Titre:	Modelagem sísmica de ondas S e imageamento Vp/Vs da crosta sob o perfil sísmico NW-SE do SE do Brasil : NE Bacia do Paraná, Faixa Brasília Meridional e Faixa Ribeira Central
Auteur(s):	Simões, Camila Hanna Sampaio Prates
Orientador(es)::	Soares, José Eduardo Pereira
Assunto::	Refração Reflexão de Ângulo Amplo Pesquisa sismológica Razão Velocidade da onda P Litosfera Paraná, Rio, Bacia Faixa Brasília Meridional Faixa Ribeira Central Razão Velocidade da onda S
Date de publication:	17-aoû-2021
Data de defesa::	28-fév-2018
Référence bibliographique:	SIMÕES, Camila Hanna Sampaio Prates. Modelagem sísmica de ondas S e imageamento Vp/Vs da crosta sob o perfil sísmico NW-SE do SE do Brasil: NE Bacia do Paraná, Faixa Brasília Meridional e Faixa Ribeira Central. 2018. 58 f., il. Dissertação (Mestrado em Geociências Aplicadas) — Universidade de Brasília, Brasília, 2018.
Abstract:	The PABBRISE profile (PAraná Basin, Brasília and RIbeira belts Seismic Experiment) consists of a wide-angle reflection and refraction experiment carried out in the State of São Paulo, as part of the project continental to ocean crustal transition in southeastern Brazil: deep seismic refraction, magnetotelluric and geological studies in the Ribeira Belt and Paraná Basin (PETROBRAS/UnB/Finatec-2012). The profile has about 700 km of extension in NW-SE direction crossing the northeastern portion of the Paraná Basin, passing through the Southern Brasília and Central Ribeira Belts. The Vp/Vs image of the crust and upper mantle under the profile was obtained from the modeling of the P and S wave velocity fields separately. This ratio is a dimension less particularly sensitive to the silica content of the rocks, but also to the presence of fluids and to the anisotropy. The Vp/Vs image differentiated the upper crust in three domains: in the northwest portion of the profile, values of Vp/Vs higher than 1.80 show that the crust was modified by mafic intrusions, possibly related to the magmatism Serra Geral in the Cretaceous; the central region of the profile presents values of Vp/Vs of intermediate to felsic composition, interpreted as Precambrian upper crust that was preserved or little modified; at the southeast end of the profile the Vp/Vs ratio is less than 1.70, indicating felsic crust, probably related to the Neoproterozoic-Cambrian granite genesis identified in surface. The lower crust shows values of Vp/Vs in general larger than 1.80, but with different meanings along the profile: in the northwest portion, the high values of Vp/Vs are associated with the mafic intrusions, also identified in the upper crust; in the central domain, with the mafic underplate suggested by the P modeling; and in the southeast portion, the Vp/Vs of 1.80 is associated with low P wave velocity (6.48 – 6.65 km/s) suggesting the presence of interstitial fluids. The lithospheric mantle presents two distinct domains characterized by high Vp (8.3 km/s) and Vp/Vs ratio of 1.80 under the basin and low Vp and Vp/Vs ratio of 1.70 outside the basin, close to the coast. It means a denser and more robust mantle under the basin than outside of it. In general, the results suggest that the lithosphere under the profile was modified since the Neoproterozoic, first with the implantation of the Paraná Basin in the Paleozoic and later with the implantation of the South Atlantic Ocean in the Mesozoic.
metadata.dc.description.unidade:	Instituto de Geociências (IG)
Description:	Dissertação (mestrado) — Universidade de Brasília, Instituto de Geociências, Programa de Pós-Graduação em Geociências Aplicadas, 2018.
metadata.dc.description.ppg:	Programa de Pós-Graduação em Geociências Aplicadas e Geodinâmica
Licença::	A concessão da licença deste item refere-se ao termo de autorização impresso assinado pelo autor com as seguintes condições: Na qualidade de titular dos direitos de autor da publicação, autorizo a Universidade de Brasília e o IBICT a disponibilizar por meio dos sites www.bce.unb.br, www.ibict.br, http://hercules.vtls.com/cgi-bin/ndltd/chameleon?lng=pt&skin=ndltd sem ressarcimento dos direitos autorais, de acordo com a Lei nº 9610/98, o texto integral da obra disponibilizada, conforme permissões assinaladas, para fins de leitura, impressão e/ou download, a título de divulgação da produção científica brasileira, a partir desta data.
Collection(s) :	Teses, dissertações e produtos pós-doutorado

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