Geochemistry and petrology of the jequie granulitic complex (Brazil): an archean basement complex
✍ Scribed by G. P. Sighinolfi; M. C. H. Figueredo; W. S. Fyfe; B. I. Kronberg; M. A. F. Tanner Oliveira
- Publisher
- Springer
- Year
- 1982
- Tongue
- English
- Weight
- 733 KB
- Volume
- 78
- Category
- Article
- ISSN
- 0010-7999
No coin nor oath required. For personal study only.
✦ Synopsis
The Jequie granulitic complex is part of the extensive high-grade metamorphic terrain located within the Sao Francisco craton of northeastern Brazil. Some Jequie rocks appear to have been formed in the middle Archean (~3.1 Ga) from preexisting sialic crust_ The dominant mineral composition of these rocks is quartz-microcline-plagioclase-hypcrstene and occurs over an extensive area (~2,000 km2).
Scattered enTichment of normal granites with many minor elements (e.g. Rb, Y, Zr, Nb, Ba, REE), and the non-depletion of other elements (e.g. Cs, U), normally considered mobile during granulite facies metamorphism, must lead either to the reconsideration of regional metasomatism subsequent to granu-lite facies metamorphism, or at least raise some doubts about common wisdom concerning the distribution of heat-producing elements at depth. The region includes large-scale thrust structures, which could play a part in influencing high-level emplacement of the rocks and their regional metasomatism and structures.