Tephra samples and analyses from Cook Inlet source volcanoes and Anchor Point, Alaska

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Frequently anticipated questions:


What does this data set describe?

Title:
Tephra samples and analyses from Cook Inlet source volcanoes and Anchor Point, Alaska
Abstract:
Tephra samples and analyses from Cook Inlet source volcanoes and Anchor Point, Alaska, Raw Data File 2023-25, provides samples and analyses collected from source volcanoes of the Cook Inlet region, Alaska, including Hayes Volcano, Mount Spurr, Redoubt Volcano, Iliamna Volcano, Augustine Volcano, Mount Douglas, Fourpeaked Mountain, and Kaguyak Crater. The report also includes tephra and soil samples and analyses from a stratigraphic section examined near Anchor Point, Alaska. These samples were collected over many years during geologic investigations of the eruptive histories for these source volcanoes, and in regional studies of eruption impacts, and are compiled here to support research characterizing the composition and impacts of these volcanoes on the Cook Inlet region. The analytical data tables associated with this report are provided in digital format as comma-separated value (CSV) files. They are available from the DGGS website: http://doi.org/10.14509/31090 and are archived in the Geologic Database of Information on Volcanoes in Alaska (GeoDIVA; Cameron and others, 2022, doi.org/10.14509/geodiva).
Supplemental_Information:
Carbon:    Radiocarbon results for a subset of samples. This table can be linked to the Samples table by the SampleID and at_num columns.	
EPMA:    Electron microprobe glass analyses. Most analyses are of matrix glass although a few melt inclusion analyses are included, as indicated by a suffix on the at_num and in the sample description. This table can be linked to the Samples table by the SampleID and at_num columns.	
GlassAvg:    Synthesizes EPMA and Laser analyses as a single row for each sample and uncertainties calculated from repeat sample analyses. This table can be linked to the Samples table by the SampleID and at_num columns.	
Laser:    Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) analyses of matrix glass. The table also includes the electron microprobe analyses associated with each laser analysis, and thus duplicates some information the EPMA table. This table can be linked to the Samples table by the SampleID and at_num columns.	
LaserStandards:    Laser ablation secondary standard results and summary statistics for laser ablation secondary standards. Unlike other tables this is not machine-readable and acts as a set of supplementary tables to the text.	
Layers:    Stratigraphic observations collected at a subset of stations. Station data can be linked with the StationID column.	
Samples:    Metadata for collected samples. Samples can be linked to the Stations or Layers data through the StationID and layer_name columns.	
Stations:    Station observations and station coordinates.
  1. How might this data set be cited?
    Loewen, M.W., Wallace, Kristi, Coombs, M.L., and Mulliken, K.M., 2023, Tephra samples and analyses from Cook Inlet source volcanoes and Anchor Point, Alaska: Raw Data File RDF 2023-25, 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: -154.119404
    East_Bounding_Coordinate: -151.655450
    North_Bounding_Coordinate: 61.896171
    South_Bounding_Coordinate: 58.557962
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 2008
    Ending_Date: 2023
    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 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?
    RDF2023-25_Carbon.csv, RDF2023-25_Carbon-data-dictionary.csv
    Radiocarbon results for a subset of samples. This table can be linked to the Samples table by the SampleID and at_num columns. (Source: AVO and DGGS staff)
    RDF2023-25_EPMA.csv, RDF2023-25_EPMA-data-dictionary.csv
    Electron microprobe glass analyses. Most analyses are of matrix glass although a few melt inclusion analyses are included, as indicated by a suffix on the at_num and in the sample description. This table can be linked to the Samples table by the SampleID and at_num columns. (Source: AVO and DGGS staff)
    RDF2023-25_GlassAvg.csv, RDF2023-25_GlassAvg-data-dictionary.csv
    Synthesizes EPMA and Laser analyses as a single row for each sample and uncertainties calculated from repeat sample analyses. This table can be linked to the Samples table by the SampleID and at_num columns. (Source: AVO and DGGS staff)
    RDF2023-25_Laser.csv, RDF2023-25_Laser-data-dictionary.csv
    Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) analyses of matrix glass. The table also includes the electron microprobe analyses associated with each laser analysis, and thus duplicates some information the EPMA table. This table can be linked to the Samples table by the SampleID and at_num columns. (Source: AVO and DGGS staff)
    RDF2023-25_LaserStandards.csv, RDF2023-25_LaserStandardSummary.csv
    Laser ablation secondary standard results and summary statistics for laser ablation secondary standards. Unlike other tables this is not machine-readable and acts as a set of supplementary tables to the text. (Source: AVO and DGGS staff)
    RDF2023-25_Layers.csv, RDF2023-25_Layers-data-dictionary.csv
    Stratigraphic observations collected at a subset of stations. Station data can be linked with the StationID column. (Source: AVO and DGGS staff)
    RDF2023-25_Samples.csv, RDF2023-25_Samples-data-dictionary.csv
    Metadata for collected samples. Samples can be linked to the Stations or Layers data through the StationID and layer_name columns. (Source: AVO and DGGS staff)
    RDF2023-25_Stations.csv, RDF2023-25_Stations-data-dictionary.csv
    Station observations and station coordinates. (Source: AVO and DGGS staff)

