Ion microprobe analysis of rock-forming minerals from the Carnmenellis Granite

In order to identify the major mineral sources for Li, Be, B, Rb, Sr, Cs and Ba in the Carnmenellis Granite, semi-quantitative ion microprobe analyses were performed. Handpicked microperthite and biotite grains were bombarded with O - ions while positive secondary ion signals were recorded. The latter were converted into elemental concentrations using the local thermodynamic equilibrium (LTE) model. The microperthitic K-feldspar was found to be the major source for K, Sr (except for the Sr rich plagioclase cores) and Ba, while biotite had the highest Li, Be, Rb and Cs contents.