Field-based 3D Modelling of Finite Deformation of the Alpine Corsica Blueschists.

Christian Le Carlier de Veslud and Frederic Gueydan and Samuel Jeanne and Cecile Palant. ( 2009 )
in: Proc. 29th Gocad Meeting, Nancy

Abstract

The 3D understanding of the finite deformation of HP-LT metamorphic units can help to discuss the applicability of the various exhumation processes. For that purpose, the Alpine Corsica is ideal because it gathers in the same area continental and oceanic units with different stiffness and thus different finite strain pattern. A new structural map at the scale of the Cap Corse is used to constrain in gOcad the positions of interfaces between different lithologies. 3D geomodelling packages are currently not well adapted for the construction of 3D structural models from spatially limited data such as field data, due to a lack of information in depth. Therefore, specific methodologies are developed for this task within the gOcad geomodeller. Data are: the DEM from SRTM database (80m resolution), geological maps and bedding of metamorphic units, that plays a major role for providing missing information in depth. A three-stage approach is used. data are integrated in 3D and their consistency is checked, beddings of units are interpolated in 3D, the main contacts are built, using bedding and outcrop lines. 3D consistence of folds variations is used to test viability of field-based interpretations and therefore constrain components of deformation. This 3D model shows that the HP-LT units of Alpine Corsica are in set of en ├ęchelon N170 oriented folds. This pattern is interpreted as the superimposition of 1/ a well defined post-peak pressure large scale, N-S trending folding of HP-LT units and 2/ several zones of nappes thinning N70 oriented, associated with subvertical beddings. These N70 structures can be interpreted as a results of localized thinning associated with ductile detachment of normal faults. This orientation is similar to that controlling the opening of Miocene St Florent and Aleria basins. Therefore, this deformation event is post-exhumation, and synchronous of basins opening.

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BibTeX Reference

@INPROCEEDINGS{LeCarlierGM2009,
    author = { Le Carlier de Veslud, Christian and Gueydan, Frederic and Jeanne, Samuel and Palant, Cecile },
     title = { Field-based 3D Modelling of Finite Deformation of the Alpine Corsica Blueschists. },
 booktitle = { Proc. 29th Gocad Meeting, Nancy },
      year = { 2009 },
  abstract = { The 3D understanding of the finite deformation of HP-LT metamorphic units can help to discuss the applicability of the various exhumation processes. For that purpose, the Alpine Corsica is ideal because it gathers in the same area continental and oceanic units with different stiffness and thus different finite strain pattern. A new structural map at the scale of the Cap Corse is used to constrain in gOcad the positions of interfaces between different lithologies. 3D geomodelling packages are currently not well adapted for the construction of 3D structural models from spatially limited data such as field data, due to a lack of information in depth. Therefore, specific methodologies are developed for this task within the gOcad geomodeller. Data are: the DEM from SRTM database (80m resolution), geological maps and bedding of metamorphic units, that plays a major role for providing missing information in depth. A three-stage approach is used. data are integrated in 3D and their consistency is checked, beddings of units are interpolated in 3D, the main contacts are built, using bedding and outcrop lines. 3D consistence of folds variations is used to test viability of field-based interpretations and therefore constrain components of deformation. This 3D model shows that the HP-LT units of Alpine Corsica are in set of en ├ęchelon N170 oriented folds. This pattern is interpreted as the superimposition of 1/ a well defined post-peak pressure large scale, N-S trending folding of HP-LT units and 2/ several zones of nappes thinning N70 oriented, associated with subvertical beddings. These N70 structures can be interpreted as a results of localized thinning associated with ductile detachment of normal faults. This orientation is similar to that controlling the opening of Miocene St Florent and Aleria basins. Therefore, this deformation event is post-exhumation, and synchronous of basins opening. }
}