Stable isotope record of Cibicidoides wuellerstorfi from Pleistocene sediments of DSDP Site 86-502 in the Caribbean Sea

Variations in the stable isotopic composition of benthic foraminifera from Deep-Sea Drilling Project (DSDP) site 502B in the Caribbean Sea are used to reconstruct Atlantic intermediate water circulation variability over the last 1.2 m.y. Comparison of this record with other North Atlantic benthic is...

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Bibliographic Details
Main Authors: deMenocal, Peter B, Oppo, Delia W, Fairbanks, Richard G, Prell, Warren L
Format: Dataset
Language:English
Published: PANGAEA 1992
Subjects:
68-502_Site
68-502B
Caribbean Sea/RIDGE
COMPCORE
Composite Core
Deep Sea Drilling Project
DRILL
Drilling/drill rig
DSDP
Glomar Challenger
Leg68
Pacific
NADW
North Atlantic Deep Water
North Atlantic
Online Access:https://doi.pangaea.de/10.1594/PANGAEA.701470
https://doi.org/10.1594/PANGAEA.701470
Description
Summary:Variations in the stable isotopic composition of benthic foraminifera from Deep-Sea Drilling Project (DSDP) site 502B in the Caribbean Sea are used to reconstruct Atlantic intermediate water circulation variability over the last 1.2 m.y. Comparison of this record with other North Atlantic benthic isotope records indicates that Atlantic intermediate water circulation was relatively enhanced during glacial maxima when North Atlantic deep water (NADW) production was reduced. However, a simple, compensatory relationship between intermediate and deepwater circulation is not apparent. Geochemical models have shown that such changes in ocean circulation can affect atmospheric CO2 levels by changing vertical nutrient and alkalinity profiles. The Delta delta13C difference between Caribbean site 502B and deep equatorial Pacific site 677 is highly coherent and in phase with ice volume. Like the delta18O record, there is an increase in amplitude (40%) and a large increase in 100 kyr power after 0.7 Ma. The 1.2 per mil Delta delta13C amplitude scales to 70 ppm V in atmospheric CO2 using Boyle's (1986) box model result. The implied increase in CO2 amplitude after 0.7 Ma may suggest a positive feedback role in effecting the higher-amplitude climatic fluctuations which characterize the last 0.7 m.y.

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