Crustal rejuvenation stabilised Earth’s first cratons

Abstract

The formation of stable, evolved (silica-rich) crust was essential in constructing Earth’s first cratons, the ancient nuclei of continents. Eoarchaean (4000–3600 million years ago, Ma) evolved crust occurs on most continents, yet evidence for older, Hadean evolved crust is mostly limited to rare Hadean zircons recycled into younger rocks. Resolving why the preserved volume of evolved crust increased in the Eoarchaean is key to understanding how the first cratons stabilised. Here we report new zircon uranium-lead and hafnium isotope data from the Yilgarn Craton, Australia, which provides an extensive record of Hadean–Eoarchaean evolved magmatism. These data reveal that the first stable, evolved rocks in the Yilgarn Craton formed during an influx of juvenile (recently extracted from the mantle) magmatic source material into the craton. The concurrent shift to juvenile sources and onset of crustal preservation links craton stabilisation to the accumulation of enduring rafts of buoyant, melt-depleted mantle.

Secular Evolution of Continents and the Earth System

“…Together with the preservation of Hadean crustal Pb and 142 Nd isotopic signatures in early Archean mafic rocks (e.g., Kamber, 2015;O'Neil et al, 2008), the Hf isotopic record of early Earth zircons, representing felsic rocks, is Gardiner et al, 2018). The dashed black vertical lines mark the age of the oldest preserved crust in each craton (Mulder et al, 2021). See Data Set S2 in Supporting Information S1 for references.…”

The Habitability of Venus and a Comparison to Early Earth

“…(2) Small enclaves of granitoid rocks from this period still exist and are occasionally associated with metamorphosed sediments (metasediments), such as the 4.3 (O'Neil et al, 2008) to 3.8 (Cates and Mojzsis, 2007) Nuvvuagittuq Greenstone Belt and the 4.02 Ga Acasta Gneiss (Bowring and Williams, 1999) in Canada, the 3.7-3.8 Ga Isua terrane in West Greenland (Moorbath et al, 1973), and the 3.5-3.2 Ga greenstone belts of the Pilbara in W. Australia (Nelson et al, 1999) and Barberton in South Africa (Lowe and Byerly, 1999b). Finally, (3) inherited uranium-lead and hafnium isotope signatures in the reworked zircon crystals provide a certain amount of information pertaining to the pre-existing Hadean crust (Mulder et al, 2021).…”

A resource for automated search and collation of geochemical datasets from journal supplements

“…Geoscience research increasingly relies on geochemical, geochronologic, or isotopic data to investigate Earth processes in deep time. Increasingly, articles are utilizing big-data to establish statistically sound secular trends and unravel large-scale, multi-system changes in the Earth 1 – 11 . This has coincided with instrumentation developments (primarily in the field of Laser Ablation Inductively Coupled Mass Spectrometry (LA-ICP-MS)) which allow for rapid production of large datasets (several hundred unknown analyses per day), translating to a rapid rise in the rate of data generation and publication (Fig.…”