Faria D.A.,Research Group on Crustal and Tectonic Evolution |
Faria D.A.,Federal University of Mato Grosso |
Ruiz A.S.,Research Group on Crustal and Tectonic Evolution |
Ruiz A.S.,Federal University of Mato Grosso |
And 8 more authors.
Brazilian Journal of Geology
The Rio Fortuna Gneiss crops out in the Serra Santa Barbara, near the Fortuna military headquarters, on the Brazil-Bolivia border. These orthogneisses are located in a portion of the Paraguá terrain affected by the Sunsás Orogeny (1.0-0.9 Ga.). They are classified as monzo to granodiorite orthogneisses and underwent at least three episodes of deformation. The U-Pb zircon age of 1,711 ± 13 Ma obtained by laser ablation MC-ICP-MS is interpreted as the crystallization age of this orthogneiss. Geochemically, these rocks form a sequence comprising acidic subalkaline magmatism, calc-alkalic-type high-K, and metaluminous to peraluminous. Source