Impact experiments are performed in order to characterize the dynamic rupture of marls coming from the region of Terres Noires (French Alps). Marly stones are dropped above a hard surface and fragmentation events are recorded. Statistical analysis shows that the impact velocity and the initial surface state (characterized by a fissuration index) are the main parameters influencing the fracture. A probability law for the rupture is therefore proposed. On the other hand, the mass, the number of previous impacts and the water saturation do not have a significant influence on the rupture. The masses of the fragments are also recorded and the empirical mass distribution of fragments is similar to what is found in existing studies about the fragmentation of brittle material.