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The sensitive high-resolution ion microprobe (also sensitive high mass-resolution ion microprobe or SHRIMP) is a large-diameter, double-focusing secondary ion mass spectrometer (SIMS) sector instrument produced by Australian Scientific Instruments in Canberra, Australia.Like other SIMS instruments, the SHRIMP microprobe bombards a sample under vacuum with a beam of primary ions that sputters secondary ions that are focused, filtered, and measured according to their energy and mass.Further advances in design have also led to multiple ion collection systems (already introduced in the market by a French company years before), negative-ion stable isotope measurements and on-going work in developing a dedicated instrument for light stable isotopes.
ARR96-114A & B: Rincon Range, Southern Sangre de Cristo Mountains just north of Mora, NM with an isotopic age of ~1.42 GA This sample is a sillimanite nodule-quartz-muscovite schist.
JB54: Tusas Mountains, Cerro Colorado near Ojo Caliente, NM.
This sample is currently used at UMass to test analytical precision.
It was hoped that the perhaps some remnant of Mazatzal metamorphism could be seen in these monazites from a sample thought to have experienced metamorphism both at ~1.65 GA and at ~1.42 Ga.
The probe data overall are consistent with the isotopic age, but with considerable variability (see the data spreadsheet, and the grain maps and images for details).