Banca de DEFESA: GABRIEL TAIRA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : GABRIEL TAIRA
DATE: 30/11/2023
TIME: 14:00
LOCAL: Sala de videoconferência e Teams
TITLE:

"The Uruaçu metamorphic complex, Central Brazil: geological significance and implications for the tectono-metamorphic evolution of the Brasília orogen".

KEY WORDS:

Uruaçu Complex; Serra da Mesa Group; Metamorphic modelling; U-Pb detrital zircon; Brasília Orogen.

PAGES: 120
BIG AREA: Ciências Exatas e da Terra
AREA: Geociências
SUBÁREA: Geologia
SPECIALTY: Geologia Regional
SUMMARY:

The Uruaçu Complex is a Neoproterozoic domed-shaped metamorphic terrain (690-650 Ma) exposed underneath the supracrustal rocks of the Serra da Mesa Group in the central portion of the Northern Brasília Belt between the mafic-ultramafic complexes and the Mara Rosa Magmatic Arc. In this study, we combine field data, metamorphic modelling, and U-Pb detrital zircon provenance to constrain the tectonic setting and the evolution of the Uruaçu Complex and its surrounding rocks from the Serra da Mesa Group. The main rocks from the Uruaçu Complex are orthogneisses with tonalitic to granitic composition, and paragneisses. The amphibolites occur as scattered bodies through the complex. The pseudosection from the paragneiss and the amphibolite coupled with conventional geothermobarometers contrains the peak metamorphic at ~7 kbar and 700°C with retrogressive metamorphism at ~ 4.42 kbar and 551°C. The Serra da Mesa Group is mainly composed of quartzites and schist with minor occurrences of marble. The pseudosection modelling based on the garnet compositional profile predicts a P-T path from 4.3 kbar and 547°C to 5.9 kbar and 616°C for the garnet schist from the Serra da Mesa Groups. In addition, normal structures were observed cross-cutting the regional foliation implying in preliminary evidence for extensional tectonics in the Northern Brasília Belt. The U-Pb detrital zircons collected from the Serra da Mesa Group suggest that the sediments were deposited in three different basins: (1) Paleo-Mesoproterozoic intracontinental extensional basin which can be the lateral correlative of the Traíras Group; (2) Neoproterozoic back-arc basin in the margins of the Mara Rosa Magmatic Arc, and (3) Neoproterozoic foreland basin also associated with the eastern portion of the Santa Terezinha Sequence. Combining these new data, we proposed that the Uruaçu Complex underwent a diapiric ascent during the collisional stage of the Brasília Orogen.

COMMITTEE MEMBERS:
Interno - 404825 - CESAR FONSECA FERREIRA FILHO
Presidente - 418965 - CLAUDINEI GOUVEIA DE OLIVEIRA
Interno - 1303786 - ELTON LUIZ DANTAS
Externo à Instituição - TICIANO JOSE SARAIVA DOS SANTOS - UNICAMP