EGU2020-10184
https://doi.org/10.5194/egusphere-egu2020-10184
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Denudation history of the French Massif Central: new insights from thermochronology, basement-basin cross-sections and semi-automated planation surfaces mapping

Thomas François1, Guillaume Baby2, Paul Bessin3, Julien Baptiste4, Jocelyn Barbarand1, François Guillocheau2, Éric Lasseur4, Justine Briais4, and Cécile Robin2
Thomas François et al.
  • 1GEOPS, UMR 8148 – CNRS, Université Paris-Sud, Université Paris-Saclay, 91405 Orsay, France (thomas.francois@u-psud.fr)
  • 2Géosciences Rennes, UMR 6118 – CRNS, Université Rennes 1, 35042 Rennes, France
  • 3Laboratoire de Planétologie et de Géodynamique (LPG), UMR 6112 – CNRS, Le Mans Université, 72085 Le Mans, France
  • 4BRGM, 45100 Orléans, France

Documenting surface uplift of basement areas is challenging, usually due to large gaps in the sedimentary record. In order to address this issue for the French Massif Central, we here investigate its denudation history through an integrated study that involves planation surface mapping, Apatite Fission-Track (AFT) Analysis and basement to basin cross-sections.

First, Planation surfaces were identified using a semi-automated fuzzy classification of pixels based on relationships between DEM derivatives (slope, curvature, ruggedness and incision) and field-recognized training samples.  Then, their different generations and age ranges were discriminated from hypsometry, fault partitioning and relationships with dated sedimentary and/or volcanic remnants, providing constraints on basement exhumation. Afterwards, integrating the previous planation surface analysis, geological cross-sections were produced from the Massif Central basement to the surrounding basins (Aquitaine Basin and Paris Basin). These sections provide local thicknesses estimates of the missing sedimentary cover over basement domains. Theses local thicknesses and exhumation phases were finally used as constraints to produce a thermal history modelling and a denudation map of different areas of the French Massif Central estimated from AFT inversion.

Our results show different burial and exhumation patterns with i) a main burial of its western parts (Limousin, Rouergue) during Jurassic times followed by an important regional denudation (1 to 2 km of missing cover and crystallized basement) during the early Cretaceous and ii) an Upper Cretaceous burial of its northeastern parts (Morvan, Forez) followed by an uppermost Cretaceous to Paleogene exhumation (<1 km of missing cover and crystallized basement). This further illustrates the different behavior of each units of the Massif Central during the Mesozoic to Cenozoic times. These results will ultimately be discussed and placed back into the western European deformation framework.

 

(This work is founded and carried out in the framework of the BRGM-TOTAL project Source-to-Sink)

How to cite: François, T., Baby, G., Bessin, P., Baptiste, J., Barbarand, J., Guillocheau, F., Lasseur, É., Briais, J., and Robin, C.: Denudation history of the French Massif Central: new insights from thermochronology, basement-basin cross-sections and semi-automated planation surfaces mapping, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-10184, https://doi.org/10.5194/egusphere-egu2020-10184, 2020

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