Banca de DEFESA: ANDRÉIA GONÇALVES DE ARAÚJO NUNES RANGEL

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : ANDRÉIA GONÇALVES DE ARAÚJO NUNES RANGEL
DATA : 07/06/2019
HORA: 09:00
LOCAL: Instituto de Geociências
TÍTULO:

ESTUDO PETROGRÁFICO E LITOQUÍMICO DO CORPO MÁFICO-ULTRAMÁFICO DA FAZENDA CAMPO DO MEIO, MARCIONÍLIO SOUZA – BAHIA - BRASIL

PALAVRAS-CHAVES:

cumulates, tholeiit, São Francisco Craton.

PÁGINAS: 41
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Geociências
SUBÁREA: Geologia
ESPECIALIDADE: Petrologia
RESUMO:

The mafic-ultramafic body in Campo do Meio’s Farm, located in the city of Marcionílo Souza, state of Bahia, is characterized as an asymmetrical body with 1300x500m and eastwest orientation. It is inserted in the São Francisco Craton, more precisely in the Jequié Block, intruded among the chonockitic granulitic encasers. Lithographically, the body shows inverted stratigraphy, being composed of peridotites (dunite, harzburgite and lherzolite) pyroxenites (olivine-ortopyroxenite, olivine websterite, websterite, pyroxenite hornblende and pyroxene hornblendite) and hornblende gabronorite as mafic representative. Ultramafic rocks present varying degrees of serpentination, as well as post-magmatic processes of chloritization and thallification. However, the primary textures were not completely obliterated, thus preserving the igneous nature of the body, exhibiting primary paragenesis represented by forsterite / chrysolite, spinel (hercinite / magnetite), enstatite, augite and magnesium-hbl. In mafic rock, the deformation was more expressive with paragenesis formed by magnesium-hbl, diopside and labradorite. The binary diagrams of larger elements, trace elements and rare earths show that in spite of the post-magmatic events that affected the rocks, there was no significant interference in the original rocks, where they present olivine and orthopyroxene as the main controlling phases fractionation of ultramafic rocks. From the lithochemical data, the body is characterized with an intrusion of continental toleitic nature and affinities with komatiitic magmas. In geotermobarometric data it is verified that the crystallization temperature of the body was 1325 to 1704ºC and metamorphic rebalancing temperatures were 869ºC with pressure around 4 to 4.5 kbar, compatible with the pressure data for the granulitic nesting rocks. The data of this article will be published in the Journal of Research in Geosciences (UFRGS), as a basic requirement for the master's degree in the Graduate Program of the Federal University of Bahia (UFBA).

MEMBROS DA BANCA:
Presidente - 1295799 - ANGELA BEATRIZ DE MENEZES LEAL
Externo ao Programa - 1248799 - REINALDO SANTANA CORREIA DE BRITO
Externo à Instituição - MARIA ZÉLIA AGUIAR DE SOUZA - UFMT