| Texto completo | |
| Autor(es): |
Maziviero, Mariana V.
[1]
;
Vasconcelos, Marcos A. R.
[1]
;
Crosta, Alvaro P.
[1]
;
Goes, Ana M.
[2]
;
Reimold, Wolf U.
[3, 4]
;
Carneiro, Cleyton De C.
[1]
Número total de Autores: 6
|
| Afiliação do(s) autor(es): | [1] Univ Estadual Campinas, Inst Geosci, Dept Geol & Nat Resources, BR-13083970 Campinas, SP - Brazil
[2] Univ Sao Paulo, Inst Geosci, Dept Sedimentary & Environm Geol, BR-05508080 Sao Paulo - Brazil
[3] Humboldt Univ, D-10099 Berlin - Germany
[4] Leibniz Inst Res Evolut & Biodivers, Museum Nat Kunde, D-10115 Berlin - Germany
Número total de Afiliações: 4
|
| Tipo de documento: | Artigo Científico |
| Fonte: | METEORITICS & PLANETARY SCIENCE; v. 48, n. 10, p. 2044-2058, OCT 2013. |
| Citações Web of Science: | 4 |
| Resumo | |
RiachAo, located at S7 degrees 42/W46 degrees 38 in MaranhAo State, northeastern Brazil, is a complex impact structure of about 4.1km diameter, formed in Pennsylvanian to Permian sedimentary rocks of the Parnaiba Basin sequence. Although its impact origin was already proposed in the 1970s, information on its geology and shock features is still scarce in the literature. We present here the main geomorphological and geological characteristics of the RiachAo impact structure obtained by integrated geophysical and remote sensing analysis, as well as geological field work and petrographic analysis. The identified lithostratigraphic units consist of different levels of the Pedra de Fogo Formation and, possibly, the Piaui Formation. Our petrographic analysis confirms the presence of shock-diagnostic planar microdeformation structures in quartz grains of sandstone from the central uplift as evidence for an impact origin of the RiachAo structure. The absence of crater-filling impact breccias and melt rocks, shatter cones, as well as the restricted occurrence of microscopic shock effects, suggests that intense and relatively deep erosion has occurred since crater formation. (AU) | |
| Processo FAPESP: | 09/12884-5 - Caracterização Geológica da Estrutura de Impacto de Riachão (MA) |
| Beneficiário: | Mariana Velcic Maziviero |
| Modalidade de apoio: | Bolsas no Brasil - Mestrado |
| Processo FAPESP: | 08/53588-7 - Estudo geológico e geofísico integrado das estruturas de impacto de Serra da Cangalha (TO) e Riachão (MA) |
| Beneficiário: | Alvaro Penteado Crósta |
| Modalidade de apoio: | Auxílio à Pesquisa - Regular |