Banca de DEFESA: Steffanie Loislen de Sousa Oliveira

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : Steffanie Loislen de Sousa Oliveira
DATE: 27/07/2023
TIME: 09:30
LOCAL: Sala de Videoconferência do IGD
TITLE:

 CONTRIBUTION TO PETROGENESIS OF THE APOTERI BASALTIC MAGMATISM FROM THE TACUTU RIFT, RORAIMA, BRAZIL.

KEY WORDS:

Amazonian craton, Tacutu rift, basaltic magmatism, Apoteri Formation, continental breakup. 

PAGES: 67
BIG AREA: Ciências Exatas e da Terra
AREA: Geociências
SUMMARY:

The Tacutu continental rift located on the border between Brazil and Guyana is related to the Central Atlantic Ocean opening process. On the Brazilian side, during to pre-rift stage, basaltic vulcanism (Apoteri Formation) associated with a fluvial-deltaic system occurred within a magma-poor rift domain. At least two magmatic pulses have been recorded (Ap1 and Ap2), which have subalkaline basalt to basalt-andesite composition, as well as a tholeiite-calcalkaline continental and intra-plate chemical signatures. However, Ap1 display aphanitic to fine porphyritic texture, while Ap2 has notable vesicular textural feature. Ap1 has low MgO, high Ti, Zr and REE, while Ap2 has high MgO, low Ti, Zr and REE. Geochemical and isotopic indicators point to different crustal contamination rates between Ap1 and Ap2 magmatic pulses, probably related to crustal residence time that is marked by different negative ƐNd values. The internal fault architecture (horst-graben) and their movements during the Tucutu rifting controlled the volume and emplacement moment of the basaltic magmatic pulses. On the Brazilian side, the Apoteri basaltic volcanism had sub-aerial characteristics, with some degree of explosivity during the Ap2 pulse, associated with a fluvial-deltaic system, while on the Guyana side occurred mainly underwater volcanism associated with a deltaic-marine system. 

COMMITTEE MEMBERS:
Externa à Instituição - ANA TAYLA RODRIGUES FERREIRA - UFRR
Interna - 1555904 - CATARINA LABOURE BEMFICA TOLEDO
Interno - 6404885 - NILSON FRANCISQUINI BOTELHO
Presidente - 1057547 - VALMIR DA SILVA SOUZA