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 appreciate field sampling and support by Chris Waythomas, Dawnika Blatter, Tim Orr, Andy Calvert, and Judy Fierstein. Analytical assistance was provided by Pavel Izbekov, Nate Graham (EPMA), Chris Russo, Andy Ungerer (LA-ICP-MS), and Alexander Cherkinsky (radiocarbon). Data preparation and metadata review was provided by Cheryl Cameron and Simone Montayne with editing by Kristen Janssen. Data review was provided by Laura Walkup. Any use of trade, firm, or product names is for descriptive purposes only and does not imply 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?

These samples were collected over many years during geologic investigations of the eruptive histories for these source volcanoes, and in regional studies of eruption impacts, and are compiled here to support research characterizing the composition and impacts of these volcanoes on the Cook Inlet region. This data describes the nature and character of samples from a past eruption to aid in the discussion of spatial and temporal patterns of Alaska volcanism. In addition, the work supports improvements to eruption scenario forecasts and hazard response.

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: 2021 (process 1 of 4)
    Field Data - Samples included in this report were collected over eight field seasons since 2004, supporting geologic investigations on individual volcanoes and regional studies. Latitude and longitude are reported in the NAD83 datum. Locations were typically determined using various handheld GPS devices and thus are only accurate to approximately 10 m. The location of sample Y-3 is unknown, and a default location was entered for the source volcano (Kaguyak Crater). Station names (StationID) were assigned to sample locations and areas of general observation (fig. 2); sample names (SampleID) correspond to specific samples and include sample descriptions. Laboratory identification numbers (at_num) were assigned during laboratory processing and analysis to keep track of "child" samples.
    Date: 2022 (process 2 of 4)
    Radiocarbon Analyses - Peat samples from station 17KWLCI025 were analyzed at the University of Georgia Center for Applied Isotope Studies (CAIS) by Accelerator Mass Spectrometry (AMS) to determine carbon (C) isotope 14C radiocarbon ages. Samples were dried at room temperature within six weeks of collection in the field then submitted to CAIS where they were treated with 1N HCl at 80 degrees C for one hour to remove carbonate material and washed with deionized water before drying at 60 degrees C. Dried samples were combusted at 900 degrees C in an evacuated sealed quartz ampoule in the presence of copper oxide (CuO). Graphite 14C/13C ratios were measured with a 0.5 MeV accelerator mass spectrometer with isotope ratios compared to Oxalic Acid II (NBS SRM 4990C). Ratios of 13C/12C were measured separately using a stable isotope ratio mass spectrometer and are reported as delta 13C relative to Pee Dee Belemnite (PDB). Reported uncalibrated ages (AgeInterpreted) are given in radiocarbon years before 1950 using a 14C half-life of 5,568 years. Calibration calculated used the R-package Bchron (Haslett and Parnell, 2008).
    Date: 2022 (process 3 of 4)
    Electron Microprobe Analyses - Tephra samples were mounted in epoxy and polished for electron microprobe analysis in the Alaska Tephra Laboratory at the U.S. Geological Survey in Anchorage Alaska. Analyses were performed at the University of Alaska Fairbanks Advanced Instrumentation Laboratory on a JEOL JXA 8530F instrument. Detailed methodology and analysis of accuracy and precision can be found in Loewen and others (2023).
    Date: 2022 (process 4 of 4)
