Late and postglacial paleoenvironments of Tierra del Fuego: terrestrial and marine evidence

BORROMEI, A.M.; CANDEL, S.; PONCE, J.F.; QUATTROCCHIO, M.

Santiago, Chile

Congreso; GEOSUR- Congreso Internacional sobre Geología y Geofísica del Hemisferio Sur; 2007

Universidad de Chile, CONICYT, Universidad Católica de Chile

Late- and Postglacial paleovegetational communities and paleoenvironments in southern Tierra del Fuego (55º S) are interpreted from pollen assemblages, organic walled and palynofacies in 14C-dated peat-bogs, glaciolacustrine sediments and marine deposits. The available evidence of the pollen sequences from the tributary Fuegian valleys close to the Beagle Channel area allows a comparison with the pollen record from the Beagle Channel peat-bog sections. The pollen-stratigraphic record of a colder period, associated with the Younger Dryas stadial event (11,000-10,000 14C yr B.P.) in the National Route 3 section, reinforce the evidence of the Late Glacial cooling episode previously recorded in the Canal Beagle area. This transitory episode interrupted the previous expansion of the arboreal component Nothofagus under moderating climatic conditions that followed the deglaciation (14,000-10,000 14C yr B.P.). At times of Late Glacial cooling the paleoenvironments were virtually treeless dominated by grass, low scrub and dwarf shrub heath communities spreading into the low and middle slopes, and the temperatures apparently were