Petrochronology is the simultaneous use of geochronology and geochemistry to address geologic problems. Petrochronology studies have mostly been conducted by using LA-ICP-MS or secondary ion mass spectrometry (SIMS) to measure dates in one analytical session.

As a special type of LA-ICP-MS technique, the laser-ablation split-stream (LASS) has the aerosol stream split and partly directed into an MC-ICP-MS for Hf isotopic ratio measurements, and the rest directed into a SC-ICP-MS for U–Pb age and trace-element abundance measurements. The LASS technique has taken advantage of the high spatial resolution of laser ablation, the superior isotopic ratio measurement capability of the MC-ICP-MS, and the capability of rapid measurement over a large mass range of the SC-ICP-MS.

Figure above shows some Hf data and U–Pb data generated with LASS technique combining the Nu Plasma HR instrument and Nu Attom instrument. The full size discrete dynode multipliers of the Nu Plasma allows for superior measurement precision of small beams, and variable zoom optics system allows for instantaneous isotope system switching when measuring transient signals, making Nu Plasma the instrument of choice for this type of work.

Data source: Kylander-Clark et al., Chemical Geology 345 (2013) 99-112