Soil genesis related to medieval climatic fluctuations in southern Patagonia and Tierra del Fuego (Argentina): Chronological and paleoclimatic considerations

Coastal and continental localities analyzed in southern Patagonia and Tierra del Fuego (Argentina) demonstrate the ubiquitous presence of a late Holocene Mollisol in eolian and colluvial deposits. This soil is buried in many places by a sandy layer of variable thickness, indicating a further reactivation of morphogenetic processes. Maximum and minimum ages obtained by 14C and oxidizable carbon ratio (OCR) methods place the beginning of this pedologic event about 1000 years ago. The regional character of this soil and the evidence of climatic fluctuations supplied from paleohydrological, pollen, and multi-proxy studies in the area suggest that the soil's origin could be related to a pulse of increasing humidity following an episode of drought during medieval times.