Stable isotope and Mg/Ca ratios of Paleogene benthic foraminifera in the western North Atlantic

Global cooling and the development of continental-scale Antarctic glaciation occurred in the late middle Eocene to early Oligocene (~38 to 28 million years ago), accompanied by deep-ocean reorganization attributed to gradual Antarctic Circumpolar Current (ACC) development. Our benthic foraminiferal...

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Bibliographic Details
Main Authors: Katz, Miriam E, Cramer, Benjamin S, Toggweiler, J Robbie, Esmay, Gar, Liu, Chengji, Miller, Kenneth G, Rosenthal, Yair, Wade, Bridget S, Wright, James D
Format: Dataset
Language:English
Published: PANGAEA 2011
Subjects:
171-1053
171-1053A
ASP-5
Carolina Slope
North Atlantic Ocean
COMPCORE
Composite Core
DRILL
Drilling/drill rig
Joides Resolution
Leg171B
North Atlantic
Ocean Drilling Program
ODP
Antarc*
Antarctic
Online Access:https://doi.pangaea.de/10.1594/PANGAEA.771562
https://doi.org/10.1594/PANGAEA.771562
Description
Summary:Global cooling and the development of continental-scale Antarctic glaciation occurred in the late middle Eocene to early Oligocene (~38 to 28 million years ago), accompanied by deep-ocean reorganization attributed to gradual Antarctic Circumpolar Current (ACC) development. Our benthic foraminiferal stable isotope comparisons show that a large d13C offset developed between mid-depth (~600 meters) and deep (>1000 meters) western North Atlantic waters in the early Oligocene, indicating the development of intermediate-depth d13C and O2 minima closely linked in the modern ocean to northward incursion of Antarctic Intermediate Water. At the same time, the ocean's coldest waters became restricted to south of the ACC, probably forming a bottom-ocean layer, as in the modern ocean. We show that the modern four-layer ocean structure (surface, intermediate, deep, and bottom waters) developed during the early Oligocene as a consequence of the ACC.

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