Geophysical methods applied to Quaternary studies in glacial environments: Río Valdez outcrop, Tierra del Fuego, Argentina

CORONATO, ANDREA M.J.; NÚÑEZ DEMARCO, PABLO A.; ORGEIRA, MARÍA J.; PONCE, JUAN F.; PREZZI, CLAUDIA B.; QUIROGA, DIEGO R.A.; 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 7m thick lacustrine sediments was identified. Taking into account geomorphological and sedimentological surveys, such outcrop was interpreted as a rhythmic glacio-lacustrine deposit, formed in a frontal morainic complex during the 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 ~220m and a minimum NNW-SSE one of ~180m were determined. A minimum thickness of ~20m 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 to MIS 2, when the Last Glacial Maximum took place in the region. The applied geophysical methods proved to be a powerful tool for theinvestigation of palaeo-lake deposits.