@Anthro @Ceedave The 4.3 Ga age is from coupled Nd-Sm systems (short and long lived); the mafic rocks do not have zircons. The younger age is from zircons in cross-cutting felsic units. This is the work of Jonathan O'Neil (now at #uottawa) https://mcgillnews.mcgill.ca/s/1762/news/interior.aspx?sid=1762&gid=2&pgid=1190

https://en.wikipedia.org/wiki/Nuvvuagittuq_Greenstone_Belt

Some of the rind remains and is compositionally distinct. Recent work has used triple oxygen to constrain seawater chemistry (https://www.sciencedirect.com/science/article/abs/pii/S0012821X22001753)
#Hadean #McGilUniversity #PillowBasalt