This data release supports the paper titled, “Tungsten skarn potential of the Yukon-Tanana Uplands, Eastern Alaska, USA-A mineral resource assessment”, published via open-access license in the Journal of Geochemical Exploration and available at: https://doi.org/10.1016/j.gexplo.2020.106700. The data release includes GIS data that map potential for tungsten skarn mineralization in permissive tracts in the Yukon-Tanana Uplands, Eastern Alaska, along with tables listing keywords and procedures used to produce the permissive tracts and score them for mineral potential. Supplementary Data part A lists keywords used to extract permissive rock types from the Geologic Map of Alaska (Wilson et al., 2015) to generate the permissive tract for tungsten skarn. Supplementary Data part B describes the tract polishing procedures. Supplementary Data part C lists the parameters for scoring tungsten skarn mineralization potential within the permissive tract features. The GIS data are encapsulated in a file geodatabase called AK_Wskarn_tract.gdb and are also available in the shapefile and KML formats. The geodatabase contains three datasets. The polygon feature class “primary_attributes” contains the scored tungsten skarn permissive tract subdivided by National Hydrography Dataset HUC12 drainages. A related table, “qualitative_assessment” contains detailed scoring information for each feature. The point feature class “mineral_sites_ranked” contains W-bearing mineral sites pulled from the Alaska Resource Data File with additional fields added for this study. The GIS data folder also includes the Python script used to score potential. The datasets and methods are described in detail in the accompanying paper.

This data release is part of a 2016-2019 study on the geology, geochemistry and geochronology of ore systems in the eastern Yukon-Tanana Upland region, Alaska. Whole rock chemistry was conducted on 185 samples, mostly from Au prospects, with lesser samples from porphyry Cu prospects. Geographically, most samples are from gold prospects near the Pogo Au mine and east to Black Mountain in the Big Delta quadrangle. Fewer samples are from prospects in the Eagle and Tanacross Quadrangles. Samples were submitted to the USGS contract laboratory and analyzed for select trace elements and gold. Sixty elements were determined by inductively coupled plasma-optical emission spectroscopy-mass spectroscopy (ICP-OES-MS), sodium peroxide fusion (ICP-60). Gold was determined by lead fusion fire assay.

This data release is part of a 2016-2019 study on the geology, geochemistry and geochronology of ore systems in the eastern Yukon-Tanana Upland region, Alaska. Whole rock chemistry was conducted on 185 samples, mostly from Au prospects, with lesser samples from porphyry Cu prospects. Geographically, most samples are from gold prospects near the Pogo Au mine and east to Black Mountain in the Big Delta quadrangle. Fewer samples are from prospects in the Eagle and Tanacross Quadrangles. Samples were submitted to the USGS contract laboratory and analyzed for select trace elements and gold. Sixty elements were determined by inductively coupled plasma-optical emission spectroscopy-mass spectroscopy (ICP-OES-MS), sodium peroxide fusion (ICP-60). Gold was determined by lead fusion fire assay.

The dataset consists of the input data, parameters, and results output from mineral resource assessment calculations.

The dataset consists of the input data, parameters, and results output from mineral resource assessment calculations.

Samples from the Alaska Placer Concentrate Collection (APCC) were retrieved from the USGS National Geochemical Sample Archives and submitted for mineralogical analysis at the Colorado School of Mines. The APPC contains samples from placer mining operations throughout Alaska. The original collection contained approximately 5,000 samples that were collected by U.S. Geological Survey geologists between 1895 and 1953 from various mining districts in Alaska (Cathrall, 1993). Much of the collection was lost and surviving samples are housed in the USGS National Geochemical Sample Archive (Cathrall, 1993). Maps showing the sample location and notebooks containing information about the samples in the APCC were retrieved from a Technical Data archive located in the Alaska Science Center in Anchorage. Site locations were digitized from APCC location maps and site information was obtained from the folders that accompany the location maps. Mineralogical analysis was performed on 68 samples selected from the APCC using automated a scanning-electron-microscope (SEM) based mineralogical automated mineralogy system. These data files contain the results of the mineralogical analysis.

Kalzas, in central Yukon, is a porphyry-style stockwork and sheeted-vein wolframite deposit. Alteration includes a potassic core, a quartz-tourmaline-sericite zone and an outer quartz-sericite-pyrite zone, the latter in excess of 2 km in diameter. Wolframite is confined to the inner two zones, in an oval area 1500 m by 800 m. The wolframite is disseminated within the quartz-tourmaline stockwork and also occurs as coarse crystals in sheeted veins. Mineralization occurs within Neoproterozoic to Early Cambrian Hyland Group quartzites and phyllites, which are likely intruded at depth by a pluton, possibly of the Cretaceous Tombstone Suite. From 1981 to 1984, Union Carbide carried out mapping, soil and rock geochemistry, an airborne magnetometer survey, road building, trenching and drilling of two diamond drill holes. Results from Copper Ridge's 2001 sample program range from 0.3% WO3 to 0.5% WO3 over widths up to 70 m. They demonstrate the potential to define a signifi cant resource of surface-mineable tungsten mineralization at a grade of 0.4% WO3 or better. Drilling is required to confirm grade continuity at depth and along strike.

Mineral-resources personnel from the Alaska Division of Geological & Geophysical Surveys conducted reconnaissance stream-sediment and pan-concentrate sampling in the Melozitna Mining District, Tanana and Melozitna quadrangles, from July 25 to August 13, 2011. This helicopter-supported sampling project was part of a statewide assessment of Alaska's potential for rare-earth element (REE) mineralization, and was funded by the Rare Earth Elements and Strategic Minerals Assessment capital improvement project. During this field project, 32 stream sediment and 28 heavy-mineral pan concentrate samples were collected for geochemical analysis (geochemical trace elements and rare earth elements). An additional historic U.S. Bureau of Mines sample from the area was also analyzed as part of this report. Highlights of the DGGS sampling project include documenting new gold-bearing drainages and identifying several samples with high REE values.

A mineral resource assessment for tungsten, a critical mineral commodity (see the critical mineral list published by Fortier and others, 2018) for the United States, was carried out by the U.S. Geological Survey (USGS) for a portion of the Great Basin region, in western Nevada and eastern California, between latitudes 36N and 42N and longitudes 116W and 120W. This study (Lederer and others, in review) integrates data from several sources, including geologic, geochemical, geophysical, remote sensing, watershed analysis, and mining with recently developed grade and tonnage models, expert estimates, and software tools and analyses to generate probabilistic estimates of undiscovered tungsten skarn resources. The assessment was conducted following the 3-part assessment methodology developed by Singer and Menzie (2010), which involved the delineation of permissive tracts, as well as the evaluation of interdisciplinary data that were then presented to a panel of experts, who made estimations that were then analyzed using economic filters. These data are presented in several formats: a GIS geodatabase, shapefiles, and tabular (csv) data. Several layers or individual files are derived or contain data from U.S. Geological Survey (USGS) and other existing, published sources, mainly the USGS National Geochemical Database (NGDB), USGS Mineral Resources Data System (MRDS), and the National Uranium Resource Evaluation (NURE) databases.

The dataset consists of the input data, parameters, and results output from mineral resource assessment calculations.