New technology and methodology for assessing sandstone composition: A preliminary case study using a quantitative electron microscope scanner (QEMScan)
Published:May 01, 2012
Jessica L. Allen, Cari L. Johnson, Matthew J. Heumann, Jared Gooley, William Gallin, 2012. "New technology and methodology for assessing sandstone composition: A preliminary case study using a quantitative electron microscope scanner (QEMScan)", Mineralogical and Geochemical Approaches to Provenance, E. Troy Rasbury, Sidney R. Hemming, Nancy R. Riggs
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Sandstone provenance is commonly characterized by point counting thin sections using a petrographic microscope. An analytical tool (QEMScan™: Quantitative Evaluation of Materials by Scanning Electron Microscopy) newly applied to provenance analyses provides complementary data and alternatives for quantifying modal compositions of sandstones. QEMScan combines scanning electron microscope (SEM) imaging and elemental analyses to create mineralogical maps of solid materials. Three different applications of QEMScan (mineralogic maps, bulk mineralogy calculations, and automated disaggregate counts) were compared to traditional (petrographic) point-count results using a test data set of 12 samples from Utah and Mongolia. Results indicate that QEMScan can provide semi-automated and rapid analyses of sandstone provenance. In the case of the manual QEMScan point-count method, the new technique largely removes operator error in grain identification. However, direct comparison to petrographic data currently requires time-consuming image processing, and adjusting QEMScan processors to recognize grain boundaries and complex grain-mineral types. Moreover, comparison of these methods provided a means to assess the operator error associated with point counting. The results of the petrographic and QEMScan methods generated comparable results, indicating that operator error does not significantly affect modal compositions through traditional techniques.