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The São Francisco Paleocontinental Block (SFPB) represents part of the Congo-São Francisco Paleocontinent (CSFP), amalgamated around 2 Ga. In the Neoproterozoic, a branched continental rift system evolved to ocean basins around most edges of the SFPB that remained only partially linked to the Congo Paleocontinent by means of the Bahia-Gabon Continental Bridge. After the Brasiliano—Pan-African orogeny, two relatively preserved CSFP sectors formed the São Francisco and Congo cratons, surrounded by Neoproterozoic orogenic belts. Recent results of upper mantle P -wave seismic tomography allowed us to suggest a delimitation in lithospheric depths of the Neoproterozoic SFPB, which comprise the São Francisco Craton, and that this would have been connected with the Congo Paleocontinent along the Araçuaí Belt. It is characterized by high-velocity anomalies and its boundaries with other blocks are marked by low-velocity anomalies at lithospheric depths. We tested the resolution of the tomographic results through synthetic models obtained by a ray tracing scheme using the observed ray configuration. We observe that the lateral resolution is adequate, but the method used was not able to set the depth reached by the SFPB. Our results indicate that the SFPB area in lithospheric depths is larger than the surface area ascribed to the São Francisco craton, and thus, the SFPB basement deeply extends beneath neighboring orogenic regions, suggesting that these Neoproterozoic mobile belts, such as Araçuaí Orogen and the Brasilia Fold Belt, reworked the continental crust. We observe a low-velocity anomaly in the SFPB central region, corresponding to the Pirapora aulacogen. Our results have a good spatial correspondence with the low Bouguer anomalies used to define the SFPB in previous studies. The limits of the SFPB are consistent with deviation of the mantle flow, as suggested by SKS fast polarization. [ABSTRACT FROM AUTHOR]

New results of travel time seismic tomography in central Brazil provide evidence that the relatively high seismicity in this region is related to the thinner lithosphere at the limit between the Amazonian and São Francisco paleocontinents. The transition between these paleocontinents is marked by low velocity anomalies, spatially well correlated with the high seismicity region, which are interpreted as related to the lithospheric thinning and consequent rise of the asthenosphere, which have increased the temperature in this region. The low-velocity anomalies suggest a weakness region, favorable to the build-up of stress. The effective elastic thickness and the strain/stress regime for the study area are in agreement with tomographic results. A high-velocity trend is observed beneath the Parnaíba Basin, where low seismicity is observed, indicating the presence of a cratonic core. Our results support the idea that the intraplate seismicity in central Brazil is related to the thin lithosphere underlying parts of the Tocantins Province between the neighboring large cratonic blocks. [ABSTRACT FROM AUTHOR]

We present a P-wave structure for the sub-continental lithospheric mantle (SCLM) beneath the southern segment of the Amazonian Craton (Central Brazil Shield – CBS) using multiple-frequency tomography. Our model includes 469 seismic events recorded between 2009 and 2017 through 314 seismic stations distributed over South America. From these events, we obtained 20507 P and 12329 PKIKP cross-correlation delays in six frequency bands centered at 0.03, 0.06, 0.13, 0.25, 0.5 and 1 Hz. Despite the limited and heterogeneous resolution throughout the CBS, because of the difficulty in the installation of seismographic stations in areas of dense coverage of tropical forest, our tests show reasonable resolution for lithospheric domains with dimensions greater than 390 × 390 km in most of the study area. We recognized a good correlation between the P-wave anomalies and the tectonic domains defined previously based on geochronology and geological data. The surface projection of these anomalies and their margins are associated with clusters of important Au, Cu–Au and IOCG deposits, as well as diamond-bearing kimberlite intrusions, allowing relating deep structures with shallow features and showing a province-scale control in the distribution of mineral deposits and occurrences in the southern Amazonian craton. • Multiple-frequency seismic tomography in areas with low seismic stations coverage. • Relationship between deep structures and shallow features. • Correlation between P-wave anomalies and mineral deposits in the Amazonian Craton. [ABSTRACT FROM AUTHOR]