Neoproterozoic A-type granitic magmatism in the Western Sierras Pampeanas (Argentina): evidence for Rodinia break-up along a proto-Iapetus rift?

BALDO, E., CASQUET, C., PANKHURST, R.J., GALINDO, C., RAPELA, C.W., FANNING, C.M., DAHLQUIST, J.A. Y MURRA, J

TERRA NOVA (PRINT)

Blackwell Publishing

Año: 2006 vol. 18 p. 388 - 394

0954-4879

A-type orthogneisses of mid Neoproterozoic age ( 774 ± 6 Ma, U-Pb SHRIMP zircon age), are reported for the first time from the Grenvillian basement of Western Sierras Pampeanas in Argentina. These anorogenic meta-igneous rocks represent the latest event of Rodinia break-up so far recognized in Grenvillian basement exposures across Andean South America. Moreover they compare well with A-type granitoids an volcanics along the Appalachian margin of Laurentia (Blue Ridge), thus adding to former evidence that the Western Sierras Pampeanas Grenvillian basement stayed on the conjugate rifted margin of eastern Laurentia during Rodinia break-up and the consequent opening of the Iapetus ocean.