Microstructures of bedding-parallel faults under multistage deformation: Examples from the Southeast Basin of France

Autor: Lemonnier N, Homberg C, Roche V, Rocher M, Boullier A. M, Schnyder J
Přispěvatelé: Institut des Sciences de la Terre de Paris (iSTeP), Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS), University College of Dublin, parent, PSE-ENV/SEDRE/UEMIS, Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Institut des Sciences de la Terre (ISTerre), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Gustave Eiffel-Université Grenoble Alpes (UGA), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Unité d'expertise et de modélisation des installations de stockage (IRSN/PSE-ENV/SEDRE/UEMIS), Service des déchets radioactifs et des transferts dans la géosphère (IRSN/PSE-ENV/SEDRE), Institut de Radioprotection et de Sûreté Nucléaire (IRSN)-Institut de Radioprotection et de Sûreté Nucléaire (IRSN)
Jazyk: angličtina
Rok vydání: 2020
Předmět:
Zdroj: Journal of Structural Geology
Journal of Structural Geology, Elsevier, 2020, 140, pp.104138. ⟨10.1016/j.jsg.2020.104138⟩
Journal of Structural Geology, 2020, 140, pp.104138. ⟨10.1016/j.jsg.2020.104138⟩
ISSN: 0191-8141
Popis: International audience; We conducted a microstructural analysis of bedding-parallel faults (BPFs) in Mesozoic clay-rich layers of the Southeast Basin of France. Various microstructures are recognized in thin sections under a petrographic microscope and by cathodoluminescence. The microscale observations are combined with outcrop observations from previous studies to provide insight into the origin of the BPFs and their evolution during successive phases of deformation in a basin that had a polyphase tectonic history. The BPFs slipped while normal faults were formed during the Oligocene extension. Then, another phase of slip occurred later during the basin inversion. These two phases of deformation are expressed by recurrent crack-seal veins, pull-apart veins and stylolites. In addition, calcite veins with an elongate blocky morphology suggest an opening normal to bedding before the reactivation. The BPFs initiated in clay layers that were shallow dipping. Such conditions may appear mechanically unfavourable for an opening normal to bedding or a shearing parallel to bedding. We suggest that the role of rock anisotropy is critical. This study furthermore demonstrates that BPFs can be long-lived brittle structures that may record successive tectonic events.
Databáze: OpenAIRE
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