Shatter Cones in Cryptoexplosion Structures (Meteorite Impact?)

Abstract

Shatter cones (striated percussion fracture cones), apparently formed by explosive percussion, are known only from four cryptoexplosion (i.e., cryptovolcanic) structures, viz., Steinheim Basin, Wells Creek Basin, the Kentland deformation, and the Crooked Creek structure. The nature of these shatter cones and their orientation at these four localities are described. It is concluded that the shatter cones may be a useful criterion for establishing that cryptoexplosion structures of the damped-wave type are probably formed by the hypervelocity and explosive impact of large meteorites. In any event, it is hoped that this paper will draw attention to these unusual structures so that geologists will be on the lookout for them in small, highly deformed, circular structures.