No zircon U-Pb evidence for a Precambrian component in the Late Eocene Yavuna trondhjemite, Fiji

It has been speculated, based on zircon Pb-α dating in the late 1950s, that the Yavuna stock on Viti Levu, Fiji, might contain pre-magmatic inherited components of Paleozoic or Neoproterozoic age. SIMS U-Pb isotopic analyses of nearly 50 zircon grains from a sample of the Yavuna trondhjemite have produced no evidence to support this suggestion. Although the analysed zircon grains do contain older cores, they are only 2.2 ± 0.3 Ma older than the 36.4 ± 0.6 Ma zircon rims that record emplacement of the trondhjemite magma in the Late Eocene.