Milna paleolake (Tierra del Fuego): new evidence of a pre-Last Glacial Maximum cooling

Abstract

The Milna deposit (54°37’ S, 67°33’ W) is situated near Lago Fagnano, in the south-central part of Isla Grande de Tierra del Fuego. The presence in the deposit of laminations, dropstones, and convoluted structures, as well as a low organic matter content, suggest a lacustrine origin under relatively cold conditions, likely in direct contact with glacial ice. Radiocarbon ages obtained in this study define a depositional period from ca. 31.5 to ca. 11.5 ka cal BP, or even older. This new evidence points towards a glacial environment for the study area well prior to the Last Glacial Maximum; that is, older than ca. 25 ka cal BP.