Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9524448 | Journal of South American Earth Sciences | 2005 | 16 Pages |
Abstract
New U-Pb and Sm-Nd isotopic data for orthogneiss and granitoid rocks from the Neoproterozoic Goiás magmatic arc in western Goiás constrain the geological evolution of this juvenile crust in the western BrasÃlia belt. Orthogneiss rock samples have U-Pb crystallization ages of 804±6, 669±3, 662±12, 634±8, 630±5, and 637±20 Ma and show εNd(T) values between +2.8 and â15.1. Rock units with negative εNd(T) are more frequent in the eastern part of the studied area to the south of Anicuns, which indicates the presence of older continental crust in that part of the arc. Metagranitoids have ages of 821±10, 810±10, 792±5, 790±12, 782±14, 748±4, and 614±5 Ma and εNd(T) values between +5.1 and â3.7. The data presented here, combined with those in the literature, suggest that igneous activity in the Goiás magmatic arc took place in two episodes: between ca. 0.89 and 0.8 Ga, probably in intraoceanic settings, and between ca. 0.66 and 0.60 Ga, likely in an active continental margin at the end of the Brasiliano orogeny.
Keywords
Related Topics
Physical Sciences and Engineering
Earth and Planetary Sciences
Earth and Planetary Sciences (General)
Authors
Jorge Henrique Laux, Márcio Martins Pimentel, Elton Luiz Dantas, Richard Armstrong, Sergio Luiz Junges,