Rochechouart impact structure or Rochechouart astrobleme is an impact structure in France. Erosion has over the millions of years has mostly destroyed its impact crater, the initial surface expression of the asteroid impact leaving highly deformed bedrock and fragments of the crater's floor as evidence of it. In 2008, the French State acknowledged the heritage value of the Rochechouart impact structure creating the “” on 12 sites representative of characteristics geological features of the impact structure. Location Named after the town of Rochechouart, the Rochechouart impact structure is located on the western margin of the French Massif Central near the city of Limoges, approximately south of Paris. Rochechouart (population about ) is built with rocks created or modified by the impact (impactites). Chassenon, a third of the size of Rochechouart, is also built of impactites. Impactite was used 2000 years ago for building Chassenon's monumental Roman baths of Cassinomagus. Rochechouart impact structure is traversed by an administrative boundary separating the Charente and Haute-Vienne departments. The name of Chassenon (in Charente) was added to Rochechouart (in Haute-Vienne) for naming the Natural Reserve for political reasons aimed at obtaining larger support from both departments. History The impact origin of the structure was recognized by F. Kraut in 1969. The occurrence of an unusual set of rock types referred to as breccias on the crystalline rocks of the Massif Central was reported in the Rochechouart area at the start of geology, in the early 1800s. However, their interpretation either as sedimentary, volcanic, tectonic, or a mix of these, was a major subject of debate until impact became progressively recognized as a geological process in the 1960s. The impact origin of Rochechouart was definitely confirmed in the mid 1970s with the recognition by P. Lambert of the projectile signal in the various rocks bearing up to 500 times the nickel content of the target rocks. Rochechouart was then the first impact structure to be confirmed by the presence of projectile contamination, in the absence of meteorite debris and in the absence of crater morphology. This is significant because after shock metamorphism has been recognized and used by early impact geologists as the criteria for identifying impact structures in the absence of projectile, the opponent to impact craters on Earth postulated an endogenic process so called cryptovolcanism, capable of creating the extreme shock waves responsible for craters and shock metamorphism. Rochechouart was thus on the