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Superimposed tectonic and hydrothermal events during the late‐orogenic extension in the Western French Massif Central: a structural and 40 Ar/ 39 Ar study
Author(s) -
Roig JeanYves,
Faure Michel,
Maluski Henri
Publication year - 2002
Publication title -
terra nova
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.353
H-Index - 89
eISSN - 1365-3121
pISSN - 0954-4879
DOI - 10.1046/j.1365-3121.2002.00384.x
Subject(s) - massif , geology , leucogranite , geochemistry , tectonics , sinistral and dextral , metamorphic rock , crust , cataclastic rock , hydrothermal circulation , basement , carboniferous , overprinting , structural geology , seismology , paleontology , petrology , gneiss , structural basin , archaeology , history
In the Western French Massif Central, the Argentat fault is a major structure through which As–Au fluids percolated in the Late Carboniferous along brittle fractures. New petrostructural investigations show that an early ductile normal‐dextral faulting, coeval to leucogranite emplacement took place during the Late Visean syncollisional extension of the belt and was accompanied by a hydrothermal event marked by the growth of muscovites whose 40 Ar/ 39 Ar ages cluster around 335 Ma. This early fluid channelling is associated with brittle deformation only in the hangingwall of the Argentat fault, whereas ductile deformation is restricted to the footwall. These results provide new evidence for the upper crust implication during the syncollisional extension in the French Massif Central. This study stresses the interest of a detailed multimethod analysis to characterize hydrothermal processes, especially in basement areas where the tectonic, plutonic and metamorphic evolution is polyphased.