Banca de DEFESA: IVANARA PEREIRA LOPES DOS SANTOS

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : IVANARA PEREIRA LOPES DOS SANTOS
DATA : 28/07/2021
HORA: 15:00
LOCAL: Videoconferência RNP
TÍTULO:

THE NORDESTINA KIMBERLITIC PROVINCE: PETROGRAPHY AND MINERALOGY

PALAVRAS-CHAVES:

Kimberlite. Lamprophyre. Diamond.

PÁGINAS: 82
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Geociências
SUBÁREA: Geologia
ESPECIALIDADE: Petrologia
RESUMO:

Kimberlites are alkaline, igneous rocks, which have exotic characteristics and represent “mantle windows”, been genetically correlated to the diamond mineralization. Currently, more than 18 kimberlitic widely distributed occurrences have been studied in Brazil. The Bahia State is almost entirely composed by the Precambrian basement rocks of the São Francisco Craton. Its main kimberlitic occurrences are in the Nordestina area, Northeastern Bahia region, in the Archean Serrinha Nucleus. This work presents the results of the Master Dissertation intitled “The Nordestina Kimberlite Province: Petrography and Mineralogy”. This kimberlitic Province comprises 20 small pipes and dykes of hypabyssal facies, known as the Brauna Field, as well as diverse other bodies which are still not studied in detail. It holds the first diamond mine of South America in source rocks. These kimberlitic rocks are emplaced in Archean/Paleoproterozoic TTGs and ~2.1 Ga alkaline-potassic-ultrapotassic rocks. Nordestina kimberlites are, until now, the only register of Neoproterozoic magmas (0.55-0.64 Ga) in Serrinha Nucleus and they preserve zircon crystals of diverse provenience, with records of the Eo-Paleoarchean crust and of an intense Mesoproterozoic potassic-ultrapotassic magmatism that act as an important source of zircon xenocrystals. The new petrographic data made possible to define the Nordestina Kimberlite Province, which includes not only the dykes and pipes of Brauna field but also the occurrences of Icó, Umbu and Aroeira.  They increase the available data for Brazilian kimberlitic rocks (s.l.) and collaborate to a better understanding of the kimberlites from Northeastern Bahia, the nature of the sub-continental lithosphere and of the mantle enrichment event at this region of Sao Francisco Craton.

MEMBROS DA BANCA:
Interna - 2334411 - DEBORA CORREIA RIOS
Externo à Instituição - BASILIO ELESBAO DA CRUZ FILHO
Externo à Instituição - PEDRO MACIEL DE PAULA GARCIA - UFMT