Climatically sensitive eolian and hemipelagic deposition in the Cariaco Basin, Venezuela, over the past 578,000 years: Results from Al/Ti and K/Al

Al/Ti and K/Al ratios in bulk sediment are used to interpret wind-blown and hemipelagic sources of deposition to a 578 kyr record in the Cariaco Basin , Venezuela (Ocean Drilling Program site 1002). Graphical and cross-spectra l analyses indicate that these ratios vary extremely closely with planktoni c foraminiferal delta(18)O, with both ratios being significantly higher dur ing interglacials and lower during glacials. K/Al indicates that during gla cials the lower sea level that results in relative basin isolation increase s the relative proportion of kaolinite derived from local rivers draining t he relatively humid Venezuelan margin. Al/Ti decreases during glacials, sug gesting greater proportions of eolian rutile sourced from the northern Saha ra (due to increased wind strength and/or aridity). This interpretation is consistent with previous studies of the chemistry and mineralogy of Saharan -derived eolian matter in the Caribbean and with a mass balance determining the effect of changes in eolian rutile accumulation on the bulk sedimentar y Al/Ti ratio.