Tectono‐stratigraphic evolution of the rift and post‐rift systems in the Northern Campos Basin, offshore Brazil

Strugale, Michael; Cartwright, Joe

doi:10.1111/bre.12674

Cited by 16 publications

(25 citation statements)

References 120 publications

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“…High‐resolution carbon isotope (δ 13 C) data from the eastern Brazilian margin were recently correlated with well‐calibrated Tethyan sections by Tedeschi et al (2019). These new correlations conclude that major evaporite deposition in the South Atlantic occurred in the early Aptian (124–125 Ma), suggesting the underlying pre‐salt sag sequence is approximately late Barremian and the deeper rift sequence is approximately Hauterivian–lower Barremian (Strugale & Cartwright, 2022—see their fig. 2).…”

Section: Geological Contextmentioning

confidence: 87%

“…The authors interpreted the base‐salt unconformity as a result of significant long‐term sub‐aerial exposure. Karner and Gamboa (2007) and Strugale and Cartwright (2022) also suggest that rift‐related normal faults were locally active during salt deposition in the Santos and Campos basin, respectively, offsetting the base of the salt and causing block uplift and erosion within basement lows.…”

Section: Discussionmentioning

confidence: 99%

“…In the West African basins, the authors estimated at least 500–650 m of erosion measuring canyon cutting and incisions in early‐mid Aptian clinoforms. Strugale and Cartwright (2022) documented base‐salt erosion in the hinge of fault‐propagation folds, footwall blocks and one basement low in the northern Campos Basin. The authors interpreted the base‐salt unconformity as a result of significant long‐term sub‐aerial exposure.…”

Section: Discussionmentioning

confidence: 99%

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The cryptic stratigraphic record of the syn‐ to post‐rift transition in the offshore Campos Basin, SE Brazil

do Amarante,

Kuchle,

Jackson

et al. 2023

Basin Research

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Rift basins typically comprise three main tectono‐stratigraphic stages; pre‐, syn‐ and post‐rift. The syn‐rift stage is often characterised by the deposition of asymmetric wedges of growth strata that record differential subsidence caused by active normal faulting. The subsequent post‐rift stage is defined by long‐wavelength subsidence driven by lithospheric cooling and is typified by the deposition of broadly tabular stratal packages that drape any rift‐related relief. The stratigraphic contact between syn‐ and post‐rift rocks is often thought to be represented by an erosional unconformity. However, the late syn‐rift to early post‐rift stratigraphic record is commonly far more complex since (i) the associated tectonic transition is not instantaneous; (ii) net subsidence may be punctuated by transient periods of uplift; and (iii) strain often migrates oceanward during rifting until continental breakup is achieved with crustal rupture. Previous publications on the Eastern Brazilian marginal basins have not historically used the tripartite scheme outlined above, with the post–pre‐rift interval instead being subdivided into rift, sag and passive margin tectono‐stratigraphic stages. In addition, the sag stage has been previously described as late syn‐rift, early post‐rift or as a transition between the two, with the passive margin stage being equivalent to the classically defined post‐rift, drift stage. Two (rather than one) erosional unconformities are also identified within the rift‐to‐sag succession. In this work, we use 2D and 3D seismic reflection and borehole data to discuss the expression of and controls on the syn‐ to post‐rift transition in the shallow and deep water domains of the south‐central Campos Basin, south‐east Brazil. We identified three seismic–stratigraphic sequences bounded by unconformities, named lower and upper pre‐salt and salt. The lower pre‐salt interval is characterised by wedge‐shaped packages of reflections that thicken towards graben and half‐graben‐bounding normal faults. This stage ends with the development of an angular unconformity, inferred to form as a result of the onset of the oceanward migration of deformation. The upper pre‐salt is typically defined by packages of subparallel and relatively continuous reflections that are broadly lenticular and thin towards fault‐bound basement highs, but that locally contain packages that thicken against faults. The pre‐salt to salt contact is defined by an erosional unconformity that is largely restricted to basement highs, and which is inferred to have formed due to base‐level fall and uplift associated with local fault reactivation, resulting in the formation of channels of possible fluvial origin. Based on its geometries and seismic facies, we conclude that the lower pre‐salt interval is syn‐rifting and syn‐tectonic, deposited during active continental extension and upper crustal faulting affecting the entire evolving margin, whereas the overlying upper pre‐salt is syn‐rifting and post‐tectonic in the Campos Basin, deposited when extension and faulting had migrated seaward to the future location of the spreading centre. The results of our study support the arising notion that the syn‐rift sequence does not only display syn‐tectonic sedimentary packages, and thus the tripartite tectono‐stratigraphic model for rift development is too simplistic and cannot be applied when assessing rifts in the context of the regional development of continental margins.

