Banca de QUALIFICAÇÃO: YARA VELOSO MAGALHAES FRANK

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : YARA VELOSO MAGALHAES FRANK
DATE: 28/11/2022
TIME: 10:00
LOCAL: Departamento de Petrologia e Geotectônica
TITLE:

POST-APTIAN MAGMATISM AND VOLCANOSEDIMENTARY PALEOENRIVONMENT
IN CAMPOS BASIN, SE BRAZIL

KEY WORDS:

Campos basin; vulcanosedimentary paleoenvironment; magmatism, post-aptian

PAGES: 100
BIG AREA: Ciências Exatas e da Terra
AREA: Geociências
SUBÁREA: Geologia
SPECIALTY: Petrologia
SUMMARY:

The Campos Basin offshore SE Brazil originated as a rift basin during the Gondwana breakup in the Lower

Cretaceous and evolved to a passive margin sedimentary basin throughout the opening of the South Atlantic

ocean. Magmatic processes occurred coeval to the sedimentary and tectonic evolution of the basin as recorded

in its rift, post-rift and drift supersequences. The crustal structure of Campos Basin is well constrained on the

basis of 2D and 3D geophysical data. However, the lack of petrological data prevents the assessment of the

composition and structure of the mantle underneath the basin. Well data, petrographic and lithogeochemical

data were obtained for post-Aptian magmatic rocks drilled by two wells in an area of Campos where magmatic

structures are well discriminated by geophysical data. The wells include volcaniclastic, volcanic and intrusive

magmatic alkaline rocks. Magmatism in well A and well B are taken as a record the Santonian magmatic event

in the basin. Geochemical modeling showed that differentiation involved fractional crystallization, indicating

the presence of continental crust thick enough to sustain subvolcanic-volcanic linked structures or plumbing

systems. Binary modeling pointed to mixing between shallow-seated, depleted mantle source and the enriched,

SCLM site. It is proposed that the geodynamics at the Santonian-Coniacian in Campos Basin involved

continental lithosphere thinning that allowed the uprising of the depleted asthenosphere. heat conduction

would have been enough to melt the most fuse, volatile-rich portions of the local SCLM whose composition

is well represented by alkaline lamprophyres that occur in the continental area adjoining Campos and Santos

basins.

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