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Deformação tectónica no bordo ocidental da bacia de Rio Maior : a falha do Cidral
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Advisor(s)
Abstract(s)
SUMMARY: The Rio Maior basin is a NNW-SSE elongated tectonic basin, controlled by main faults with the
same orientation. The basin was filled with sediments during the Pliocene, over Miocene deposits. Borehole data show a depocenter located near its eastern margin with the Pliocene sediments forming a dissymmetrical synform controlled by the NNW-SSE Cidral border fault. The sedimentation culminates in Pleistocene conglomeratic sandstones, apparently not deformed. During recent field work in a sand exploration quarry located in the SE extremity of the basin, a N-S fault affecting the Miocene and Pliocene was identified along ca. 400 m. Striated slickensides in the Miocene deposits indicate a predominant normal dip-slip component. This was interpreted as a prolongation or major ramification of the Cidral fault. Considering the proximity of extruded Jurassic evaporitic sediments at Fonte da Bica diapir, the extensional deformation in the Rio Maior area during the Pliocene is probably related with tectonic diapirism.
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Resumo alargado
Keywords
Bacia de Rio Maior Pliocénico Tectónica Diapirismo Rio Maior basin Pliocene Tectonics Diapirism
Citation
Ressurreição, Ricardo; Dias, Ruben Pereira; Cabral, João; Charifo, G. (2023) - Deformação tectónica no bordo ocidental da bacia de Rio Maior : a falha do Cidral. In: Lopes, F. C., Dinis, P. A., Duarte, L. V. e Cunha, P. P. (Coords.). XI Congresso Nacional de Geologia: Geociências e Desafios Globais. Livro de Resumos. Coimbra, 16- 20 julho de 2023, Departamento de Ciências da Terra da Universidade de Coimbra (eds.), p. 249-250. ISBN: 978-989-98914-8-7
Publisher
Departamento de Ciências da Terra da Universidade de Coimbra