Are there really Archaean mantle rocks in Greenland?

I plan to do field work in SW Greenland with the aim of reevaluating a recent claim that ultramafic rocks South of Isua represents the oldest preserved mantle rocks on Earth. Such a claim has major implications, not only for our understanding of the tectonic processes in the early Earth, but more importantly it would have major consequences for recent modelling of the delivery of Earth´s ocean building blocks during the Late Accretion event. Therefore, it is critical to make an independent geochemical reassessment of those rocks.