The growth and contamination mechanism of the Cana Brava layered mafic-ultramafic complex: new field and geochemical evidences

Author(s)

Giovanardi, Tommaso ; Girardi, Vicente A. V. ; Correia, Ciro T. ; Sinigoi, Silvano ; Tassinari, Colombo C. G. ; Mazzucchelli, Maurizio

• Document type: Journal article
• Source: MINERALOGY AND PETROLOGY; v. 111, n. 2, p. 291-314, APR 2017.
• Web of Science Citations: 3

Abstract

The Cana Brava complex is the northernmost of three layered complexes outcropping in the Goias state (central Brasil). New field and geochemical evidences suggest that Cana Brava underwent hyper- to subsolidus deformation during its growth, acquiring a high-temperature foliation that is generally interpreted as the result of a granulite-facies metamorphic event. The increase along the stratigraphy of the incompatible elements abundances (LREE, Rb, Ba) and of the Sr isotopic composition, coupled with a decrease in epsilon Nd-(790), indicate that the complex was contaminated by the embedded xenoliths from the Palmeirpolis Sequence. The geochemical data suggest that the contamination occurred along the entire magma column during the crystallization of the Upper Mafic Zone, with in situ variations determined by the abundance and composition of the xenoliths. These features of the Cana Brava complex point to an extremely similarity with the Lower Sequence of the most known NiquelA cent ndia intrusion (the central of the three complexes). This, together with the evidences that the two complexes have the same age (c.a. 790 Ma) and their thickness and units decrease northwards suggests that Cana Brava and NiquelA cent ndia are part of a single giant Brasilia body grown through several melt impulses. (AU)

• FAPESP's process: 13/19519-6 - Geochemistry and modelling of basic intrusions in the Cana Brava and Niquelândia Mafic-Ultramafic Complexes.
• Grantee: Tommaso Giovanardi
• Support Opportunities: Scholarships in Brazil - Post-Doctoral