Lateglacial and Holocene wet--dry cycles in southern Patagonia: chronology, sedimentology and geochemistry of a lacustrine record from Laguna Potrok Aike, Argentina

Abstract

A high-resolution multiproxy geochemical approach was applied to the sediments of Laguna Potrok Aike in an attempt to reconstruct moist and dry periods during the past 16 000 years in southeastern Patagonia. The age–depth model is inferred from AMS 14C dates and tephrochronology, and suggests moist conditions during the Lateglacial and early Holocene (16 000–8700 cal. BP) interrupted by drier conditions before the beginning of the Holocene (13 200–11 400 cal. BP). Data also imply that this period was a major warm phase in southeastern Patagonia and was approximately contemporaneous with the Younger Dryas chronozone in the Northern Hemisphere (12 700–11 500 cal. BP). After 8650 cal. BP a major drought may have caused the lowest lake level of the record. Since 7300 cal. BP, the lake level rose and was variable until the ‘Little Ice Age’, which was the dominant humid period after 8650 cal. BP.