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    • Oxide and Cation Compositions of Feldspar Grains from Drill Core of the Duluth Complex, Minnesota

    Metadata Updated: December 11, 2025

    The table contains oxide and cation compositions of feldspar grains from drill core of the Duluth Complex. The oxides were determined by electron probe microanalysis (EPMA) and are are reported in weight percent (wt%). The cations were then calculated and are reported in mole percent (mol%). Feldspar grains are a group of rock-forming tectosilicate minerals with potassium (K), sodium (Na), and calcium (Ca) endmembers. Anorthite has a chemical formula CaAlSi3O8; albite has the formula NaAlSi3O8; and orthoclase has the chemical formula KAlSi3O8. To better understand the composition of the measured feldspars, we calculated the anorthite content (An%) as (Ca/(Ca+Na+K)) x 100 and report the values in mol%. Albite (Ab%) was calculated as (Na/(Ca+Na+K))x100, and orthoclase (Or%) as (K/(Ca+Na+K)) x 100.

    Access & Use Information

    Public: This dataset is intended for public access and use. License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

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    Dates

    Metadata Created Date September 12, 2025
    Metadata Updated Date December 11, 2025

    Metadata Source

    Harvested from DOI USGS DCAT-US

    Other Data Resources

    Additional Metadata

    Resource Type Dataset
    Metadata Created Date September 12, 2025
    Metadata Updated Date December 11, 2025
    Publisher U.S. Geological Survey
    Maintainer
    Identifier http://datainventory.doi.gov/id/dataset/usgs-59dcd1a3e4b05fe04ccbd549
    Data Last Modified 2020-08-21T00:00:00Z
    Category geospatial
    Public Access Level public
    Bureau Code 010:12
    Metadata Context https://project-open-data.cio.gov/v1.1/schema/catalog.jsonld
    Metadata Catalog ID https://ddi.doi.gov/usgs-data.json
    Schema Version https://project-open-data.cio.gov/v1.1/schema
    Catalog Describedby https://project-open-data.cio.gov/v1.1/schema/catalog.json
    Harvest Object Id f9b2898b-d684-4d66-94b7-80cc4b85b21c
    Harvest Source Id 2b80d118-ab3a-48ba-bd93-996bbacefac2
    Harvest Source Title DOI USGS DCAT-US
    Metadata Type geospatial
    Source Datajson Identifier True
    Source Hash aac2d7db1a32fbe3a1ef39abb8d6488eec211c8567e30072dcd1dec37a9f46fe
    Source Schema Version 1.1

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