EGU21-4078, updated on 04 Mar 2021
https://doi.org/10.5194/egusphere-egu21-4078
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Deep structure of the Atlantic margins and neighboring oceanic crust from wide-angle seismic data and plate kinematic reconstructions.

Frauke Klingelhoefer1, Youssef Biari2, Dieter Franke3, Thomas Funck4, Lies Loncke5, Jean-Claude Sibuet1, Christophe Basile6, James Austin7, Caesar Rigoti8, Mohamed Sahabi9, Massinissa Benabdellouahed10, and Walter Roest1
Frauke Klingelhoefer et al.
  • 1Ifremer, Dept. Marine Geosciences, ZI de la Pointe du Diable, CS10070, 29280 Plouzané, France (frauke.klingelhoefer@ifremer.fr)
  • 2Capgemini - Oil& Gas Centre of Excellence, Technopole Hélioparc Bâtiment Newton, 4 Rue Jules Ferry, 64000 Pau, France
  • 3BGR - BundesanstaltfürGeowissenschaften und Rohstoffe, Hannover, Germany
  • 4GEUS-Geological Survey of Denmark and Greenland, Copenhagen, Denmark
  • 5Cefrem, Université de Perpignan 52, av. Paul Alduy66860, Perpignan cedex, France
  • 6ISTerre, Université Grenoble Alpes, 1381rue de la Piscine, 38610 GIERES
  • 7John A. and Katherine G. Jackson School of Geosciences, Institute forGeophysics, University of Texas at Austin, Austin, Texas, USA
  • 8Petrobras/E&P/EXP, Rua Tonelero 204/601, Rio de Janeiro CEP 22030-002, RJ, Brazil
  • 9UniversitéChouaïb Doukkali – Faculté Des Sciences, Laboratoire Géosciences marines et Sciences des sols – URAC 45, BP 20, 24000 El Jadida, Morocco
  • 10CESI (centre des études supérieures industrielles), 93 Boulevard de la Seine, 92000 Nanterre, France

In order to study opening mechanisms and their variation in the Atlantic ocean basins, we compiled existing wide-angle and deep seismic data along conjugate margins and performed plate tectonic reconstructions of the original opening geometries to define conjugate margin pairs. A total of 23 published wide-angle seismic profiles from the different margins of the Atlantic basin were digitized, and reconstructions at break-up and during early stages of opening were performed. Main objectives were to understand how magma-rich and magma-poor margins develop and to define more precisely the role of geologic inheritance (i.e., preexisting structures) in the break-up phase. At magma-poor margins, a phase of tectonic opening without accretion of a typical oceanic crust often follows initial rupture, leading to exhumation of serpentinized upper mantle material. Along volcanic margins the first oceanic crust can be overthickened, and both over- and underlain by volcanic products. The first proto-oceanic crust is often accreted at slow to very slow rates, and is thus of varied thickness, mantle content and volcanic overprint. Accretion of oceanic crust at slow to very slow spreading rates can also be highly asymmetric, so the proto oceanic crust at each side of conjugate margin pairs can differ. Another major aim of this study was to understand the mechanisms of formation and origins of transform marginal plateaus. These are bathymetric highs located at the border of two ocean basins of different ages and are mostly characterized by one or several volcanic phase during their formation. They often form conjugate pairs along a transform margin as it evolves and might have been the last land bridges during breakup, thereby influencing mammal migration and proto-oceanic currents in very young basins. At these plateaus, volcanic eruptions can lead to deposits of (at least in part subaerial) lava flows several km thick, better known by their geophysical signature as seaward dipping reflectors. Continental crust, if present, is heavily modified by volcanic intrusions. These marginal plateaus might form when rifting stops at barriers introduced by the transform margin, leading to the accumulation of heat in the mantle and increased volcanism directly before or after the cessation of rifting.

How to cite: Klingelhoefer, F., Biari, Y., Franke, D., Funck, T., Loncke, L., Sibuet, J.-C., Basile, C., Austin, J., Rigoti, C., Sahabi, M., Benabdellouahed, M., and Roest, W.: Deep structure of the Atlantic margins and neighboring oceanic crust from wide-angle seismic data and plate kinematic reconstructions., EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-4078, https://doi.org/10.5194/egusphere-egu21-4078, 2021.

Display materials

Display file