This contribution aims to characterize the Proterozoic granites of San Ignacio orogeny, western Bolivia, describing their chemical composition, U-Pb and Sm/Nd isotopic to identify sources and process of the crustal formation. The results of chemical and isotopic granitoids of Cachuela, Motacusal and Talcoso, present U/Pb age in zircon between 1307 and 1333 Ma, suggesting an important epoch of generation of granitoids in the Bolivian pre-Cambrian. Chemistry (A-Type granites) and Nd isotopes (εNd(1330) between-0.77 and-3.86) signatures here reported suggest an anorogenic environment and the spider diagram indicate the within-plates tectonic setting for the formation of these granites, instead of arc-related environment is suggested in the literature for these rocks. The data here reported suggest a geological evolution for the Bolivian pre-Cambrian composed of the San Ignacio event is represented by magmatic arc with participation of continental crust previously formed representing an important collisional period in the SW Amazonian craton.
|Título traducido de la contribución||Geology, geochemistry and geocronology of the granitic rocks of san ignÁcio orogeny (BolÍvia)|
|Número de páginas||18|
|Estado||Publicada - 2020|
Nota bibliográficaPublisher Copyright:
© 2020, Universidade Estadual Paulista(UNESP). All rights reserved.