Tectonic control of the oil-rich large igneous-carbonate-salt province of the South Atlantic rift

Szatmári, Péter; Milani, Édison J.

doi:10.1016/j.marpetgeo.2016.06.004

Cited by 88 publications

(40 citation statements)

References 95 publications

(136 reference statements)

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“…Available AHe and apatite fission track data in the southern exposures of the orogen are predominantly coeval with the onset of the Paraná LIP or younger, indicating that most of the belt was already exposed to near‐surface conditions prior to the South Atlantic rifting (Hueck et al, ; Oliveira et al, ). Hence, the distinct responses to exhumation stages along the passive margin are probably controlled by transverse structures with NW‐SE orientation, associated with the early stages of continental break‐up and rotation of the South American plate (Salomon et al, ; Szatmari & Milani, ). These structures are associated with the doming of the sediments of the Paraná Basin (Milani et al, ; Rostirolla et al, ) and with the formation of the main fracture zones in the South Atlantic (Stica et al, ; Torsvik et al, ).…”

Section: Discussionmentioning

confidence: 99%

(U‐Th)/He Thermochronology and Zircon Radiation Damage in the South American Passive Margin: Thermal Overprint of the Paraná LIP?

et al. 2018

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New zircon and apatite (U-Th)/He data (AHe and ZHe) from the crystalline basement of the South American passive margin in southern Brazil present a wide distribution of Phanerozoic apparent ages, recording its prerift evolution. Its geological significance can be investigated by modeling the influence of the accumulated radiation damages on the measured crystals in its He ages during a long upper crust residence. Despite the presence of a significant fault in the studied area, the samples essentially constrain a uniform thermal history for the entire study area. Zircon helium ages spread from 472 to 26 Ma and correlate strongly with the radioactive element content of the crystals. Although the region was probably covered by Paleozoic sediments of the Paraná Basin, the ZHe system experienced a more intense thermal overprint, most likely the onset of the Paraná Large Igneous Province (LIP), causing its dispersion. The nearby intrusion of a feeding system of the LIP, the Florianópolis Dyke Swarm, may have contributed for keeping geothermal gradients elevated for a period long enough to promote the observed reset. After the extrusion of the volcanism, the study area was probably covered by up to 2 km of basalt floods, imprinting temperatures above the AHe partial retention zone on the crystalline basement. These were eroded during rapid cooling between 75 and 55 Ma, as indicated by thermal modeling. Additional analyses with Raman spectroscopy were used for calculating radiation damage ages in the zircon crystals measured for (U-Th)/He, resulting in a comparable set of ages.

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Section: Discussionmentioning

confidence: 99%

(U‐Th)/He Thermochronology and Zircon Radiation Damage in the South American Passive Margin: Thermal Overprint of the Paraná LIP?

et al. 2018

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“…A factor that further fuels the need to understand the very specifics of the separation, is the discovery of, and exploration for, major hydrocarbon reserves that are found within the sedimentary basins formed during the rift to drift separation of the continents (e.g. Szatmari and Milani, 2016;Masse and Laurent, 2016).…”

Section: Introductionmentioning

confidence: 99%

Volcanic constraints on the unzipping of Africa from South America: Insights from new geochronological controls along the Angola margin

et al. 2019

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The breakup of Africa from South America is associated with the emplacement of the Paraná-Etendeka flood basalt province from around 134 Ma and the Tristan da Cunha plume. Yet many additional volcanic events occur that are younger than the main pulse of the Paraná-Etendeka and straddle the rift to drift phases of the main breakup. This contribution reports on new geochronological constraints from the Angolan part of the African Margin. Three coastal and one inland section have been sampled stretching across some 400 Km, with 39 Ar/ 40 Ar, U-Pb and Palaeontology used to provide age constraints. Ages from the new data range from ~100 to 81 Ma, with three main events (cr. 100, 91 and 82-81 Ma). Volcanic events are occurring within the Early to Late Cretaceous, along this part of the margin with a general younging towards Namibia. With the constraints of additional age information both onshore and offshore Angola, a clear younging trend at the early stages of rift to drift is recorded in the volcanic events that unzip from North to South. Similar age volcanic events are reported from the Brazilian side of the conjugate margin, and highlight the need to fully incorporate these relatively low volume volcanic pulses into the plate tectonic breakup models of the South Atlantic Margin.

