APPLICATIONS OF LAM-ICP-MS ANALYSIS TO MINERALS

Laser-ablation microprobe ICP-MS (LAM-ICP-MS) is rapidly emerging as a n exciting new analytical tool in the earth sciences. Here we present the results of a series of isotopic and trace-element studies of vario us minerals; we used a commercially available Fisons-VG Laserprobe and PQ2 + ICP-MS capable of ablation at spot-sizes of 20 to 60 mu m. Resu lts are presented for Pb/Pb dating elf zircon, for which an accuracy o f <1% is attainable. For carbonate and mafic minerals of igneous origi n, detection limits of 100 ppb and precisions of 2-5% are attained for many trace elements. In general, calibration is possible using synthe tic or natural standards; as elemental responses are controlled by the efficiency of the ionization of ablated material in the ICP-plasma, m atrix-matched calibrations are not as important as for ion-probe analy sis, owing to the efficiency of ionization in the plasma torch. In the future, new high-sensitivity ICP - mass spectrometers, coupled with h igh-spatial-resolution UV laser microprobes, should provide detection limits at the ppt level and spatial resolution comparable with that at tained with an ion microprobe.