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Abstract

High-resolution palaeorecords of climate are critical to improving currentunderstanding of climate variability, its sensitivity and impact on the envi-ronment in the past and in the future. Sediments from the Cariaco Basin offthe coast of Venezuela have proven to be sensitive recorders of tropicalpalaeoclimate variability down to an annual scale. However, the fingerprintof climate and sea level in the sediments of the last glacial period is still notcompletely understood. In this study, lamination analysis of sediments fromthe Cariaco Basin is extended to the last glacial period. Detailed sedimento-logical and geochemical analysis (laser ablation–inductively coupledplasma–mass spectrometry) reveals couplets of light-coloured, terrigenous-rich and dark-coloured, biogenic opal-rich laminae, which are interpreted toreflect the seasonal migration of the Intertropical Convergence Zone. In addi-tion, a previously undescribed, nearly pure terrigenous lamina type isobserved, which is referred to hereafter as a ‘C-layer’. The C-layers in thesedimentary sequence are interpreted as flood layers that originate from localrivers. The occurrence of these C-layers is investigated for two core locationsin the Cariaco Basin over the last 110 kyr by continuous X-ray fluorescencescanning. Dansgaard–Oeschger oscillations are most clearly traced by proxiesreflecting productivity and marine organic matter content of the sediment. Incontrast, the abundance of terrigenous material differs at times between thetwo sites. On an interglacial to glacial timescale, the ability to record eventscausing C-layers is likely to be influenced by changes in sea level and sourceproximity. On a millennial scale, both sediment cores contain more C-layersduring warmer interstadials compared with colder stadials during MarineIsotope Stage 3. This finding implies that interstadials were not only wetterthan stadials, but probably also characterized by increased rainfall variabi-lity, leading to an enhanced frequency of flooding events in the hinterlandof the Cariaco Basin.