Shatter cones from the Azuara impact structure (Spain).

Because of thick post-impact sediments in the inner part of the Azuara structure, the find of shatter cones is restricted to the sediments of the rim zone. In this zone, the shock wave was already weakened to the lower pressure limit of shatter-cone formation. Consequently, it is not surprising that shatter cones are rarely found and that the fracture cones often display only diffuse horsetail structures.

Shatter cones from the Azuara impact structure (Spain); Jurassic limestone. The black specimen is a silicon cast of a shatter cone negative.

Diffuse shatter coning in Jurassic limestone, Azuara impact structure. Photograph by courtesy of Tanja Katschorek.

Shatter coning in a Jurassic limestone, front and rear side of the sample. Azuara impact structure. Photographs by courtesy of H. Müller.

Stereo image of a shatter cone in Jurassic limestone, Azuara impact structure. Photograph by courtesy of G. Mayer