Sea-surface temperature variability in the Southeast Pacific during the last glacial/interglacial cycle and relationships to paleoenvironmental changes in central and southern Chile

Abstract

The role and dynamic of the Southern Hemisphere (SH) mid- to high latitudes in abrupt climate changes is still poorly documented and understood. The Southeast Pacific (SEP) region which is under the influence of the major oceanographic and atmospheric circulation members of the SH mid-latitudes is ideally situated to reconstruct past climate changes. Based on an unprecedented, high-resolution sediment record located off southern Chile (ODP Leg 202 Site 1233; 41 degrees S), as well as a second record located further north (GeoB 7139-2; 30 degrees S), it has been possible to show that the evolution of the sea-surface temperature (SST) in the SEP was closely linked to the SH high latitudes involving latitudinal shifts of the Antarctic sea-ice cover, the Westerly winds, the Antarctic Circumpolar Current and ultimately the SEP subtropical high pressure cell. Reconstructions of paleo-environmental changes on the adjacent land (Patagonian Ice Sheet, PIS, fluctuations and vegetation amount) within the same archives suggest a close relation to the SSTs evolution and a strong influence of the deglacial melting of the PIS on the oceanographic circulation.