Shatter Cones
Image A Image B
(A) An embankment of irregular, cross-laminated, twisted, up thrust shatter cones in shale.
(B) A good example of shatter cones found here. Caused by shock deformation, they are characterized by lamina pushed into cone shaped structures with ridges or grooves radiating away from the top of the rock and spreading out in a "horsetail" fashion. They were first identified by Robert S. Dietz and can only be found in impact structures.
Since shatter cones and tektites are so very important to the identification of astroblemes, it was imperative that these stones were found. Although most of them were buried or destroyed along with other debris, it was not impossible, these being found along the innter rim.