Lay summary

Aseries of long sediment cores was retrieved from Laguna Potrok Aike, SouthernPatagonia, within the framework of PASADO (Potrok Aike Maar Lake SedimentArchive Drilling Project), an ICDP (International Continental ScientificDrilling Program) lake drilling project. This maar lake, located at 52°S 70°Win the Province of Santa Cruz (Argentina), in the southernmost continental areaof the world, is one of the few permanent lakes in the region, providing a uniquecontinuous paleoclimatic and paleoecological lacustrine record for the LastGlacial Cycle. Previous multiproxy studies of this site have characterized theenvironmental history of these dry lands in the Patagonian Steppe for the last16 cal ka BP. This new series of sediment cores provides a much longer recordof climate variability in Southern Patagonia since 51.1 cal ka BP. Using a multiproxystrategy, a set of samples (mostly from core catcher material) was analyzed forphysical properties, rock magnetism, geochemistry, CNS elemental analysis,stable isotopes, pollen and diatoms. Additionally, the Swiss contributionincluded investigations in living microbial communities within the sediments tocharacterize the subsurface biosphere in such a unique maar environment emphasizingintegrated studies of microbiology, geochemistry (pore waters), and mineral authigenesis/diagenesis.

This multiproxy limnogeological interpretation sheds new light on the regional Pleistocene and Holocene environmental history, revealing lake level variations through time and identifying time windows of interest where higher resolution analyses will be carried out.