Tomografia sísmica com ondas P e S para o estudo do manto superior no Brasil

Rocha, Marcelo Peres

doi:10.11606/t.14.2008.tde-29092008-212459

Cited by 3 publications

(3 citation statements)

References 59 publications

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“…The SCLM type of lithosphere has high seismic wave velocities mapped under continents. There are several available published maps and depth slices of seismic velocity anomaly tomography for the Brazilian Eastern margin (Assumpção et al, 2017;Rocha, 2008;Rocha et al, 2011. The latest 100 km deep slice prepared from data from Rocha et al ( 2019) was used to produce Figure 4 and is used as the image of the seismic lithosphere.…”

Section: R a F Tmentioning

confidence: 99%

Defining Lithospheric Limits with Deep Sourced Geophysics: The Case of São Francisco Craton and Borborema Province

Filho

Seoane

2022

Braz J Geophys

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The East Brazilian Shield is a product of the Neoproterozoic convergence and collage of rigid Archean lithospheric blocks, which stabilized at the end of the Paleoproterozoic Trans-Amazonian event (2.0 Ga). The areal extent of the São Francisco Craton is well understood by regional gravimetric surveys, but its northern limit with the Borborema Province is not so clear. The integration of gravity, magnetics and seismic velocity anomaly maps allows mapping this northern limit to the Borborema Province. Applying the vertical integration low-pass filter to satellite magnetics yields a remarkable match to the probable lithospheric suture zone. This magnetic map identifies the deep response from thinner/thicker lithospheres of Neoproterozoic mobile belts or stable cratons. One potential microcraton is the NE extension of the Borborema Province, one site of the oldest rocks in South America, a residue of the Benino-Nigerian Craton, separated from the main occurrence by the opening of the Atlantic. The Sergipana, Riacho do Pontal and Rio Preto Neoproterozoic fold-and-thrust belts mark areas of the foreland tectonism, hundreds of kilometers inside the São Francisco Craton lithospheric block. The presence of younger rocks inside the deep geophysical limits may be evidence of a large detachment of younger continental crust over the old cratonic lithosphere.

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Section: R a F Tmentioning

confidence: 99%

Defining Lithospheric Limits with Deep Sourced Geophysics: The Case of São Francisco Craton and Borborema Province

Filho

Seoane

2022

Braz J Geophys

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“…Com o mapa de primeira derivada vertical da continuação para cima à altura de 100 km (Fig. 6.8b) (Feng et al, 2007;Rocha, 2008). (a) mapa de anomalias Bouguer continuado para cima para a altura de 100 km; (b) derivada vertical do mapa do item (a); resultados tomográficos de Feng et al (2007) para onda S, profundidade de 100 km (c) e 150 km (d); resultados tomográficos de Rocha (2008) para onda P para profundidade de 150 km.…”

Section: Aproximação Do Regional Por Uma Superfície Polinomialunclassified

“…al. (1993 Quadro comparativo entre os resultados obtidos nesta tese e de tomografia sísmica (Feng et al, 2007;Rocha, 2008 No capítulo 5, discute-se a relação entre anomalia gravimétrica regional e residual, com a tentativa de obter-se o campo gravimétrico regional a partir de dados sismológicos do método da função do receptor utilizando o algoritmo de Parker (1973). É apresentado também o campo gravimétrico regional obtido a partir do ajuste polinomial e da continuação para cima.…”

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Interpretação de dados gravimétricos e eletromagnéticos do sul do cráton São Francisco: novos modelos crustais e litosféricos

Pinto¹

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Interpretação de dados gravimétricos e eletromagnéticos do sul do cráton São Francisco: novos modelos crustais e litosféricos ABSTRACT PINTO, L. G. R., 2009. Interpretação de dados gravimétricos do sul do cráton São Francisco: novos modelos crustais e litosféricos. Thesis (Doctor) -Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo, São Paulo. 145pp.This thesis comprises of two parts in which two geophysical studies are described improving the knowledge of the lithosphere of the south São Francisco craton. In the first part, we propose an alternative method for defining the limits of lithosphere plate using gravity data. We used the first vertical derivative of Bouguer anomaly upwarded to 100 km height. Crustal results along a deep refraction seismic profile in the Goiás state together with a 2-D gravity model along a profile between Minas Gerais and São Paulo states were used to calibrate the vertical derivative results. Recent geochemical, petrological data and seismic topography data reinforce the gravity results that the southern and western parts of the São Francisco plate extends under parts the Brasília Belt and parts of the Paraná basin. In the second part, the interpretation of a positive Bouguer gravity anomaly, circular shaped and + 25 mGal amplitude gravity anomaly is presented. This gravity anomaly coincides with a positive, circular shaped, 7 m amplitude geoid anomaly with 250 km of radius. Receiver function results do not show a crustal thinning, excluding this possibility as the cause of gravity high. Deep magnetotelluric soundings along two profiles radial to gravity anomaly indicate a region in the mantle with lower electrical resistivity (< 100 Ω.m) from the depth of 200 km and extending upward and reaching the lower crust. The residual Bouguer anomalies are inverted using a 3-D algorithm and indicate that the denser lower crust reaches 12 km of thickness for + 50 kg/m 3 of density contrast. Coincident with a denser lower crust, magnetotelluric soundings reveal a low electrical resistivity crust, reinforcing the presence of magmatic underplating. At the surface, the contamination of magmatic material in the lower crust is supported by the presence of basaltic tholeiitic dike swarms similar, in composition, to the basalts of northern Paraná basin (high TiO 2 ) of Early Cretaceous age. Tholeiitic dikes swarms are distributed throughout the southern region of the craton. Lithospheric mantle with lower electrical resistivity reaches 200 km of depth, indicating that the lithospheric

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Assinatura Geofísica dos Complexos Alcalinos Fazenda Buriti e Arenópolis, porção norte da Província Alcalina de Goiás

Feitoza

Carmelo

Huelsen

et al. 2011

12th International Congress of the Brazilian Geophysical Society &Amp; EXPOGEF, Rio De Janeiro, Brazil, 15–18 August 2011

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Tomografia sísmica com ondas P e S para o estudo do manto superior no Brasil

Cited by 3 publications

References 59 publications

Defining Lithospheric Limits with Deep Sourced Geophysics: The Case of São Francisco Craton and Borborema Province

Defining Lithospheric Limits with Deep Sourced Geophysics: The Case of São Francisco Craton and Borborema Province

Interpretação de dados gravimétricos e eletromagnéticos do sul do cráton São Francisco: novos modelos crustais e litosféricos

Assinatura Geofísica dos Complexos Alcalinos Fazenda Buriti e Arenópolis, porção norte da Província Alcalina de Goiás

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