Importance of the Landes High in the structuration of the Landes Parentis area. - INSU - Institut national des sciences de l'Univers Access content directly
Conference Papers Year : 2018

Importance of the Landes High in the structuration of the Landes Parentis area.

Jean-Noël Proust
Thierry Nalpas
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The ”Landes-Parentis area” (LPA) is located at the transition between the eastern end of the abyssal plain of the Bay of Biscay, the Aquitaine basin to the east and the highly inverted Basque-Cantabrian basin to the south. It includes the Meso-Cenozoic Parentis basin (PB) bordered to the south by a Paleozoic high named Landes High (LH). The purpose of the study is to highlight the deformation of the Landes-Parentis area during extension from the end of Jurassic to the early Cretaceous, and then during inversion from the Upper Cretaceous onward. To understand this evolution, we analyzed ten regional 2D seismic lines through the LPA from the coast to the oceanic crust and from the LH to the Armorican margin. We mapped the main structures and stratigraphic unconformities. Well data from the PB has been used for the age dating of the different unconformities. The maps show that the Mesozoic cover observed in the PB extends to the foot of the con- tinental slope while all the Jurassic and Lower Cretaceous series are absent on the LH. The LPA continental slope is structured with west dipping normal fault. Further east, the contact area between PB and LH is particularly complex. Indeed, the PB presents an asymmetry between a gentle south dipping northern flank and a steep and faulted southern flank in a direct contact with LH. The LPA is also crossed by a NW-SE to NNW-SSE oriented, sinistral accident: the Landes transfer zone (LTZ). This transfer zone seems to continue in the LH by a set of NW-SE normal faults. East of this accident, the southern flank of the BP shows EW-oriented anticlines structures, attributed to salt ripples. The structural style shows normal faults inverted during the Tertiary and ramp anticlines. To the west, the southern flank presents two tilted blocks limited by EW- oriented crustal faults with a north-dipping normal movement. These faults affect the Triassic to Lower Cretaceous sedimentary series. They are sealed by the Upper Cretaceous to Tertiary sedimentary deposits. The structural scheme is mainly extensive. These results show that the NW-SE direction of the LPA, oblique with respect to the main NNE-SSW transfer zones of the Pyrenees and the lateral partitioning of the local deformation are probably strongly influenced by the presence of Landes High that play the role of a rigid block.
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insu-01916065 , version 1 (08-11-2018)


  • HAL Id : insu-01916065 , version 1


Matthieu Roger, Isabelle Thinon, Jean-Noël Proust, Thierry Nalpas. Importance of the Landes High in the structuration of the Landes Parentis area.. 26ème Réunion des Sciences de la terre - RST, Oct 2018, Lille, France. pp.237. ⟨insu-01916065⟩
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