Stable isotope record during the past 1 Myr of ODP Site 162-980 in the subpolar North Atlantic

Benthic foraminiferal carbon isotope records from a suite of drill sites in the North Atlantic are used to trace variations in the relative strengths of Lower North Atlantic Deep Water (LNADW), Upper North Atlantic Deep Water (UNADW), and Southern Ocean Water (SOW) over the past 1 Myr. During glacia...

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Bibliographic Details
Main Authors: Flower, Benjamin P, Oppo, Delia W, McManus, Jerry F, Venz, Kathryn A, Hodell, David A, Cullen, James L
Format: Other/Unknown Material
Language:English
Published: PANGAEA 2008
Subjects:
162-980
COMPCORE
Composite Core
Joides Resolution
Leg162
North Atlantic Ocean
Ocean Drilling Program
ODP
NADW
North Atlantic Deep Water
North Atlantic
Southern Ocean
Online Access:https://doi.pangaea.de/10.1594/PANGAEA.700836
https://doi.org/10.1594/PANGAEA.700836
Description
Summary:Benthic foraminiferal carbon isotope records from a suite of drill sites in the North Atlantic are used to trace variations in the relative strengths of Lower North Atlantic Deep Water (LNADW), Upper North Atlantic Deep Water (UNADW), and Southern Ocean Water (SOW) over the past 1 Myr. During glacial intervals, significant increases in intermediate-to-deep delta13C gradients (commonly reaching >1.2 per mil ) are consistent with changes in deep water circulation and associated chemical stratification. Bathymetric delta13C gradients covary with benthic foraminiferal delta18O and covary inversely with Vostok CO2, in agreement with chemical stratification as a driver of atmospheric CO2 changes. Three deep circulation indices based on delta13C show a phasing similar to North Atlantic sea surface temperatures, consistent with a Northern Hemisphere control of NADW/SOW variations. However, lags in the precession band indicate that factors other than deep water circulation control ice volume variations at least in this band.

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