A better-ventilated ocean triggered by Late Cretaceous changes in continental configuration

Area of Science:

• Paleoceanography
• Climate Modeling
• Geochemistry

Background:

• Oceanic anoxic events (OAEs) are linked to deep ocean deoxygenation during warm periods.
• Continental configurations significantly influence oceanic circulation and deep ocean oxygenation.

Purpose of the Study:

• To investigate how Late Cretaceous continental changes affected oceanic circulation.
• To assess the impact of altered circulation on deep ocean oxygenation and neodymium isotope (ɛNd) values.

Main Methods:

• Utilized a coupled ocean-atmosphere climate model.
• Simulated ocean dynamics for two distinct Late Cretaceous time slices (94 and 71 Ma).
• Compared model outputs with existing neodymium isotope (ɛNd) data.

Main Results:

• Simulations revealed a shift in southern deep-water production from the South Pacific to the South Atlantic and Indian Oceans.
• Deep-water production in the North Pacific remained continuous.
• Model results align with observed decreases in ɛNd values in Atlantic and Indian deep waters.

Conclusions:

• Intensified southern Atlantic deep-water production was a key factor in Late Cretaceous oceanographic changes.
• Reversal of deep-water flow through the Caribbean Seaway contributed to observed ɛNd trends.
• Continental configuration changes played a crucial role in modulating ocean circulation and deep-sea geochemistry.