{"accessLevel": "public", "bureauCode": ["010:12"], "contactPoint": {"@type": "vcard:Contact", "fn": "Bradley S. Van Gosen", "hasEmail": "mailto:bvangose@usgs.gov"}, "description": "This data release contains the whole-rock major and trace element analyses of 51 samples of intrusive igneous rocks from the Wet Mountains area of Custer and Fremont counties of south-central Colorado, collected by U.S. Geological Survey (USGS) geologists. \nThe samples were collected from breccias, veins and thin dikes, and a variety of carbonatite, felsic, mafic, and ultramafic intrusions across the area. The first 41 samples listed in this data release were collected in July 2007, originally as part of a reconnaissance study of the thorium deposits of the area (Van Gosen and others, 2009). The samples are grab samples from outcrops, shallow open-pit excavations, and mineral prospect trenches. The last 10 samples listed in this data release were originally collected and geochemically analyzed in 1976 as part of a USGS study of carbonatites in this area (Armbrustmacher, 1976, 1979; Armbrustmacher and Brownfield, 1978). These 10 carbonatite samples were reanalyzed by modern analytical methods in 2007, and the new data are included in this data release.\nThe Wet Mountains area hosts a variety of alkaline intrusions (Armbrustmacher, 1984), which includes three Cambrian-age alkaline complexes (Olson and others, 1977) that intruded the surrounding Precambrian terrane. These are (1) the McClure Mountain Complex (Shawe and Parker, 1967; Armbrustmacher, 1984), (2) the Gem Park Complex (Parker and Sharp, 1970), and (3) the complex at Democrat Creek (Armbrustmacher, 1984). In the Wet Mountains area, elevated concentrations of thorium and rare earth elements (REEs) occur in veins, syenite dikes, fracture zones, breccias, and carbonatite dikes (Armbrustmacher, 1988). These thorium-REE deposits are distal to the alkaline complexes but are thought to be genetically associated. \nCharacteristics of the thorium and REE deposits in the area, as well as typical concentrations and resource estimates, are detailed in the publications listed in the supplementary file \u201cWet Mountains area publications.pdf\u201d. Armbrustmacher (1988) determined that vein and fracture zone deposits contain most of the thorium and REE resources in the area. These are linear features, typically 1\u20132 meters thick, but a few are as much as 15 meters thick. Some individual thorium veins can be traced in outcrop for 1,500 m and some radioactive fracture zones for as much as 13 kilometers. Most of these vein- and fracture-zone deposits occur within a 57 square kilometers tract of Precambrian gneiss and migmatite (Scott and others, 1976) located south and southeast of the quartz syenite complex at Democrat Creek; in this area Christman and others (1953, 1959) mapped nearly 400 veins. \nMost of the samples in this data release are examples of unaltered alkaline igneous rocks of the intrusive complexes rather than the mineral deposits. These samples were selected in the field to study possible relationships between the magmatic complexes and the thorium-REE deposits. \nAll samples included in this data release were analyzed by laboratories contracted by the USGS. Major and trace element concentrations were determined by inductively coupled plasma-atomic emission spectrometry (ICP-AES) and inductively coupled plasma-mass spectrometry (ICP-MS). An acceptable criteria for the data has been identified based on (1) if recovery of each element is within a designated percentage at five times the lower limit of determination, and (2) the calculated relative standard deviation of duplicate samples is no greater than that percentage. The reported laboratory percentages for the acceptance criteria are +/- 15 percent for ICP-AES and ICP-MS. Ten carbonatite samples were additionally analyzed by wavelength dispersive X-ray fluorescence (WDXRF) to determine the concentrations of major elements as oxides. The reported laboratory percentages for the acceptance criteria are +/- 5 percent for WDXRF.\nData are reported in a comma-separated values (CSV) file that lists the samples that were analyzed, latitude/longitude location information, brief sample descriptions, and relevant publications. The column headings and abbreviations are explained in the accompanying data dictionary.