Southeast trade wind variations during the last 135 kyr: evidence from pollen spectra in eastern South Atlantic sediments

Influx of aeolian pollen trapped in marine sediments off Namibia provides a wind variation record for the last 135 kyr. The influx of major pollen com ponents is derived from the southwest African desert/semi-desert zone and s hows six periods during which enhanced southeast trade winds contributed to strong upwelling and reduced sea surface temperatures. The most prominent of these occurred during 17-23 cal. kyr, 42-56 kyr and before 130 kyr B.P. Correspondence between the pollen influx record and the Vostok deuterium is otope record suggests that pronounced glacial Antarctic cooling was accompa nied by intensification of the southeast trades throughout the Late Quatern ary. However, during 42-23 kyr B.P. the combination of strong Antarctic gla ciation with a decrease of wind zonality induced by low latitude precession al insolation changes caused strong alongshore winds and Ekman pumping that resulted in strong upwelling and reduced sea surface temperatures without pollen influx enhancement. (C) 2001 Elsevier Science B.V. All rights reserv ed.