Tectonophysics2022，Vol.82221.DOI:10.1016/j.tecto.2021.229112

Compared structure and evolution of the conjugate Demerara and Guinea transform marginal plateaus

Loncke, Lies de Lepinay, Marion Mercier Basile, Christophe Maillard, Agnes Roest, Walter R. De Clarens, Philippe Patriat, Martin Gaullier, Virginie Klingelhoefer, Frauke Graindorge, David Sapin, Francois
Tectonophysics2022，Vol.82221.DOI:10.1016/j.tecto.2021.229112
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  • NSTL
  • Elsevier

Compared structure and evolution of the conjugate Demerara and Guinea transform marginal plateaus

Loncke, Lies 1de Lepinay, Marion Mercier 1Basile, Christophe 2Maillard, Agnes 3Roest, Walter R. 4De Clarens, Philippe 5Patriat, Martin 4Gaullier, Virginie 6Klingelhoefer, Frauke 4Graindorge, David 7Sapin, Francois5
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作者信息

  • 1. Univ Perpignan Via Domitia
  • 2. Univ Joseph Fourier
  • 3. Univ Toulouse
  • 4. IFREMER
  • 5. Total SA
  • 6. Univ Lille
  • 7. Univ Brest
  • 折叠

Abstract

The Demerara and Guinea plateaus are conjugate Transform Marginal Plateaus (TMPs) formed at the junction of the Jurassic Central Atlantic Ocean and the Cretaceous Equatorial Atlantic Ocean. We compare their structure and evolution through a combined industrial/academic seismic dataset tied by well data. We show that these TMPs record a complete evolution history from the Jurassic Central Atlantic to the Equatorial Atlantic breakup and seafloor spreading phases. Both plateaus first formed as volcanic margins displaying successive SDR wedges migrating towards the newly forming Central Atlantic domain. In this context, Demerara and Guinea, conjugates of the Bahamas, seem to have formed in relation to plume activity at the southern end of the Central Atlantic domain. Our dataset suggests that the Demerara and Guinea plateaus initially represented two distinct extrusive centres separated by a crustal basement high. Later, during the Cretaceous Equatorial opening phase, both plateaus separated in a transform mode following this discontinuity. Deformation is notably asymmetric during this phase: Aptian to Albian folding, strike-slip, transtensive deformation and complex vertical movements on the Demerara side and only minor deformation on the Guinean side, except on its divergent Sierra Leone termination. The deformation is sealed on both plateaus by a regional upper Albian erosion unconformity. Extensional reactivation occurs on the Guinea side (probably through a general collapse?). To conclude, this study provides new insights into the nature and origin of TMPs and the key tectono-sedimentary archives they may contain to understand the polyphase breakup conditions of Gondwana.

Key words

Transform marginal plateau/Passive margin/Volcanic margin/Atlantic/Demerara/Guinea/ATLANTIC-OCEAN/SUBSIDENCE/INVERSION

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出版年

2022
Tectonophysics

Tectonophysics

EISCI
ISSN：0040-1951
被引量4
参考文献量37
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