Pliocene-Pleistocene oxygen isotope record DSDP Site 586, Ontong Java Plateau, Pacific Ocean i ...

• Main Authors: Whitman, Jill M, Berger, Wolfgang H
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA 1992
• Subjects: Composite Core; Leg89; Glomar Challenger; Deep Sea Drilling Project DSDP; Antarctic; Pacific; Antarc*; North Atlantic
• Online Access: https://dx.doi.org/10.1594/pangaea.683836; https://doi.pangaea.de/10.1594/PANGAEA.683836

Oceanographic changes in the western equatorial Pacific during the past 6 Ma are inferred from oxygen isotopic analyses of planktic and benthic foraminifera from Ontong Java Plateau (DSDP Site 586). The taxa are Globigerinoides sacculifer, Pulleniatina, Cibicidoides wuellerstorfi, and Oridorsalis umbonatus. Cooling and ice buildup are indicated by an 18O enrichment of 0.3 per mil in the planktic species near 3.4 Ma. This shift apparently is compensated in the benthic data by a warming of the deep waters by between 1° and 2° C. We suggest that the dominant source of upper deep water supply to the Pacific changed from Antarctic to North Atlantic at that time, the North Atlantic-derived water being warmer. Near 2.8 Ma (approximately) the planktic foraminifera again record an enrichment in 18O (Delta delta18O=0.25 per mil). We suggest ice buildup in the northern hemisphere as the cause, because of subsequent sharp increase in fluctuations of the delta18O signal, that is, instability. The enrichment is magnified ... : Supplement to: Whitman, Jill M; Berger, Wolfgang H (1992): Pliocene-Pleistocene oxygen isotope record Site 586, Ontong Java Plateau. Marine Micropaleontology, 18(3), 171-198 ...