Schreibersite Growth and Its influence on the Metallography of Coarse-Structured Iron Meteorites: Smithsonian Contributions to the Earth Sciences, Number 21

摘要

Meteorites are currently understood to be the oldest rocks available for scientific study, containing components and structures that span the period from the final stages of solar nebula condensation to the present (Anders, 1962, 1971; Grossman and Larimer, 1974; Wasson, 1974). They are fragments of parent bodies that accreted from preexisting aggregations of material during the period of planetary system formation some 4.6 billion years ago. These parent bodies were subsequently disrupted into smaller objects that then had independent existences in space. Individual fragments eventually intercepted the earth and landed as recoverable meteorites. Meteorite structures and compositions have undergone varying degrees of modification while resident in their parent bodies, as small bodies in space, on their passage through the atmosphere, and on landing on the earth's surface. Further changes result from long residence time on the ground and may continue during storage in collections. Bearing evidences of these complex histories, meteorites are samples not only from a far distant place but also from a far distant time, having been preserved in a remarkably gentle environment when compared to terrestrial or lunar rocks. As a consequence, meteorites have a unique place in the study of the development of the planetary system, yielding information that is available from no other source.