Paleomagnetism of the Pavón Formation, San Rafael Block (Argentina): paleolatitude of the Cuyania terrane in the late Ordovician

RAPALINI, AUGUSTO E.; CINGOLANI, CARLOS A.

Serie Correlación Geológica (INSUGEO)

Universidad Nacional de Tucumán

Lugar: San Miguel de Tucumán; Año: 2003 vol. 17 p. 539 - 543

1514-4186

The Argentine Precordillera has been interpreted as an Early Paleozoic Laurentian derived exotic terrane (i.e.e.g.,  Dalla Salda et al., 1992, Astini et al., 1995,  Mahlburgh Kay et al., 1996, Thomas and Astini, 1996, Dalziel, 1997, Keller et al., 1998, Benedetto, 1998, among many others). Ramos (1995) proposed that the Precordillera is part of a larger composite terrane (Cuyania)  that comprise includes also the San Rafael Block and the Pie de Palo Rrange in the Western Sierras Pampeanas. In all these areas, in all of which Grenvillian-age basement is exposed.  For these most authors, several lines of evidence coincide in that Cuyania most likely originated in from the Ouachita embayment of North America. This reconstruction  has been strongly supported by paleomagnetic data from the Early Cambrian Cerro Totora Formation (Rapalini and Astini, 1998). However, no consensus exists on around the wayhow this terrane was transferred from Laurentia to Gondwana and its agethe timing of its of accretion, which varies in different models from Mid -Ordovician tthrougho Devonian. Although, there are models which try to interpret the origin of the Precordillera  to be terrane as being autochthonous (González Bonorino and González Bonorino, 1991) or that it represents a parautochthonous displaced terrane (Baldis et al., 1989, Aceñolaza et al., 2002). Recently, Finney et al. (2002) with newly acquired U-Pb ages on detrital zircons interpreted an Early Gondwanan provenance for of this terrane based on new  U-Pb ages from detrital zircons.  All these antecedents stimulate new research regarding the paleogeographical evolution of  Precordillera  during the Early Paleozoic.