The Central Chartreuse Thrust Zone

This major thrust zone runs through the middle of the Chartreuse massif.  It is well exposed at the mountain of Grand Som.  Here the thrust carries the Urgonian limestone up onto upper Cretaceous marls.  There is an extra slice of Urgonian caught up as a small horse.  Use the view to zoom in for a closer look.

Looking north onto the thrust zone.  See the sketch for key to units.

Click on the box to visit the thrust!

The thrust at the base of the horse of Urgonian - carrying it onto a footwall of Upper Cretaceous marls and limestones. Notice the intensely brecciated (rubbly) rock below the overhanging fault surface (being studied by the geologist in the photograph). This fault breccia is characteristic of the main thrusts in the Chartreuse. The main fault plane has been measured in two places:   1.  fault surface 032-44SE, striations plunge 42 towards 099   2. fault surface 034 -26SE, striations plunge 22 towards 110.