Neodymium-142 Evidence for Hadean Mafic Crust

Neodymium-142 data for rocks from the Nuvvuagittuq greenstone belt in northern Quebec, Canada, show that some rock types have lower ¹⁴²Nd/¹⁴⁴Nd ratios than the terrestrial standard (ɛ¹⁴²Nd = 0.07 to 0.15). Within a mafic amphibolite unit, ¹⁴²Nd/¹⁴⁴Nd ratios correlate positively with Sm/Nd ratios and produce a ¹⁴⁶Sm-¹⁴²Nd isochron with an age of 4280-81+53 million years. These rocks thus sample incompatible-element-enriched material formed shortly after Earth formation and may represent the oldest preserved crustal section on Earth.