Abstract
Quartz deformation lamellae parallel to the basal (0001) plane, identical to lamellae produced experimentally at ordinary laboratory strain rates, occur to the exclusion of lamellae of other orientations in specimens from six cryptoexplosive structures, including the Vredefort Ring, South Africa, Barringer Crater, Arizona, and Clearwater Lakes, Quebec. The basal lamellae are randomly oriented in space and are significantly different in character and crystallographic orientation from lamellae of all other natural occurrences. Available data indicate that the shear stress differences required to produce the basal lamellae could easily result from shock due to impact of an extraterrestrial body but could not reasonably result from natural explosions generated within the Earth.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
