Impact Structures: Their Origin, Mineralogy, and the Geologic Significance of Catastrophic Impacts
Kurtz K.M. Miller
Abstract
Ever year, mass (approximately 100 million kilograms) is added to the Earth by cosmic dust and meteorites which survive the journey through the atmosphere. Less often in the geologic history of the Earth, catastrophic impacts occur. Recently, much information has been published on the origin of such impactors, the mineralogic and geologic significance of impacts, and the evolutionary implications. Although no direct terrestrial impacts of this magnitude have been observed, planetary geologists and terrestrial geologists have looked to the rock record on the Earth and other planets to better understand this phenomenon.