{
  "abstract": "Understanding the genesis and composition of Earth's earliest crust is critical for reconstructing the planet's early differentiation and geodynamic evolution. However, direct evidence from the Hadean (>4.0 Ga) remains elusive owing to the near-complete absence of preserved rocks from that eon. Paleoarchean layered gneisses from the Acasta Gneiss Complex (AGC, Northwest Territories, Canada) preserve isotope signatures inherited from a Hadean crustal precursor. To investigate the petrogenesis of this precursor, whole-rock 146,147 Sm-142,143 Nd data were obtained from a suite of samples cut parallel to the compositional layering of the gneiss to obtain chemically and mineralogically diverse rock slices. Additional analyses, including whole-rock major and trace element compositions, 176 Lu-176 Hf isotope systematics, and apatite ( 147 Sm-143 Nd and 176 Lu-176 Hf) and zircon (U-Pb) geochronology, were conducted to evaluate the preservation of primary isotope systematics and reconstruct the evolutionary history of the AGC.\n\nZircon U-Pb data from felsic layers define major age clusters at 3.6 to 3.5 Ga, consistent with a whole-rock 147 Sm-143 Nd isochron age of 3.53 ± 0.11 Ga, supporting their interpretation as crystallization age. In contrast, apatite Sm-Nd and Lu-Hf dates between 2.5 and 2.1 Ga record a mostly undocumented recrystallization event, likely linked to a major phase of cratonization and breakup of the Sclavia supercraton, constituting the Slave and neighbouring cratonic blocks. Two mafic samples yield Nd-and Hf-isotope compositions indicative of a primitive or enriched Archean source, whereas five intermediate-to-felsic samples with calc-alkaline affinity indicate derivation from a Hadean crustal source. This Hadean crust, represented by three felsic samples, had an average µ 142 Nd of -8.1 ± 0.7 and a corresponding ε 143 Nd 3.53Ga of -5.3 ± 0.4. From these values, a two-stage 142,143 Nd model age of 4.21 ± 0.01 Ga and a 147 Sm/ 144 Nd source value of ~ 0.14 are estimated for the AGC precursor crust. Considering the observed correlations among Sm/Nd, Lu/Hf, and SiO 2 in global crustal rocks, the AGC protocrust is inferred to have had a SiO 2 content of ≥ 55 wt% and a 176 Lu/ 177 Hf source value of ~0.014.\n\nCombined with an extraction age of 4.21 Ga, the modeled isotopic evolution of this reservoir aligns with ε 176 Hf i of zircon from the Acasta Gneiss Complex. Together, the mineral and whole-rock isotope data document the preservation of a long-lived (≥600 Myr) basaltic-andesitic Hadean protocrust that underwent episodic re-melting and differentiation into felsic continental crust, revealing a protracted history of crustal reworking and chemical differentiation in the Acasta Gneiss Complex.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": null,
  "author_total": 8,
  "authors": [
    {
      "name": "Alessandro Maltese"
    },
    {
      "name": "Guillaume Caro"
    },
    {
      "name": "Klaus Mezger"
    },
    {
      "name": "Jasper Berndt"
    },
    {
      "name": "Peter Sprung"
    },
    {
      "name": "Dieter Garbe-Schönberg"
    },
    {
      "name": "Wouter Bleeker"
    },
    {
      "name": "Erik E Scherer"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/6x2fah4aqch40.bib",
  "cited_by": 0,
  "doi": "10.1016/j.gca.2026.05.017",
  "fulltext_url": null,
  "id": "6x2fah4aqch40",
  "issns": [
    "0016-7037",
    "1872-9533"
  ],
  "landing_url": "https://hal.science/hal-05839100v1",
  "language": "en",
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "hal",
      "0.sdu"
    ],
    [
      "openalex",
      "1908|Geological and Geochemical Analysis"
    ]
  ],
  "openalex": "W7161708179",
  "pdf_url": "https://hal.science/hal-05839100/document",
  "pmcid": null,
  "pmid": null,
  "published": "2026-07-01",
  "publisher": "Elsevier",
  "ris": "https://research.draconitic.com/paper/6x2fah4aqch40.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:01Z",
      "native_id": "hal-05839100",
      "source": "hal",
      "url": "https://hal.science/hal-05839100v1"
    }
  ],
  "subjects": [
    {
      "field": "earth",
      "origin": "openalex:1908|Geological and Geochemical Analysis",
      "subfield": "geophysics"
    }
  ],
  "title": "Isotopic evidence for a long-lived Hadean basaltic–andesitic precursor to the Acasta Gneiss Complex, Canada",
  "title_text": "Isotopic evidence for a long-lived Hadean basaltic–andesitic precursor to the Acasta Gneiss Complex, Canada",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:18:01Z",
  "url": "https://research.draconitic.com/paper/6x2fah4aqch40",
  "venue": "Geochimica et Cosmochimica Acta",
  "versions": []
}