Banca de QUALIFICAÇÃO: MARLOS ELIAS BORGES

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : MARLOS ELIAS BORGES
DATE: 02/02/2023
TIME: 14:00
LOCAL: Remoto Plataforma Microsoft Teams
TITLE:

STRUCTURAL GEOLOGY ANS 3D MAGNETIC MODELING OF THE MAGNETIC PRATINHA ANOMALY

KEY WORDS:

Alto Paranaiba Alkaline Province, Pratinha Magnetic Anomaly, aeromagnetometry, structural geology.

PAGES: 64
BIG AREA: Ciências Exatas e da Terra
AREA: Geociências
SUBÁREA: Geofísica
SPECIALTY: Geomagnetismo
SUMMARY:

The Alto Paranaíba Igneous Province (APIP) is a region in southeastern Brazil where a set of aligned circular structures occurs that resulted from alkaline magmatism that occurred in the Upper Cretaceous. Intrusive processes have modified the geometry of brittle and ductile structures imprinted on the rocks of the Brasília Belt since pre-Cretaceous times. APIP has alkaline-carbonatite intrusions that are characterized by the presence of associated magnetic anomalies. The Pratinha magnetic anomaly, the focus of this dissertation, is one of these alkaline intrusions, which presents a tripolar magnetic anomaly of about 50 km in diameter and which does not have an outcropping igneous body. Thus, the best way to approach this anomaly and understand its origin and dimension is through indirect methods, such as geophysics, direct observation of outcrops, through structural geology. The study of structural geology tries to understand how, or if, the intrusion caused changes in the geometry of brittle and ductile structures in the vicinity of the intrusion, even if it is located in depth, in addition to being able to serve as a basis for future work, in case the body comes to be explored. The structural geology study involved the use of digital elevation model and satellite images to collect regional brittle fracturing and foliation ductile data and was complemented with fieldwork to collect brittle deformation data close to the anomaly. The geophysical study uses magnetic data inversion to determine the depth as well as the size of the intrusion. Three inversion models were generated varying the cell size with dimensions of 1000x1000 m, 500x500 m and 250x250 m. The first inversion returned 2 bodies as responsible for the anomaly, their tops would be 1400 meters below the surface and their volume would be about 253 Km³. The other models, in turn, returned a single body responsible for the anomaly about 2 km from the surface and having a volume of approximately 700 km³.

 

 

COMMITTEE MEMBERS:
Presidente - HILDOR JOSE SEER
Externa à Instituição - ADALENE MOREIRA SILVA - UnB
Externo à Instituição - MARCELO HENRIQUE LEÃO SANTOS - UnB