This award provides two years of support to continue developmental work aimed at adapting the technique of Fourier Transform Mass Spectrometry (FTMS) for the isotopic analysis of natural geological samples. FTMS is potentially a fast and relatively inexpensive method of isotopic microanalysis, but the analysis of geologically interesting elements (for example, dating the age of rocks using uranium-lead radioactive decay systematics) raises problems regarding unwanted isotopic fractionation effects that must be resolved before FTMS can be used profitably in geochemical research.