"QEMSCAN Analysis for Antarctic Granite Partial Melt Samples"
Grant in Aid of Research
Final Report: "QEMSCAN utilizes a scanning electron microscope to identify and quantitatively assess minerals in rock thin-sections. The GIAR funds I received were used to analyze five samples from a granite partial melt zone in Antarctica. The results have exceeded expectations. The images returned are of publication quality—they clearly show the locations where hydrothermal deposition of minerals has taken place (in the subsolidus) and which minerals are interacting in melting (above the solidus). This information can be tied directly to a phase diagram, a tool in which useful parameters like temperature (at the time of melting) can be extracted. The minerals identified by QEMSCAN added to my overall understanding of the rocks. Oxides that were not identifiable under a normal petrographic microscope have been detailed in full, and several complicated clay minerals were detected. These findings will allow me to provide a much more specific description of the mineralogy in publication, and may open doors to new avenues of research in the future. One of the main sought after outcomes from the QEMSCAN analysis was an increase in precision of mineral proportions. QEMSCAN has the capability of capturing the modal percentage of minerals with ~0.02% error. Compared to typical point counting techniques (3% error), QEMSCAN is approximately 75 times more accurate. Comparing my early point count estimates with those returned by QEMSCAN, many estimates were off by ~3%, and in one case 5%. With these updated, and more accurate estimates, I can report modal percentages that will be accepted with confidence by the petrology community. The QEMSCAN analyses funded by GIAR have boosted my data to the publishable level. In the coming months, I plan on developing the manuscript and submitting to the Journal of Petrology, one of the highest impact factor journals in geology (behind only Nature and Science)."