Palaeoceanography of the Banda Sea, and Late Pleistocene initiation of the Northwest Monsoon

Today, the core site is characterised by high sea-surface temperature and high precipitation, which results in the formation of a low-salinity boundary layer. Sea-surface temperature estimates down core indicate minimal cooling during the last glacial maximum. Mean sea-surface temperatures ranged between 29.8 °C and 26.6 °C for the past ∼ 80,000 yr; sea-surface seasonality never increased above 3 °C. In addition, the abundance of the planktonic foraminifera Neogloboquadrina dutertrei, Neogloboquadrina pachyderma, and Globigerinoides quadrilobatus indicates that the mixed layer (the low-salinity boundary layer of the Throughflow) thinned during Marine Isotope Stages 3 and 2. This enhanced a deep chlorophyll maximum (DCM) layer. The Northwest Monsoon was less intense for about 60,000 yr and then 'switched on' at ∼ 15,000 cal yr BP. This thickened the mixed layer, reducing the DCM, and increased SST seasonality in the Banda Sea.