Mimicking Alpine thrusts by passive deformation of synsedimentary normal faults: a record of the Jurassic extension of the European margin (Mont Fort nappe, Pennine Alps)
العنوان: | Mimicking Alpine thrusts by passive deformation of synsedimentary normal faults: a record of the Jurassic extension of the European margin (Mont Fort nappe, Pennine Alps) |
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المؤلفون: | Jean-Luc Epard, Adrien Pantet, Henri Masson |
المصدر: | Swiss Journal of Geosciences, vol. 113, no. Special issue, pp. 35-59 Swiss Journal of Geosciences, Vol 113, Iss 1, Pp 1-25 (2020) |
بيانات النشر: | Springer Science and Business Media LLC, 2020. |
سنة النشر: | 2020 |
مصطلحات موضوعية: | QE1-996.5, geography, geography.geographical_feature_category, Paleozoic, Penninic, Western Alps, Inversion (geology), Geology, Paleofaults, Orogenic deformation, Hyper-extended continental margin, Fault (geology), Fault scarp, Tethyan distal margins, Nappe, Tectonics, Paleontology, Breccia |
الوصف: | The Mont Fort nappe, former uppermost subunit of the Grand St-Bernard nappe system, is an independent tectonic unit with specific structural and stratigraphic characteristics (Middle Penninic, NW Italy and SW Switzerland). It consists in a Paleozoic basement, overlain by a thin, discontinuous cover of Triassic-Jurassic metasediments, mainly breccias, called the Evolène Series. The contact of this Series over the Mont Fort basement is debated: stratigraphic or tectonic? We present new observations that support the stratigraphic interpretation and consequently imply that the Evolène Series belongs to the Mont Fort nappe. We moreover show that the Mont Fort nappe was strongly affected by normal faulting during Jurassic. These faults went long unnoticed because Alpine orogenic deformation blurred the record. Alpine strain erased their original obliquity, causing confusion with an Alpine low-angle thrust. These Jurassic faults have been passively deformed during Alpine tectonics, without inversion or any other kind of reactivation. They behaved like passive markers of the Alpine strain. Detailed field observations reveal the link between observed faults and specific breccia accumulations. Areas where the Evolène Series is missing correspond to sectors where the fault scarps were exposed on the bottom of the sea but were too steep to keep the syn- to post-faulting sediments. The Mont Fort nappe thus represents an example of a distal rifted margin. The succession of synsedimentary extensional movements followed by orogenic shortening generated a situation where passively deformed normal faults mimic an orogenic thrust. |
وصف الملف: | application/pdf |
تدمد: | 1661-8734 1661-8726 |
URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::fcb31d6569fa6f9360e693a31f706d6c https://doi.org/10.1186/s00015-020-00366-2 |
حقوق: | OPEN |
رقم الأكسشن: | edsair.doi.dedup.....fcb31d6569fa6f9360e693a31f706d6c |
قاعدة البيانات: | OpenAIRE |
تدمد: | 16618734 16618726 |
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