期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2004
卷号：101
期号：18
页码：6847-6851
DOI：10.1073/pnas.0401565101
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Physical and chemical reactions occurring as a result of the high-velocity impacts of meteorites and micrometeorites and of cosmic rays and solar-wind particles are major causes of space weathering on airless planetary bodies, such as the Moon, Mercury, and asteroids. These weathering processes are responsible for the formation of their regolith and soil. We report here the natural occurrence of the mineral hapkeite, a Fe2Si phase, and other associated Fe-Si phases (iron-silicides) in a regolith breccia clast of a lunar highland meteorite. These Fe-Si phases are considered to be a direct product of impact-induced, vapor-phase deposition in the lunar soil, all part of space weathering. We have used an in situ synchrotron energy-dispersive, single-crystal x-ray diffraction technique to confirm the crystal structure of hapkeite as similar to the structure of synthetic Fe2Si. This mineral, hapkeite, is named after Bruce Hapke of the University of Pittsburgh, who predicted the presence and importance of vapor-deposited coatings on lunar soil grains some 30 years ago. We propose that this mineral and other Fe-Si phases are probably more common in the lunar regolith than previously thought and are directly related to the formation of vapor-deposited, nanophase elemental iron in the lunar soils.
