Shock effects and pre-shock microstructures in hydrothermal quartz veins from the Rochechouart impact structure, France

Microfabrics in hydrothermal quartz veins in gneisses of the Massif Central, France, from the Rochechouart impact structure and St. Paul la Roche, ∼40 km to the SE of the centre of the structure, have been investigated. In the quartz veins from the Rochechouart impact structure, planar deformation features in the basal plane and cataclastic zones indicate low shock pressures (