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Section: Geological Contextmentioning

confidence: 87%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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The cryptic stratigraphic record of the syn‐ to post‐rift transition in the offshore Campos Basin, SE Brazil

do Amarante,

Kuchle,

Jackson

et al. 2023

Basin Research

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“…The stratigraphy of the Campos Basin can be broadly divided into three tectonostratigraphic or megasequences (rift, sag, and passive margin), although it should be noted that this and the associated age constraints are widely debated (Figure 1b) (e.g. Tedeschi et al, 2019;Strugale and Cartwright, 2022;Szatmari et al,2021). The rift sequence initiated at c. 135 Ma with the intense volcanic activity that emplaced basaltic and volcanoclastic rocks of Cabiúnas Formation (Baksi, 2018).…”

Section: Geological Contextmentioning

confidence: 99%

The cryptic stratigraphic record of the syn- to post-rift transition in the offshore Campos Basin, SE Brazil

Amarante¹,

Küchle²,

Jackson³

et al. 2023

Preprint

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Rift basins typically comprise three main tectono-stratigraphic stages; pre-, syn-, and post-rift. The syn-rift stage is characterized by the deposition of asymmetric wedges of growth strata that record differential subsidence caused by active normal faulting. The subsequent post-rift stage is defined by long-wavelength subsidence driven by lithospheric cooling, and is typified by the deposition of broadly tabular stratal packages that drape any rift-related relief. The stratigraphic contact between syn- and post-rift rocks is often expressed as an erosional unconformity. However, the late syn-rift to early post-rift stratigraphic record is commonly far more complex since: (i) the associated tectonic transition is not instantaneous; (ii) net-subsidence may be punctuated by transient periods of uplift; and (iii) strain often migrates oceanward during rifting and continental breakup. The marginal basins of southeastern Brazil, including the Campos Basin, have not historically used the tripartite scheme outlined above, with the post-pre-rift interval instead being subdivided into rift, sag, and passive margin tectono-stratigraphic stages. The sag stage has been previously described as late syn-rift, early post-rift, or as a transition between the two, with the passive margin stage being equivalent to the classically defined post-rift stage. Two (rather than one) erosional unconformities are also identified within the rift-to-sag succession. We here use 2D and 3D seismic reflection and borehole data to discuss the expression of and controls on the syn- to post-rift transition in the south-central Campos Basin, offshore southeast Brazil. We mapped three intervals bounded by unconformities. The Barremian - lower Aptian interval is characterized by wedge-shaped packages of reflections that thicken towards graben and half-graben-bounding normal faults. This stage ends with a development of an angular unconformity, inferred to form during the onset of the oceanward migration of deformation. The upper Aptian interval is subdivided into two units; the pre-salt and salt. The pre-salt is typically defined by packages of subparallel and relatively continuous reflections that are broadly lenticular and thin towards fault-bound basement highs, but that locally diverge towards rift-related normal faults. The pre-salt to salt contact is defined by an erosional unconformity that is largely restricted to basement highs, and which is inferred to have formed due to base-level fall and uplift associated with local fault reactivation. Based on their geometries and seismic facies, we conclude that the Barremian – lower Aptian interval is syn-rifting and syn-tectonic, deposited during active continental extension and upper crustal faulting affecting the entire evolving margin, whereas the overlying upper Aptian interval is syn-rifting and post-tectonic, deposited when extension and faulting had migrated seaward to the future location of plate rupture and ocean development. The results of our study support the arising notion that the tripartite tectono-stratigraphic model for rift development is too simplistic and cannot be applied when assessing rifts in the context of the regional development of continental margins.

