Multi-collector mass spectrometers like the WiscAr Noblesse have led to improvement in precision/accuracy of up>40up>Ar/up>39up>Ar data.
The high mass resolving power of the Noblesse allows for partial resolution of interfering species at m/e 36.
Single crystal dates from the Alder Creek sanidine are nearly identical to the age suggested by Rivera et al. (2013).
Use of the Fish Canyon sanidine standard in up>40up>Ar/up>39up>Ar-based refinement of the geologic timescale must be done with caution.
High precision up>40up>Ar/up>39up>Ar dating of sanidine is now capable of leveraging interpretation of U–Pb ID-TIMS zircon dates.