Trace elements in glass and silicates minerals (e.g., Feldspar, Pyroxene, etc.)
The SHRIMP-RG is uniquely equipped to perform trace element analyses of glass or silicate mineral with high spatial resolution and analytical precision at the ppm or ppb level, for most elements. Due to the high mass resolving power (MRP) of the SHRIMP-RG, many interfering molecules can be fully resolved from the isotope of interest, particularly for elements like Sc, Ti, Nb, Sr, Rb, and REE.
Materials that we have analyzed include: rhyolitic and basaltic glasses, feldspars, Ti-in-quartz, olivine and pyroxenes, garnet, mica, etc. Concentrations are calculated by measuring multiple standards of the same mineral, or where none exists, glass standards that have similar bulk chemistry to the mineral of interest. An example of standardization of Rb in glass is shown below, where ATHO, RLS, and Macusani are natural rhyolitic glasses, and the published concentration is plotted on the x-axis and the measured intensity (normalized to SiO) is plotted on the y-axis. The slope of the line, or "calibration curve," is used to calculate concentrations for unknown samples.
These analyses can be performed in-situ on thin section chips, or on mineral grain mounts.