The study of the crust using receiver functions can provide valuable geological information, such as average crustal composition, its formation dynamics and the tectonic evolution of a region, as well as serve as an initial reference for the generation of seismic wave velocity models to improve earthquake location. To fill in gaps in information on the crust of the Amazonian Craton and adjacent provinces in Brazil, we used receiver functions and H-k stacking to estimate crustal thicknesses and the VP/VS ratios. The results indicate that the crust of the study region is predominantly felsic, with an average VP/VS around 1.73 and an average thickness of 38.2 km, with a range of 27.4–48.6 km. Minimum curvature interpolation of the crustal thickness values has made it possible to delimitate of the Amazonian Craton, which corresponds to the area with an average thickness equal to or greater than 39 km. In addition, it was possible to identify its potential cratonic blocks, as well as the Paranapanema Block of Paraná Basin. The geometry of the craton, defined by its crustal thickness, is corroborated by the distribution of natural seismicity that accompanies its edges. These are related to suture zones between the Amazonian, São Francisco/Congo and Paranapanema paleocontinents. The sedimentary basins that have undergone rifting processes have a thinner crust, usually less than 37 km thick. Due to the great variability of the results, it was not possible to determine a characteristic value of crustal thickness or VP/VS ratio for each structural province located in the study region.
Bibliographical noteFunding Information:
DFA thanks CAPES for supporting this research (G.N. 1477700 ). We thank the Seismological Observatory at the University of Brasília, and the Brazilian Seismographic Network (RSBR) for providing the seismological data. We also thank all the station operators, especially Paulo Araújo de Azevedo, and those who provided computing support, especially Fernando Paiva. GSF thanks for his PQ grant ( 307251/2016-0 ) and this research received support by MCTI/CNPq-Universal “Tectonics studies in the Parecis Basin” 456560/2014-9 .
© 2017 Elsevier Ltd
- Amazonian Craton
- Crustal thickness
- Receiver function
- V/V ratio