The Open UniversitySkip to content
 

Cenozoic North Atlantic deep circulation history recorded in contourite drifts, offshore Newfoundland, Canada

Boyle, Patrick R.; Romans, Brian W.; Tucholke, Brian E.; Norris, Richard D.; Swift, Stephen A. and Sexton, Philip F. (2017). Cenozoic North Atlantic deep circulation history recorded in contourite drifts, offshore Newfoundland, Canada. Marine Geology, 385 pp. 185–203.

Full text available as:
Full text not publicly available
Due to copyright restrictions, this file is not available for public download until 18 January 2018
Click here to request a copy from the OU Author.
DOI (Digital Object Identifier) Link: https://doi.org/10.1016/j.margeo.2016.12.014
Google Scholar: Look up in Google Scholar

Abstract

In the North Atlantic Ocean, contour-following deep currents have created regional erosional unconformities and deposited contourite drifts that exceed 2 km in thickness and extend for 100 s of km. The stratigraphic records in the drifts have been used to reconstruct variations in North Atlantic deep-water circulation throughout the Cenozoic; however, uncertainties remain about certain aspects of the timing, intensity, depth distribution, and region- al impact of these currents. Here, we use an integrated dataset of seismic-reflection profiles and IODP core data (lithology, biostratigraphy, and magnetostratigraphy) to document sedimentation history and the development of current effects in the Cretaceous to present sedimentary record on the J-Anomaly Ridge and Southeast Newfoundland Ridge, offshore Newfoundland, Canada. The Newfoundland ridges are in a key location, lying between well-studied areas in the northern and western North Atlantic and under the path of both the modern Deep Western Boundary Current and the Gulf Stream. Late Cretaceous through Early Eocene sedimentation on the ridges was dominated by biogenic pelagic sedimentation, but at ~47 Ma, near the Early-Middle Eocene boundary, well developed contourite drifts began to accrete in paleo-water depths of ~4000–4500 m, accompanied by an order-of-magnitude increase in terrigenous sediment mass accumulation rates. From this time forward, drift deposition, interrupted by brief episodes of erosion, continued unabated. This timing for the onset of persistent deep currents is coincident with reorganization of Atlantic circulation inferred from a change from biosiliceous to non-biosiliceous sedimentation in the western North Atlantic (Horizon AC) and with the current-eroded Intra-Eocene Unconformity (IEU) in the northern North Atlantic. A change in sedimentation style occurred within the Middle Eocene to upper Oligocene drift sequence, and it likely was related to a shift to deeper, more intense currents that eroded the widespread Horizon AU along the margin of eastern North America about Early Oligocene time. Beginning in the Late Oligocene (~25 Ma) a thick drift exhibiting seismically laminated mudwaves was deposited in a distinct belt at ~3500–4500 m paleodepth on the Southeast Newfoundland Ridge. This development correlates with widespread Late Oligocene through Miocene-Pliocene drift accumulation throughout the North Atlantic. The most recent phase of drift deposition, since Late Pliocene time (~3 Ma), occurred after a shift to the ‘modern’ circulation system of deeper, swifter currents, and it includes mixed pelagic-hemipelagic sediments and ice-rafted debris that reflect glacial-interglacial influences on sedimentation.

Item Type: Journal Item
Copyright Holders: 2017 Elsevier B.V.
ISSN: 0025-3227
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: seismic stratigraphy; contourite drifts; abyssal circulation; J-Anomaly Ridge; Southeast Newfoundland Ridge; North Atlantic Ocean
Academic Unit/School: Faculty of Science, Technology, Engineering and Mathematics (STEM) > Environment, Earth and Ecosystem Sciences
Faculty of Science, Technology, Engineering and Mathematics (STEM)
Interdisciplinary Research Centre: Centre for Earth, Planetary, Space and Astronomical Research (CEPSAR)
Item ID: 48441
Depositing User: Philip Sexton
Date Deposited: 08 Feb 2017 10:04
Last Modified: 16 May 2017 20:48
URI: http://oro.open.ac.uk/id/eprint/48441
Share this page:

Altmetrics

Actions (login may be required)

Policies | Disclaimer

© The Open University   + 44 (0)870 333 4340   general-enquiries@open.ac.uk