Multi‐millennial scale climate variability during MIS 3 and MIS 2 inferred from luminescence dating of coastal sand dunes and buried paleosol sequences in central Chile, 32°S

Abstract

ABSTRACTThe eolian morphostratigraphic archive along the coast of central Chile (∼37–30°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 °C (pIRIR225) of potassium‐rich feldspar that show the timing of past climate variability as evidenced from sand dune/buried paleosol couplets at 32°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.