oligocene is also supported by the onset of drift deposition in the northeast Atlantic (Davies et al, ) and δ 13 C deep‐water aging gradients (Elsworth et al, ), though Abelson and Erez () suggest NCW and the onset of modern‐like Atlantic meridional overturning circulation (AMOC) occurred during the late Eocene, immediately before the EOT. We interpret the long‐term decreasing trend at our study sites to be related to the increase in NCW contribution to proto‐CDW.…”

Section: Discussionmentioning

confidence: 96%

No Change in Southern Ocean Circulation in the Indian Ocean From the Eocene Through Late Oligocene

Wright

Scher

Seton

et al. 2018

Paleoceanog and Paleoclimatol

View full text Add to dashboard Cite

Deciphering the evolution of Southern Ocean circulation during the Eocene and Oligocene has important implications for understanding the development of the Antarctic Circumpolar Current and transition to Earth's “icehouse” climate. To better understand ocean circulation patterns in the Indian Ocean sector of the Southern Ocean, we generated a new fossil fish tooth neodymium isotope record (εNd) from the upper Eocene to upper Oligocene sections (36–23 Ma) of Ocean Drilling Program Sites 744 and 748 (Kerguelen Plateau, Indian Ocean). Reconstructed seawater εNd values from fossil fish teeth are used to trace changes in water masses across ocean basins. The records from Site 748 and Site 744 reveal a gradual shift from εNd values around −6.5 to −7.5 in the late Eocene to εNd values between −7.5 and −8.3 by the late Oligocene, consistent with a Circumpolar Deep Water (CDW) influence at the Kerguelen Plateau throughout the Oligocene. We interpret the shift to less radiogenic values to reflect the increased export of Northern Component Water to the Southern Ocean, likely into the proto‐CDW. However, the records show no major change in water mass composition around the Kerguelen Plateau that would accompany an increase in Pacific throughflow related to the opening of Drake Passage and imply that Pacific throughflow via the Drake Passage occurred by the late Eocene. High‐frequency variability in ɛNd values at Site 744 is interpreted as an imprint of Oligocene glacial activity, with a particularly pronounced excursion at 32.6 Ma roughly coinciding with other glacial weathering indicators around Antarctica.

show abstract

“…Finally, we suggest from the coincidence between the circulation proxies and climatic indicators (δ 18 O and CO 2 ) that in the traditional question, circulation versus CO 2 as driving factors for the EOT cooling [e.g., Kennett , ; Berggren and Hollister , ; DeConto and Pollard , ; Huber and Nof , ; Katz et al ., ; Pagani et al ., ; Sijp et al ., ], as suggested very recently by Elsworth et al . [] the answer can be both, and these factors could have been coupled. However, unlike Elsworth et al .…”

Section: Introductionmentioning

confidence: 99%

“…However, unlike Elsworth et al . [], we use different proxies to suggest the onset of modern‐like AMOC immediately prior to the EOT, rather than its mere intensification some 2 Myr earlier.…”

Section: Introductionmentioning

confidence: 99%

The onset of modern‐like Atlantic meridional overturning circulation at the Eocene‐Oligocene transition: Evidence, causes, and possible implications for global cooling

Abelson

Erez

2017

Geochem Geophys Geosyst

View full text Add to dashboard Cite

A compilation of benthic δ18O from the whole Atlantic and the Southern Ocean (Atlantic sector) shows two major jumps in the interbasinal gradient of δ18O (Δδ18O) during the Eocene and the Oligocene: one at ∼40 Ma and the second concomitant with the isotopic event of the Eocene‐Oligocene transition (EOT), ∼33.7 Ma ago. From previously published circulation models and proxies, we show that the first Δδ18O jump reflects the thermal isolation of Antarctica associated with the proto‐Antarctic circumpolar current (ACC). The second marks the onset of interhemispheric northern‐sourced circulation cell, similar to the modern Atlantic meridional overturning circulation (AMOC). The onset of AMOC‐like circulation slightly preceded (100–300 kyr) the EOT, as we show by the high‐resolution profiles of δ18O and δ13C previously published from DSDP/ODP sites in the Southern Ocean and South Atlantic. These events coincide with the onset of antiestuarine circulation between the Nordic seas and the North Atlantic which started around the EOT and may be connected to the deepening of the Greenland‐Scotland Ridge. We suggest that while the shallow proto‐ACC supplied the energy for deep ocean convection in the Southern Hemisphere, the onset of the interhemispheric northern circulation cell was due to the significant EOT intensification of deepwater formation in the North Atlantic driven by the Nordic antiestuarine circulation. This onset of the interhemispheric northern‐sourced circulation cell could have prompted the EOT global cooling.

show abstract

Enhanced weathering and CO2 drawdown caused by latest Eocene strengthening of the Atlantic meridional overturning circulation

Cited by 81 publications

References 29 publications

Climate sensitivity and meridional overturning circulation in the late Eocene using GFDL CM2.1

Climate sensitivity and meridional overturning circulation in the late Eocene using GFDL CM2.1

No Change in Southern Ocean Circulation in the Indian Ocean From the Eocene Through Late Oligocene

The onset of modern‐like Atlantic meridional overturning circulation at the Eocene‐Oligocene transition: Evidence, causes, and possible implications for global cooling

Contact Info

Product

Resources

About