{"accessLevel": "public", "bureauCode": ["010:12"], "contactPoint": {"@type": "vcard:Contact", "fn": "Amy K Gilmer", "hasEmail": "mailto:agilmer@usgs.gov"}, "description": "This U.S. Geological Survey (USGS) data release presents previously unpublished 40Ar/39Ar and uranium-lead (U-Pb) geochronologic data for igneous rocks of central Colorado. The release comprises 77 interpreted ages from 68 samples: 74 40Ar/39Ar ages determined on biotite, hornblende, K-feldspar, sanidine, groundmass, and white mica, and 3 U-Pb isotope dilution thermal ionization mass spectrometry (ID-TIMS) zircon ages from the Pikes Peak batholith. Interpreted ages range from approximately 15 to 492 million years (Ma) for the 40Ar/39Ar data and from 1084.8 to 1088.9 Ma for the U-Pb data. Analyses were performed at the USGS laboratories in Reston, Virginia, and Denver, Colorado, and at the New Mexico Geochronology Research Laboratory. Data are compiled in the USGS Geochron data compilation templates (Thomson and others, 2025) to support their inclusion in the USGS Geochron database.", "distribution": [{"@type": "dcat:Distribution", "accessURL": "https://doi.org/10.5066/P149A3ZN", "description": "Landing page for access to the data", "format": "XML", "mediaType": "application/http", "title": "Digital Data"}, {"@type": "dcat:Distribution", "description": "The metadata original format", "downloadURL": "https://data.usgs.gov/datacatalog/metadata/USGS.6a84c6111ba49b3133cd82bd.xml", "format": "XML", "mediaType": "text/xml", "title": "Original Metadata"}], "identifier": "http://datainventory.doi.gov/id/dataset/USGS_6a84c6111ba49b3133cd82bd", "keyword": ["Boulder County", "Chaffee County", "Clear Creek County", "Colorado", "Custer County", "Eagle County", "Fremont County", "Gilpin County", "Grand County", "Gunnison County", "Huerfano County", "Jackson County", "Jefferson County", "Larimer County", "Park County", "Pitkin County", "Routt County", "Summit County", "Teller County", "USGS:6a84c6111ba49b3133cd82bd", "absolute age", "argon", "geochemistry", "geochronology", "geoscientificInformation", "igneous rocks", "isotope geochemistry", "lead", "mass spectrometry", "plutonic rocks", "uranium", "volcanic rocks"], "modified": "2026-08-26T00:00:00Z", "publisher": {"@type": "org:Organization", "name": "U.S. Geological Survey"}, "spatial": "-106.8847, 37.6713, -105.1427, 40.3544", "theme": ["geospatial"], "title": "40Ar/39Ar and U-Pb ID-TIMS geochronologic data for selected igneous rocks of central Colorado, U.S.A."}