Northern South America basement tectonics and implications for paleocontinental reconstructions of the Americas

This paper summarizes geological data from the basement massifs of the northern Andes. Geological and geochronological data from this region indicate that the metamorphic basement consolidated during the Orinoquiense (∼1.0 Ga) and Caparonensis (∼0.47 Ga) orogenic events. The latter formed part of a proto-Andean orogen that extended from Venezuela to northern Argentina. Interactions between Laurentia and the peri-Amazonian proto-Andes during Late Proterozoic–Paleozoic times, is supported by geological, geochronological, isotopic data and by faunal affinities of the sedimentary sequences overlying the basement complex. This interaction may have included possible terrane transfer between Laurentia and Amazonia. Geological, tracer–isotopic and geochronological data suggest that a fragment of the proto-Andean orogen is presently located at the southern end of Mexico (Oaxaquia). The transfer of Oaxaquia from the northern termination of the proto-Andes, most likely occurred in late Paleozoic time and was left attached to N. America upon the disaggregation of Pangea.