Campanian-Maastrichtian ocean circulation in the tropical Pacific.

Jung, Claudia, Voigt, Silke, Friedrich, Oliver, Koch, Mirjam C. and Frank, Martin (2013) Campanian-Maastrichtian ocean circulation in the tropical Pacific. Open Access Paleoceanography, 28 (3). pp. 562-573. DOI 10.1002/palo.20051.

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Abstract

The Pacific Ocean is the largest water body on Earth, and circulation in the Pacific
contributed significantly to climate evolution in the latest Cretaceous, the culmination of a
period of long-term cooling. Here, we present new high-resolution late Campanian to
Maastrichtian benthic and planktic foraminiferal stable isotope data and a neodymium (Nd)
isotope record obtained from sedimentary ferromanganese oxide coatings of Ocean Drilling
Program Hole 1210B from the tropical Pacific Ocean (Shatsky Rise). These new records
resolve 13 million years in the latest Cretaceous, providing insights into changes in surface
and bottom water temperatures and source regions of deep to intermediate waters covering
the carbon isotope excursions of the Campanian-Maastrichtian Boundary Event (CMBE)
and the Mid-Maastrichtian event (MME). Our new benthic foraminiferal δ18O and Nd
isotope records together with published Nd isotope data show markedly parallel trends
across the studied interval over a broad range of bathyal to abyssal water depths interpreted
to reflect changes in the intensity of deep-ocean circulation in the tropical Pacific. In
particular, we observe a three-million-year-long period of cooler conditions in the early
Maastrichtian (72.5 to 69.5 Ma) when a concomitant change toward less radiogenic
seawater Nd isotope signatures probably marks a period of enhanced admixture and
northward flow of deep waters with Southern Ocean provenance. We suggest this change to
have been triggered by intensified formation and convection of deep waters in the high
southern latitudes, a process that weakened during the MME (69.5 to 68.5 Ma). The early
Maastrichtian cold interval is closely related to the negative and positive carbon isotope
trends of the CMBE and MME. The millions-of-years long duration of these carbon cycle
perturbations suggests a tectonic forcing of climatic cooling, possibly related to changes in
ocean basin geometry and bathymetry.

Document Type: Article
Additional Information: WOS:000325628700015
Keywords: Campanian-Maastrichtian; Shatsky Rise; neodymium isotopes; carbon and oxygen isotopes; ocean circulation
Research affiliation: OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-P-OZ Paleo-Oceanography
Refereed: Yes
Open Access Journal?: No
Publisher: AGU (American Geophysical Union), Wiley
Date Deposited: 23 Oct 2013 07:17
Last Modified: 28 Jul 2017 08:29
URI: https://oceanrep.geomar.de/id/eprint/22213

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