Stable-isotope stratigraphy for the last 750,000 years : "Meteor" core 13519 from the eastern equatorial Atlantic

• Main Authors: Sarntheim, M., Erlenkeuser, H., Grafenstein, R. von, Schröder, C.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Bornträger 1984
• Subjects: North Atlantic Deep Water; North Atlantic
• Online Access: https://oceanrep.geomar.de/id/eprint/56723/; https://oceanrep.geomar.de/id/eprint/56723/1/Sarnthein_M_1984_C.pdf

From a 10.7 m long gravity core from the Sierra Leone Rise (5° 39,5' N, 19° 51'W) a detailed oxygen and carbon isotope record of both planktonic and benthonic foraminifera species was obtained extending from the Recent to the Jaramillo event. The analysis yielded six major results. 1. Benthos oxygen isotopes varied by 1.8-2.2‰ from interglacial to glacial times and may indicate a synglacial cooling of North Atlantic Deep Water at 2800 m depth by 1-3° C. 2. Variable anomalies between the benthos and plankton δ18 O record indicate a cooling of sea-surface temperatures (SST) by up to 6° C during some glacial stages. 3. Southerly trade winds and equatorial upwelling may exert the primary control of SST variations, in particular of extreme values of cold and warm stages and of the abrupt character of climate transitions and their leads and lags, and finally, of variable sedimentation rates. 4. The benthos δ13C record correlates well with the flux and preservation of organic matter. 5. A new time scale, CARPOR, was established from the assumption that terrigenous sediment supply was ± constant but CaC03 varied considerably. When applied to the δ18O record, three major and numerous short-term variations of sedimentation rates (0.8 to 4.0 cm/kyr) can be distinguished. 6. The climatic record was modified by bioturbation much more strongly during cold than during warm stages.