Banca de QUALIFICAÇÃO: LIDYANE MAYARA LIMA DE ARAÚJO

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE : LIDYANE MAYARA LIMA DE ARAÚJO
DATA : 03/07/2019
HORA: 09:00
LOCAL: Sala 24
TÍTULO:

MINERALOGY OF AMYGDALES IN VOLCANIC ROCKS OF THE RIO PIRANHAS-SERIDÓ DOMAIN, BORBOREMA PROVINCE, NE BRAZIL

PALAVRAS-CHAVES:

AMYGDALES; MINERALOGY; BASALTIC ROCKS; RIO PIRANHASSERIDÓ DOMAIN

PÁGINAS: 26
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Geociências
RESUMO:

Volcanic igneous rocks commonly show cavities or vesicles that were formed by scape (expansion) of gas during magma cooling. These vesicles can be filled by different minerals through late- to post-magmatic processes that turn vesicles into amygdales. The identification and characterization of these processes are commonly done by mineralogical and textural studies of the host-rocks. The Rio Grande do Norte state was affected by three important mesocenozoic volcanic events of basaltic compositions, namely the Rio Ceará-Mirim, Serra do Cuó and the youngest Macau magmatism. A number of occurrences of these three events showing vesicular and amygdaloidal textures are found within the Rio Piranhas-Seridó Domain of the Borborema Province. This work presents a preliminary characterization of the minerals filling-in amygdales in the Rio Ceará-Mirim, Serra do Cuó and Macau basalts and microgabbros based on textural, and X Ray powder diffraction (XRD) analyses. The recognized amygdales were classified in four main types, with distinct filling minerals associated with each one of the studied volcanics. The amygdales are filled-in with late- and post-magmatic minerals, and these include volcanic glass and clinopyroxenes (late-magmatic phases), as well as calcite, chalcedony, zeolite-group minerals (laumontite), and plombierite, the last two being identified by XRD. Results suggest that the nature and characteristics of the studied amygdales (shape, color and size) are related to compositional and textural contrasts among the host-rocks. Thus, host-rocks of tholeiitic affinity and coarse textures have larger amygdales, whereas those with alkaline affinity have smaller amygdales.

MEMBROS DA BANCA:
Externo ao Programa - 1149358 - FRANCISCO OLIVEIRA DA SILVA
Presidente - 2042352 - FREDERICO CASTRO JOBIM VILALVA
Interno - 1513243 - MARCOS ANTONIO LEITE DO NASCIMENTO
Externa ao Programa - 1298966 - RAQUEL FRANCO DE SOUZA