The tectonic evolution of Cenozoic extensional basins, northeast Brazil: Geochronological constraints from continental basalt 40Ar/39Ar ages

Spatial and temporal uplift history of South America from calibrated drainage analysis

“…Volcanic necks, plugs, and basaltic flows of the Macau‐Queimadas alignment have ages of 93–6.4 Ma. K‐Ar whole rock and 40 Ar/ 39 Ar dates suggest that two phases of magmatism occurred [ Misuzaki et al ., ; Souza et al ., ; Knesel et al ., ]. The first phase coincides with the Cuó volcanic episode that is restricted to the southern portion of the onshore Potiguar Basin with a peak age of Ma.…”

“…Green circles = loci of apatite fission track analyses [ Morais Neto et al ., ]; yellow/orange/red diamonds/circles = dated volcanic rocks (diamonds = 40 Ar/ 39 Ar ages from Souza et al . []; Nascimento et al . []; Knesel et al .…”

“…89 Ma) subaerial unconformity occurs at the top of the Janda ıra Formation carbonate platform [Gil, 1997]. Second, the Miocene Neto et al, 2009]; yellow/orange/ red diamonds/circles 5 dated volcanic rocks (diamonds 5 40 Ar/ 39 Ar ages from Souza et al [2003Souza et al [ , 2013; Nascimento et al [2003]; Knesel et al [2011]; circles 5 K-Ar ages from Misuzaki et al [2002]); white circles 5 loci of nodes; dark blue polygons 5 Santana Formation. (c) Black line with gray band 5 average predicted uplift rate history with 61r for nodes shown in Figure 8a where dashed lines show changes obtained by covarying v and m within ranges 5 v 18 and 0:325 m 0:375; histogram 5 magmatic samples (red bars 5 40 Ar/ 39 Ar ages, black bars 5 K-Ar ages); solid circles with horizontal error bars 5 timings of exhumation events from thermochronologic studies; green arrow 5 start of increased clastic input into offshore basins (Potiguar, Pernambuco and Sergipe-Alagoas Basins) C ordoba et al, 2007;Campos Neto et al, 2007]; (d) Black line with gray band 5 average predicted cumulative uplift history for node shown in Figure 8a Geochemistry, Geophysics, Geosystems 10.1002/2017GC006909 denudation event coincides with a transition from carbonate ramp to progradational clastic deposition observed in sedimentary basins along both the eastern (Pernambuco, Para ıba, Sergipe-Alagoas) [C ordoba et al, 2007;Campos Neto et al, 2007] and equatorial (offshore Potiguar, Cear a) [Cond e et al, 2007;Pessoa Neto et al, 2007] margins.…”

Contemporaneous intraplate magmatism on conjugate South Atlantic margins: A hotspot conundrum

“…The two provinces comprise suites of volcanic and plutonic igneous rocks that span the ocean-continent boundary, show no linear age progression and have experienced prolonged magmatic activity (Fitton, 1987;Knesel et al, 2011;Njome and de Wit, 2014;Perlingeiro et al, 2013;Silveira, 2006;Souza et al, 2013). The two areas were adjacent to one another before continental separation at ~105 Ma (Rabinowitz and LaBrecque, 1979).…”

“…CL magmatism started at about 65 Ma (Njome and de Wit, 2014), ~40 Myr after continental break-up, and continues to the present day with the active Mount Cameroon. NEB was magmatically active between ~52 and ~1 Ma and has surprisingly few plutonic rocks exposed at the surface (Silveira, 2006;Knesel et al, 2011;Perlingeiro et al, 2013;Souza et al, 2013). There are no other volumetrically comparable continental occurrences of Cenozoic volcanism along the entire Atlantic conjugate margins of South America and Africa.…”