Electron Microscope Observations of Mechanical Metamorphism in Iron Meteorites

It is now generally accepted that meteorites are fragments produced by the collision of parent bodies of asteroidal dimensions. Optical metallographic evidence suggests that there exists a group of iron meteorites which exhibit structures similar to those observed in explosively shock loaded iron. It seems likely that shock loading of meteorites could be produced by preterrestrial impact of their parent bodies as mentioned above. We have therefore looked at the defect structure of one of these meteorites (Trenton) and compared the results with those made on a) an unshocked ‘standard’ meteorite (Canyon Diablo) b) an artificially shocked ‘standard’ meteorite (Canyon Diablo) and c) an artificially shocked specimen of pure α-iron.