| Texto completo | |
| Autor(es): |
Bologna, Mauricio S.
;
Dragone, Gabriel N.
;
Barbosa, Alane N.
Número total de Autores: 3
|
| Tipo de documento: | Artigo Científico |
| Fonte: | Journal of South American Earth Sciences; v. 153, p. 10-pg., 2025-02-15. |
| Resumo | |
In the northern sector of the Paraguay Belt, at the southeast margin of the Amazonian Craton, two- and three-dimensional inversions of an orthogonally deployed 200 km long broadband magnetotelluric profile provide a vertical section of the lithosphere showing diverse resistivity anomalies. A thickening of >2 km of the Parana Basin and the lack of an underlying rift-related resistivity anomaly favors strike-slip tectonics rather than a rift basin derived from the impact of the Trindade mantle Plume. At 3-4 km depth, a conductive horizon may be due to a high saline fractured aquifer, likely truncated by strike-slip faults. The most prominent electrical features are associated with the Paraguay-Araguaia conductivity anomaly (PACA), mapped as a pair of conductors with the top at middle to lower crustal depths. Our results confirm that the PACA occurs under the most deformed part of the Paraguay belt, which suggests graphite as the primary source of enhanced conductivity and a chronological association between the PACA and the main metamorphic event in the belt, estimated at similar to 600 Ma. The Amazonian Craton lithosphere is relatively conductive, suggesting local re-fertilization during an Upper Cretaceous kimberlitic magmatism. A resistive lithosphere under the northwestern Parana Basin may be a microplate that collided with the Amazonian Craton in the Neoproterozoic-Cambrian boundary. In this context, the PACA would represent the suture of this collision. Our findings suggest a plate margin more significant than the closing of a relatively narrow aulacogen or foreland molassic basin. (AU) | |
| Processo FAPESP: | 00/00806-5 - Estruturas geoelétricas no manto superior sob o escudo no Centro-Sul do Brasil |
| Beneficiário: | Icaro Vitorello |
| Modalidade de apoio: | Auxílio à Pesquisa - Temático |
| Processo FAPESP: | 09/54006-4 - Um cluster de computadores para o Departamento de Astronomia do IAG-USP e para o Núcleo de Astrofísica da UNICSUL |
| Beneficiário: | Elisabete Maria de Gouveia Dal Pino |
| Modalidade de apoio: | Auxílio à Pesquisa - Programa Equipamentos Multiusuários |