LA-ICP-MS uranium-lead detrital zircon data from metamorphic and sedimentary rocks from the Yukon-Tanana Upland, Alaska

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Frequently anticipated questions:

What does this data set describe?
Who produced the data set?
Why was the data set created?
How was the data set created?
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What does this data set describe?

Title:

LA-ICP-MS uranium-lead detrital zircon data from metamorphic and sedimentary rocks from the Yukon-Tanana Upland, Alaska

Abstract:

LA-ICP-MS uranium-lead detrital zircon data from metamorphic and sedimentary rocks from the Yukon-Tanana Upland, Alaska, Raw Data File 2026-13, presents uranium-lead (U-Pb) geochronologic data from single zircon spots analyzed by laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). U-Pb isotopic zircon data were collected from 42 metamorphic and sedimentary rock samples. Division of Geological & Geophysical Survey (DGGS) geologists collected the samples during the 2022, 2023, and 2024 field seasons, in support of the United States Geological Survey's Earth Mapping Resources Initiative (USGS Earth MRI). This report contains samples from the Steese, Chena, and Mount Harper (2024, 2023, and 2022, respectively) geologic mapping projects within the Livengood, Circle, Charley River, Fairbanks, Big Delta, and Eagle quadrangles. These Earth MRI projects are part of a broader effort to modernize geologic mapping of the nation's surface and subsurface with a focus on collecting data in areas of potential critical mineral resources. The USGS selected the Yukon-Tanana Upland (YTU) as the most likely area for new potential mineral resources in Alaska, and it has been the primary focus area of the DGGS Mineral Resources Section since 2019. Geologic mapping was completed across the roughly 34,500 km2 area with new helicopter- and vehicle-supported fieldwork and the compilation of existing DGGS, USGS, industry, and academic datasets. The goal of this geochronologic dataset is to delineate the depositional timeframe and provenance of metamorphic and sedimentary rock packages and, where possible, to define the timing of metamorphism, thereby supporting future geologic mapping and elucidating the tectonic history of the YTU. These data and accompanying discussion are released as a DGGS Raw Data File, and all publication components are available from the DGGS website at: http://doi.org/10.14509/32080.

Supplemental_Information:

ytu_dz_zircon_grain_data: Analytical lab data and accompanying data dictionary	
ytu_dz_zircon_summary_data: Summary data spreadsheet and accompanying data dictionary

How might this data set be cited?
Buchanan, J.W., Barrera, M.L., Gavel, M.M., Truskowski, C.M., Wildland, A.D., Moshrefzadeh, J.A., and Regan, S.P., 2026, LA-ICP-MS uranium-lead detrital zircon data from metamorphic and sedimentary rocks from the Yukon-Tanana Upland, Alaska: Raw Data File RDF 2026-13, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.
Online Links:
- https://doi.org/10.14509/32080
Other_Citation_Details: 5 p.
What geographic area does the data set cover?
West_Bounding_Coordinate: -147.662245
East_Bounding_Coordinate: -142.758433
North_Bounding_Coordinate: 65.162614
South_Bounding_Coordinate: 63.897066
What does it look like?
Does the data set describe conditions during a particular time period?

Beginning_Date: 2022

Ending_Date: 2026

Currentness_Reference:

ground condition
What is the general form of this data set?
Geospatial_Data_Presentation_Form: spreadsheet
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.
How does the data set describe geographic features?

rdf2026-13-ytu_dz_zircon_grain_data.csv, rdf2026-13-ytu_dz_zircon_grain_data_dictionary.csv
Analytical lab data and accompanying data dictionary (Source: DGGS)

rdf2026-13-ytu_dz_zircon_summary_data.csv, rdf2026-13-ytu_dz_zircon_summary_data_dictionary.csv
Summary data spreadsheet and accompanying data dictionary (Source: DGGS)

Who produced the data set?

Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
- Buchanan, J.W.
- Barrera, M.L.
- Gavel, M.M.
- Truskowski, C.M.
- Wildland, A.D.
- Moshrefzadeh, J.A.
- Regan, S.P.
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 agreements G22AC00288, G23AC00372, and 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.
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?

The purpose of this dataset is to provide U-Pb zircon geochronologic information that constrains the depositional age, provenance, and metamorphic history of metamorphic and sedimentary rock units in the Yukon-Tanana Upland. These data support DGGS and USGS Earth MRI geologic mapping efforts by supplying age constraints from 42 samples collected during recent field seasons, enabling improved interpretation of regional tectonic evolution and refinement of geologic map units across multiple quadrangles.

How was the data set created?

From what previous works were the data drawn?
How were the data generated, processed, and modified?

Date: 2024 (process 1 of 3)
Sample collection - Fresh, unweathered rock samples were collected from surface outcrops by DGGS field geologists during geologic mapping in the Big Delta and Circle quadrangles. Location data for samples were recorded in the WGS84 datum using GPS-enabled field tablets. Samples were selected for age dating based on terrane, map unit, and the presence of viable mineral phases suitable for 40Ar/39Ar analysis. Each sample was examined as a hand specimen under a binocular microscope and as a thin section under a petrographic microscope to identify unaltered mineral phases and confirm suitability for geochronologic analysis.
Date: 2024 (process 2 of 3)
Sample preparation - To generate single-grain zircon data, DGGS geologists worked at the Arizona LaserChron Center (ALC) at the University of Arizona under the direction of laboratory staff. Whole-rock samples were sent to the ALC, where they were cleaned and processed through a jaw crusher and roller mill. Zircon grains were isolated using magnetic separation and gravimetric separation with methylene iodide (MI). "Soft" minerals, those that are highly damaged, fractured, altered, or are otherwise less resistant, were removed using a Wig-L-Bug amalgamator, if necessary. Pyrite and apatite were removed by acid wash before hand-picking of zircon grains, if necessary. Heavy mineral grains (~2500) from a portion of the isolated mineral separate for each sample were poured onto double-sided tape and then mounted into 1-inch-diameter epoxy pucks, with one sample per puck.
Date: 2024 (process 3 of 3)
Sample analysis - Back-scatter electron, cathodoluminescence, and transmitted light images were collected for each sample, and some zircon grains were analyzed in multiple areas to examine complex internal textures. The analysis_number field identifies each analysis by sample name, grain number, and zircon morphology. LA-ICP-MS data were collected using an Element2 HR mass spectrometer, and zircon grains were ablated with a Teledyne/Photon Machines Analyte G2 excimer laser equipped with HelEx. Most samples included about 315 zircon spot analyses using 15 to 20 micron diameter spots, except where fewer grains were available. Spots were cleaned with rapid-burst laser shots using 40 micron diameters before isotopic data collection, and ablated material was carried in helium to the plasma source. Isotopes measured included 204Pb, 206Pb, 207Pb, 208Pb, 232Th, 235U, and 238U. Standards FC-1, SL-2, and R33 were analyzed between unknowns to monitor instrument drift. Data reduction followed published methods and was performed at ALC using the MATLAB-based program AgeCalcML. Raw data were corrected for common Pb, backgrounds, and isobaric interference, and isotopic ratios were compared to reference values to determine fractionation factors. Internal uncertainties were propagated following established procedures.
What similar or related data should the user be aware of?
Buchanan, J.W., 2026, Geochemical reanalysis of archival igneous rock pulp samples, Yukon-Tanana Upland, Alaska: Raw Data File RDF 2026-16, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.
Online Links:
- https://doi.org/10.14509/32120
Other_Citation_Details: 4 p
Buchanan, J.W., Barrera, M.L., and Newberry, R.J., 2026, LA-ICP-MS uranium-lead zircon data from igneous rocks collected during the 2025 field season from the Steese-White Mountains and Chena project areas, Yukon-Tanana Upland, Alaska: Raw Data File RDF 2026-11, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.
Online Links:
- https://doi.org/10.14509/32064
Other_Citation_Details: 4 p
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:
- https://doi.org/10.14509/31731
Other_Citation_Details: 4 p
Buchanan, J.W., Gavel, M.M., Barrera, M.L., Regan, S.P., and Newberry, R.J., 2025, LA-ICP-MS uranium lead geochronologic data of zircon from igneous and meta-igneous rocks in the Chena project area, Circle, Big Delta, and Eagle quadrangles, Alaska: Raw Data File RDF 2025-14, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.
Online Links:
- https://doi.org/10.14509/31553
