This data release is the result of a hydrogeochemical sampling campaign during summer 2021 to investigate whether high resolution geochemical analysis of waters for element chemistry can be used as an exploration tool for identifying gold-rich occurrences in parts of the Big Delta B-1 and B-2 quadrangles, within the Yukon-Tanana Upland region, Alaska. Historical USGS conventional stream sediment geochemical data yielded variable indications of geochemical anomalies in conventional stream sediment geochemistry results, probably related to relative exposure of mineralized rock. Previous studies of waters in the Pogo area (western part of current study) utilized conventional analytical methods not capable of measuring low concentrations of many elements (Wang et al., 2005). In the current study, water samples were collected from 36 stream sample sites, with a focus on streams around Black Mountain to the east and the Pogo Au deposit area to the west. Both areas have known gold-rich mineral occurrences. In the eastern Black Mountain area, this included the Gray Lead, Blue Lead, and Michigan prospects, among others (U.S. Geological Survey, 1996). Sampling in the Pogo area was restricted to streams outside Leise Creek area due to anthropogenic disturbance as part of mining. Stream water samples were collected in 2021 and analyzed for cation and anion concentrations using high-resolution ICP-MS for cations and ion chromatography (IC) for anions.

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.

This data release is part of a study designed to test geochemical methods that best delineate known mineral deposits in the northeast part of the Tanacross 1° x 3° quadrangle, within the Yukon-Tanana Upland region, Alaska. The total area sampled is about 3,200 km2. Extensive tundra cover and patchy spruce/alder vegetation and very limited outcrop exposure characterize the area. Soils and stream sediments contain mixtures of weathered bedrock, sand derived from dunes developed during the Pleistocene, and volcanic ash deposits from the 1.2 Ky eruption of the nearby Mount Churchill volcano. Several mineral deposits are known in the area, including the Late Cretaceous to earliest Tertiary porphyry Cu (+/-Mo-Au) deposits at Taurus, Bluff, and Oreo; and poorly understood epithermal(?) Cu-Au (+/- Pb-Zn) deposits at Pika, Fishhook, and Pushbush. Stream water and sediment samples were collected near these occurrences, as well as in surrounding areas, to determine methods that most effectively enhance geochemical signals related to mineralization. Sediment samples were collected during two sampling campaigns (2017 and 2018). Each sample was dried, homogenized, and split into multiple aliquots. One aliquot of sediment was subsequently sieved to recover the minus-80 mesh portion of the sample, whereas a second was sieved to recover the minus-230 mesh portion of the sample. Both aliquots were analyzed by three techniques, all of which included ICP-OES/ICP-MS analysis following (1) sodium peroxide fusion, 2) leaching by aqua regia; and 3) leaching by cold hydroxylamine-HCL. Stream water samples were collected from select sites in August 2018 and analyzed for cation and anion concentrations using high-resolution ICP-MS for cations and Ion Chromatography (IC) for anions.

This data release is part of a study designed to test geochemical methods that best delineate known mineral deposits in the northeast part of the Tanacross 1° x 3° quadrangle, within the Yukon-Tanana Upland region, Alaska. The total area sampled is about 3,200 km2. Extensive tundra cover and patchy spruce/alder vegetation and very limited outcrop exposure characterize the area. Soils and stream sediments contain mixtures of weathered bedrock, sand derived from dunes developed during the Pleistocene, and volcanic ash deposits from the 1.2 Ky eruption of the nearby Mount Churchill volcano. Several mineral deposits are known in the area, including the Late Cretaceous to earliest Tertiary porphyry Cu (+/-Mo-Au) deposits at Taurus, Bluff, and Oreo; and poorly understood epithermal(?) Cu-Au (+/- Pb-Zn) deposits at Pika, Fishhook, and Pushbush. Stream water and sediment samples were collected near these occurrences, as well as in surrounding areas, to determine methods that most effectively enhance geochemical signals related to mineralization. Sediment samples were collected during two sampling campaigns (2017 and 2018). Each sample was dried, homogenized, and split into multiple aliquots. One aliquot of sediment was subsequently sieved to recover the minus-80 mesh portion of the sample, whereas a second was sieved to recover the minus-230 mesh portion of the sample. Both aliquots were analyzed by three techniques, all of which included ICP-OES/ICP-MS analysis following (1) sodium peroxide fusion, 2) leaching by aqua regia; and 3) leaching by cold hydroxylamine-HCL. Stream water samples were collected from select sites in August 2018 and analyzed for cation and anion concentrations using high-resolution ICP-MS for cations and Ion Chromatography (IC) for anions.

