Contention For Record
In 2008, a McGill University team reported a 4.28 billion year old outcrop in the Nuvvuagittuq greenstone belt on the eastern shores of Hudson Bay, 40 kilometres south of Inukjuak, Quebec, Canada. However, the dating method used did not involve similar radiometric dating of zircon crystals and it remains somewhat contentious whether the reported date represents the age that the rock itself formed or a residual isotopic signature of older material that melted to form the rock. Mafic rocks from the Nuvvuagittuq greenstone belt have recorded isotopic compositions that can only be produced in the Hadean (i.e. older than 4 billion years ago) and the complete isotopic study of all the lithologies included in the Nuvvuagittuq greenstone belt suggests that it was formed nearly 4.4 billion years ago
Read more about this topic: Acasta Gneiss
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