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“…Karst features in deep reservoirs are commonly attributed to hypogene dissolution (hypogene speleogenesis) resulting from upwelling and migration of thermal groundwaters (Andreychouk et al, 2009;Dublyansky, 1990;Klimchouk, 2007Klimchouk, , 2019. Hydrothermal alteration in carbonate reservoirs resulting in cavernous vugs and nonmatrix permeability is a common phenomenon, especially along fault and fracture zones (Álvaro, 2013;Fernández-Ibáñez, Jones, et al, 2022;Strugale & Cartwright, 2022;Zhou et al, 2014). These hypogene karst processes generate non-fabric-selective interconnected pore systems, resulting in heterogeneous porosity and highly anisotropic rock permeability (Fernández-Ibáñez, Jones, et al, 2022;Trice, 2005), which has implications not only for hydrocarbon exploration but also for the characterization of geothermal resources and groundwater reserves (Audra et al, 2022;Goldscheider et al, 2010;Montanari et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Hydrothermal silicification and hypogene dissolution of an exhumed Neoproterozoic carbonate sequence in Brazil: Insights from fluid inclusion microthermometry and silicon‐oxygen isotopes

et al. 2023

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Hypogene dissolution‐precipitation processes strongly affect the petrophysical properties of carbonate rocks and fluid migration pathways in sedimentary basins. In many deep carbonate reservoirs, hypogene cavernous voids are often associated with silicified horizons. The diagenesis of silica in carbonate sequences is still a poorly‐investigated research topic. Studies exploring the complexity of silica dissolution‐precipitation patterns in hypogene cave analogues are therefore fundamental to unravel the diagenetic and speleogenetic processes that may affect this kind of reservoir. In this work, we investigated an exhumed and silicified Neoproterozoic carbonate sequence in Brazil hosting a 1.4 km‐long cave. Quartz mineralization and silicified textures were analyzed with a multidisciplinary approach combining petrography, fluid inclusion microthermometry, silicon‐oxygen stable isotope analyses and U‐Th‐Pb dating of monazite crystals. We found that an early silicification event caused the replacement of the dolostone layers with micro‐crystalline quartz forming chert nodules. This event was likely associated with mixing fluids (ancient Neoproterozoic seawater and hydrothermal solutions sourced from the underlying Mesoproterozoic basement) at relatively low temperatures (ca. 50–100°C) and shallow depth. After the tectonic deformation produced by the Brasiliano orogeny, silica dissolution was promoted by high temperature and alkaline hydrothermal solutions rising from the quartzite basement along deep‐rooted structures. Hypogene hydrothermal alteration promoted the dissolution of the cherty layers and the precipitation of chalcedony and megaquartz. Homogenization temperatures from primary fluid inclusions in megaquartz cement indicate minimum formation temperatures of 165–210°C. Similar temperature estimates (110–200°C) were obtained from the δ30Si and δ18O isotope systematics of quartz precipitated from hydrothermal solutions. The dissolved salts in the fluid inclusions were evaluated as NaCl + CaCl2 from microthermometric data combined with cryogenic Raman spectroscopy, corresponding to salinity ranging between 17 and 25 wt.%. No reliable age constraints for hydrothermal silica dissolution‐precipitation phases were obtained from monazite U‐Th‐Pb dating. However, our results, interpreted in the regional context of the São Francisco Craton, suggest that the Cambrian tectono‐thermal events could have been amongst the possible drivers for this hypogene process in the basin.

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Tectono‐stratigraphic evolution of the rift and post‐rift systems in the Northern Campos Basin, offshore Brazil

Cited by 16 publications

References 120 publications

The cryptic stratigraphic record of the syn‐ to post‐rift transition in the offshore Campos Basin, SE Brazil

The cryptic stratigraphic record of the syn‐ to post‐rift transition in the offshore Campos Basin, SE Brazil

The cryptic stratigraphic record of the syn- to post-rift transition in the offshore Campos Basin, SE Brazil

Hydrothermal silicification and hypogene dissolution of an exhumed Neoproterozoic carbonate sequence in Brazil: Insights from fluid inclusion microthermometry and silicon‐oxygen isotopes

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