{
  "abstract": "Nickel, copper, cobalt, and the platinum-group metals are all on the final 2025 U.S. List of Critical Minerals, and the 1.1-billion-year-old Midcontinent Rift around Lake Superior hosts some of the largest domestic resources of them. The rock chemistry needed to study these systems is public but fragmented: it is spread across the U.S. Geological Survey (USGS) National Geochemical Database, project-level USGS data releases, the GEOROC compilation, and individual EarthChem datasets, each with its own units, method codes, and conventions for values below or above analytical limits. We present MCR-GeoChem v1.0.0, an open, versioned, reproducible compilation of 3,524 Midcontinent Rift samples and 168,748 geochemical determinations (88 analytes) from Michigan, Minnesota, and Wisconsin. Every value is converted to a common unit scheme (oxides in wt%, trace elements in ppm, Auand platinum-group elements in ppb) while retaining its original form; censored values are decoded into an explicit qualifier and limit; 89 source method codes are mapped to a common vocabulary of technique, digestion, and completeness; and each sample carries a rift-membership label tied to the USGS State Geologic Map Compilation. An open checker, mcrqa, adds value- and sample-level flags for below-detection results, uninformative detection limits, semi-quantitative and partial-digestion methods, unit errors, oxide-total problems, likely post-magmatic alteration, coordinate quality, and cross-source duplicates. The compilation shows that 27% of determinations derive from legacy semi quantitative emission spectrography, that 501 of 1,304 platinum results are below-detection values whose limits are too high to constrain the rock, and that 488 of 2,821 igneous whole-rock samples carry at least one alteration flag. The full pipeline rebuilds the release from public sources with identical results. The dataset, the method and detection-limit crosswalk, and the checker are released under open licenses to support critical-mineral research in the Lake Superior region.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": null,
  "author_total": 2,
  "authors": [
    {
      "name": "Bezali Kwame Danso"
    },
    {
      "name": "Saadatu Abdullah"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/e0849h57n4srz.bib",
  "cited_by": 0,
  "doi": "10.31223/x5zv47",
  "fulltext_url": null,
  "id": "e0849h57n4srz",
  "issns": [],
  "landing_url": "https://eartharxiv.org/repository/view/15631/",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/legalcode",
  "metadata_licence": null,
  "native_subjects": [
    [
      "bepress",
      "Duluth Complex"
    ],
    [
      "bepress",
      "Earth Sciences"
    ],
    [
      "bepress",
      "Education"
    ],
    [
      "bepress",
      "Environmental Sciences"
    ],
    [
      "bepress",
      "Geochemistry"
    ],
    [
      "bepress",
      "Geology"
    ],
    [
      "bepress",
      "Higher Education"
    ],
    [
      "bepress",
      "Keweenawan"
    ],
    [
      "bepress",
      "Midcontinent Rift"
    ],
    [
      "bepress",
      "Physical Sciences and Mathematics"
    ],
    [
      "bepress",
      "critical minerals"
    ],
    [
      "bepress",
      "data quality"
    ],
    [
      "bepress",
      "detection limits"
    ],
    [
      "bepress",
      "geochemical data harmonization"
    ],
    [
      "bepress",
      "platinum-group elements"
    ],
    [
      "openalex",
      "1908|Geological and Geochemical Analysis"
    ]
  ],
  "openalex": "W7223112367",
  "pdf_url": "https://eartharxiv.org/repository/object/15631/download/27400/",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-21",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/e0849h57n4srz.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:49Z",
      "native_id": "15631",
      "source": "eartharxiv",
      "url": "https://eartharxiv.org/repository/view/15631/"
    }
  ],
  "subjects": [
    {
      "field": "earth",
      "origin": "bepress:Environmental Sciences",
      "subfield": "environmental-science"
    },
    {
      "field": "earth",
      "origin": "bepress:Geochemistry",
      "subfield": "geology-geochemistry"
    }
  ],
  "title": "MCR-GeoChem: A harmonized, quality-flagged open compilation of whole-rock and mineral geochemistry for the 1.1 Ga Midcontinent Rift in Michigan, Minnesota, and Wisconsin",
  "title_text": "MCR-GeoChem: A harmonized, quality-flagged open compilation of whole-rock and mineral geochemistry for the 1.1 Ga Midcontinent Rift in Michigan, Minnesota, and Wisconsin",
  "type": "preprint",
  "updated_at": "2026-10-30T12:17:49Z",
  "url": "https://research.draconitic.com/paper/e0849h57n4srz",
  "venue": "EarthArXiv",
  "versions": []
}