Asteroid and comet bombardment of the Earth.

Abstract

Discusses populations of earth-crossing bodies, the production of impact craters on the continents (crater scaling and present cratering rates), historic collisions, small impact craters formed by iron meteorites, young large impact craters, ancient Phanerozoic impact structures, and large Precambrian impact structures. There is a concluding section on the effects of bombardment on terrestrial life. -K.Clayton impact craters scaling cratering rates meterorites astroblemes