Single zircon U-Pb geochronology of the Limpopo Belt by secondary ion mass spectrometry

Abstract

Single zircon U-Pb chronology was applied to help understanding the evolution of the Limpopo Belt in southern Africa. High mass resolution = 6000) obtained by a CAMECA IMS-3F ion microprobe was sufficient to determine Pb/U ratios of zircon crystals without any significant mass interferences. U-Pb ages of euhedral zircons from the belt cluster at around 3.2 Ga for the Central Zone and 2.8 Ga for the Northern Marginal Zone. The difference in age between the two zones can be explained by difference in protolith age. Timing of metamorphism was identified for the Northern Marginal Zone as 2 to 1.7 Ga which is younger than previously reported metamorphic ages of the Limpopo Belt. © 1995, GEOCHEMICAL SOCIETY OF JAPAN. All rights reserved.