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Craig A Johnson

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These data consist of sulfur and carbon isotope compositions, concentrations of selected elements, and concentrations of pyrite sulfur and organic carbon in mudstone samples collected from five cores drilled in the Howards Pass district, Yukon-Northwest Territories, Canada. The cores were drilled between 2006 and 2014, site visits and core sampling took place between 2009 and 2016, and laboratory work was conducted between 2011 and 2017. The data were obtained as part of a research project described in the following publication: Johnson, Craig A., Slack John F., Dumoulin, Julie A., Kelley, Karen D., and Falck, Hendrick, 2018, Sulfur isotopes of host strata for Howards Pass (Yukon-Northwest Territories) Zn-Pb deposits...
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This U.S. Geological Survey (USGS) data release contains analytical data from a suite of rock and mineral samples collected from drill core within the Elk Creek alkaline complex, southeast Nebraska. This complex hosts the Elk Creek carbonatite, a multilithologic carbonatite enriched in niobium, rare earth elements (REEs), scandium, and titanium. Mineralized carbonatites are the world’s primary source of rare earth elements (REEs) and niobium, but only a few deposits are responsible for meeting the current demand of these critical elements such that there is increasing interest in other carbonatites that have the potential to help meet future demands. This study focuses on the Elk Creek carbonatite, the largest...
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Elemental concentrations and stable oxygen and carbon isotope ratios are reported for five mammillary calcite specimens collected from the groundwater-filled fissures Devils Hole and Devils Hole II in the southern Amargosa Desert, south-western Nevada. Previous studies of these specimens yielded oxygen and carbon isotope chronologies of paleoclimatic and paleo hydrologic conditions over an approximately 500,000-year time period as defined by uranium series dates (Winograd and others, 1992, 2006; Landwehr and others, 1997, 2011). The elemental concentration measurements reveal additional chronologies in the mammillary calcite. The specimens were sampled by milling contiguous 0.050-inch-thick layers (1.27 millimeters)...
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These data are sulfur isotope determinations (34S/32S ratios) for sulfur-bearing minerals collected from epithermal veins in the Lowland mining district, Montana, USA and from metasedimentary rocks that host the Black Angel zinc-lead-silver deposit, Greenland. The samples were collected by cooperators as parts of larger ore genesis studies. The determinations were performed between February 2019 and March 2021 on 35 samples of pyrite, sphalerite, galena, and chalcopyrite from Lowland vein occurrences and 5 samples of anhydrite from Black Angel host rocks.
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These data represent sulfur isotope analyses of chalcopyrite from a base metal deposit in the Aliabad-Khanchy area in northwestern Iran. Rock samples were collected from outcrops, and chalcopyrite was separated for analysis by hand picking. The separates were analyzed for the ratio 34-S/32-S by elemental analyzer-isotope ratio monitoring mass spectrometry. Standardization was performed by analyzing internationally-distributed standards along with the unknowns and then normalizing the results to the accepted values for the standards. These data support the following publication: Kouhestani, H., Mokhtari, M.A.A., Chang, Z., and Johnson, C.A., 2018, Intermediate sulfidation type base metal mineralization at Aliabad-Khanchy,...
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