Assessing the role of climate and mountain fluvial erosion in sediment supply for Pleistocene dune formation in the Pacific subtropical semiarid coast of Chile

To present the Quaternary eolian stratigraphic record along the Pacific coast of subtropical semiarid Chile (35-28ºS) has been mostly studied regarding their paleoclimate significance, nonetheless other main environmental factors are known to affect dune evolution at the millennial to multimillennial time scale, including sediment (i.e., mineral sand) supply linked to glacial and fluvial erosion and transport, eustatic sea level, coastal drift, ocean storminess, wind intensity, others. In Chile, Pleistocene to Holocene dated dunes occur on tectonically elevated marine terraces and to the north of heavily loaded sediment river outlets to the Pacific Ocean. Rhythmic development of clay-rich Bt paleosols punctuate the dune stratigraphy and denote multimillennial conspicuous humidity changes linked to the latitudinal migration of the southern westerly wind belt. Here, we present new post-IR infrared stimulated luminescence 225 ºC (pIRIR225) and provenance Zr ages from fluvial, dune and paleodune sediments in the Pupío coastal mountain fluvial catchment, and discuss a basin conceptual model in order to asses the role of Pleistocene climate change, fluvial erosion & transport of sediments, sea level, and coastal drift in the paleodune formation of coastal semiarid Chile.