Geochemical data from samples collected in 2025 for the Steese and Tolovana projects, Yukon-Tanana Upland, Alaska

Metadata also available as - [Parseable text] - [XML]

Frequently anticipated questions:


What does this data set describe?

Title:
Geochemical data from samples collected in 2025 for the Steese and Tolovana projects, Yukon-Tanana Upland, Alaska
Abstract:
Geochemical data from samples collected in 2025 for the Steese and Tolovana projects, Yukon-Tanana Upland, Alaska, Raw Data File 2026-20, presents major-oxide and trace-element geochemistry of igneous, metamorphic, and potentially mineralized rocks collected during DGGS' 2025 field season for the Steese and Tolovana projects as part of 1:100,000-scale bedrock geologic mapping within the Yukon-Tanana Upland of eastern Interior Alaska. This mapping covered parts of the Big Delta, Circle, Fairbanks, and Livengood quadrangles, an area identified by the U.S. Geological Survey's Earth Mapping Resources Initiative (USGS Earth MRI) as a priority for modernizing geologic mapping and evaluating regional favorability for rare-earth elements (REEs) and both critical and non-critical mineral resources. The geologic area of interest has experienced episodic magmatism from the Devonian through the Cenozoic. This magmatic and deformational period is associated with gold (+/- W, Te, Bi, Sb, and As) mineralization at the Fort Knox mine, Golden Summit, and other mineral deposits in the Fairbanks and Circle mining districts. The Roy Creek prospect hosts U, Th, REE, and F mineralization associated with a ca. 90 Ma peralkaline syenite stock. Magmatism during the latest Cretaceous and early Paleogene may be expressed as plutonic or hypabyssal intrusive rocks; notable intrusions of this age include the Lime Peak-Cache Mountain area (granite-related Sn-W prospects) and Table Mountain and Mount Prindle areas (Au, W) (Newberry and others, 1996; Robinson and others, 1990; Smith and others, 1987; Wiltse and others, 1995). This dataset helps refine interpretations of the region's geologic framework and supports tectonic and mineral resource studies across east-central Alaska. These data are provided as a Raw Data File and are available on the DGGS website at: http://doi.org/10.14509/32140.
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?
    Moshrefzadeh, J.A., Barrera, M.L., Buchanan, J.W., Naibert, T.J., Newberry, R.J., Norwood, L.P., Regan, S.P., Szumigala, D.J., Twelker, Evan, Walser, S.L., and Wilson, K.R., 2026, Geochemical data from samples collected in 2025 for the Steese and Tolovana projects, Yukon-Tanana Upland, Alaska: Raw Data File RDF 2026-20, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 7 p.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -148.728614
    East_Bounding_Coordinate: -143.914065
    North_Bounding_Coordinate: 65.732374
    South_Bounding_Coordinate: 64.453407
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 2025
    Currentness_Reference:
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: data
  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 0.0000001. Longitudes are given to the nearest 0.0000001. Latitude and longitude values are specified in decimal degrees. The horizontal datum used is NAD83.
      The ellipsoid used is GRS 80.
      The semi-major axis of the ellipsoid used is 6378137.
      The flattening of the ellipsoid used is 1/298.257222101.
  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?
    We acknowledge that our geologic work takes place throughout the unceded lands of the Indigenous Peoples of Alaska. Our offices are located on the traditional territories of the lower Tanana Dene Peoples and the Dena'ina Peoples. The DGGS Tolovana and Steese projects are funded by the State of Alaska and the USGS Earth Mapping Resources Initiative program under Cooperative Agreement numbers G24AC00323 and G23AC00372. 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 U.S. Government. Mention of trade names or commercial products does not constitute their endorsement by the U.S. Government.
  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?

This dataset provides geochemical data from 2025 DGGS bedrock mapping in the Yukon-Tanana Upland to help Alaska evaluate rare-earth, critical mineral, and gold resource potential in a historically productive mining region and to refine the geologic framework of east-central Alaska.

