Banca de QUALIFICAÇÃO: ROANNY ASSIS DE SOUZA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE : ROANNY ASSIS DE SOUZA
DATA : 14/07/2017
HORA: 09:00
LOCAL: Auditório do LGGP
TÍTULO:

STRUCTURAL STYLE AND TECTONOSTRATIGRAPHIC RELATIONS OF THE UBAJARA GROUP IN NW OF CEARÁ

PALAVRAS-CHAVES:

Borborema Province, Ubajara Group, structural style and kinematics.

PÁGINAS: 22
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Geociências
RESUMO:

The Ubajara Group is a neoproterozoic (ediacaran) metasedimentary unit that outcrops adjacent to the Transbrasiliano Lineament at NW Ceará. This lineament corresponds to a NE-trending dextral strike-slip shear zone. The Ubajara Group is part of the Middle Coreaú Belt, being totally delimitated by middle to low temperature shear zones, either with the Martinópole Group (also of neoproterozoic age) to the north, either with the ediacaran-cambrian Jaibaras Group, further south/SE, all of them displaying the dextral transcurrent kinematic signature characteristic to this region. The literature describes complex contractional structures (thrusts and folds) in the Ubajara Group, related to the Brasiliano Cycle . This work deals with the structural style and tectonostratigraphic relations of the Ubajara Group as regards to other adjacent units, based on the interpretation of remote sensing imagery, field and microscopic structural data. Geometric and kynematic analysis of macrostructures displayed in orbital images and CPRM/UFPA map, as well as in mesoscale structures, allowed to recognize four deformation phases affecting the Ubajara Group. The D1, ductile phase is characterized by thrusts and recumbent to reclined folds, with a gently dipping S1 foliation, transported to the NW. D2 is less developed in the area and occurs as tight NW-SE to W-E trending folds with S2 displaying strong dips. A third (D3) phase comprises structures of transcurrent regime with dextral kinematics, including steep-dipping NE-trending shear zones, low rake stretching lineations and open to tight folds; S3 foliation trends N-S to NNE. The en cornue shape of the Mucambo Granite attests the role of this phase during its emplacement. D3 phase is concentrated along NE-trending belts displaying higher metamorphic grade; the main one is marked by mylonites developed after (initially) E-W trending granite dykes filling extension joints late as regards to the Mucambo Pluton. Finally, an evolution (late stage) to ductile-brittle or brittle structures sharing the same dextral transcurrent kinematics characteristic of the D3 phase (being thus referred as late D3 or D3t) expressed as NE-trending dextral-normal and E-W to ENE trending normal faults and extension joints, being correlated to the transtensional tectonics that controls the pull-apart Jaibaras graben.

MEMBROS DA BANCA:
Externo ao Programa - 2490483 - ALEX FRANCISCO ANTUNES
Presidente - 346469 - EMANUEL FERRAZ JARDIM DE SA
Interno - 350630 - ZORANO SERGIO DE SOUZA