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“…The onshore Namibe, Kwanza, and Lower basins were formed during the Neocomian rifting related to the breakup of Pangea (Pletsch et al, 2001;Szatmari & Milani, 2016). This asynchronous opening in time and space led to the initiation of four segments (equatorial, central, southern, and "Falkland") bounded by major oceanic fracture zones (Torsvik et al, 2009;Moulin et al, 2010;Beglinger et al, 2012;von Nicolai et al, 2013).…”

Section: Structural Contextmentioning

confidence: 99%

“…A very likely source of dissolved silica in Presalt diagenetic fluids is the alteration of volcanic products (Tosca & Wright, 2015;Szatmari & Milani, 2016;Teboul et al, 2017).…”

Section: Source Of Aqueous Silica During Presalt Diagenesismentioning

confidence: 99%

“…Consequently, the deposits preceding salt deposition are commonly referred-to as "presalt deposits". The most commonly prospected reservoir formations include the coquina succession (skeletal carbonate; Thompson et al, 2015), microbialites, spherulites, and calcitic shrubs (radiaxial calcite), and possible hydrothermal carbonates (Terra et al, 2010;Saller et al, 2016;Szatmari & Milani, 2016). These deposits are interpreted as mostly derived from freshwater to hypersaline lakes (Saller et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

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Diversity and origin of quartz cements in continental carbonates: Example from the Lower Cretaceous rift deposits of the South Atlantic margin

Teboul

Durlet

Girard

et al. 2019

Applied Geochemistry

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Silica precipitation in continental carbonates is a common process occurring during sedimentation and diagenesis. The Lower Cretaceous rift deposits of the South Atlantic equatorial margin, which are intensively explored by petroleum companies, provide good examples of such silicifications in carbonates, exhibiting a wide diversity of petrographic habit of early to late quartz cements. In order to understand the palaeoenvironmental and diagenetic conditions leading to this diversity, we integrated detailed petrography of diagenetic sequences and quartz habit with δ 18 O quartz measurements (by SIMS) of individual cements observed in samples from the offshore and onshore basins of the West African margin. The petrographic description highlights the omnipresence of early fibrous microquartz cements exhibiting either length-fast or length-slow habit, in addition to laminated microquartz and micro-or mega-quartz forms. Amongst the isotopic analysis, the δ 18 O quartz data show that length-slow cements are generally strongly enriched in 18 O (δ 18 O quartz ranging from 31 to 37‰ SMOW), whereas length-fast forms show less elevated values ACCEPTED MANUSCRIPT 2 (<32‰ SMOW). The highest δ 18 O quartz values for fibrous microquartz are interpreted to reflect precipitation from evaporated meteoric fluids at temperatures >25°C and <100°C. The alkalinity required to favor the precipitation of length-slow fibrous microquartz cements is probably related to fluid/rock interactions with underlying mantel-related or basic volcanic rocks. Such interactions would be in agreement with the recent geodynamic models of the South Atlantic passive margin. The length-fast fibrous microquartz associated with δ 18 O quartz values ranging from 27 to 32‰ SMOW, probably reflect precipitation from moderately to non evaporated, fairly neutral to acid, fluids. The partial dissolution of carbonate cements prior to quartz cementations represents the signature of those acidic conditions. We therefore suggest that acidic pH was obtained through fluid/rock interactions with the intermediate to acid volcanic rocks encountered along the palaeohydrological pathway. Other quartz phases, such as the megaquartz cement, exhibit highly variable δ 18 O quartz values ranging from 20 to 40 ‰. This variation may reflect significant variation in temperature conditions (between 100 and 200°C) or changes in fluid δ 18 O at the small scale. For these populations of non-fibrous quartz cement, the very high δ 18 O quartz values may reflect a contribution of fluids that have either suffered strong evaporation or strong water/rock interaction.

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Tectonic control of the oil-rich large igneous-carbonate-salt province of the South Atlantic rift

Cited by 88 publications

References 95 publications

(U‐Th)/He Thermochronology and Zircon Radiation Damage in the South American Passive Margin: Thermal Overprint of the Paraná LIP?

(U‐Th)/He Thermochronology and Zircon Radiation Damage in the South American Passive Margin: Thermal Overprint of the Paraná LIP?

Volcanic constraints on the unzipping of Africa from South America: Insights from new geochronological controls along the Angola margin

Diversity and origin of quartz cements in continental carbonates: Example from the Lower Cretaceous rift deposits of the South Atlantic margin

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