Mo. Figueiredo et al., Synchrotron XRF microprobe analysis of geological samples: Influence of size and orientation of single mineral grains, X-RAY SPECT, 28(4), 1999, pp. 251-254
The results of a photon microprobe study on the influence of size and orien
tation of single mineral grains on geochemical data when analysing geologic
al samples are presented. A large crystal of primary pegmatitic muscovite a
nd an aggregate of small lamellar secondary lepidolite grains were analysed
at various points. The primary synchrotron radiation beam orientation has
a negligible effect upon geochemical data for tetrahedral and octahedral ca
tions in both minerals. Conversely, the analytical results for the large in
terlayer cations are significantly more dispersed when the incident beam is
parallel to the (001) plane of the crystal(s), Furthermore, the analysis o
f the sub-parallel aggregate of lepidolite minute crystals provided higher
concentration figures for substituting large cations (particularly caesium)
when the incoming beam was so oriented. Copyright (C) 1999 John Wiley & So
ns, Ltd.