Bulk element compositions of meteorites: A guide for interpreting remote-sensing geochemical measurements of planets and asteroids

Abstract

We report a large database of bulk meteorite elemental abundances, compiled to aid in the interpretation of elemental abundance data determined by remote-sensing instrumentation on planetary missions. A custom user interface was developed for easy access and manipulation of the abundance data. The database contains almost 3000 individual analyses of more than 1000 individual meteorites. Most major and minor elements are included, as well as small number of trace elements measurable by remote-sensing gamma-ray spectroscopy (notably Th and U). All meteorite classes show variability in bulk compositions between individual analyses. Some of this spread is intrinsic to the parent bodies of the meteorites. However, some variability is undoubtedly due to systematic uncertainties, caused by inter-laboratory bias, misclassification, effect of weathering, and unrepresentative sampling. We use the database here to investigate both how well different meteorite groups can be distinguished on the basis of bulk compositions and how bulk compositions can be related to the cosmochemical and geological processes that produced them. The major elements measurable by X-ray and gamma-ray remote-sensing-oxygen, magnesium, aluminum, silicon, sulfur, calcium and iron-reflect to differing degrees nebular elemental fractionations and parent-body igneous processes and can be used together to distinguish most classes and sub-classes of meteorites. Potassium is potentially useful as a tracer of thermal processes in the early solar system. Thorium and uranium abundances could be used to trace igneous processes on differentiated asteroids.