Investigation of rare‐metal granites, pegmatites, and metasomatites minerals of Mongolia by scanning electron microscopy and x‐ray electron probe microanalysis methods

The multicomponent technique of x‐ray electron probe microanalysis for rock‐forming and minor minerals of granites, pegmatites, and metasomatites was developed using the scanning electron microscopy (SEM) and x‐ray electron probe microanalysis (EPMA) methods. The conditions for excitation and recording of elements analytical lines were chosen taking into account the properties of the investigated material. The distortion of analytical signal due to the effect of mutual overlapping of determined elements analytical lines was corrected using overlap coefficients, previously determined on the samples that did not contain the determined element. An assessment of metrological characteristics of EPMA technique showed, that it satisfies the requirements for the second category of quality of quantitative determinations and the second category of analyses adopted in the International Program for Professional Testing of Geoanalytical Laboratories (GeoPT). This developed technique was used for studying rare‐metal granites, pegmatites, and metasomatites of Central Mongolia (multiphase Baga Gazriin massif).