| Description |
Rock samples that were collected for slab XRF analysis were cut into nominal 4-cm-diameter disks using a tile saw. The surfaces to be analyzed were polished to a smooth, uniform surface using 60 grit and 220 grit compound on a lap wheel. The XRF analyses were run on a PANalytical Axios spectrometer using SuperQ software. Nb, Rb, Sr, Y, and Zr were measured using SuperQ 37mmRbSrYZr routine software program; other elements were measured with the IQ+37mmVac software program. The 37mmRbSrYZr routine uses specific predetermined peak and background positions for which X-Ray intensities are measured for 2-800 seconds (depending on the element). The intensity of the RhCompton peak is used to estimate mass-absorption coefficients (MACs) for both unknowns and well-characterized natural standards. Peak intensities are computed and converted to concentrations using calibration curves employing at least ten natural rock standards. Note: the reported values may be below instrumentation detection limits. The total value reported may be slightly above or below 100% due to instrumental error. |