\nReferences cited above:\nArmbrustmacher, T. J., 1976, Thorium deposits in the Wet Mountains area, Fremont and Custer Counties, Colorado: U.S. Geological Survey Open-File Report 76\u2013284, 18 p.,\nhttps://doi.org/10.3133/ofr76284\nArmbrustmacher, T.J., 1979, Replacement and primary magmatic carbonatites from the Wet Mountains area, Fremont and Custer Counties, Colorado: Economic Geology, v. 74, no. 4, p. 888\u2013901, http://doi.org/10.2113/gsecongeo.74.4.888\nArmbrustmacher, T.J., 1984, Alkaline rock complexes in the Wet Mountains area, Custer and Fremont Counties, Colorado: U.S. Geological Survey Professional Paper 1269, 33 p., https://doi.org/10.3133/pp1269\nArmbrustmacher, T.J., 1988, Geology and resources of thorium and associated elements in the Wet Mountains area, Fremont and Custer Counties, Colorado: U.S. Geological Survey Professional Paper 1049\u2013F, 34 p., 1 plate, https://doi.org/10.3133/pp1049f\nArmbrustmacher, T.J., and Brownfield, I.K., 1978, Carbonatites in the Wet Mountains area, Custer and Fremont Counties, Colorado\u2014Chemical and mineralogical data: U.S. Geological Survey Open-File Report 78\u2013177, 6 p., 3 sheets, https://doi.org/10.3133/ofr78177\nChristman, R.A., Brock, M.R., Pearson, R.C., and Singewald, Q.D., 1959, Geology and thorium deposits of the Wet Mountains, Colorado\u2014A progress report: U.S. Geological Survey Bulletin 1072\u2013H, p. 491\u2013535, https://doi.org/10.3133/b1072h\nChristman, R.A., Heyman, A.M., Dellwig, L.F., and Gott, G.B., 1953, Thorium investigations 1950\u201352, Wet Mountains, Colorado: U.S. Geological Survey Circular 290, 40 p., 5 plates, https://doi.org/10.3133/cir290\nOlson, J.C., Marvin, R.F., Parker, R.L., and Mehnert, H.H., 1977, Age and tectonic setting of lower Paleozoic alkalic and mafic rocks, carbonatites, and thorium veins in southcentral Colorado: U.S. Geological Survey Journal of Research, v. 5, no. 6, p. 673\u2013687, https://doi.org/10.3133/70007423\nParker, R.L., and Sharp, W.N., 1970, Mafic-ultramafic igneous rocks and associated carbonatites of the Gem Park Complex, Custer and Fremont Counties, Colorado: U.S. Geological Survey Professional Paper 649, 24 p., https://doi.org/10.3133/pp649\nScott, G. R., Taylor, R. B., Epis, R. C., and Wobus, R. A., 1976, Geologic map of the Pueblo 1\u00b0x2\u00b0 quadrangle, south-central Colorado: U.S. Geological Survey Miscellaneous Field Studies Map MF\u2013775, scale 1:250,000, https://doi.org/10.3133/mf775\nShawe, D.R., and Parker, R.L., 1967, Mafic-ultramafic layered intrusion at Iron Mountain, Fremont County, Colorado: U.S. Geological Survey Bulletin 1251\u2013A, 28 p., https://doi.org/10.3133/b1251A\nVan Gosen, B.S., Gillerman, V.S., and Armbrustmacher, T.J., 2009, Thorium deposits of the United States\u2014Energy resources for the future?: U.S. Geological Survey Circular 1336, 21 p., https://doi.org/10.3133/cir1336", "distribution": [{"@type": "dcat:Distribution", "accessURL": "https://doi.org/10.5066/P99YBJLX", "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.5fa5aee1d34ed3698f92dfcc.xml", "format": "XML", "mediaType": "text/xml", "title": "Original Metadata"}], "identifier": "http://datainventory.doi.gov/id/dataset/USGS_5fa5aee1d34ed3698f92dfcc", "keyword": ["Cambrian", "Colorado", "Custer County", "DOI", "Democrat Creek", "Democrat Creek complex", "Department of the Interior", "Energy and Minerals Mission Area", "Fremont County", "GGGSC", "Gem Park", "Gem Park Complex", "Geology, Geophysics, and Geochemistry Science Center", "ICP-AES", "ICP-MS", "Inductively Coupled Plasma-Atomic Emission Spectrometry", "Inductively Coupled Plasma-Mass Spectrometry", "Iron Mountain", "MRP", "McClure Mountain", "McClure Mountain Complex", "Mineral Resources Program", "Precambrian", "Region 7: Upper Colorado Basin", "U.S. Geological Survey", "USA", "USGS", "USGS:5fa5aee1d34ed3698f92dfcc", "United States of America", "WDXRF", "Wavelength Dispersive X-Ray Fluorescence Spectrometry", "Wet Mountains", "data release", "economic geology", "geochemistry", "geology", "geoscientificinformation", "mass spectroscopy", "metallic mineral resources", "mineral resources", "rare earth elements", "south-central Colorado", "thorium"], "modified": "2020-12-15T00:00:00Z", "publisher": {"@type": "org:Organization", "name": "U.S. Geological Survey"}, "spatial": "-105.55257, 38.22300, -105.35500, 38.52419", "theme": ["geospatial"], "title": "Whole-rock geochemical data for alkaline intrusive rocks in the Wet Mountains area of Custer and Fremont Counties, south-central Colorado, USA"}