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: 2025 (process 1 of 3)
    Sample collection - Fresh, unweathered rock samples were collected from surface outcrops by DGGS field geologists during geologic mapping. Location data for samples were recorded in the WGS84 datum using GPS-enabled field tablets. The samples collected and analyzed for this report were separated into two groups: those collected for whole-rock major-oxide, minor-oxide, and trace-element analyses (MOX; n=193), and those collected for trace-element geochemistry (GX; n=86) based on the presence of visible mineralization or alteration. MOX samples are igneous, metaigneous, or metasedimentary rocks that show little alteration or weathering.
    Date: 2025 (process 2 of 3)
    Sample preparation - DGGS staff trimmed weathered surfaces from MOX samples to analyze fresh material only, but left GX samples untrimmed to preserve alteration and mineralization. At ALS Geochemistry (ALS), all samples were processed and analyzed. During preparation, 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.
    Date: 2025 (process 3 of 3)
    Sample analysis - ALS Geochemistry (ALS) analyzed MOX samples using package CCP-PKG01, which included lithium borate fusion with inductively coupled plasma atomic emission spectroscopy (ICP-AES) for major and minor oxides (ME-ICP06); lithium borate fusion with inductively coupled plasma mass spectrometry (ICP-MS) for trace and rare earth elements (ME-MS81); four-acid digestion with ICP-AES for Ag, Cd, Co, Cu, Li, Mo, Ni, Pb, Sc, and Zn (ME-4ACD81) and for ore-grade As (As-OG62); aqua regia digestion with ICP-MS for As, Bi, Hg, In, Re, Sb, Se, Te, and Tl (ME-MS42); induction furnace for total C and S (C-IR07, S-IR08); and fire assay for Au (Au-ICP21) and for Pt and Pd (PGM-MS23). GX samples were analyzed for trace elements by four-acid digestion and ICP-MS (ME-MS61L), for Au, Pt, and Pd by the same fire assay methods, and for B by sodium peroxide fusion and ICP-MS (B-MS82L). Sample 25MLB138 was identified as naturally occurring radioactive material (~11 µSv) and was processed separately in the ALS NORM facilities, so it could not be analyzed for Au or Pt and Pd because the NORM policy excludes fire assay; its over-limit rare earth elements, U, and Y were reanalyzed by fusion with ICP-AES (ME-OGREE) and by lithium borate fusion, dilution, and ICP-MS (U-DILMS81, Y-DILMS81). For all other over-limit results, As was reanalyzed by four-acid digestion and ICP-AES (ME-OG62), Ba by sodium peroxide fusion and ICP-AES (ME-ICP81), and Sample 25Z365, which contained visible gold, by fire assay with a gravimetric finish (Au-GRA21). In addition to the ALS internal quality control, DGGS submitted one blind reference standard for every 20 unknown samples.
  3. What similar or related data should the user be aware of?
    Buchanan, J.W., Wypych, Alicja, Barrera, M.L., Biegel, J.M., Gavel, M.M., Harvey, D.A., Ketcham, R.A., Muller, I.P., Naibert, T.J., Newberry, R.J., Regan, S.P., Szumigala, D.J., Twelker, Evan, and Wildland, A.D., 2025, Geochemical data from samples collected in 2023 for the Chena and Mount Harper projects, Big Delta, Circle, Fairbanks, and Eagle quadrangles, Alaska: Raw Data File RDF 2024-2, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 5 p
    Moshrefzadeh, Jamshid, Acosta, M.D., Barrera, M.L., Buchanan, J.W., Naibert, T.J., Newberry, R.J., Norwood, L.P., Regan, S.P., Szumigala, D.J., and Twelker, Evan, 2025, Geochemical data from samples collected in 2024 for the Chena and Steese projects, Big Delta, Circle, Fairbanks, and Livengood quadrangles, Alaska: Raw Data File RDF 2025-17, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 3 p
    Moshrefzadeh, J.A., Barrera, M.L., Buchanan, J.W., Naibert, T.J., Newberry, R.J., Norwood, L.P., Regan, S.P., Szumigala, D.J., Twelker, Evan, Walser, S.L., and Wilson, K.R., 2025, Field station locations and magnetic susceptibility data collected in 2025 for the Steese project, Yukon-Tanana Uplands, Alaska: Raw Data File RDF 2025-28 v. 2, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 3 p
    Newberry, R.J., Bundtzen, T.K., Clautice, K.H., Combellick, R.A., Douglas, Tom, Laird, G.M., Liss, S.A., Pinney, D.S., Reifenstuhl, R.R., and Solie, D.N., 1996, Preliminary geologic map of the Fairbanks mining district, Alaska: Public Data File PDF 96-16, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 17 p., 2 sheets, scale 1:63,360
    Robinson, M.S., Smith, T.E., and Metz, P.A., 1990, Bedrock geology of the Fairbanks mining district: Professional Report PR 106, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 2 sheets, scale 1:63,360
    Wiltse, M.A., Reger, R.D., Newberry, R.J., Pessel, G.H., Pinney, D.S., Robinson, M.S., and Solie, D.N., 1995, Geologic map of the Circle mining district, Alaska: Report of Investigation RI 95-2A, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 1 sheet, scale 1:63,360

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

  1. How well have the observations been checked?
    This publication is a DGGS Raw Data File (RDF). Reports in the RDF series present field data and analytical results with limited or no interpretation by DGGS staff or project collaborators. The report and accompanying data have been evaluated by project staff for general readability and logical consistency but have not undergone technical peer review. Information presented in this release is subject to change.
  2. How accurate are the geographic locations?
    Location data for field stations were collected using GPS-enabled tablets or smartphones running the Esri Field Maps app. The devices have a reported error of 10-12 m.
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    This data release 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 2026-20
  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-2026
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 Tue Oct 20 16:33:28 2026