Structure of the crust and upper mantle beneath the Parnaíba Basin, Brazil, from wide-angle reflection–refraction data

Soares, Joelson Lima; Stephenson, Randell; Fuck, Reinhardt A.; Lima, Marcus Vinicius Aparecido Gomes de; Araújo, Vitto César Miranda de; Lima, Flávio T.; Rocha, Fábio A S; Trindade, C.

doi:10.1144/sp472.9

Cited by 17 publications

(17 citation statements)

References 23 publications

(34 reference statements)

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“…Both basins had very similar evolution with the first subsidence stage in the Paleozoic, and both had a significant magmatic event in the Mesozoic, producing large volumes of flood basalts. This difference in crustal thickness may be compensated by differences in the upper mantle, such as a thick lithospheric lid beneath the Paraná Basin with high velocities (Feng et al, ; Schaeffer & Lebedev, ; Rocha et al, ) and high density (Chaves et al, ), whereas beneath the Parnaíba Basin high Pn velocities were found only along a small 400‐ to 500‐km section in its center (Soares et al, ). This may imply that the cratonic block beneath the Parnaíba Basin is smaller and thinner compared with that of the Paraná Basin in the south.…”

Section: Resultsmentioning

confidence: 99%

“…Besides the data analyzed in this study, other published results were included such as (a) the Moho models from active experiments in the Parnaíba Basin, northern Brazil (Daly et al, 2014;Soares et al, 2018), and the continental shelf in southern Brazil (Evain et al, 2015), (b) crustal thicknesses from RF studies in the Parnaíba Basin and Boborema Province (Coelho et al, 2018;Julià et al, 2018;Trindade et al, 2014), and (c) new RF results from the Andes in Bolivia, Peru, and Colombia (Condori et al, 2017;Poveda et al, 2015;Ryan et al, 2016). Stations with good results from Albuquerque et al (2017) in the Amazon region were also included.…”

Section: Updated Crustal Thickness Map Of South Americamentioning

confidence: 99%

“…More details can be found in Bianchi et al (2018). The publications used to compile recent results from the literature, since the previous compilation of 2013, are from Argentina (Ammirati et al, 2013;Perarnau et al, 2012), Brazil Assumpção et al, 2015;Berrocal et al, 2004;Coelho et al, 2018;Daly et al, 2014;Evain et al, 2015;Julià et al, 2018;Luz et al, 2015a;Luz et al, 2015b;Moreira, 2013;Soares et al, 2018;Trindade et al, 2014), Colombia (Monsalve et al, 2013;Poveda et al, 2015), Ecuador (Araujo, 2013;Font et al, 2013), Peru (Condori et al, 2017;James & Snoke, 1994;Ryan et al, 2016), and Patagonia (Buffoni et al, 2019;Rodríguez & Russo, 2016) and can be found in the supporting information. The database is available in the Zenodo platform (https://doi.org/10.5281/zenodo.2604359).…”

Section: Data and Resourcesmentioning

confidence: 99%

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An Updated Crustal Thickness Map of Central South America Based on Receiver Function Measurements in the Region of the Chaco, Pantanal, and Paraná Basins, Southwestern Brazil

et al. 2019

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Previous compilation of crustal structure in South America had large unsampled areas including the thin crust in the Sub‐Andean lowlands, largely estimated by gravity data, and the sparsely sampled Amazon Craton. A deployment of 35 seismic stations in Brazil, Bolivia, Paraguay, Argentina, and Uruguay improved the coverage of the Pantanal Basin in Western Brazil, the intracratonic Paraná and the Chaco Basins. Crustal thicknesses and Vp/Vs ratios were estimated with a modified H‐k method by producing three stacked traces to enhance the three Moho conversions (the direct Ps and the two multiples Ppps and Ppss). This modified method gives lower uncertainties than previous studies and shows more regional consistency between nearby stations. The temporary stations and the Brazilian Network (RSBR) have characterized the crustal structure as follows. The Paraná Basin has a thick crust 40–45 km and average Vp/Vs ratio (1.71–1.77), while the Chaco Basin has a slightly thinner crust (35–40 km) and higher Vp/Vs ratio (1.75–1.79). This confirms the lack of widespread magmatic underplating in the Paraná Basin that could be related to the origin of the flood basalts during the South Atlantic opening. A belt of thin crust (30–35 km) with low Vp/Vs (<1.74) is confined to the eastern edge of the Pantanal Basin. Normal crust (38–43 km) is observed along the western edge of the Pantanal, from the southern part of the Amazon craton to the Rio Apa cratonic block. This study, combined with other published data, provides an updated crustal thickness map of South America.

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Section: Resultsmentioning

confidence: 99%

Section: Updated Crustal Thickness Map Of South Americamentioning

confidence: 99%

Section: Data and Resourcesmentioning

confidence: 99%

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An Updated Crustal Thickness Map of Central South America Based on Receiver Function Measurements in the Region of the Chaco, Pantanal, and Paraná Basins, Southwestern Brazil

et al. 2019

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“…The geophysical experiments discussed below build on the data from this deep seismic reflection profile. Soares et al (2018) discuss the results of the wide-angle refraction-reflection (WARR) experiment conducted from east to west across the middle of the Parnaíba Basin, approximately along the same route as the deep seismic reflection profile of Daly et al (2014) (Fig. 2).…”

