Late Pleistocene-Holocene environments in Valle Carbajal, Fuegian Andes valleys, southern South America

BORROMEI, A; CORONATO, A.; QUATTROCCHIO, M.; RABASSA, J.; GRILL, S.; ROIG, C.

JOURNAL OF SOUTH AMERICAN EARTH SCIENCES

Elsevier

Lugar: London; Año: 2007 p. 321 - 335

0895-9811

Late Pleistocene - Holocene depositional environments in one of the Fuegian Andes valleys are discussed, taking into account palynological, geomorphological and sedimentological analyses from two sites located near the Canal Beagle, one at Valle Carbajal (Oyarzun peat-bog, 54o 44´ lat. S, 68o 12´ long. W ) and the other, at a National Route 3 exposure (54º 43´ lat. S , 68º 9´ long. W). The results obtained at these localtities reinforce and refine the Late Pleistocene – Holocene climatic pattern previously recorded along the Canal Beagle, located immediately southwards. Noteworthy is the evidence of a colder period, associated with the Younger Dryas stadial event, suggested by a minimum of Nothofagus pollen frequency while communities of grass, low scrub and shrub heath expanded into the low/middle slopes (National Route 3, Unit 2, 10,310 14C yr B.P.). By ca. 9500 14C yr B.P., trends toward warmer and drier conditions indicated by development of open-grown vegetation in the valleys floor (Pollen Zone O-3), was followed by expansion of open Nothofagus woodland (Pollen Zone O-2) in the middle Holocene. The milder climate changed later as indicated by the spreading of the closed forest and mire (Pollen Zone O-1) under more humid and cooler conditions during the last ca. 5000 yr B.P. Keywords: palynology, sedimentology, geomorphology, paleoenvironment, paleoclimate, Late Pleistocene – Holocene, Valle Carbajal, Tierra del Fuego.