1. (nuclear) A nuclear reaction involving the ejection of many particles from an atomic nucleus, following a collision with a high-energy particle. Both the mass number and the atomic number of the target nucleus are changed by the event.
2. (planetary geol.) The removal of the surface layers of a rock by the interaction of a compressional shock wave with the surface, caused by micrometeorite impact. See ‘ZAP PITS’.
"spallation." A Dictionary of Earth Sciences. . Encyclopedia.com. (May 28, 2018). http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/spallation
"spallation." A Dictionary of Earth Sciences. . Retrieved May 28, 2018 from Encyclopedia.com: http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/spallation