Abstract

The eolian morphostratigraphic archive along the coast of central Chile (similar to 37-30 degrees S) includes sand dune and buried paleosol sequences that despite their potential as a proxy for past environmental change, remain mostly unstudied north of Patagonia and south of the Atacama Desert core. Here, we present results of a stratigraphic and geochronologic study using the post-infrared infrared stimulated luminescence signal stimulated at 225 degrees C (pIRIR225) of potassium-rich feldspar that show the timing of past climate variability as evidenced from sand dune/buried paleosol couplets at 32 degrees S. Our record shows that periods of sand dune accumulation during Marine Isotope Stages MIS 6, 4, 3 and 2 occurred within ice ages and associated low sea-level stands, probably affected by similar to, or drier than, present conditions. Intercalated wetter periods inferred from pedogenesis occurred between 53 +/- 4 and 52 +/- 3 ka, at some time between 52 +/- 3 and 36 +/- 2 ka, and at some time between 31 +/- 2 and 22 +/- 2 ka, and reflect times when the southern westerlies rain belt shifted north. Our data reveal that central Chile experienced multi-millennial periodicity of westerly precipitation throughout the last glacial period. We provide evidence for a humid local Last Glacial Maximum.