| Texto completo | |
| Autor(es): |
Louro, Vinicius
;
Raposo, Maria Irene Bartolomeu
Número total de Autores: 2
|
| Tipo de documento: | Artigo Científico |
| Fonte: | JOURNAL OF APPLIED GEOPHYSICS; v. 241, p. 16-pg., 2025-10-01. |
| Resumo | |
The Arraial do Cabo area display a diverse geological environment. From Paleoproterozoic host rocks to Eocene intrusive igneous rocks, the area displays different orthogneisses, diabases, lamprophyres, and felsic-alkaline. This paper proposes an analysis of the current theories on the magmatic evolution of the Arraial do Cabo based on these rocks' spatial distribution, geometric relationships and magnetization. To achieve this, we used airborne and unmanned aerial vehicle (UAV) collected magnetic field and rock magnetization data to model the area's primary magnetic features. The model suggests the existence of a deep magmatic chamber within the Paleoproterozoic gneisses of the Regiao dos Lagos Unit, situated approximately 800 to 1000 m below the current surface. This chamber would have produced at least five to eight pulses, forming sill-shaped structures along the southern and western boundaries of Cabo Frio Island, followed by the emplacement of trachyte breccias. The crustal deformation caused by these magmatic events likely facilitated the further intrusion of nepheline-syenites and syenites, that form the bulk of Cabo Frio Island, including subsequent dike and sill intrusions. A similar process likely occurred at Pontal do Atalaia, including the Pedra do Macaco magnetic source, which can be attributed to the initial magmatic event based on its location and similar physical properties. This geophysical-geological interpretation adds a layer to the previous theories on the formation and evolution of the Cabo Frio Island, establishing spatially and petrophysically the relationships between the main bodies' emplacement events and the prior and posterior dike intrusions. (AU) | |
| Processo FAPESP: | 19/22084-8 - A Província Magmática Paraná: petrogênese, cronologia e impacto ambiental do magmatismo toleítico, alcalino e silícico Cretáceo na Plataforma Brasileira |
| Beneficiário: | Valdecir de Assis Janasi |
| Modalidade de apoio: | Auxílio à Pesquisa - Temático |
| Processo FAPESP: | 19/20371-0 - Anisotropias magnéticas do enxame de diques Serra do Mar, na região do Estado do Rio de Janeiro: implicações na abertura do Atlântico Sul |
| Beneficiário: | Maria Irene Bartolomeu Raposo |
| Modalidade de apoio: | Auxílio à Pesquisa - Regular |