Crust and upper mantle structure in central Brazil derived by receiver functions and SKS splitting analysis

Rosa, João; Rosa, José Wilson Corrêa; Fuck, Reinhardt A.

doi:10.1016/j.jsames.2011.09.001

Cited by 10 publications

(4 citation statements)

References 47 publications

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“…Analyzing cratonic basins in North America and West Siberia, Armitage and Allen (2010) noted that the slow extension of relatively thick continental lithosphere causes permanent, long-lived thermal subsidence in cratonic basins. In fact, a 40 km thick crust, derived from receiver functions by Rosa et al (2012) and 3-D gravity inversion , occurs in the western part of the Parnaíba basin, where the sag deposits are thicker and the thermal subsidence lasted for a longer time (2BAC curve in Fig. 11).…”

Section: Subsidence Evolutionmentioning

confidence: 99%

Geophysical evidence of pre-sag rifting and post-rifting fault reactivation in the Parnaíba basin, Brazil

et al. 2016

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Abstract. This study investigated the rifting mechanism that preceded the prolonged subsidence of the Paleozoic Parnaíba basin in Brazil and shed light on the tectonic evolution of this large cratonic basin in the South American platform. From the analysis of aeromagnetic, aerogravity, seismic reflection and borehole data, we concluded the following: (1) large pseudo-gravity and gravity lows mimic graben structures but are associated with linear supracrustal strips in the basement.(2) Seismic data indicate that 120-200 km wide and up to 300 km long rift zones occur in other parts of the basins. These rift zones mark the early stage of the 3.5 km thick sag basin. (3) The rifting phase occurred in the early Paleozoic and had a subsidence rate of 47 m Myr −1 . (4) This rifting phase was followed by a long period of sag basin subsidence at a rate of 9.5 m Myr −1 between the Silurian and the late Cretaceous, during which rift faults propagated and influenced deposition. These data interpretations support the following succession of events: (1) after the Brasiliano orogeny (740-580 Ma), brittle reactivation of ductile basement shear zones led to normal and dextral oblique-slip faulting concentrated along the Transbrasiliano Lineament, a continentalscale shear zone that marks the boundary between basement crustal blocks. (2) The post-orogenic tectonic brittle reactivation of the ductile basement shear zones led to normal faulting associated with dextral oblique-slip crustal extension. In the west, pure-shear extension induced the formation of rift zones that crosscut metamorphic foliations and shear zones within the Parnaíba block. (3) The rift faults experienced multiple reactivation phases. (4) Similar processes may have occurred in coeval basins in the Laurentia and Central African blocks of Gondwana.

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Section: Subsidence Evolutionmentioning

confidence: 99%

Geophysical evidence of pre-sag rifting and post-rifting fault reactivation in the Parnaíba basin, Brazil

et al. 2016

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“…We compiled crustal thickness estimates from all recently published receiver function studies including stations in South America, especially those from the Brazilian Lithosphere Seismic Project (BLSP) in Brazil (Bianchi, 2008;Julià et al, 2008;Lloyd et al, 2010). Crustal thickness estimates from other stations in central and northern Brazil were also compiled from Krüger et al (2002), Rosa et al (2012), Albuquerque et al (2011) and unpublished monographs such as Pedreschi (1989) and Costa (2005). The compiled studies report both crustal thickness (H) and Vp/Vs ratio (k) estimated with different techniques, such as the Hek stacking procedure of Zhu and Kanamori (2000), the waveform matching technique of Meijde et al (2003) and Lloyd et al (2010), the phase- (2004) and Assumpção et al (2004), and the joint inversion of receiver functions and surface-wave dispersion velocities of Julià et al (2000Julià et al ( , 2003.…”

Section: Receiver Functionsmentioning

confidence: 99%

Crustal thickness map of Brazil: Data compilation and main features

Assumpção

Bianchi

Julià

et al. 2013

Journal of South American Earth Sciences

116

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“…SKS measurements are from Becker et al [2012] and updates of the Wüstefeld et al [2009] database, as of September 2014. Individual studies include the following: Abt et al [2010],Assumpção et al [2006Assumpção et al [ , 2011,Barruol et al [1997],Barruol and Hoffmann [1999],Bock et al [1998],Fontaine et al [2005],Growdon et al [2009], Heintz et al [2003,Helffrich et al [1994],Helffrich et al [2002],James and Assumpção [1996], Silver, 1992, Krüger et al [2002],Masy et al [2011],Meade et al [1995],Murdie and Russo [1999],Piñero-Feliciangeli and Kendall, 2008, Polet et al [2000],Rosa et al [2012],…”

mentioning

confidence: 99%

Seismic anisotropy and slab dynamics from SKS splitting recorded in Colombia

Porritt

Becker

Monsalve

2014

Geophysical Research Letters

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The Nazca, Caribbean, and South America plates meet in northwestern South America where the northern end of the Andean volcanic arc and Wadati-Benioff zone seismicity indicate ongoing subduction. However, the termination of Quaternary volcanism at~5.5°N and eastward offset in seismicity underneath Colombia suggest the presence of complex slab geometry. To help link geometry to dynamics, we analyze SKS splitting for 38 broadband stations of the Colombian national network. Measurements of fast polarization axes in western Colombia close to the trench show dominantly trench-perpendicular orientations. Orientations measured at stations in the back arc, farther to the east, however, abruptly change to roughly trench parallel anisotropy. This may indicate along-arc mantle flow, possibly related to the suggested "Caldas" slab tear, or a lithospheric signature, but smaller-scale variations in anisotropy remain to be explained. Our observations are atypical globally and challenge our understanding of the complexities of subduction zone seismic anisotropy.

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Crust and upper mantle structure in central Brazil derived by receiver functions and SKS splitting analysis

Cited by 10 publications

References 47 publications

Geophysical evidence of pre-sag rifting and post-rifting fault reactivation in the Parnaíba basin, Brazil

Geophysical evidence of pre-sag rifting and post-rifting fault reactivation in the Parnaíba basin, Brazil

Crustal thickness map of Brazil: Data compilation and main features

Seismic anisotropy and slab dynamics from SKS splitting recorded in Colombia

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