SEARCH FOR RODINIA IN SOUTH AMERICA: GEOLOGICAL RECORDS AND PROBLEMS

Compilation of available geological maps allows new insights into Rodinia amalgamation and subsequent break-up as recorded in the South American continent. Three main domains related to Rodinia evolution were recognized: i) the most complete record appears in northern South America, within the Amazon Craton. In its southwestern portion the craton displays Mesoproterozoic fold belts (from 1.5 up to 1.1 Ga) and corresponding foreland exposures, with coeval intracratonic intrusions and cover successions. ii) In eastern South America small crustal fragments of inferred Rodinia ascent were variably reworked during Neoproterozoic Brasiliano orogenic events, rendering it difficult to recognize and map Meso-Neoproterozoic (Grenvillian) mobile belts. So far only the Punta del Este, Uruguay, terrain and the Cariris Velhos, northeastern Brazil, area seem to bear evidence of being related with the final events of Rodinia amalgamation. iii) The third domain comprises a number of scattered basement exposures within the Andean Cordillera, from Venezuela and Colombia (Guajira, Santa Marta) to northwest Argentina (Pampia, Occidentalia). Although deeply reworked and fragmentary in exposure, these basement exposures seem to represent the largest litho-structural record of the Meso-Neoproterozoic orogenic collage in South America, apparently making up the western border of the South American Platform.