Major Element Chemical Heterogeneity in Geo2 Olivine Microbeam Reference Material: A Spatial Approach to Quantifying Heterogeneity in Primary Reference Materials

作者：Pankhurst Matthew J^*; Walshaw Richard; Morgan Daniel J

来源：Geostandards and Geoanalytical Research, 2017, 41(1): 85-91.

DOI：10.1111/ggr.12134

• chemical mapping
• olivine
• natural mineral reference material
• microbeam
• primary reference material
• microanalysis
• characterisation

A 270 spot-analysis study was conducted across a large (ca. 1200mx1200m) chip of Geo2 olivine from a commercially available GEO Mk2 block (P and H Developments , Standards for EPMA), which revealed an 8.7% relative range in FeO abundance. Interleaved and overlapping grids of different resolutions were measured sequentially to prove spatial patterns are not due to drift or other external sources of error. Results were mapped and interpolated using commercially available geographical information system software, such that composition could be predicted according to location with high accuracy. The simple, systematic zonation pattern observed demonstrates that useful-sized regions of acceptable homogeneity do exist for some elements. This knowledge allows a user to target individual regions of a characterised chip for use as distinct measurement standards. As analysis times decrease and data sets grow, this approach may maximise laboratory efficiency by characterising large chips and extending time between conventional block repolish and coating, particularly in those cases where the avoidance of prior beam damage is a key concern.

• 出版日期2017-3