Geochemical data from samples collected in 2022 for the Mount Harper geologic mapping project, Big Delta, Mount Hayes, and Eagle quadrangles, Alaska

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What does this data set describe?

Title:
Geochemical data from samples collected in 2022 for the Mount Harper geologic mapping project, Big Delta, Mount Hayes, and Eagle quadrangles, Alaska
Abstract:
Geochemical data from samples collected in 2022 for the Mount Harper geologic mapping project, Big Delta, Mount Hayes, and Eagle quadrangles, Alaska, Raw Data File 2023-24, presents whole-rock and major- and trace-element geochemistry of rock samples collected to support geologic mapping and mineral exploration in the Mount Harper area of the Melozitna mining district. During the 2022 field season, geologists from the Alaska Division of Geological & Geophysical Surveys (DGGS) conducted 1:100,000-scale bedrock geologic mapping of ~3,100 mi2 (~8,000 km2) within the Big Delta, Mount Hayes, and Eagle quadrangles. This project aims to produce more detailed and modern geologic maps and supporting datasets to promote mineral resource exploration in eastern Interior Alaska. The project area includes known gold (Au) mineralization, recently explored in the Richardson mining district, including the SAM project and the nearby Democrat Lode and associated prospects, and in the Goodpaster mining district at the LMS and Healy intrusion-related gold prospects. The Mount Harper area hosts a cluster of molybdenum (Mo) and tungsten (W) prospects, including porphyry Mo and W skarn styles, both of which have had industry interest over the decades. Ultramafic rocks occur in the South Fork and Volkmar river drainages; these bodies have an as-yet poorly understood potential to host platinum group elements (PGE), chrome (Cr), cobalt (Co), and nickel (Ni) resources. The DGGS map area includes a section of pre-Mississippian to Permian metasedimentary and metaigneous rocks and Triassic to Paleogene intrusive and volcanic rocks. Major- and trace-element geochemistry for these rocks was analyzed to further our understanding of the resources in the area, including distinguishing between igneous and sedimentary protoliths for metamorphic rocks and characterizing and differentiating Mesozoic and Cenozoic magmatic events in the area. Highlights of this geochemical report include sampling of the Healy and LMS projects and multiple prospects on Mount Harper and elsewhere in the map area. Sample 22Z336, collected south of the Brink prospect, yielded 1.52 ppm Au and 500 ppm W. A few samples collected at the LMS prospect yielded elevated silver (Ag) concentrations (for example, sample 22Z409 yielded up to 12.95 ppm). Additionally, sample 22Z406 yielded 1.48 ppm Au, 7.65 ppm Ag, and 1,787 ppm arsenic (As). Samples collected at Larsen Ridge/Lucky 13 prospect near the top of Mount Harper yielded high Ag and W values. For example, 22Z271 (a massive quartz vein) yielded 18.87 ppm Ag and 1,100 ppm W, 22TJN157 (a skarn) yielded 5.75 ppm Ag, 2,348 ppm copper, 4,422 ppm manganese (Mn), and 600 ppm W, and 22Z270 (a granite) yielded 2,356 ppm Mo and 200 ppm W. The Richardson mining district has been previously sampled by DGGS. This data file is released as a Raw Data File with an open end-user license. The data are available from the DGGS website: http://doi.org/10.14509/31089.
Supplemental_Information:
geochemistry-download:    Digital data available through the Alaska Geochemistry database online. Download files include data, analytical methods, and detection limits.
  1. How might this data set be cited?
    Wypych, Alicja, Twelker, Evan, Naibert, T.J., Gavel, M.M., Newberry, R.J., Szumigala, D.J., Wildland, A.D., Barrera, M.L., Harvey, D.A., Muller, I.P., Fessenden, S.N., and Blackwell, N.J., 2023, Geochemical data from samples collected in 2022 for the Mount Harper geologic mapping project, Big Delta, Mount Hayes, and Eagle quadrangles, Alaska: Raw Data File RDF 2023-24, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 3 p.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -146.995576
    East_Bounding_Coordinate: -142.019858
    North_Bounding_Coordinate: 64.548147
    South_Bounding_Coordinate: 63.491908
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 2022
    Currentness_Reference:
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: csv
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a point data set.
    2. What coordinate system is used to represent geographic features?
      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.000001. Longitudes are given to the nearest 0.000001. Latitude and longitude values are specified in decimal degrees. The horizontal datum used is WGS84.
      The ellipsoid used is WGS 84.
      The semi-major axis of the ellipsoid used is 6378137.
      The flattening of the ellipsoid used is 1/298.257223563.
  7. How does the data set describe geographic features?
    geochemistry-download
    Digital data available through the Alaska Geochemistry database online. Download files include data, analytical methods, and detection limits. (Source: Alaska Division of Geological & Geophysical Surveys (DGGS))

