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Deformation and motion in the Western Alpine Arc
Author(s) -
Choukroune Pierre,
Ballèvre Michel,
Cobbold Peter,
Gautier Yann,
Merle Olivier,
Vuichard JeanPaul
Publication year - 1986
Publication title -
tectonics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.465
H-Index - 134
eISSN - 1944-9194
pISSN - 0278-7407
DOI - 10.1029/tc005i002p00215
Subject(s) - geology , metamorphism , deformation (meteorology) , kinematics , metamorphic rock , massif , displacement (psychology) , eclogite , arc (geometry) , geodesy , geometry , seismology , tectonics , petrology , paleontology , subduction , physics , oceanography , mathematics , classical mechanics , psychology , psychotherapist
We attempt to reconstruct the kinematics (deformation and motion) of the Western Alpine Arc between the Mercantour and Aar Massifs. First, we compile a map showing principal extension (X) direction within three major structural units. In the external zone, X directions are broadly radial to the Alpine Arc; in the internal zone, they are uniform or smoothly varying in some domains; whereas in the intermediate zone they often show much scatter. Next, we use geochronological data and P‐T conditions, estimated from metamorphic mineral reactions, to time the deformation. On each of a series of interval maps, we show X‐directions for strain accumulated during a chosen time interval. We argue that these incremental X‐directions are approximately equivalent to segments of particle paths, showing displacements relative to stable Europe. For 120–100 Ma, the displacement direction was about N150 and coeval with eclogite facies metamorphism; it is interpreted as a direction of overthrusting by the African Plate. Around 40 Ma, the displacement in the south part of the arc became westerly. Finally, between 25 and 15 Ma, displacement directions were generally radial to the arc.