Unraveling late Quaternary atmospheric circulation in the Southern Hemisphere through the provenance of Pampean loess

The Pampean loess is the most extensive continental paleo-record of aeolian material in Southern Hemisphere, recording deposition dust transported by two major zonal wind systems: southern westerly winds and subtropical jets. In order to increase understanding on paleo-atmospheric circulation over we evaluate provenance through REE, Nd, Sr Pb isotopes three sections deposited during late Pleistocene-early Holocene across 700 km belt region central Argentina. isotopic comparison from with South American (SSA) potential sources show that (1) Altiplano latitudes northern Patagonia supplied Pampas, (2) slight SrNd difference between fine coarse may be attributable grain size effects rather than differences provenance, (3) higher mass accumulation rates Pampas are associated an increased presence originated Puna spans 43–41 ka BP, 20–18 14.6–12.6 BP 11.4–8.9 BP. We associate these rises fluxes climatic transitions wetter drier periods Puna-Altiplano Plateau related synchronous shifts humid conditions at Plain, probably triggered El Niño-like conditions. modern SSA indicates similar compared paleo-dust records, suggesting almost constant MIS 3 times and/or modest changes geochemical signature under activation/deactivation different sources. Moreover, contrasting more distal palaeoarchives (i.e., Atlantic Ocean marine sediment cores Antarctic ice cores), new data suggest contrary previous ideas, Loess was not important source regions. Also, a common cold (e.g., Last Glacial Maximum Cold Reversal) supports idea atmospheric transport efficiency can better explain flux variations observed glacial/interglacial distant provenance.