Banca de QUALIFICAÇÃO: ISABELLE TEIXEIRA DA SILVA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : ISABELLE TEIXEIRA DA SILVA
DATE: 23/04/2025
TIME: 14:30
LOCAL: Videoconferência / Google meet
TITLE:

Provenance Sedimentary of the Cretaceous of the Barreirinhas and Pará-Maranhão Basins, Brazilian Equatorial Atlantic Margin.

 

KEY WORDS:

Heavy Minerals; Sedimentary Provenance; Barreirinhas Basin; Pará-Maranhão Basin; Brazilian Equatorial Margin.

 

PAGES: 75
BIG AREA: Ciências Exatas e da Terra
AREA: Geociências
SUMMARY:

The present research aims to study provenance through the use of heavy minerals in sandstones from Cretaceous turbidite deposits in the Barreirinhas and Pará-Maranhão basins, belonging to the Brazilian Equatorial Margin. Currently, the Brazilian Equatorial Atlantic Margin represents a new exploratory frontier, as a result of recent oil discoveries in turbidite deposits in deep waters. The study of  provenance through the use of heavy minerals is an important tool in interpreting the relationships between source areas and the sedimentary basin. The mineralogy of the clastic sediments present in a sedimentary basin is directly related to the composition of the source areas. Therefore, the main objective of this study is to identify the mineralogical assemblage and possible source areas of the sediments deposited during the Cretaceous in these basins and to obtain information about the climatic conditions, type of transport, distance from the source areas, relief and the main routes of destruction of these sediments. The main methodology used in this study consists of the description of petrographic thin section of heavy minerals, associated with mineralogical scanning through QEMSCAN and U-Pb dating of detrital zircons, together with cathodoluminescence images. The samples are concentrated in the Upper Cretaceous (Cenomanian, Santonian and Maastrichian) of the Barreirinhas Basin, lithostratigraphically corresponding to the Areinhas/Ilha de Santana and Travosas formations, and in the Lower Cretaceous (Albian) of the Pará-Maranhão Basin, included in the Canary Group. Petrographic analysis made it possible to identify the assemblage of heavy minerals and their paragenesis present in the studied intervals, as well as their morphological characteristics. Catholuminescence, in addition to providing the crystallization age of detrital zircons, allowed for a more refined analysis, where it was possible to recognize the different textural and crystallization patterns of zircons. With the preliminary results it was possible to identify the following minerals: zircon, tourmaline, rutile, amphibole, staurolite, garnet, monazite, epidote, aluminum minerals, pyroxene, apatite and olivine. The mineralogical maturity index (ZTR) revealed that the studied intervals of wells that are closer to the coast, in the current shallow platform context, present a greater mineralogical maturity due to the significant presence of more resistant minerals such as: zircon, tourmaline and rutile. However, in the intervals studied in wells further from the coast, in a deeper depositional environment, and those on a shallow platform with Albian age, maturity decreases with an increase in the amount of amphiboles and staurolites, with rutile being the most common resistate. According to the morphological analysis of the grains, it is possible to detect different distances and trajectories. The studies have helped to identify the source areas of turbidite deposits in the studied basins and will help in the tectonic and paleogeographic reconstruction of the Cretaceous in this region of the Brazilian Equatorial Margin.

 

 

COMMITTEE MEMBERS:
Externo à Instituição - EMILSON FERNANDES SOARES
Externa à Instituição - LILIANE RABELO CRUZ
Presidente - 1149363 - VALERIA CENTURION CORDOBA