The Río de la Plata craton and the Precambrian continents and supercontinents

RAPALINI, AUGUSTO E.

Praga

Congreso; 26th International Union of Geodesy and Geophysics General Assembly; 2015

International Union of Geodesy and Geophysics (IUGG)

Isolated paleomagnetic poles and fragments ofthe apparent polar wander path for the Rio de la Plata craton (RP) in thePrecambrian allow some constraints on its paleogeographic evolution from around2.1 Ga until de Ediacaran-Cambrian boundary. Significant geologic similaritiesbetween this craton and proto-Amazonia, Congo-Sao Francisco and West Africa inthe mid-Paleoproterozoic led to the hypothesis of the Atlantica continent,which was proposed to have a paleogeographic configuration similar to WesternGondwana. Apparent polar wander paths for these four cratons between around 2.1and 2.0 Ga strongly suggest that this continent never existed or had a verydifferent configuration. A single paleomagnetic pole of ca. 1.79 Ga for RP allowsat least three possible positions of this block in the Columbia supercontinent.The late Neoproterozoic (ca. 600-500 Ma) apparent polar wander path for RPindicates that this was not the conjugate margin of eastern Laurentia duringthe final stages of Rodinia break-up and suggests that its position intraditional paleogeographic reconstructions of this supercontinent must be re-evaluated.