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We present a new P‐wave seismic tomographic model for the region of the Paraná Basin and surroundings using a multiple‐frequency approach, providing better resolution than previous regional studies. We processed a total of 62,692 cross‐correlation delays for P, PKIKP, PcP, and PP phases distributed among 1,081 events using six different central frequencies (0.03, 0.06, 0.13, 0.25, 0.50, and 1 Hz). We merged our data with a previous multiple‐frequency study of the Amazonian Craton to cover regions outside of the study area, obtaining a total of 75,187 cross‐correlation delays. The data used are from the stations of the Brazilian Seismographic Network, and mainly from a temporary network (XC network) installed exclusively to study the region. The basement of the Paraná Basin is represented as a NE‐SW trending P‐wave high‐velocity anomaly, extending from the northern limit of the basin to the southwestern border of Brazil, consistent with previous reports. The limit between this block and the São Francisco Craton is characterized by decreased amplitude of the P‐wave high‐velocity anomaly. Synthetic tests show that a narrow boundary between these two blocks displays the same behavior. At the southeastern portion of this anomaly, decreasing amplitude is consistent with the limit of the Luiz Alves Craton, which was also corroborated by synthetic tests. The northern portion of the Rio Apa Block agrees with a previous tomographic model, confirming that it does not extend under the Pantanal Basin, however, in our model this structure does not extend as far south.

The Posselândia Diorite intrudes Archean granite-greenstone terrains of the region of Hidrolina, Central Goiás, Brazil. U-Pb radiometric determinations in two fractions of zircon crystals from the diorite yield an age of 2,146 ±1.6 Ma, interpreted as the cristallization age of the intrusion. The lack of deformation in the intrusion demonstrates that condolidation of the granite-greenstone terrains in the Hidrolina-Pilar de Goiás-Crixás area took place before 2,146 Ma.

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The basaltic Mosquito and Sardinha formations in the Parnaíba Basin are related to the opening of the Atlantic Ocean at the Triassic–Jurassic boundary and in the early Cretaceous, respectively. The Mosquito Formation consists of tholeiitic flows with both high-Ti (>1.5 wt%) and low-Ti (<1.5 wt%) compositions and the petrogenetic characteristics of enriched mantle reservoirs. The Mosquito Formation basalts have an initial 87Sr/86Sr isotopic composition of 0.70296–0.70841 and a low Nd isotopic composition (0.512245–0.512677) associated with an enrichment in large ion lithophile and high field strength elements relative to primitive mantle compositions. The Sardinha Formation is composed of high-Ti and low-Ti tholeiitic dykes with subordinate alkali basalts. The Sardinha Formation rocks have trace element and isotopic features associated with enriched mantle end-members. The initial isotopic compositions range from 0.702859 to 0.706703 and 0.512184 to 0.512671 for 87Sr/86Sr and 143Nd/144Nd, respectively. The concentrations of large ion lithophile and high field strength elements are elevated relative to primitive mantle values. Although the Mosquito and Sardinha formations share some similarities, they can be differentiated by their unique petrographic characteristics and trace element concentrations. These differences allow the discrimination of the basaltic magmatism in the Parnaíba Basin and their association with large igneous provinces, such as the Central Atlantic Magmatic Province or the Paraná–Etendeka Magmatic Province.Supplementary material: Microprobe analyses for clinopyroxene (Table A1), plagioclase (Table A2) and olivine (Table A3) for the Mosquito and Sardinha formations, along with mixing calculation parameters for the geochemical model (Table A4) are available at: https://doi.org/10.6084/m9.figshare.c.3985437

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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