Divergent and convergent margins in the North-Western alps confrontation to actualistic models |
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| Authors: | Gérard M Stampfli Michel Marthaler |
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| Institution: | Institut de Géologie et Paléontologie, Université de Lausanne, BFSH 2-CH 1015, Lausanne. |
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| Abstract: | AbstractDivergent and convergent margins actualistic models arc reviewed and applied to the history of the western Alps. Tethyan rifting history and geometry are analyzed : (he northern European margin is considered as an upper plate whereas the southern Apulian margin is a lower plate; the Bréche basin is regarded as the former break-away trough; the internal Bríançonnais domain represents the northern rift shoulder whilst the more external domains are regarded as the infill of a complex rim basin locally affected by important extension (Valaisan and Vocontian trough).The Schistes lustres and ophioliles of the Tsaté nappe are compared to an accretionary prism : the imbrication of this nappe elements is regarded as a direct consequence of the accretionary phenomena already active in early Cretaceous; the Gels/Simme complex could originate from a more internal part of the accretionary prism. Some eclogitic basements represent the former Apulian margin substratum (Sesia) others (Mont-Rose) are interpreted as the former edge of the European margin. The history of the closing Tethyan domain is analyzed and the remaining problems concerning the cinematics, the presence/absence of a volcanic arc and the eoalpine melamorphism are discussed. |
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| Keywords: | Divergent margins Convergent margins Rift Accretionary prism Tcthys Alps |
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