DOI: 10.1126/science.ads8461 ISSN: 0036-8075

Evidence for Hadean mafic intrusions in the Nuvvuagittuq Greenstone Belt, Canada

C. Sole, J. O’Neil, H. Rizo, J.-L. Paquette, D. Benn, J. Plakholm

Many questions remain regarding Earth’s earliest crust owing to the rarity of Hadean (>4.03 billion-year-old) rocks and minerals. The Nuvvuagittuq Greenstone Belt (NGB) in Canada may be the only known remnant of Hadean crust, although its age is debated, ranging from ≥3.75 to 4.3 billion years old. Mafic intrusions within this belt were specifically sampled and analyzed to investigate the timing of their magmatic differentiation. Correlations between samarium/neodymium (Sm/Nd) and 143 Nd/ 144 Nd and 142 Nd/ 144 Nd ratios correspond to ages of 4157 ± 174 and 4196 81 + 53 million years for the long-lived 147 Sm- 143 Nd and the short-lived 146 Sm- 142 Nd systems, respectively. The age agreement between both extant and extinct radiogenic systems, in rocks related through igneous fractionation, is compelling evidence for preservation of Hadean rocks in the NGB, opening a rare window into Earth’s earliest times.

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