A paleomagnetic dating study of Río Valdéz paleolake outcroup (Tierra del Fuego, Argentina)

PALERMO, P.; GOGORZA C. S. G.; ORGEIRA, MARÍA J.; SINITO A. M.; IRURZUN M. A.; CORONATO, A.

LatinMag Letters

Universidad Nacional Autónoma de México

Lugar: México DF; Año: 2017 vol. 7 p. 1 - 4

2007-9656

A sedimentary sequence from Río Valdéz outcrop (Tierra del Fuego Island, Southernmost Argentina) provides high-resolution and continuous paleoclimate and paleoenvironmental records in the Late Pleistocene. The 14C dating method has inherent inaccuracies in dating these glaciolacustrine sediments as they contain a very low amount of organic matter and the period covered by them exceeds the age limit for the method. In order to overcome this drawback, the known changes of the Earth?s magnetic field recorded in the sedimentary sequences were used to produce a more detailed and accurate timescale. The variations in the inclination and declination were compared to the paleosecular variations over the last 52,000 years recorded in the lake sediments from Laguna Potrok Aike. This correlation made it possible to construct a high-resolution time-scale for the sediments from Río Valdéz outcrop during the period 33,000 - 52,000 years B.P. This work further showed that the geomagnetic secular variations can serve as an effective tool to determine the sediments? age and correlate the stratigraphy for the different deposition environments in a wide region.