Rodinia descendants in South America

Abstract

Geological structures and Precambrian rock units thought to be related to Rodinia Supercontinent evolution were recognized in three main domains of South America: (i) Mesoproterozoic fold belts ca. 1.5–1.1 Ga old and corresponding foreland cover successions and coeval cratonic intrusions exposed in the southwestern portion of the Amazonian Craton make up the most complete and best preserved record of interpreted Rodinia amalgamation in South America. Recently obtained paleomagnetic data place this part of the Amazonian Craton close to the southernmost segment of Laurentia's Grenville margin. Inferred collision of both continents is reflected in the Nova Brasilândia and Aguapeí-Sunsas fold belts, as well as in the Llano Uplift area. (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, the best candidates to represent possible fragments of such mobile belts were recognized in the Punta del Este, Uruguay, terrain, in the Serra do Itaberaba, São Paulo, eastern Brazil area and in the Cariris Velhos, northeastern Brazil area. (iii) The third domain comprises a number of scattered basement exposures within the Andean Cordillera, from Venezuela and Colombia (Guajira, Santa Marta) in the north to northwest Argentina (Pampia, Arequipa-Antofalla) in southern South America. Although deeply reworked and fragmentary in exposure, these basement inliers 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.