Title :

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

Author(s) :

Loncke, Lies [Auteur]
Université de Perpignan Via Domitia [UPVD]
Mercier de Lépinay, Marion [Auteur]
Université de Perpignan Via Domitia [UPVD]
Basile, Christophe [Auteur]
Maillard, Agnès [Auteur]
Géosciences Environnement Toulouse [GET]
Roest, Walter R. [Auteur]
Laboratoire Géosciences Océan [LGO]
de Clarens, Philippe [Auteur]
TotalEnergies [[Total Energies. Anciennement : Total, TotalFina, TotalFinaElf]]
Patriat, Martin [Auteur]
Laboratoire Géosciences Océan [LGO]
Gaullier, Virginie [Auteur]
Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 [LOG]
Klingelhoefer, Frauke [Auteur]
Laboratoire Géosciences Océan [LGO]
Graindorge, David [Auteur]
Laboratoire Géosciences Océan [LGO]
Sapin, François [Auteur]
TotalEnergies [[Total Energies. Anciennement : Total, TotalFina, TotalFinaElf]]

Journal title :

Tectonophysics

Publication date :

2022

English keyword(s) :

Transform marginal plateau
Passive margin
Volcanic margin
Atlantic
Demerara
Guinea

HAL domain(s) :

Planète et Univers [physics]

English abstract : [en]

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 ...
Show more >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.Show less >

Language :

Anglais

Popular science :

Non

Collections :

• Laboratoire d'Océanologie et de Géosciences (LOG) - UMR 8187

Source :

Harvested from HAL