Banca de DEFESA: CLEBER FELIX DAS CHAGAS

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : CLEBER FELIX DAS CHAGAS
DATA : 21/02/2017
HORA: 08:30
LOCAL: Auditório do Departamento de Geofísica
TÍTULO:

CHARACTERIZATION OF THE CONTACT METAMORPHISM PROVOKED BY THE EDIACARAN TOTORÓ PLUTON, NE BRAZIL

PALAVRAS-CHAVES:

Plutonism; Thermal aureole; Ediacaran; Borborema Province; NE Brazil.

PÁGINAS: 80
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Geociências
RESUMO:

The northeastern of Borborema Province is marked by a massive Neoproterozoic plutonism of basic to acid composition, intrusive into metasupracrustal rocks of Seridó Group. In this context, the Totoró pluton, NW of Currais Novos / RN, is associated laterally to the SSW-NNE Serra Seriema shear zone. The pluton is composed of a sequence of basic to intermediate types, the earlier ones being gabbro-norites, followed by granodiorites / tonalites (the main facies), biotite-bearing equigranular granites, biotite bearing porphyritic granites, and fine-grained hololeucocratic granites. Geological mapping and microscopic analysis allowed visualizing a significant mineralogical variation in micaschists country rocks at different distances from the contact of the intrusion. This is reflected in metamorphic parageneses portarying different proportions of cordierite, andalusite, sillimanite and garnet, besides migmatized micaschists with relicts of paleosome and leucosomes of trondhjemitic composition, wich characterizes a metamorphic aureole that can extend until 2 km from the contact. Thermobarometric results showed that the emplacement temperature of pluton varied of the 800-900ºC under pressures of 1.6-2.7 kb. Modelling based on rock conductivity revealed that the temperature at the pluton contact reached 688-756 degrees Celsius and the heat could remain at about 500 ºC until 1800 m from a time span of 365.000 years. The results reported for the Totoró pluton and comparison with other granitoid bodies to the North of the Patos Lineament show that at least some of the ediacaran batoliths have been emplaced at relatively shallow crustal level under condition of high geothermal gradient, although still registering the vanishing phase of the transpressive ductile regional tectonics.

MEMBROS DA BANCA:
Externo à Instituição - FERNANDO ANTONIO PESSOA LIRA LINS - UFRN
Externo à Instituição - GORKI MARIANO - UFPE
Presidente - 350630 - ZORANO SERGIO DE SOUZA