Other_Citation_Details: 4 p
Buchanan, J.W., Gavel, M.M., Wildland, A.D., and Newberry, R.J., 2025, LA-ICP-MS uranium lead geochronologic data of zircon from igneous and meta-igneous rocks in the Mount Harper project area, Eagle, Tanacross, Mount Hayes, and Big Delta quadrangles, Alaska: Raw Data File RDF 2025-4, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.
Online Links:
- https://doi.org/10.14509/31552
Other_Citation_Details: 5 p
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:
- https://doi.org/10.14509/31123
Other_Citation_Details: 5 p
Gavel, M.M., Regan, S.P., Holland, Mark, Wildland, A.D., Wypych, Alicja, Naibert, T.J., and Twelker, Evan, 2023, U-Pb zircon geochronology of bedrock samples collected in the Eagle and Tanacross quadrangles, eastern Alaska: Preliminary Interpretive Report PIR 2023-2, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.
Online Links:
- https://doi.org/10.14509/31013
Other_Citation_Details: 38 p
Gavel, M.M., Twelker, Evan, Wypych, Alicja, Naibert, T.J., Newberry, R.J., Szumigala, D.J., Wildland, A.D., Barrera, M.L., Biegel, J.N., Harvey, D.A., Ketcham, R.A., Muller, I.P., and Regan, S.P., 2023, Field station locations and magnetic susceptibility data for the Chena-Pogo and Mount Harper projects, Big Delta and Circle quadrangles, Alaska, collected June-September 2023: Raw Data File RDF 2023-27, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.
Online Links:
- https://doi.org/10.14509/31096
Other_Citation_Details: 3 p
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:
- https://doi.org/10.14509/31537
Other_Citation_Details: 6 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:
- https://doi.org/10.14509/31736
Other_Citation_Details: 3 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:
- https://doi.org/10.14509/31476
Other_Citation_Details: 5 p
Moshrefzadeh, J.A., Naibert, T.J., Hofmann, Florian, Newberry, R.J., Twelker, Evan, and Buchanan, J.W., 2026, 40Ar/39Ar geochronology data from the Big Delta and Circle quadrangles, Alaska: Raw Data File RDF 2026-14, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.
Online Links:
- https://doi.org/10.14509/32086
Other_Citation_Details: 55 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:
- https://doi.org/10.14509/31692
Other_Citation_Details: 3 p
Naibert, T.J., Heizler, M.T., Newberry, R.J., Twelker, Evan, and Wypych, Alicja, 2023, 40Ar/39Ar geochronology data from the Tanacross and Eagle quadrangles, Alaska: Raw Data File RDF 2023-23, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.
Online Links:
- https://doi.org/10.14509/31085
Other_Citation_Details: 19 p
Naibert, T.J., Wypych, Alicja, Newberry, R.J., Twelker, Evan, Gavel, M.M., Wildland, A.D., Barrera, M.L., Avirett, D.F., Muller, I.P., Blackwell, N.J., and Szumigala, D.J., 2024, Bedrock geologic map of the Taylor Mountain area, Eagle and Tanacross quadrangles, Alaska: Preliminary Interpretive Report PIR 2024-6B, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.
Online Links:
- https://doi.org/10.14509/31168
Other_Citation_Details: 1 sheet, scale 1:100,000
Newberry, R.J., and Moshrefzadeh, J.A., 2026, Interior Alaska amphibolite mineral compositions: A key to distinguishing metamorphic assemblage: Preliminary Interpretive Report PIR 2026-2, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.
Online Links:
- https://doi.org/10.14509/32081
Other_Citation_Details: 33 p
Truskowski, C.M., Heizler, M.T., Naibert, T.J., Newberry, R.J., Twelker, Evan, and Szumigala, D.J., 2025, 40Ar/39Ar geochronology data from the Big Delta, Eagle, and Mount Hayes quadrangles, Alaska: Raw Data File RDF 2025-11, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.
Online Links:
- https://doi.org/10.14509/31534
Other_Citation_Details: 21 p
Twelker, Evan, 2026, Geologic investigation of the Chena-Pogo area, interior Alaska: Preliminary Interpretive Report PIR 2026-3, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.
Online Links:
- https://doi.org/10.14509/32111
Other_Citation_Details: 1 p
Twelker, Evan, Newberry, R.J., Naibert, T.J., Wypych, Alicja, Gavel, M.M., Barrera, M.L., Szumigala, D.J., Truskowski, C.M., Muller, I.P., Fessenden, S.N., Blackwell, N.J., Harvey, D.A., and Wildland, A.D., 2025, Bedrock geologic maps of the Mount Harper-Middle Fork area, Volkmar River-Healy River area, Goodpaster River-Shaw Creek area, and the Richardson Mining District, Alaska: Preliminary Interpretive Report PIR 2025-2, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.
Online Links:
- https://doi.org/10.14509/31648
Other_Citation_Details: 38 p
Wypych, Alicja, Gavel, M.M., Naibert, T.J., Avirett, D.F., Barrera, M.L., Hubbard, A.K., Newberry, R.J., Regan, S.P., Twelker, Evan, Wildland, A.D., and Wyatt, W.C., 2022, Geochemical data from samples collected in 2021 for the Taylor Mountain project, Tanacross and Eagle quadrangles, Alaska: Raw Data File RDF 2022-4, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.
Online Links:
- https://doi.org/10.14509/30843
Other_Citation_Details: 3 p
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:
- https://doi.org/10.14509/31089
Other_Citation_Details: 3 p

