Sondagens magnetotelúricas transversais à Bacia de Taubaté

Brito, Paula M. A.

doi:10.1590/s0102-261x1999000200020

Cited by 2 publications

(3 citation statements)

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“…It comprises the following layers: 1. the upper and lower crust are represented by blocks of 10,000 ohm.m, as observed in the 2D inversion of Brito's (1998) study; 2. a thin layer of 20 m and resistivity of 30 ohm.m (not shown in Fig. 8) is included at the top of the upper crustal resistivity block to account for the weathered overburden, as defined from AMT studies (Padilha and Vitorello, 1992); 3. an enhanced conductivity in the crust detected in Brito's (1998) study is represented by a layer of 20 S (thickness of 2 km and resistivity of 100 ohm.m) at a depth of 10 km. The geoelectrical structure for the oceanward part was derived from available bathymetry and geological/geophysical data for the Santos Basin published by PETROBRAS's (Petróleo Brasileiro S.A.) researchers (e.g., Macedo, 1989;Pereira and Feijó, 1994).…”

Section: Ocean Effectsmentioning

confidence: 53%

“…8). The landward conductivity structure is a simplified version of the geoelectrical model derived by Brito (1998) for the same profile across the Taubaté Basin, but without considering the ocean effect. It comprises the following layers: 1. the upper and lower crust are represented by blocks of 10,000 ohm.m, as observed in the 2D inversion of Brito's (1998) study; 2. a thin layer of 20 m and resistivity of 30 ohm.m (not shown in Fig.…”

Section: Ocean Effectsmentioning

confidence: 99%

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Magnetotelluric soundings across the Taubaté Basin, Southeast Brazil

2014

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Thirteen magnetotelluric (MT) soundings were carried out in Neoproterozoic crystalline terrains and Tertiary sediments of the Taubaté basin, southeastern Brazil. The soundings were deployed in a cross-strike profile bisecting the basin along one of its thickest sub-basins and extending over mountain plateaus to the southeast and the northwest. Occurrences of numerous alkaline plugs and aligned tectonic grabens in the region are records of intense Mesozoic-Cenozoic tectonic activity. MT analysis techniques were used to evaluate data quality, infer strike direction, and correct for near-surface distortion. As the studied area is located only some tens of kilometers away from the Atlantic Ocean and in one of the most densely populated regions of the country, the data are severely distorted by industrial interference and the coast effect. Because of such effects, the data are modelled using a 2D inversion scheme within periods shorter than 0.1 s for the Taubaté Basin sites and shorter than 1-10 s for the offbasin sites, the latter depending on the distance of the site from the coast. The main result observed in the modelling is the identification of a conducting zone below 10 km depths beneath the region. There is poor resolution in the data of structures below this conductor, which is also not imaged beneath the basin. Studies carried out in different tectonic regions of the world have also reported conductive layers at about the same depth but in the studied area it is impossible to reach any conclusion about the total conductance of the layer with the available MT data.

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Section: Ocean Effectsmentioning

confidence: 53%

Section: Ocean Effectsmentioning

confidence: 99%

Magnetotelluric soundings across the Taubaté Basin, Southeast Brazil

2014

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“…As sondagens MT discutidas neste trabalho permitiram mapear em subsuperfície as unidades geológicas até uma profundidade de aproximadamente 8 km, onde se verifica o topo de um condutor que tende a superfície em ambos os extremos do perfil em estudo. Brito (1999) menciona que devido à característica de propagação difusa dos sinais eletromagnéticos no interior da Terra, o número finito de sondagens disponíveis e a presença de ruído afetando as medidas, o estudo MT por si só não consegue definir de forma absoluta da profundidade e as espessuras das estruturas em subsuperfície. Além disso o poder de resolução do método decresce com a profundidade.…”

Section: Interpretações E Conclusõesunclassified

Investigação Magnetotelúrica em um Perfil entre Belo Horizonte (MG) e Vitória (ES), Brasil / Magnetotelluric Investigation in a Profile between Belo Horizonte (MG) and Vitória (ES), Brazil

Dias¹

2021

Braz. Ap. Sci. Rev.

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O método magnetotelúrico (MT) é um método geofísico utilizado para a compreensão das características geológicas superficiais e profundas da Terra, dentre outras aplicações. O MT foi utilizado na faixa de freqüência de 0.01 e 100 Hz, com 15 estações ao longo de um perfil de 172 km entre os Estados de Minas Gerais e Espírito Santo. As medidas ao longo do perfil são localizadas sobre terrenos Pré-Cambrianos relacionados a Faixa Ribeira. Os dados foram interpretados através de modelos de inversão unidimensionais (1D) e bidimensionais (2D), sendo o modelo 1D utilizado somente para a correção do static shift. O modelo geoelétrico 2D resultante da inversão 2D de subsuperfície apresenta uma boa correlação com a geologia superficial. O condutor crustal observado em várias partes do mundo, inclusive no sudeste do Brasil, também é verificado no perfil em estudo. Entretanto, diferentemente dos condutores crustais observados, apresenta uma variação na profundidade de seu topo que vai aproximadamente de 3 até10 km. Sua parte mais rasa foi observada no extremo oeste do perfil, o qual pode estar associada a uma descontinuidade denominada de Abre Campo.

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Sondagens magnetotelúricas transversais à Bacia de Taubaté

Cited by 2 publications

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Magnetotelluric soundings across the Taubaté Basin, Southeast Brazil

Magnetotelluric soundings across the Taubaté Basin, Southeast Brazil

Investigação Magnetotelúrica em um Perfil entre Belo Horizonte (MG) e Vitória (ES), Brasil / Magnetotelluric Investigation in a Profile between Belo Horizonte (MG) and Vitória (ES), Brazil

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