Pb-207/Pb-206 determination of zircons by laser probe-inductively coupled plasma mass spectrometry

Laser probe-inductively coupled plasma mass spectrometry (LP-ICP-MS) was us ed to determine Pb-207/Pb-206 ratios in single zircon grains. A Nd: YAG las er operating at 1 064 nm and a Fisons-VG PQII Turbo ICP-MS were employed. F or the known zircons, the Pb-207/Pb-206 results of LP-ICP-MS are: close to the thermal ionization mass spectrometry (TIMS) results. The spatial resolu tion of this method is 40-50 mu m and the sensitivities for lead isotopes a re about 300-400 ops/ppm. The precision of Pb-207/Pb-206 ratio is 0.3%-4% a nd depends on the lead concentration of the sampling pits. LP-ICP-MS provid es a simple, rapid and economic method for zircon Pb-207/Pb-206 determinati on.