The Open UniversitySkip to content
 

Astronomically paced changes in overturning circulation in the Western North Atlantic during the middle Eocene

Vahlenkamp, Maximilian; Niezgodzki, Igor; De Vleeschouwer, David; Bickert, Torsten; Harper, Dustin; Kirtland Turner, Sandra; Lohmann, Gerrit; Sexton, Philip; Zachos, James and Pälike, Heiko (2018). Astronomically paced changes in overturning circulation in the Western North Atlantic during the middle Eocene. Earth and Planetary Science Letters, 484 pp. 329–340.

Full text available as:
[img]
Preview
PDF (Version of Record) - Requires a PDF viewer such as GSview, Xpdf or Adobe Acrobat Reader
Download (3MB) | Preview
DOI (Digital Object Identifier) Link: https://doi.org/10.1016/j.epsl.2017.12.016
Google Scholar: Look up in Google Scholar

Abstract

North Atlantic Deep Water (NADW) currently redistributes heat and salt between Earth’s ocean basins, and plays a vital role in the ocean-atmosphere CO2 exchange. Despite its crucial role in today’s climate system, vigorous debate remains as to when deep-water formation in the North Atlantic started. Here, we present datasets from carbonate-rich middle Eocene sediments from the Newfoundland Ridge, revealing a unique archive of paleoceanographic change from the progressively cooling climate of the middle Eocene. Well-defined lithologic alternations between calcareous ooze and clay-rich intervals occur at the ∼41-kyr beat of axial obliquity. Hence, we identify obliquity as the driver of middle Eocene (43.5–46 Ma) Northern Component Water (NCW, the predecessor of modern NADW) variability. High-resolution benthic foraminiferal δ18O and δ13C suggest that obliquity minima correspond to cold, nutrient-depleted, western North Atlantic deep waters. We thus link stronger NCW formation with obliquity minima. In contrast, during obliquity maxima, Deep Western Boundary Currents were weaker and warmer, while abyssal nutrients were more abundant. These aspects reflect a more sluggish NCW formation. This obliquity-paced paleoceanographic regime is in excellent agreement with results from an Earth system model, in which obliquity minima configurations enhance NCW formation.

Item Type: Journal Item
Copyright Holders: 2017 The Authors
ISSN: 0012-821X
Project Funding Details:
Funded Project NameProject IDFunding Body
Ocean circulation and carbon cycling during Eocene 'greenhouse' warmth (SE-12-047-PS)NE/K001663/1NERC (Natural Environment Research Council)
Keywords: NADW; AMOC; astronomical forcing; middle Eocene; IODP
Academic Unit/School: Faculty of Science, Technology, Engineering and Mathematics (STEM) > Environment, Earth and Ecosystem Sciences
Faculty of Science, Technology, Engineering and Mathematics (STEM)
Item ID: 52972
Depositing User: Philip Sexton
Date Deposited: 24 Jan 2018 11:10
Last Modified: 02 May 2019 15:40
URI: http://oro.open.ac.uk/id/eprint/52972
Share this page:

Metrics

Altmetrics from Altmetric

Citations from Dimensions

Download history for this item

These details should be considered as only a guide to the number of downloads performed manually. Algorithmic methods have been applied in an attempt to remove automated downloads from the displayed statistics but no guarantee can be made as to the accuracy of the figures.

Actions (login may be required)

Policies | Disclaimer

© The Open University   contact the OU