LA-ICP-MS uranium-lead zircon data from samples in the Chena and Steese project areas

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Frequently anticipated questions:


What does this data set describe?

Title:
LA-ICP-MS uranium-lead zircon data from samples in the Chena and Steese project areas
Abstract:
LA-ICP-MS uranium-lead zircon data from samples in the Chena and Steese project areas, Raw Data File 2025-25, provides uranium-lead (U-Pb) geochronologic data and trace and rare earth element (TREE) data from single zircon spots analyzed using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The two methods were run concurrently resulting in U-Pb age data and TREE data from the same zircon volume. Alaska Division of Geological & Geophysical Surveys (DGGS) staff collected zircon data from 51 samples of igneous and meta-igneous rocks primarily collected during the 2024 field season in support of the Earth Mapping Resources Initiative (Earth MRI) Steese and Chena projects. The goal of this dataset is to delineate the age of igneous activity to support geologic mapping efforts, tectonic interpretations, and characterization of mineralization in the Yukon-Tanana Uplands, Alaska. Data are organized in the age summary data table with our interpreted crystallization ages, sample location information, and sample descriptions. The zircon grain data table contains U-Pb isotopic age data and TREE data for each zircon spot analyzed. These data are provided as a Raw Data File under an open end-user license and are available on the DGGS website: http://doi.org/10.14509/31731.
Supplemental_Information:
chena_steese-zircon:    Data spreadsheets and accompanying data dictionaries
  1. How might this data set be cited?
    Buchanan, J.W., Barrera, M.L., Moshrefzadeh, J.A., Truskowski, C.M., and Newberry, R.J., 2025, LA-ICP-MS uranium-lead zircon data from samples in the Chena and Steese project areas: Raw Data File RDF 2025-25, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 4 p.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -148.392677
    East_Bounding_Coordinate: -143.814911
    North_Bounding_Coordinate: 65.491436
    South_Bounding_Coordinate: 64.289053
  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: spreadsheet
  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?
    rdf2025-25_chena_steese-zircon_grain_data.csv, rdf2025-25_chena_steese-zircon_grain_data_dictionary.csv, rdf2025-25_chena_steese-zircon-age_summary.csv, rdf2025-25_chena_steese-zircon-age_summary_data_dictionary.csv
    Data spreadsheets and accompanying data dictionaries (Source: 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 authors thank the University of Arizona LaserChron Center staff for their contributions to data collection, technical discussions, and other support. The analytical work was funded by the U.S. Geological Survey's Earth Mapping Resources Initiative (Earth MRI) under cooperative agreement G24AC00323 and 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 U.S. Geological Survey. Mention of trade names or commercial products does not constitute their endorsement by the U.S. 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?

This dataset provides U-Pb zircon age data from igneous rocks in Interior Alaska to refine geologic maps, improve understanding of mineralizing systems, and guide resource exploration. By supporting the Earth MRI initiative, it enhances Alaska's ability to evaluate mineral potential, strengthen economic development, and manage natural resources for the benefit of the state.

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 2)
    Sample selection - Field staff collected fresh, unaltered felsic to intermediate igneous rocks (e.g., granite, rhyolite, porphyry dikes) and, in metamorphic terrains orthogneiss or felsic layers likely to contain zircon. Approximately 2-3 kg of material was sampled from unweathered interiors, avoiding heavily altered rocks. Each sample location was documented with GPS coordinates, lithologic descriptions, and geologic context including contacts and intrusive relationships. Samples were later processed to separate zircon grains for U-Pb geochronology and trace/rare earth element analysis using LA-ICP-MS.
    Date: 2025 (process 2 of 2)
    Analytical methods - Samples were processed to separate zircon grains for U-Pb geochronology and trace and rare earth element (TREE) analysis using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Analytical procedures followed established techniques described by Gehrels et al. (2008), Gehrels and Pecha (2014), Pullen et al. (2018), and Sundell et al. (2021). Additional details on laboratory methods and data reduction are provided in the accompanying report.
  3. What similar or related data should the user be aware of?
    Moshrefzadeh, J.A., and Newberry, R.J., 2025, Electron probe microanalyzer data collected on samples from the Chena and Steese projects, Yukon-Tanana Uplands, Alaska: Raw Data File RDF 2025-13, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 6 p
    Moshrefzadeh, J.A., Buchanan, J.W., Naibert, T.J., Twelker, Evan, Newberry, R.J., Szumigala, D.J., Barrera, M.L., Norwood, L.P., Acosta, M.D., and Regan, S.P., 2025, Field station locations and magnetic susceptibility data collected in 2024 for the Chena and Steese projects, Yukon-Tanana Uplands, Alaska: Raw Data File RDF 2025-5, 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

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

  1. How well have the observations been checked?
    The accompanying report and data tables provide a comprehensive discussion of processing methods, with errors reported in the tables where applicable. This data is being released as part of the DGGS RDF series, which includes content describing approved techniques and methods for the collection, storage, visualization, analysis, and interpretation of scientific data. While the information has been reviewed by several geologists familiar with the study area, the data and report have not undergone formal review for technical content or conformity to DGGS editorial standards. For inquiries regarding analytical values or procedures, the originating lab is the best point of contact.
  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. Data were merged into an ArcGIS geodatabase. 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 2025-25
  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: 17-Nov-2025
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 Nov 18 15:51:28 2025