Evolution of the Walvis Ridge‐Rio Grande Rise Hot Spot System: Implications for African and South American Plate motions over plumes

O’Connor, John; Duncan, Robert A.

doi:10.1029/jb095ib11p17475

Cited by 377 publications

(238 citation statements)

References 107 publications

(18 reference statements)

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“…This striking asymmetry has been explained by: (1) a topographic barrier along the African margin (White & McKenzie, 1989); (2) an o -centre Tristan plume (O'Connor & Duncan, 1990); (3) asymmetric simple shear during rifting (Peate, 1990); (4) thin lithosphere below the ParanaÂ Basin (Thompson & Gibson, 1991); and (5) a horizontal magmatic pressure gradient between the axial rift zone and the ParanaÂ Basin (Harry & Sawyer, 1992).…”

Section: Onshore Magmatismmentioning

confidence: 99%

Role of subaerial volcanic rocks and mantle plumes in creation of South Atlantic margins: implications for salt tectonics and source rocks

Jackson¹,

Cramez

Fonck

2000

Marine and Petroleum Geology

174

147

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Seaward-dipping re¯ectors (SDRs) represent¯ood basalts rapidly extruded during either rifting or initially subaerial sea-¯oor spreading. Evaporites can form on this basaltic proto-oceanic crust, as in the Afar Triangle today. Evidence for SDRs in South Atlantic deep-water regions comes from proximity to the uniquely large ParanaÂ ±Etendeka volcanic province onshore, the Tristan and Gough hot spots, drilled volcanic rocks, and seismic pro®les showing SDR provinces more than 100 km wide, as much as 7 km thick, and thousands of kilometers long. SDRs are clearest adjoining the Aptian salt basins. However, we speculate that SDRs are also present but seismically obscured below the salt basins. We argue that the conjugate Aptian salt basins are post-breakup, not pre-breakup; they were separated from the start by a mid-oceanic ridge; distal salt accumulated on proto-oceanic crust, not rift basins. This hypothesis is supported by: seismic stratigraphy and structure; magnetic anomalies; plate reconstructions; and hydrothermal potash evaporites. An important implication for exploration is that thick basalts, rather than rift-age source rocks, may underlie distal parts of the salt basins. 7

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Section: Onshore Magmatismmentioning

confidence: 99%

Role of subaerial volcanic rocks and mantle plumes in creation of South Atlantic margins: implications for salt tectonics and source rocks

Jackson¹,

Cramez

Fonck

2000

Marine and Petroleum Geology

174

147

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“…Kinematics of the South Atlantic and its continental margins are strongly dependent upon the understanding of the relationships between rifting and the Tristan da Cunha hot spot. The latter was responsible for the formation of the prominent morpho-tectonic feature of the South Atlantic (Rio Grande Rise and Walvis ridge (O'Connor and Duncan, 1990), and emplacement of basaltic plateaux of Parana in South America and Etendeka in Namibia (Renne et al, 1996).…”

Section: Structural Frameworkmentioning

confidence: 99%

South Atlantic continental margins of Africa: A comparison of the tectonic vs climate interplay on the evolution of equatorial west Africa and SW Africa margins

Séranne¹,

Anka²

2005

Journal of African Earth Sciences

135

106

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Africa displays a variety of continental margin structures, tectonic styles and sedimentary records. The comparative review of two representative segments: the equatorial western Africa and the SW Africa margins, helps in analysing the main controlling factors on the development of these margins. Early Cretaceous active rifting south of the Walvis Ridge resulted in the formation of the SW Africa volcanic margin that displays thick and wide intermediate igneous crust, adjacent to a thick unstretched continental crust. The non-volcanic mode of rifting north of the Walvis ridge, led to the formation of the equatorial western Africa margin, characterised by a wide zone of crustal stretching and thinning, and thick, extensive, synrift basins. Contrasting lithologies of the early post-rift (salt vs shale) determined the style of gravitational deformation, whilst periods of activity of the decollements were controlled by sedimentation rates. Regressive erosion across the prominent shoulder uplift of SW Africa accounts for high clastic sedimentation rate during Late Cretaceous to Eocene, while dominant carbonate production on equatorial western Africa shelf suggests very little erosion of a low hinterland. The early Oligocene long-term climate change had contrasted response in both margins. Emplacement of the voluminous terrigenous Congo deep-sea fan reflects increased erosion in equatorial Africa, under the influence of wet climate, whereas establishment of an arid climate over SW Africa induced a drastic decrease of denudation rate, and thus reduced sedimentation on the margin. Neogene emplacement of the African superswell beneath southern Africa was responsible for renewed onshore uplift on both margins, but it accelerated erosion only in the Congo catchment, due to wetter climatic conditions. Neogene high sedimentation rate reactivated gravitational tectonics that had remained quiescent since late Cretaceous.

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“…4) have been dated to 137-127Ma (Turner et al 1994) and 130-125Ma (Erlank et al 1984: Milner et al 1992, respectively. They are linked by the Waivis Ridge-Rio Grande Rise along the Tristan plume trail (O'Connor & Duncan 1990). Large extrusive constructions exist on both conjugate margins south of the plume trail (Table 3) (e.g.…”

Section: Namibia and Other South Atlantic Marginsmentioning

confidence: 99%

Atlantic volcanic margins: a comparative study

Eldholm

Gladczenko

Skogseid

et al. 2000

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Volcanic margins in the Atlantic Ocean reveal a series of common crustal units and structural features developed during continental extension and break-up. We suggest that four main crustal zones can be recognized on volcanic margins. This tectono-magmatic zonation implies a history of development where tectonic and magmatic styles and dimensions depend on the interaction of lithospheric and asthenospheric properties and dynamics. The amount of excess igneous activity depends on the temperature and fluid content of the asthenosphere along the incipient plate boundary and the dynamic history of the lithosphere during the rift phase. An adequate understanding of the margin history requires studies of the entire rift, i.e. the conjugate margins. We also note that the spectacular wedges of seaward-dipping reflectors observed along many rifted margins are only one of many igneous features originating during the process of break-up and initial seafloor spreading. Probably, most passive rifted margins represent intermediate cases relative to the volcanic and non-volcanic end-members. A mantle plume impinging on lithosphere already under extension emplacing Large Igneous Province-type initial oceanic crust, including an extensive extrusive cover, is considered the most likely explanation for volcanic margins. Hydrocarbon resource evaluations of volcanic margins have to include their characteristic tectono-magmatic features and their consequences for vertical motion, erosion, sedimentation, thermal and burial histories, and maturation.

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Evolution of the Walvis Ridge‐Rio Grande Rise Hot Spot System: Implications for African and South American Plate motions over plumes

Cited by 377 publications

References 107 publications

Role of subaerial volcanic rocks and mantle plumes in creation of South Atlantic margins: implications for salt tectonics and source rocks

Role of subaerial volcanic rocks and mantle plumes in creation of South Atlantic margins: implications for salt tectonics and source rocks

South Atlantic continental margins of Africa: A comparison of the tectonic vs climate interplay on the evolution of equatorial west Africa and SW Africa margins

Atlantic volcanic margins: a comparative study

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