This U.S. Geological Survey (USGS) data release contains data from stream water, groundwater, and soil samples collected in 2019 and 2020 in the North Quartz Creek watershed in central Colorado. Fourteen streambank wells were installed in pairs at seven locations in August 2020 to capture the emerging groundwater from the left bank and right banks (relative to downstream-facing direction) and a synoptic sampling campaign was conducted to quantify metal contributions to the stream. A continuous, instream injection of sodium bromide (NaBr) was initiated at the head of the 5 km study reach several days prior to the synoptic sampling campaign and maintained throughout the duration of the study. Bromide concentrations were subsequently used to determine streamflow in the primary study reach (upper 1.3 km) using the tracer-dilution method, and as an indicator of hydrologic connections between North Quartz Creek and subsurface water. Streamflow was quantified in a secondary study reach (lower 3.7 km) using data from a series of sodium chloride slug additions wherein specific conductivity readings were used as a surrogate for the tracer concentration. Surface water samples were collected along North Quartz Creek including inflows from the left (LBI) and right (RBI) banks. Soil and sediment samples were collected along the transport path from source material (natural weathering and mine tailings/mine drainage) to the stream.

This U.S. Geological Survey (USGS) data release contains data from stream water, groundwater, and soil samples collected in 2019 and 2020 in the North Quartz Creek watershed in central Colorado. Fourteen streambank wells were installed in pairs at seven locations in August 2020 to capture the emerging groundwater from the left bank and right banks (relative to downstream-facing direction) and a synoptic sampling campaign was conducted to quantify metal contributions to the stream. A continuous, instream injection of sodium bromide (NaBr) was initiated at the head of the 5 km study reach several days prior to the synoptic sampling campaign and maintained throughout the duration of the study. Bromide concentrations were subsequently used to determine streamflow in the primary study reach (upper 1.3 km) using the tracer-dilution method, and as an indicator of hydrologic connections between North Quartz Creek and subsurface water. Streamflow was quantified in a secondary study reach (lower 3.7 km) using data from a series of sodium chloride slug additions wherein specific conductivity readings were used as a surrogate for the tracer concentration. Surface water samples were collected along North Quartz Creek including inflows from the left (LBI) and right (RBI) banks. Soil and sediment samples were collected along the transport path from source material (natural weathering and mine tailings/mine drainage) to the stream.

Data for 819 pan concentrated stream-sediment samples, nonmagnetic heavy-mineral concentrate (HMC) samples, and chemical data for 93 of HMC samples. The samples were collected in 2004-2008 as part of a reconnaissance geochemical geological survey of drainage basins mostly in the Taylor Mountains 1:250,000-scale quadrangle in southwestern Alaska. Samples were collected from first- or second-order streams, as shown on USGS 1:63,360-scale maps. The data reported here are from hand lens inspection of the panned concentrate samples in the field, microscopic examination of the non-magnetic fraction of the HMC samples in the lab, and chemical analyses by Inductively Coupled Plasma-Atomic Emission Spectrometry-Mass Spectrometry (ICP-AES-MS) of selected nonmagnetic HMC samples.

Data for 819 pan concentrated stream-sediment samples, nonmagnetic heavy-mineral concentrate (HMC) samples, and chemical data for 93 of HMC samples is presented in data file geology_mineralogy_geochemistry_TaylorMtns_Alaska_Wang.csv. The samples were collected in 2004-2008 as part of a reconnaissance geochemical geological survey of drainage basins mostly in the Taylor Mountains 1:250,000-scale quadrangle in southwestern Alaska. Samples were collected from first- or second-order streams, as shown on USGS 1:63,360-scale maps. The data reported here are from hand lens inspection of the panned concentrate samples in the field, microscopic examination of the non-magnetic fraction of the HMC samples in the lab, and chemical analyses by Inductively Coupled Plasma-Atomic Emission Spectrometry-Mass Spectrometry (ICP-AES-MS) of selected nonmagnetic HMC samples. Details of sample processing and analysis are provided in the supplemental document Supplemental_Info_Methods_Collection_Processing_Analytical.pdf. For citations regarding other analysis and samples collected during the survey see the references provided in supplemental documentation Supplemental_Info_Citations_Related_Datasets.pdf.

This set of data files contains analyses of samples representing Triassic units (Shublik and Ivishak Formations and Karen Creek Sandstone) in Alaska. The samples were collected from 20 outcrop localities in northeastern Alaska. The data set includes total organic carbon (TOC) and geochemical data from inductively coupled plasma-optical emission spectroscopy-mass spectroscopy (ICP-OES-MS) and portable X-ray fluorescence (p-XRF). The data presented here are described and interpreted in a paper titled "Facies Variation within Outcrops of the Triassic Shublik Formation, Northeastern Alaska".