A history of Proterozoic terranes in southern South America: From Rodinia to Gondwana

Abstract

The role played by Paleoproterozoic cratons in southern South America from the Mesoproterozoic
to the Early Cambrian is reconsidered here. This period involved protracted continental amalgamation
that led to formation of the supercontinent Rodinia, followed by Neoproterozoic continental
break-up, with the consequent opening of Clymene and Iapetus oceans, and finally continental
re-assembly as Gondwana through complex oblique collisions in the Late Neoproterozoic to Early
Cambrian. The evidence for this is based mainly on a combination of precise U-Pb SHRMP dating
and radiogenic isotope data for igneous and metamorphic rocks from a large area extending from the
Rio de la Plata craton in the east to the Argentine Precordillera in the west and as far north as Arequipa
in Peru. Our interpretation of the paleogeographical and geodynamic evolution invokes a hypothetical
Paleoproterozoic block (MARA) embracing basement ultimately older than 1.7 Ga in the Western Sierras