Strontium isotope data from DSDP Sites 32-305 and 62-463 and ODP Sites 113-689 and 113-690

Fluctuations in oxygen (d18O) and carbon (d13C) isotope values of benthic foraminiferal calcite from the tropical Pacific and Southern Oceans indicate rapid reversals in the dominant mode and direction of the thermohaline circulation during a 1 m.y. interval (71-70 Ma) in the Maastrichtian. At the o...

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Bibliographic Details
Main Authors: Barrera, Enriqueta C, Savin, Samuel M, Thomas, Ellen, Jones, Charles E
Format: Other/Unknown Material
Language:English
Published: PANGAEA 1997
Subjects:
113-689
113-690
32-305
62-463
COMPCORE
Composite Core
Deep Sea Drilling Project
DRILL
Drilling/drill rig
DSDP
Glomar Challenger
Joides Resolution
Leg113
Leg32
Leg62
North Pacific/CONT RISE
North Pacific/SEAMOUNT
Ocean Drilling Program
ODP
South Atlantic Ocean
Southern Ocean
Online Access:https://doi.pangaea.de/10.1594/PANGAEA.712680
https://doi.org/10.1594/PANGAEA.712680
Description
Summary:Fluctuations in oxygen (d18O) and carbon (d13C) isotope values of benthic foraminiferal calcite from the tropical Pacific and Southern Oceans indicate rapid reversals in the dominant mode and direction of the thermohaline circulation during a 1 m.y. interval (71-70 Ma) in the Maastrichtian. At the onset of this change, benthic foraminiferal d18O values increased and were highest in low-latitude Pacific Ocean waters, whereas benthic and planktic foraminiferal d13C values decreased and benthic values were lowest in the Southern Ocean. Subsequently, benthic foraminiferal d18O values in the Indo-Pacific decreased, and benthic and planktic d13C values increased globally. These isotopic patterns suggest that cool intermediate-depth waters, derived from high-latitude regions, penetrated temporarily to the tropics. The low benthic d13C values at the Southern Ocean sites, however, suggest that these cool waters may have been derived from high northern rather than high southern latitudes. Correlation with eustatic sea-level curves suggests that sea-level change was the most likely mechanism to change the circulation and/or source(s) of intermediate-depth waters. We thus propose that oceanic circulation during the latest Cretaceous was vigorous and that competing sources of intermediate- and deep-water formation, linked to changes in climate and sea level, may have alternated in importance.

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