Banca de DEFESA: Eder Luis Mathias Medeiros

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : Eder Luis Mathias Medeiros
DATE: 28/02/2023
TIME: 14:00
LOCAL: Auditório do IGD e Teams
TITLE:

GEOTTECTONIC SIGNIFICANCE OF THE BASEMENT HIGH OF CORRENTINA – BAHIA.

KEY WORDS:

Cratonization; decratonization; Transbrasilian Lineament

PAGES: 130
BIG AREA: Ciências Exatas e da Terra
AREA: Geociências
SUMMARY:

A large part of the basement of the northwest portion of the São Francisco Craton is covered by sedimentary rocks from the São Francisco Basin and the São Franciscana Basin. In this scenario, with little exposure of the crystalline basement, the Correntina- Coribe (BA) erosive window and the region of Júlio Borges and Avelino Lopes (PI) represents a strategic region from the scientific point of view, as it exposes the crystalline basement northwest of the CSF. For this study we combined geological mapping, micropetrography of mineral assemblages, geophysical maps of magnetic anomaly and first vertical derivative and integration of the results of Sm-Nd and U-Pb data analysis. The objective is to understand the isotopic data of the rocks present on the edge and interior of the Craton and establish a correlation with the surrounding basement inliers present in the Brasilia and Rio Preto orogens. Furthermore, this work aims to verify evidence and records of possible loss of cratonic stability in the NW portion of the CSF and its influence on the current tectonic configuration. Data from the analysis of U-Pb zircon (LA-ICP-MS) for the granitic rocks of the Correntina Complex, and units of the Júlio Borges Complex, together with the mansidão-type granites, indicate the presence of riatian crust cores, with crystallization ages of 2.15 Bad. Sm-Nd analyzes indicate juvenile values with TDM between 2.2 2.1 Ga, indicating a short interval from extraction to crystallization, typical in intraoceanic arc systems. The Correntina syenogranites correspond to the evolution of the intraoceanic arc to a continental arc with reworking and contamination in a post collision scenario. Sm – Nd isotopic analyzes show negative ƐNd(t) values, indicating intensive crustal recycling, and TDM values between 3.0 to 2.26 Ga indicating reworking and melting of older crustal rocks. The sample set indicates a great petrogenetic proximity and shows that the blocks that make up the cratonic basement in the northwest portion represent an importante episode of crustal growth and accretion that evolved during the Riatian and culminated in the amalgamation of the basement of the Paleo continent São Francisco Congo 2, 3 and 1.9 Ga. The new Paleoproterozoic supercontinent has suffered, throughout its evolutionary history, several regional thermal events that are related to possible mantle plumes with occurrences of statherian and tonian dykes. The large lineaments identified in the geophysical maps are interpreted as an extension of the Transbrasiliano Lineament damage area and play a very important role in the configuration of the NW border of the CSF, since its delineation was generated through a tectonic escape system given by transcurrent shear zones that deeply rotate the crustal basement blocks, reactivating existing structures. Microstructural analysis of these rocks allowed the identification of four stages of deformation (E1, E2, E3 and E4) that operate at different scales and show the transition from rocks of the mylonitic series to rocks of the cataclastic series.

BANKING MEMBERS:
Externo à Instituição - LAURO CÉZAR MONTEFALCO DE LIRA SANTOS - UFPE
Externa ao Programa - 3000894 - ELIZA INEZ NUNES PEIXOTO
Presidente - 1303786 - ELTON LUIZ DANTAS
Interno - 001.539.401-82 - REINHARDT ADOLFO FUCK - UnB
Externa à Instituição - SIMONE CERQUEIRA PEREIRA CRUZ - UFBA