Section: Lithospheric and Crustal Structure Of The Parnaíba Cratonic mentioning

confidence: 99%

Cratonic basin formation: a case study of the Parnaíba Basin of Brazil

Daly

Fuck

Julià

et al. 2018

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Cratonic basins comprise a significant component of the Earth's continental crust and surface geology. Their subcircular form and large areas of flat-lying, largely undeformed sedimentary rocks characterize the central regions of many continents, and are also a significant habitat for water, mineral and petroleum resources. These basinal regions have been extensively studied, yet there is little consensus on the driving mechanism of their subsidence or their greater tectonic context. Here we present the results of an integrated basin analysis of the Paleozoic-Early Mesozoic Parnaíba cratonic basin of NE Brazil. The analysis integrates existing geological and geophysical data, and a new deep-crustal geophysical dataset, to determine the deep structure of the basin and the underlying crust and mantle. Several major features have emerged from this which constrain the basins genesis: (1) continental-shallow-marine stratigraphy characterized by an exponentially decreasing tectonic subsidence with a relatively long time constant of the order of 70-90 myr; (2) a complex Proterozoic-Early Paleozoic basement that comprises at least three major crustal blocks defined by seismic facies and conductivity contrasts with no evidence of an extensive rift system beneath the basin; (3) a mid-crustal fabric that appears to define the top of a dense and seismically fast lower crust (V p 6.7-6.8 km s −1 and V s 3.7-3.8 km s −1) and upper mantle (V p 8.2-8.4 km s −1) directly beneath the basin, and which correlates with a sediment-corrected Bouger gravity anomaly high of +40-60 mGal; (4) a Moho that is generally as deep or deeper beneath the basin (40-45 km) than its surrounding region (34-40 km), and which appears stepped at the terrane boundaries; (5) a relatively conductive crust and upper mantle beneath the basin, and relatively resistive crust along the boundaries of the basement blocks; and (6) igneous events immediately before and after formation of the cratonic megasequence and a geochemically enriched mantle beneath the basin that sourced two major episodes of Mesozoic igneous intrusions. These latter events are responsible for the development of an atypical gas-prone petroleum system dependent on local magmatic events for heat generation and trapping configurations. The data describing these features are presented and discussed, and their implications used to draw conclusions about the formation of the Parnaíba Basin specifically and cratonic basins more generally. Cratonic basins are large, isolated, basinal areas developed exclusively on continental lithosphere (Fig. 1). They occupy a little over 10% of today's exposed continental crust and are characterized by large areas of mostly undeformed, flat-lying sedimentary rocks. Several features are universal in the categorization of a cratonic basin, notably: development upon thickened lithosphere (>150 km) (McKenzie & Priestley 2016); a subcircular to equant outline; a pronounced basal unconformity of the cratonic megasequence (Daly et al. 2014); a long-lived stratigraphic me...

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“…The origin of the Parnaíba basin is also under debate. Recent research with seismic (Coelho et al, ; Soares et al, ) and gravity (Tozer et al, ) data indicates that the main subsidence mechanism could be flexural, which contrasts with the prevalent view that invoked mechanical stretching of the lithosphere (De Castro et al, , ). Similarly, the Amazon basin is also debated to have formed in relation to a failed rift concealed under the basin's sediments (De Castro et al, ) or to flexural subsidence and lithospheric relaxation due to a dense body in the basin's underlying lower crust (Nunn & Aires, ).…”

Section: Introductionmentioning

confidence: 96%

Joint Inversion of Receiver Functions and Surface‐Wave Dispersion in the Pantanal Wetlands: Implications for Basin Formation

2020

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The origin and evolution of the Pantanal basin have been investigated through velocity‐depth profiles developed from the joint inversion of receiver functions and surface‐wave dispersion velocities at 33 broadband stations. The Pantanal basin is a shallow and wide depression in South‐Central Brazil that developed within the Andean foreland in response to loads and flexural bending of the South American plate. Our results reveal the existence of up to four different crustal types that correlate with surface geology: (i) crust of 35 km with VS < 4.0 km/s, under the basin and along the SW projection of the Transbrasiliano lineament (TBL); (ii) crust of 45 km with VS > 4.0 km/s below 40 km depth, flanking the basin to the east and west; (iii) crust of 50–55 km with VS > 4.0 km/s below 40 km depth, flanking the basin to the north and south and along the TBL; and (iv) crust of 42.5–45.0 km with VS < 4.0 km/s in the neighboring Paraná basin. Existing geodynamic models propose that the Pantanal basin formed either in the back‐bulge of the flexural system or at the top of the forebulge, due to extensional bending stresses that reactivated preexisting faults in the shallow upper crust. We argue that the Pantanal basin was formed in a structurally weaker portion of the foreland crust that was affected by delamination and enhanced bending of the South American plate. Our findings do not allow for discrimination among the competing models but suggest that the TBL was critical in marking the location, origin, and evolution of this basin.

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Structure of the crust and upper mantle beneath the Parnaíba Basin, Brazil, from wide-angle reflection–refraction data

Cited by 17 publications

References 23 publications

An Updated Crustal Thickness Map of Central South America Based on Receiver Function Measurements in the Region of the Chaco, Pantanal, and Paraná Basins, Southwestern Brazil

An Updated Crustal Thickness Map of Central South America Based on Receiver Function Measurements in the Region of the Chaco, Pantanal, and Paraná Basins, Southwestern Brazil

Cratonic basin formation: a case study of the Parnaíba Basin of Brazil

Joint Inversion of Receiver Functions and Surface‐Wave Dispersion in the Pantanal Wetlands: Implications for Basin Formation

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