Paleoenvironmental changes in southern South American dust sources during the last glacial/interglacial transition: Evidence from clay mineral assemblages of the pampean loess.

ROMERO, NATÍAS; TORRE, GABRIELA; , GAIERO, DIEGO M.

QUATERNARY INTERNATIONAL

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2021 vol. 580 p. 11 - 21

1040-6182

Paleoclimatic reconstruction is critical for understanding present-day climate and for testing models that arecurrently used to predict future climatic changes. Different climatic conditions produce different clay mineralsthat can be recorded in geological archives providing insights into past weathering scenarios. However, insouthern South America, scarce information is available from clay mineral assemblages found in aeolian sediments, such as loess deposits. Moreover, there is a lack of studies employing clay minerals for paleoclimaticreconstruction at dust sources and loess deposits. Therefore, this work explores clay mineral composition ofmodern dust source areas in southern South America and in the pampean loess records to gain insight intopaleoenvironmental conditions prevailing during the late Pleistocene-early Holocene in the region. Clay mineralsrecovered from the loess deposits are of an allochthonous origin, implying their formation at the ?arid diagonal?,then blown away, and deposited downwind in the Pampas without post-depositional changes. Clay mineralassemblages indicate that these minerals and rare earth elements (REE) analyzed in two loess sections of thePampean Plain helped to reconstruct past climatic scenarios in the dust source areas during the transition fromthe last glacial to the current interglacial period. Furthermore, our work contributes to the assessment of thestrengthening/weakening of the different South American dust sources in light of recent published geochemicaland textural evidence.