The Precambrian drift history and paleogeography of Rio de la Plata craton

Abstract

The Río de la Plata craton is composed by the Piedra Alta and Tandilia terranes, that achieved tectonic stability around 2.0 Ga. Paleomagnetic data are availabale for three short time-spans. Nine pole positions for the Piedra Alta terrane in the interval 2.11-2.05 Ga suggest high latitudes with fast drift rates. Comparison with coeval poles from other cratons cast serious doubts on the existence and configuration of the mid-Paleoproterozoic Atlantica continent. A single pole from the 1.79 Ga Florida dyke swarm indicates low paleolatitudes, probably in the northern hemisphere, although its position in the Columbia (Nuna) supercontinent is ambiguous. The late Neoproterozoic is represented by seven pole positions from about 595 Ma to 550 Ma, suggesting fast drift in southern latitudes. Comparison of high quality poles ca. 575 Ma from West Gondwana cratons suggests that most of this continent was already assembled by middle Ediacaran.