Palinología y palinofacies de una secuencia marina del Holoceno medio-tardío: Albufera Lanushuaia, Canal Beagle, Tierra del Fuego, Argentina

Abstract

Palynological analysis, with emphasis on palynofacial analysis was carried out on Holocene marine deposits located on the northern coast of the Beagle Channel, Argentina. This analysis allowed paleoenvironmental assessments and paleoclimatic inferences. A fossil section from Albufera Lanushuaia (54°52'04.4"S-67°60'44.9"O), located on the northern coast of the Beagle Channel was analyzed. The set of particulate organic matter indicate the proximity of the area of continental input to the marine environments, with distances and/or times of transport relatively short. The presence of pyrite suggests reducing conditions, probably associated with marginal-marine environments. At the Albufera Lanushuaia, from the ca. 5,800 years 14C BP, palynological associations reveal the same pattern of regional vegetation with a closed forest of Nothofagus and an assemblage of Peridiniales dinocysts dominated by taxa that suggest marginal-marine environments, with low to moderate salinity and high nutrient concentrations in shallow marine waters, probably due to the contribution of freshwater due to surface runoff. For the past 3,000 years, a decrease in pollen records of Nothofagus and an increase in shrub and herb pollen with a limited occurrence of aquatic palynomorphs were observed. These reflects the development of a more open forest and adjacent areas of herbaceous and shrub with marginal-marine influence, associated to a regressive event. © 2011 by the Sociedade Brasileira de Paleontologia.