title: Neodymium-142 evidence for Hadean mafic crust.
abstract: 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 (epsilon142Nd = -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.
authors.affiliation: Earth and Planetary Sciences Department, McGill University, 3450 University Street, Montreal, Quebec, H3A 2A7, Canada. oneil_jo@eps.mcgill.ca
authors.forename: Jonathan
authors.initials: J
authors.lastname: O'Neil
authors.forename: Richard W
authors.initials: RW
authors.lastname: Carlson
authors.forename: Don
authors.initials: D
authors.lastname: Francis
authors.forename: Ross K
authors.initials: RK
authors.lastname: Stevenson