SINGLE ZIRCON U-PB GEOCHRONOLOGY OF THE LIMPOPO BELT BY SECONDARY-IONMASS-SPECTROMETRY

Single zircon U-Pb chronology was applied to help understanding the ev olution of the Limpopo Belt in southern Africa. High mass resolution ( M/Delta M = ca. 6000) obtained by a CAMECA IMS-3F ion microprobe was s ufficient to determine Pb/U ratios of zircon crystals without any sign ificant mass interferences. U-Pb ages of euhedral zircons from the bel t cluster at around 3.2 Ca for the Central Zone and 2.8 Ga for the Nor thern Marginal Zone. The difference in age between the two zones can b e explained by difference in protolith age. Timing of metamorphism was identified for the Northern Marginal Zone as 2 to 1.7 Ga which is you nger than previously reported metamorphic ages of the Limpopo Belt.