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
  2. Who also contributed to the data set?
    The geologic-mapping portion of the DGGS Mount Harper project was funded by the US Geological Survey Earth Mapping Resources Initiative (Earth MRI) program under Cooperative Agreement Number G22AC00288 and by State of Alaska capital improvement and general funds. The geochemical analyses reported here are funded by the State of Alaska. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the opinions or policies of the US Geological Survey. Mention of trade names or commercial products does not constitute their endorsement by the US Geological Survey.
  3. To whom should users address questions about the data?
    Alaska Division of Geological & Geophysical Surveys
    Metadata Manager
    3354 College Road
    Fairbanks, AK
    USA

    (907)451-5020 (voice)
    (907)451-5050 (FAX)
    dggspubs@alaska.gov
    Hours_of_Service: 8 am to 4:30 pm, Monday through Friday, except State holidays
    Contact_Instructions:
    Please view our website (https://www.dggs.alaska.gov) for the latest information on available data. Please contact us using the e-mail address provided above when possible.

Why was the data set created?

Mount Harper geologic mapping project aims to produce more detailed and modern geologic maps and supporting datasets to promote mineral resource exploration in eastern interior Alaska. Major- and trace-element geochemistry for these rocks was analyzed to further our understanding of the resources in the area, including distinguishing between igneous and sedimentary protoliths for metamorphic rocks and characterizing and differentiating Mesozoic and Cenozoic magmatic events in the area.

How was the data set created?

  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
    Date: 2022 (process 1 of 4)
    Field data collection - During the 2022 field season, geologists from the Alaska Division of Geological & Geophysical Surveys (DGGS) conducted 1:100,000-scale bedrock geologic mapping of about 3,100 mi2 (about 8,000 km2) within the Big Delta, Mount Hayes, and Eagle quadrangles.
    Date: 2022 (process 2 of 4)
    Sample selection - Rock samples were collected for two different purposes. Visibly mineralized or altered rock samples were preferentially collected and analyzed for trace-element geochemistry. Additionally, igneous and metaigneous rocks showing little alteration or weathering were collected for whole-rock major-oxide, minor-oxide, and trace-element analyses to aid in the classification and study of petrogenesis and tectonic setting. Most samples are grab samples collected for their overall representation of the outcrop. However, as noted in the sample field description, a few are select samples more deliberately collected from a specific feature.
    Date: 2022 (process 3 of 4)
    Sample preparation - Rock samples were processed by Bureau Veritas Commodities Canada Ltd. Mineral Laboratories (BV Mineral Laboratories) using their PRP70-250 package. The samples were crushed to greater than 70 percent passing 2 mm, and a 250 g split was pulverized to greater than 85 percent passing 75 microns. Before crushing, samples for whole-rock analysis were trimmed by DGGS staff to remove weathering.
    Date: 2023 (process 4 of 4)
    Geochemistry - Depending on the sample type, samples were analyzed for various suites of major and trace elements. Whole- rock geochemistry samples and major- and minor-oxides were analyzed by lithium borate fusion digestion and inductively coupled plasma emission spectroscopy (ICP-ES, BV Mineral Laboratories method LF300). Trace elements, including rare-earth elements, were determined using lithium metaborate fusion digestion and inductively coupled plasma mass spectroscopy (ICP-MS, BV Mineral Laboratories method LF100). Ag, As, Au, Bi, Cd, Cu, Hg, Mo, Ni, Pb, Sb, Se, Tl, and Zn were determined by aqua regia digestion and ICP-ES/MS (BV Mineral Laboratories method AQ200). Total C and S were analyzed by IR Combustion (BV Mineral Laboratories method TC000). Pt, Pd, and Au were determined by fire assay with ICP-MS finish (BV Mineral Laboratories method FA130). Major- and trace-element values for rock samples were determined by BV Mineral Laboratories method MA250: Four-acid digestion followed by inductively coupled plasma-mass spectroscopy (ICP-MS); Au values were analyzed using flux digestion and fire assay and ICP-ES (BV Mineral Laboratories method FA330-Au). Samples that exceeded detection limits for elements of interest were reanalyzed using specific elemental tests. Over-limit values for Zn were analyzed using aqua-regia digestion followed by ICP-ES (BV Mineral Laboratories method AQ370). Mn, W, Pb, Cu, and Ni were reanalyzed using four-acid digestion followed by ICP-ES (BV Mineral Laboratories method MA370).
  3. What similar or related data should the user be aware of?
    Emond, A.M., and Twelker, Evan, 2022, DGGS's completed Yukon-Tanana Upland Earth MRI airborne geophysics program and CY 2023 Mag, Rad, and EM acquisition plans (presentation): Alaska Miners Association Annual Meeting, Anchorage, Alaska, November 8-10, 2022: Poster and Presentation Emond, A.M. and Twelker, Evan, 2022, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 31 p
    Gavel, M.M., Twelker, Evan, Wypych, Alicja, Naibert, T.J., Newberry, R.J., Szumigala, D.J., Wildland, A.D., Barrera, M.L., Blackwell, N.J., Fessenden, S.N., Harvey, D.A., and Muller, I.P., 2023, Field station locations and magnetic susceptibility data collected in 2022 for the Mount Harper project, Eagle, Big Delta, and Mount Hayes quadrangles, Alaska: Raw Data File RDF 2023-6, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 3 p
    Naibert, T.J., Wypych, Alicja, Twelker, Evan, Gavel, M.M., Wildland, A.D., Newberry, R.J., Szumigala, D.J., Barrera, M.L., and Fessenden, S.N., 2022, Updates on DGGS geologic mapping efforts in eastern Interior Alaska (presentation): Alaska Miners Association annual convention, Anchorage, Alaska, November 8, 2022: Poster and Presentation Naibert, T.J. and others, 2022, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 27 p

