Mineral chemistry and genetic implications of garnet from the São João del Rei Pegmatitic Province, Minas Gerais, Brazil

4Citations
Citations of this article
6Readers
Mendeley users who have this article in their library.

Abstract

The pegmatites of the São João del Rei Pegmatitic Province are related to the Siderian protoliths of the Cassiterita and Resende Costa orthogneisses and to the Ritápolis metagranitoid of Ryacian age. Chemical analysis of garnet from twelve pegmatites reveal two different types of grains, which were found in the same pegmatitic body in six of these samples. One garnet type has almandine-spessartine composition (Sps11.7-58.8Alm36.8-86.5Prp0.1-4.1Grs0.0-1.4Adr0.0-2.6), grains with orange and pink tones, and scarce mineral inclusions. These garnet grains may have been formed at the magmatic stage of pegmatite crystallization. The composition of these grains plot exclusively on the Alm-Sps axis at the Prp+Grs+Adr+Uvr × Alm × Sps diagram, as expected from garnet crystallized in pegmatites, and an expansion of the field associated to pegmatites is proposed. The second type has a distinct chemical composition (Sps26.9-84.8Alm3.6-40.0Prp0.0-10.4Grs9.3-45.6Adr0.1-3.4), displaying enrichment in Ca. This Ca-enriched garnet has irregular shaped colourless grains and abundant mineral inclusions. These grains may have been formed by Ca-metasomatism during the late-stage crystallization of the pegmatites.

Cite

CITATION STYLE

APA

da Cruz Guimarães Sousa, S. S., Ávila, C. A., Neumann, R., Faulstich, F. R. L., Alves, F. E. A., Cidade, T. P., & da Silva, V. H. R. M. (2020). Mineral chemistry and genetic implications of garnet from the São João del Rei Pegmatitic Province, Minas Gerais, Brazil. Brazilian Journal of Geology, 51(1). https://doi.org/10.1590/2317-4889202120190136

Register to see more suggestions

Mendeley helps you to discover research relevant for your work.

Already have an account?

Save time finding and organizing research with Mendeley

Sign up for free