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Late quaternary paleoceanography of the Banda Sea

1995; Elsevier BV; Volume: 122; Issue: 4 Linguagem: Inglês

10.1016/0025-3227(94)00116-3

1872-6151

Syed Masood Ahmad, F. Guichard, K. Hardjawidjaksana, Mimin Karmini Adisaputra, L. Labeyrie,

Methane Hydrates and Related Phenomena

A stable oxygen and carbon isotopic record of benthic (Uvigerina and Cibicidoides species) and planktonic (Globigerinoides ruber) foraminifera recovered from a deep-sea core in the Banda Sea was obtained to develop a better understanding of surface- and deep water hydrography in this region over the last ~180 kyr. Higher glacial to interglacial δ18O amplitudes of planktonic and benthic foraminifera (1.8 and 1.7%., respectively) indicate an increase in Banda surface and deep water salinity during glacial conditions. Planktonic data is influenced by the precession (23 kyr periodicity) while benthic values reflect intermediate Pacific water fluctuations. The benthic δ13C exhibits a depletion of about 0.3%. for the last glacial maximum (LGM) relative to the Holocene. A still higher depletion of benthic δ13C (0.4–0.6%.) occurs during the penultimate full glaciation (stage 6). The main characteristics of δ13C in the Banda Sea are a direct record of the δ13C global oceanic signal and an evolution similar to intermediate and deep Pacific waters. Banda Sea records indicate a general good ventilation that remained unchanged between glacial and interglacial periods. Variations in the carbon isotopic composition of planktonic foraminifera are attributed to the local variability in monsoonal upwelling or changes in throughflow of Pacific intermediate-water masses via Indonesian seas. An increase in the alkalinity and deepening of the lysocline has resulted in higher carbonate content during glacial periods, similar to the results reported in the North Pacific.