Molecular stratigraphy of cores off northwest Africa: Sea surface temperature history over the last 80 Ka

Abstract

The molecular stratigraphy of Biogeochemical Oceanic Flux Study core 31K (19°N, 20°10′W) and Ocean Drilling Program Hole 658C (20°45′N, 18°35′W;) has been studied for C37 alkenone abundances over the past 80 ka at high resolution (∼circa 200–500 years). The derived Uk37′ sea surface temperature record for both cores shows a range of temperatures from about 18°C during the last glacial to 21.5°C during the early Holocene. Both records also reveal changes in sea surface temperature as much as 2°‐4°C over a few hundred years, which correlate well with similar abrupt climatic changes observed in cores from elsewhere in the NE Atlantic, associated with “Heinrich events.” Our results indicate that meltwater produced by these ice‐rafting events was transmitted southward by the Canary Current, where it had considerable impact on sea surface temperatures in the subtropical eastern Atlantic.