The world-class meteorite collection at the Field Museum is an invaluable resource to the cosmochemistry and meteoritics community. The meteorite collection currently includes about 1500 different meteorites and more than 10,000 specimens. The sixth edition of the fully searchable meteorite catalog includes the recent accessions and can be downloaded below (comma-separated text file) for import into most spreadsheet programs. Loan requests can be submitted by qualified scientists.
Why are museum meteorite collections important to science?
Meteorite curation at the Field Museum
Meteorites in the Field Museum collection at the Robert A. Pritzker Center for Meteoritics and Polar Studies are curated at the highest possible level of care and stewardship. The Museum recently commissioned a dedicated climate-controlled, secure facility for its meteorite collection stored in dust-tight metal cabinets. To minimize contamination of meteorites, our staff is required to handle specimens only with dedicated, clean, single-use gloves, and only use cleaned tools on clean surfaces. Such strict specimen handling rules and monitored storage conditions are necessary to prevent contamination and uncontrolled alteration of the meteorites. Once a specimen entered the Museum collection, its detailed history including its use in research, exhibition, and education is documented.
The Field Museum houses many falls and well-studied meteorites
Some research projects, such as studies of organic material in meteorites, require particularly clean samples. When loaning a specimen for such a study we need to have a record of how the specimen was stored and handled, to assess possible sources of contamination. For such studies the freshest material possible, like a recent meteorite fall, is desirable. In contrast to the more abundant finds, falls are often collected and carefully stored shortly after they reached Earth and are therefore not compromised by terrestrial weathering and significant contamination.
Well-characterized and intensively studied meteorites are often the samples of choice for research projects that employ new techniques and methods. To have confidence in new approaches scientists need to compare their findings with results from previous studies before studying previously unknown samples.
We see it as our obligation to permit use of our collection for current and future high-quality research projects at well-respected institutions, for both non-destructive and destructive analysis. At the same time, we need to conserve enough material for future generations of scientists, and for reproducibility studies and verifications of controversial results.
The need for sample consumption
Non-destructive analytical methods can be performed on meteorites, such as X-ray tomography and fluorescence, measurements of the density, volume, and magnetic susceptibility and gamma rays from radioactive decays. Because they are non-destructive such methods are nowadays often applied on precious extraterrestrial samples before anything destructive. However, many essential methods in meteoritics are destructive and require partial consumption of specimens. The cutting, grinding, and polishing of a specimen to prepare a polished section for classification, study of mineralogy, and surface analysis already consumes some material. To establish a chronology of the Solar System, dating of meteorites or their components by mass spectrometry is necessary. This requires dissolution chemistry, combustion, or melting. Thanks to improved instruments, analytical techniques, and protocols, detection sensitivities increase, and smaller samples can be used. Another notable example that requires destruction is the discovery and isolation of presolar stardust from meteorites: Through decades of acid dissolution experiments of fragments of primitive meteorites, in 1987 scientists at the University of Chicago isolated presolar grains, isotopically anomalous solid samples of stars. These grains are the oldest material that we can study on Earth (more than 4.6 billion years old) and represent the tiny fraction of material that survived the formation and evolution of our Solar System. This discovery, based on destructive sample preparation, opened up a new interdisciplinary field in cosmochemistry and astrophysics. Thanks to presolar grains, the only solid samples of stars that we can study on Earth, we are beginning to improve our physical understanding of the Solar System’s parent stars.