Banca de QUALIFICAÇÃO: LUANNA CELLY SILVA DE AZEVEDO

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : LUANNA CELLY SILVA DE AZEVEDO
DATE: 14/12/2022
TIME: 14:30
LOCAL: videoconferência https://www.youtube.com/c/PPGGUFRNTransmiss%C3%A3odeBancas
TITLE:

RADIOGENIC HEAT PRODUCTION AND MAGNETIC SUSCEPTIBILITY OF EDIACARAN GRANITES FROM THE NORTHEASTERNMOST BORBOREMA PROVINCE

KEY WORDS:

Radiogenic Heat Production; Magnetic Susceptibility; Litochemistry; Petrophysics; Plutonism.

PAGES: 73
BIG AREA: Ciências Exatas e da Terra
AREA: Geociências
SUMMARY:

The Rio Piranhas-Seridó (DPS) and São José do Campestre (DJC) domains, in the northernmost extreme of the Borborema Province, are marked by a voluminous plutonic magmatism of Ediacaran-Cambrian age. This magmatism gave rise to dozens of batholiths, stocks and plutons of contrasting petrographic and geochemical characteristics. Several works have been done in order to characterize this magmatism, but an analysis of these granitoids in the light of their petrophysical parameters and radiogenic heat production is still lacking. The present work compares, from a lithochemical, radiogenic heat production (A) and magnetic susceptibility (K) point of view, granitoids from the DPS and DJC domains. The studied rocks vary from quartz diorites, granodiorites to granites and quartz syenites with biotite ± hornblende as main mafics, with metaluminous to peraluminous character and calc-alkaline to alkaline signatures. The granitoids of both domains are classified as low heat-producing (LHP) and medium heat-producing (MHP) granites, with A values between 0.51 - 4.82 µW/m³ in DJC and 0.66 - 4.92 µW/m³ in DPS. The contribution of Th to the A values is dominant for both domains, followed by U and K in the DJC domain, and by K and U in the RPS domain. The radiogenic heat production values correlate positively with quartz modal contents and SiO₂ and total alkali contents (weight %) and negatively with mafic mineral contents and TiO₂, FeO_t, MgO, CaO and P₂O₅ contents. Granitoids at DJC exhibit K values between 0.95 - 32.6 x 10-3 SI (mean 5.08 x 10-3), while those at DPS record K values between 0.2 - 16.2 x 10-3 SI (mean 3.93 x 10-3). There are no significant correlations between K and the chemical composition of the studied rocks. On the other hand, higher modal contents of opaque minerals (and to a lesser extent plagioclase and mafic minerals) are associated with higher K values. 

COMMITTEE MEMBERS:
Externa à Instituição - SUZE NEI PEREIRA GUIMARÃES - ON/MCT
Presidente - 2042352 - FREDERICO CASTRO JOBIM VILALVA
Interno - 1513243 - MARCOS ANTONIO LEITE DO NASCIMENTO