Banca de DEFESA: André Sena de Oliveira

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : André Sena de Oliveira
DATE: 17/11/2022
TIME: 08:00
LOCAL: Sala de videoconferência do IGD
TITLE:

Tectonic magnetic fabric inside and outside a Craton: Insights from aeromagnetic data of the Gurupi Belt, Brazil.

KEY WORDS:

Orogenic Belt, Gurupi Belt, São Luís Craton, magnetometry, deformation pattern.

PAGES: 77
BIG AREA: Ciências Exatas e da Terra
AREA: Geociências
SUMMARY:

The boundaries between Craton and Mobile Belt consist of geologically active regions and record, after their evolutionary history, a complex superposition of deformational events. The São Luís Craton and the Gurupi Belt, located in northern Brazil, are examples of Precambrian terrains that show evidence of a complex deformational history derived from the Paleoproterozoic, Neoproterozoic orogenies and subsequent fragmentation of the West African Craton with the opening of the Atlantic Ocean. However, the understanding of the deformational styles of the São Luís Craton and the Gurupi Belt remains poorly understood. In this context, this study takes a multidisciplinary approach that integrates high resolution aerogeophysical data with existing geological data to investigate the deformations and mechanisms involved in the evolution of the São Luís Craton in the Gurupi Belt. The processing of the aeromagnetic data resulted in different depths for the region: 22 km, 5.7 km and 0.53 km. For the greatest depth, four geophysical domains were defined, in which the boundary between the São Luís Craton and the Belt is given by the WSZ lineament of NW-SE direction, while in the São Luís Craton three domains with E-W to NE-SW directions were found. . In the shallower depths of the studied area, the magnetic lineaments defined ductile deformation patterns. Over the São Luís Craton, the magnetic lineaments vary from E-W to NE-SW and are interpreted as a D1 deformation event. Over the Gurupi Belt, the deformation patterns are sigmoidal with sinistral kinematics, associated with Tentugal shear zones with NW-SE direction, and are interpreted as a D2 deformation event. The third deformational event with N-S and E-W direction was associated with the third event D3 with brittle-ductile regime. From the digital elevation model and the analytical signal, the surface lineaments reveal a conjugated pair of faults in the NE-SW and NW-SE direction and, from the Euler solutions, the depths show to be less than 500 m. Additionally, occurrences and auriferous deposits located in the Gurupi Belt are spatially distributed in the NW-SE direction of ductile character and in secondary directions N-S of brittle character. Finally, after kinematic analysis of the region and its correlation with other parts of the world, it is suggested that this region should be inserted into the Paleoproterozoic and Neoproterozoic supercontinent cycle model, on a global scale.

BANKING MEMBERS:
Interna - 1555904 - CATARINA LABOURE BEMFICA TOLEDO
Interno - 1303786 - ELTON LUIZ DANTAS
Externo à Instituição - ROBERTO VIZEU LIMA PINHEIRO - UFPA
Interno - 1057547 - VALMIR DA SILVA SOUZA