Rifting, erosion, and uplift history of the Recôncavo‐Tucano‐Jatobá Rift, northeast Brazil

Abstract

The Recôncavo‐Tucano‐Jatobá (RTJ) Rift and many other smaller sedimentary basins in northeast Brazil formed during South Atlantic rifting and were subsequently uplifted and exhumed so that Albian marine sediments are now located up to 800 m above sea level some 400 km inland from the Atlantic margin. Local erosion caused by footwall uplift and regional erosion, probably resulting from magmatic underplating and uplift, has removed a large part of the thermal sag phase sediments from the RTJ Rift. The flexural cantilever model, incorporating the flexural isostatic response to simple‐shear faulting in the upper crust and pure‐shear necking of the lower crust and upper mantle, can explain the main geometrical features observed in the RTJ Rift without resorting to lithosphere scale detachments. The model has also been used to estimate the amount of uplift and erosion of the faulted rift flanks. Rift flank erosion can produce uplift and erosion across the whole RTJ Rift, thus explaining the postrift unconformity which preceded deposition of the Aptian age Marizal Formation. The largest uplift is predicted to occur at the edges of the basin and may explain the anomalously shallow depth to onset of oil generation at the basin margins deduced from vitrinite reflectance data. The model also predicts that maximum burial of much of the basin fill in the RTJ Rift occurred at the end of rifting and not during the postrift infill, as is usually the case. The amount of observed coarse conglomeratic detritus in the Recôncavo subbasin suggests that about 25% of the eroded footwall detritus was deposited and preserved in the adjacent hanging wall half‐graben, with the rest being transported more distally as finer material.

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

“…9). In a few basins, such as the Araripe and TucanoJatobá basins, Paleozoic sedimentary units are intensively deformed, and this deformation has been attributed to Mesozoic rifting (Magnavita et al, 1994;Assine, 2007;Kuchle et al, 2011). However, early Paleozoic rifting episodes may also have affected these basins, which have been subjected to rifting in the Early Paleozoic and in the Jurassic-Cretaceous.…”

Ground Penetrating Radar investigation of depositional architecture: the São Sebastião and Marizal formations in the Cretaceous Tucano Basin (Northeastern Brazil)

“…The basin encompasses alluvial fan deposits (Salvador Formation), lacustrine deposits (Candeias Formation), deltaic deposits (Ilhas Group), and fluvial deposits (São Sebastião Formation) (Magnavita 1992, Magnavita et al 1994, Costa et al 2007a, 2007b, covered by the Marizal Formation, a thin succession of fluvial deposits with a record of marine incursion (e.g. Arai 2014, Amaral & Brito 2012, deposited during a late reactivation of the rift .…”

Fluid escape structures as possible indicators of past gas hydrate dissociation during the deposition of the Barremian sediments in the Recôncavo Basin, NE, Brazil

“…1A -Barbosa da Silva et al, 2007). Since the 1950's, oil and gas exploration, and development activities have raised a solid knowledge about its sedimentary records and the basin evolution, from the pre-rift to syn-rift and post-rift stages (Netto & Oliveira, 1985;Magnavita, 1992; Barbosa da Silva et al, 2007).…”

“…124 Ma -Barbosa da Silva et al, 2007), depicting an initial lacustrine setting, followed by deltaic and fluvial-deltaic deposition as the basin was filled. Basinal shales and deposits related to turbidites and mass gravity flows characterize the early rift lacustrine strata of both Candeias and Maracangalha formations (Netto & Oliveira, 1985;Magnavita, 1992).…”

“…124 Ma -Barbosa da Silva et al, 2007), depicting an initial lacustrine setting, followed by deltaic and fluvial-deltaic deposition as the basin was filled. Basinal shales and deposits related to turbidites and mass gravity flows characterize the early rift lacustrine strata of both Candeias and Maracangalha formations (Netto & Oliveira, 1985;Magnavita, 1992).Gravity flows triggered by earthquakes (Raja Gabaglia, 1991) are recorded by turbidite lobes and channel sandstones as well as slurry deposits, defining sequences of sandstones, sandy lutites and siltstones (Caixeta, 1988). The Caruaçu Member of the Maracangalha Formation is primarily composed of stratified and massive (slurry) turbidite sandstones.…”