Orbitally paced paleoproductivity variations in the Timor Sea and Indonesian throughflow variability during the last 460 kyr

Abstract

A high-resolution (∼1-2 kyr) multiproxy record from the Timor Sea in the easternmost Indian Ocean (International Marine Global Change (IMAGES) Program Core MD01-2378, latitude 13°04.95′S, longitude 121°47.27′E, 1783 in water depth) closely tracks changes in intermediate water ventilation and paleoproductivity over the last 460 kyr within one of the main outflow passages of the Indonesian Throughflow. Spectral analysis of five different flux-based productivity proxies indicates spectral power concentrated in the 100 kyr (glacial-interglacial) and the 23 kyr and 19 kyr (precessional) periods. Paleoproductivity maxima lead ice volume (benthic δ18O) maxima by 20° to 40° (∼1300 to 2600 years) at the precession band. The spectral differences in tropical paleoproductivity records from the Pacific and Indian oceans suggest that local processes (wind and circulation patterns driven by insolation) are dominant in driving productivity rather than large-scale tropical features. In the Timor Sea, productivity fluctuations over the last 460 kyr were strongly influenced by monsoonal wind patterns offshore NW Australia (23 and 19 kyr) and were also modulated by sea level-related variations in the intensity of the Indonesian Throughflow (100 kyr). Copyright 2005 by the American Geophysical Union.