Mindanao Eddy, Halmahera Eddy: Variability of West Pacific Warm Pool and Indonesian Throughflow (inflow passages and main gateway)

• Applicant: Professor Dr. Wolfgang Kuhnt
• Subject Area: Palaeontology
• Term: from 2006 to 2011
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 26477151

We propose two new Calypso coring targets to investigate the relative role of the Halmahera and Mindanao eddies in controlling the influx of North and South Pacific waters into the main passage of the Indonesian Throughflow (ITF). The main ITF inlets are close to the tropical Pacific front that divides water masses of North Pacific and South Pacific origin with different temperature, nutrient and salinity properties. Changes in the position of this front in relation to the inflow passages (Mindanao passage to the North and Halmahera passage to the South) led to major hydrographic changes, which substantially modified the paleoceanography and climatic role of the Indian and Pacific Oceans during the late Pleistocene. Until now, however, the magnitude and frequency of these changes remain virtually unknown. Our main objectives will be (1) to compare the hydrographic profiles of the two main inflow paths (Halmahera and Mindanao Passages) and to develop proxy records for the isotopic and geochemical characteristics of North Pacific thermocline water and South Pacific intermediate water, which form the two main components of the ITF (2) to reconstruct sea surface temperature (SST), salinity (SSS), nutrients, export production and bottom currents within the gateway over several glacial cycles; (3) to monitor the variability of the ITF inflow on various timescales (sub-millennial to orbital) during the late Pleistocene and (4) to test modeling predictions of a strongly reduced throughflow during glacials.

• DFG Programme: Research Grants