    Laser Ablation Analyses - After electron microprobe analysis, a subset of suitably glassy tephras were analyzed by LA-ICP-MS at the Oregon State University W.M. Keck Collaboratory for Plasma Spectrometry using Photo Machines Analyte G2 193 nm ArF Excimer Laser coupled to a Thermoscientific X Series 2 (2018) or iCAP RQ (2022) ICP-MS. Ablation was performed with a 50 microns (2018) or 30 microns (2012) spot, 4.8 J/cm2 (2018) or 6.3 J/cm2 (2022) beam energy, and 7 Hz pulse rate for approximately 25 seconds. Prior to analysis the carbon coat was removed with light polishing, and analysis locations were pre-ablated with four pulses of a 110-microns-diameter beam. Concentrations were determined using in-house reduction software written in Visual Basic and described in Loewen and Kent (2012), using GSE-1G as a calibration standard and using the silicon (Si) isotope 29Si - as independently constrained by electron microprobe analysis - as an internal standard. Secondary standards included GSD-1G, NIST-612, BHVO-2G, BCR-2G, and ATHO-G.
  3. What similar or related data should the user be aware of?
    Loewen, M.W., Wallace, K.L., Lubbers, Jordan, Ruth, Dawn, Izbekov, P.E., Larsen, J.F., and Graham, Nathan, 2023, Glass electron microprobe analyses methods, precision and accuracy for tephra studies in Alaska: Miscellaneous Publication MP 174, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 20 p
    Loewen, M.W., Wallace, Kristi, Coombs, M.L., and Mulliken, K.M., 2023, Tephra samples and analyses from Cook Inlet source volcanoes and Anchor Point, Alaska: Raw Data File RDF 2023-25, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 4 p
    Lubbers, Jordan, Loewen, M.W., Wallace, Kristi, and Coombs, M.L., 2023, Source compositions of large tephra-production eruptions in Alaska: Raw Data File RDF 2023-26, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 3 p
    Mulliken, K.M., Schaefer, J.R., and Cameron, C.E., 2018, Geospatial distribution of tephra fall in Alaska: a geodatabase compilation of published tephra fall occurrences from the Pleistocene to the present: Miscellaneous Publication MP 164, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 46 p
    Schaefer, J.R., Mulliken, K.M., Cameron, C.E., and Wallace, K.L., 2017, Digitizing Alaska's ashfall record: a tephra geospatial database (poster): International Association of Volcanology and Chemistry of the Earth's Interior (IAVCEI) 2017 Scientific Assembly, November 14-18, 2017: Poster and Presentation Schaefer, J.R. and others, 2017, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 1 sheet
    Wallace, K.L., Cameron, C.E., Waythomas, C.F., and Perreault, J.M., 2020, Major-oxide and trace-element geochemical data from the tephra collected on Veniaminof volcano, Alaska: Raw Data File RDF 2020-17, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 5 p
    Wallace, K.L., Hayden, L.A., and Neal, C.A., 2017, Major-element glass compositions of tephra from the circa 3.6 ka eruption of Aniakchak volcano, Alaska Peninsula, Alaska: Raw Data File RDF 2017-9, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 9 p
    Worden, A.K., Schaefer, J.R., and Mulliken, K.M., 2018, Tephra occurrence in Alaska: a map-based compilation of stratigraphic tephra data: Miscellaneous Publication MP 165, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 19 p

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

  1. How well have the observations been checked?
    The data tables provide calculated 2 sigma level uncertainty values for all ages and isotope ratios.
  2. How accurate are the geographic locations?
    Locations were typically determined using various handheld GPS devices and thus are only accurate to ~10 m. The location of sample Y-3 is unknown, and a default location was entered for the source volcano (Kaguyak Crater).
  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 2023-25
  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: 30-Jan-2024
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 Feb 02 16:40:49 2024