Glacial to Holocene Paleoceanographic and Continental Paleoclimate Reconstructions Based on ODP Site 1233/GeoB 3313 Off Southern Chile

Abstract

ODP Site /GeoB 3313 located at the upper continental slope off southern Chile (41°S) is ideally located to study latitudinal shifts of atmospheric and oceanographic circulation off southwestern South America. Extraordinarily high sedimentation-rates allow for high resolution reconstructions and detailed comparisons of various continental climate and paleoceanographic proxy records within the same archive avoiding problems linked to age model uncertainties. We discuss the major paleoclimatic findings of Site 1233/GeoB 3313 in chronological order from the last glacial to the Holocene within the regional context and explore links to tropical and high southern latitude records. During the last glacial, sea surface temperatures (SSTs) off southern Chile were about 4.5°C colder than today and ∼6–7°C colder than during the early Holocene maximum. Deglacial warming started at ∼18.8 kyr BP with a ∼2-kyr-long increase of nearly 5°C and was followed by relatively stable SSTs until the beginning of a second warming step of ∼2°C during the early halve of the Northern Hemisphere Younger Dryas cold period. Maximum warm conditions in the early Holocene (∼12–9 kyr BP) were followed by a gradual decline towards modern SSTs in the Late Holocene. The paleoceanographic changes and related regional continental climate variations since the last glacial are primarily controlled by latitudinal shift of both the oceanographic and the atmospheric circulation systems in the southeast Pacific. In general, they appear to be closely linked to changes in the Southern Ocean and Antarctica.