Caracterização sísmica e gravimétrica da litosfera sob a linha de refração sísmica profunda de Porangatu, Província Tocantins, Brasil Central

Ventura, Dhébora Batista Rosa; Soares, Joelson Lima; Fuck, Reinhardt A.; Caridade, Lucas da Costa Coutrim

doi:10.25249/0375-7536.2011411130140

Cited by 17 publications

(18 citation statements)

References 22 publications

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“…2.2b). This means that the craton's lithospheric mantle has higher P-and S-wave velocities (*2-3 % higher), but roughly the same density, or even slightly lower density as modeled by Koosah et al (2007) and Ventura et al (2011). This is consistent with a Fe-depleted composition for Archean cratons (e.g., Hawkesworth et al 1990;Durrheim and Mooney 1991;Artemieva 2009) and lower temperatures, which account for the buoyancy of the craton's root allowing stability over its entire evolution.…”

Section: Discussionsupporting

confidence: 65%

“…2.2b). Based on gravity modeling and a re-interpretation of Moho reflected phases, Ventura et al (2011) placed this transition *40 km to the east, beneath shot point 3. The Moho was modeled about 5 km deeper (*50 km instead of 45 km) based on receiver function analysis at a station near Porangatu.…”

Section: Gravity Modelingmentioning

confidence: 99%

“…2.2b), the differences in crustal thicknesses are smaller, less than 4 km. Ventura et al (2011) did not interpret the eastern section of the seismic experiment, so here we used the model of Soares et al (2006), which covers part of the SFC, as a basis to extrapolate the crustal structure beneath the central and eastern part of the craton. We extended the crustal seismic model of Soares et al (2006) across the SFC to estimate possible variations of crustal thickness as well as to see if the gravity data indicated any changes in upper mantle density.…”

Section: Gravity Modelingmentioning

confidence: 99%

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Lithospheric Features of the São Francisco Craton

Assumpção

Azevedo

Rocha

et al. 2016

São Francisco Craton, Eastern Brazil

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Studying the thick lithosphere of cratons is important to help understand their formation and the mechanisms for their preservation. We present a synthesis of the information available for the deep structure in Eastern Brazil, from seismological and gravity data, to characterize the São Francisco Craton (SFC) and help better define its lateral boundaries at depth. Crustal thicknesses of the SFC, known mainly from receiver function studies, range from 38 to 42 km, except for a localized thickening (up to 44 km) in the northern part, and crustal thinning towards the Atlantic continental margin in Bahia state. Overall, the crust is slightly thicker near the geologically-defined surface boundaries (40-42 km) and slightly thinner in the center (38-40 km), which is consistent with generally low Bouguer anomalies and high topography to the East and to the West of the craton probably defining the suture zones during the Gondwana amalgamation. Modeling of gravity anomalies with some seismic constraints indicates a relatively low-density lithospheric mantle for the SFC, despite higher Pn velocity, which is consistent with a Fe-depleted, buoyant lithosphere, which helps preserve the cratons's root. Surface-wave continental-scale tomography suggested the thickest lithosphere, around 200 km, to be in the Archean southern part of the SFC, consistent with regional P-and S-wave tomography. Both the surface-wave and the body-wave tomographies show high upper mantle velocities beneath the Brasilia fold belt, next to the SFC's surface limits, which is interpreted as a continuation at depth of the craton's lithosphere, beneath the low-grade external metamorphic domain of the Brasilia fold belt. Analysis of the SFC seismicity shows that most earthquakes now occur on shallow (<2 km) normal faults formed during the formation of the Brasiliano continental margin, now reactivated under the present E-W compressional stresses.

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Section: Discussionsupporting

confidence: 65%

Section: Gravity Modelingmentioning

confidence: 99%

Section: Gravity Modelingmentioning

confidence: 99%

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Lithospheric Features of the São Francisco Craton

Assumpção

Azevedo

Rocha

et al. 2016

São Francisco Craton, Eastern Brazil

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“…Gravimetric data reinterpretation coupled with newly acquired deep seismic refraction information (Assumpç ão et al, 2004;Berrocal et al, 2004;Soares et al, 2006;Perosi, 2006;Ventura et al, 2011) indicated an upwelling Moho boundary under the Goiás Magmatic Arc and the Crixás-Goiás and Campinorte domains. Additionally, CPRM (Brazil Geological Survey) magnetic surveys show the continuity of Hidrolina Complex low magnetic anomalies and Guarinos greenstone belt high magnetic anomalies into the Campinorte Domain, underneath the Serra da Mesa Group, which most likely represent covered lithologies/structures trending out of the Crixás-Goiás Domain.…”

Section: Comparison With Crixás-goiás Metasedimentary Rocksmentioning

confidence: 98%

The Paleoproterozoic Campinorte Arc: Tectonic evolution of a Central Brazil pre-Columbia orogeny

Cordeiro

Oliveira

Giustina

et al. 2014

Precambrian Research

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“…8 Soares et al (2006) and Ventura et al (2011) analyzed the partitioning of Precambrian crust of the Tocantins Province in the region indicated in Figures 1 and 2 (section S1) using deep seismic-refraction and gravity data. These authors proposed that crustal thickness increases westward from 36-38 km in the Goiás Magmatic Arc to 42-43 km in the Araguaia Belt.…”

Section: Accepted Manuscriptmentioning

confidence: 99%