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

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.
How accurate are the geographic locations?
Location data for samples were recorded in the WGS84 datum using GPS-enabled field tablets and provided here in the NAD83 datum. Sample location coordinates have a typical reported accuracy of about 10 meters.
How accurate are the heights or depths?
Where are the gaps in the data? What is missing?
This data release is complete.
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.

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.
What's the catalog number I need to order this data set? RDF 2026-13
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.
How can I download or order the data?
- Availability in non-digital form:
  DGGS publications are available as free online downloads or you may purchase paper hard-copies or digital files on CD/DVD or other digital storage media by mail, phone, fax, or email from the DGGS Fairbanks office. To purchase this or other printed reports and maps, contact DGGS by phone (907-451-5020), e-mail (dggspubs@alaska.gov), or fax (907-451-5050). Payment accepted: Cash, check, money order, VISA, or MasterCard. Turnaround time is 1-2 weeks unless special arrangements are made and an express fee is paid. Shipping charge will be the actual cost of postage and will be added to the total amount due. Contact us for the exact shipping amount.
- Cost to order the data: Contact DGGS for current pricing
- Availability in digital form:
  
  Data format: table in format spreadsheet
  
  Network links: https://doi.org/10.14509/32080
- Cost to order the data: Free download

Data format:	table in format spreadsheet
Network links:	https://doi.org/10.14509/32080

Who wrote the metadata?

Dates:

Last modified: 07-Jul-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:

https://dggs.alaska.gov/metadata/dggs.ext

Generated by mp version 2.9.50 on Tue Jul 07 18:50:57 2026