The lanthanides or rare earth elements (REE) which are present in trace concentrations in rocks are most useful for investigating the origin of these objects. Of the microbeam techniques presently used to measure the REE concentrations of individual crystals, secondary ion mass spectrometry (SIMS) is the only method sensitive enough to allow the determination of REE abundances in most natural minerals. Usually, energy filtering is applied to remove all complex molecular interferences. All the REE, down to a level of ≤ 100 ppb, can be measured in spots 5 to 20 𝜇m in diameter. A growing number of studies involving both terrestrial and extraterrestrial materials have been undertaken.
Crozaz, Ghislaine and Zinner, Ernst
"Quantitative Ion Microprobe Analysis of the Rare Earth Elements in Minerals,"
Scanning Electron Microscopy: Vol. 1986
, Article 4.
Available at: https://digitalcommons.usu.edu/electron/vol1986/iss2/4