GEOPHYSICAL METHODS APPLIED TO QUATERNARY STUDIES IN GLACIAL ENVIRONMENTS: RIO VALDEZ OUTCROP, TIERRA DEL FUEGO, ARGENTINA

PREZZI, CLAUDIA BEATRIZ; MARÍA JULIA ORGEIRA; CORONATO, ANDREA; QUIROGA, DIEGO; PONCE, FEDERICO; NÚÑEZ DEMARCO, PABLO; PALERMO, PEDRO

QUATERNARY INTERNATIONAL

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2019 vol. 525 p. 114 - 125

1040-6182

In the Río Valdez mouth, located in the southeastern coast of Fagnano lake, Tierra del Fuego, an outcrop of 7 m thick lacustrine sediments was identified. Taking into account geomorphological and sedimentological surveys, suchoutcrop was interpreted as a rhythmic glacio-lacustrine deposit, formed in a frontal morainic complex during the Last Pleistocene. Ground magnetic and resistivity surveys were carried out, trying to determine the thickness and areal extension of these lacustrine sediments. A maximum E-W extension of ~ 220 m and a minimum NNW-SSE one of ~ 180 m were determined. A minimum thickness of ~ 20 m was estimated. Taking into account this thickness and an assumed average sedimentation rate, the natural dam that promoted the paleolake and their related lacustrine sediments could have existed previously than MIS 2, when the Last Glacial Maximum took place in the region. The applied geophysical methods proved to be a powerful tool for the investigation of palaeo-lake deposits.