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?
    In addition to BV Mineral Laboratories' accredited (ISO/IEC 17025) internal quality-control program, DGGS monitored analysis quality with one reference-material standard per batch of 20 analyses.
  2. How accurate are the geographic locations?
    Location data were collected using GPS-enabled tablets and smartphones running the ESRI Field Maps App. Data were merged into an ArcGIS geodatabase. The devices have a reported error of about 10 m. Latitude and longitude are reported in the WGS84 datum.
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    This data releaase is complete.
  5. How consistent are the relationships among the observations, including topology?
    Not applicable

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints:
This report, map, and/or dataset is available directly from the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (see contact information below).
Use_Constraints:
Any hard copies or published datasets utilizing these datasets shall clearly indicate their source. If the user has modified the data in any way, the user is obligated to describe the types of modifications the user has made. The user specifically agrees not to misrepresent these datasets, nor to imply that changes made by the user were approved by the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys. The State of Alaska makes no express or implied warranties (including warranties for merchantability and fitness) with respect to the character, functions, or capabilities of the electronic data or products or their appropriateness for any user's purposes. In no event will the State of Alaska be liable for any incidental, indirect, special, consequential, or other damages suffered by the user or any other person or entity whether from the use of the electronic services or products or any failure thereof or otherwise. In no event will the State of Alaska's liability to the Requestor or anyone else exceed the fee paid for the electronic service or product.
  1. Who distributes the data set? (Distributor 1 of 1)
    Alaska Division of Geological & Geophysical Surveys
    Metadata Manager
    3354 College Road
    Fairbanks, AK
    USA

    (907)451-5020 (voice)
    (907)451-5050 (FAX)
    dggspubs@alaska.gov
    Hours_of_Service: 8 am to 4:30 pm, Monday through Friday, except State holidays
    Contact_Instructions:
    Please view our website (https://www.dggs.alaska.gov) for the latest information on available data. Please contact us using the e-mail address provided above when possible.
  2. What's the catalog number I need to order this data set? RDF 2023-24
  3. What legal disclaimers am I supposed to read?
    The State of Alaska makes no expressed or implied warranties (including warranties for merchantability and fitness) with respect to the character, functions, or capabilities of the electronic data or products or their appropriateness for any user's purposes. In no event will the State of Alaska be liable for any incidental, indirect, special, consequential, or other damages suffered by the user or any other person or entity whether from the use of the electronic services or products or any failure thereof or otherwise. In no event will the State of Alaska's liability to the Requestor or anyone else exceed the fee paid for the electronic service or product.
  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 20-Oct-2023
Metadata author:
Alaska Division of Geological & Geophysical Surveys
Attn: Simone Montayne
Metadata Manager
3354 College Road
Fairbanks, AK
USA

(907)451-5020 (voice)
(907)451-5050 (FAX)
dggspubs@alaska.gov
Hours_of_Service: 8 am to 4:30 pm, Monday through Friday, except State holidays
Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
Metadata extensions used:

Generated by mp version 2.9.50 on Fri Oct 20 19:44:44 2023