Palynofacial analysis of surface sediments from Beagle Channel and its application as modern analogues for Holocene records of Tierra del Fuego, Argentina

CANDEL, M.S.; BORROMEI A.M.; MARTINEZ M.A.; BUJALESKY, G.

PALYNOLOGY

AMER ASSOC STRATIGRAPHIC PALYNOLOGISTS FOUNDATION

Año: 2012

0191-6122

Palynofacies analysis of surface sediments from the Beagle Channel, Tierra del Fuego,Argentina, was carried out to establish modern analogues for comparison with otherHolocene marine records in southern of Isla Grande de Tierra del Fuego. Our results showthe dominance of translucent phytoclasts highly degraded, associated to amorphous organicmatter (AOM) and palynomorphs, while the opaque phytoclasts are poorly represented. Theorganic constituents indicate the proximity of the continental source area to marineenvironments, with distances and/or times of relatively short transport. The predominance oftranslucent phytoclasts associated with pyrite suggests reducing conditions, probablyassociated with marginal-marine environments. Among the terrestrial palynomorph group,the predominance of Nothofagus pollen reveals the presence of the forest along the channel.The high terrestrial organic matter inputs to the depositional area are consistent with amarginal-marine environment. The aquatic palynomorphs, mainly dinoflagellate cyst showassemblages characterized by low species diversity and low concentration values. Thedominance of Peridiniales over Gonyaulacales taxa suggests inner neritic environments.Comparison with two fossil sections of Middle-Late Holocene age (Albufera Lanushuaia andRío Ovando) shows similar distribution of the total palynological matter (palynofacies).