USGS T-3 Original Thermal Gradient, Thermal Conductivity, and Heat Flow Data from T-3 Ice Island, 1963-73

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Frequently anticipated questions:

What does this data set describe?

Title:
USGS T-3 Original Thermal Gradient, Thermal Conductivity, and Heat Flow Data from T-3 Ice Island, 1963-73
Abstract:
The T-3 (Fletcher's) Ice Island in the Arctic Ocean was the site of a scientific research station re-established by the Naval Arctic Research Laboratory starting in 1962. Starting in 1963, the USGS acquired marine heat flow data and coincident sediment cores at sites in Canada Basin, Nautilus Basin, Mendeleev Ridge, and Alpha Ridge as the ice island drifted in the Amerasian Basin. At least 584 heat flow penetrations were attempted, and data were reported at 356 of these. This dataset is the digital version of the original data table from Lachenbruch and others (2019; see cross-reference), retaining the original non-SI units for thermal conductivity and heat flow.
Supplemental_Information:
This dataset is Table 2 in: Lachenbruch, A.H., Marshall, B.V., and Ruppel, C.D., 2019, Post-expedition report for USGS T-3 Ice Island heat flow measurements in the High Arctic Ocean, 1963-1973: U.S. Geological Survey data release, https://doi.org/10.5066/P91XQ3IS. (See cross-reference.)
  1. How might this data set be cited?
    Ruppel, Carolyn D., Hutchinson, Deborah R., and Lachenbruch, Arthur H., 2019, USGS T-3 Original Thermal Gradient, Thermal Conductivity, and Heat Flow Data from T-3 Ice Island, 1963-73: data release DOI:10.5066/P97EPU2F, U.S. Geological Survey, Coastal and Marine Hazards and Resources Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

    Online Links:

    This is part of the following larger work.

    Ruppel, Carolyn D., Hutchinson, Deborah R., Lachenbruch, Arthur H., and Hall, John K., 2019, Thermal Data and Navigation for T-3 (Fletcher's) Ice Island Arctic Ocean Heat Flow Studies, 1963-73: data release DOI:10.5066/P97EPU2F, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    Ruppel, C.D., Hutchinson, D.R., Lachenbruch, A.H., and Hall, J.K., 2019, Thermal data and navigation for T-3 (Fletcher's) ice island Arctic Ocean heat flow studies, 1963-73: USGS data release, https://doi.org/10.5066/P97EPU2F.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -176.70250
    East_Bounding_Coordinate: -78.75000
    North_Bounding_Coordinate: 86.05683
    South_Bounding_Coordinate: 75.37100
  3. What does it look like?
    https://www.sciencebase.gov/catalog/file/get/5d10eb5be4b0941bde550217?name=T3heatflowgraphic.jpg (JPEG)
    Locations of heat flow data stations in this dataset are shown as white circles. The background bathymetry is from: Jakobsson, M. and others (2012), The International Bathymetric Chart of the Arctic Ocean (IBCAO) Version 3.0, Geophys. Res. Lett., 39, L12609, doi:10.1029/2012GL052219.
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 1963
    Ending_Date: 1973
    Currentness_Reference:
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: tabular digital 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 0.001. Longitudes are given to the nearest 0.001. Latitude and longitude values are specified in Decimal degrees. The horizontal datum used is North American Datum of 1927.
      The ellipsoid used is Clarke 1866.
      The semi-major axis of the ellipsoid used is 6378206.4.
      The flattening of the ellipsoid used is 1/294.978698214.
      Vertical_Coordinate_System_Definition:
      Depth_System_Definition:
      Depth_Datum_Name: Not known, but likely was water's surface below the ice.
      Depth_Resolution: 0.1
      Depth_Distance_Units: meters
      Depth_Encoding_Method: attribute values
  7. How does the data set describe geographic features?
    T3heatflow_originaltable.xlsx
    Excel 2013 Worksheet (Source: Producer Defined)
    Station
    Heat flow station (ordinal number), usually referred to in T-3 literature as "FL-" then station number. Station numbers are non-sequential where heat flow penetration failed (no data obtained). (Source: Producer Defined)
    Range of values
    Minimum:2
    Maximum:584
    Latitude (degree)
    Degrees of north latitude for heat flow penetration (Source: Producer Defined)
    Range of values
    Minimum:75
    Maximum:86
    Units:degree
    Resolution:1
    Latitude (minute)
    Minutes of latitude for position of heat flow penetration (Source: Producer Defined)
    Range of values
    Minimum:0.06
    Maximum:59.78
    Units:minutes
    Resolution:0.01
    Longitude (degree)
    Degrees of longitude (west) of heat flow penetration (Source: Producer Defined)
    Range of values
    Minimum:-176
    Maximum:-78
    Units:degree
    Resolution:1
    Longitude (minute)
    Minutes of longitude for location of heat flow penetration (Source: Producer Defined)
    Range of values
    Minimum:0.21
    Maximum:59.81
    Units:minutes
    Resolution:0.01
    Water depth (m)
    water depth in meters at location of heat flow penetration, believed to be measured based on wire-out (Source: Producer Defined)
    Range of values
    Minimum:1066
    Maximum:3818
    Units:meters
    Resolution:1
    1-2 Gradient (milliC/m)
    Thermal gradient in milliCelsius per meter between thermistors 1 and 2, with 1 being the deepest penetrating thermistor. (empty cell) for no value. (Source: Producer Defined)
    Range of values
    Minimum:24.1
    Maximum:74.5
    Units:milliCelsius per meter
    Resolution:0.1
    1-3 Gradient (milliC/m)
    Thermal gradient in milliCelsius per meter between thermistors 1 and 3, with 1 being the deepest penetrating thermistor. This gradient is used when thermistor 2 is malfunctioning. (empty cell) for no value. (Source: Producer Defined)
    Range of values
    Minimum:26.4
    Maximum:75.5
    Units:milliCelsius per meter
    Resolution:0.1
    2-3 Gradient (milliC/m)
    Thermal gradient in milliCelsius per meter between thermistors 2 and 3, with 1 being the deepest penetrating thermistor. (empty cell) for no value. (Source: Producer Defined)
    Range of values
    Minimum:6.9
    Maximum:109.0
    Units:milliCelsius per meter
    Resolution:0.1
    2-4 Gradient (milliC/m)
    Thermal gradient in milliCelsius per meter between thermistors 2 and 4, with 1 being the deepest penetrating thermistor. This gradient is used when thermistor 3 is malfunctioning. (empty cell) for no value. (Source: Producer Defined)
    Range of values
    Minimum:30.0
    Maximum:62.7
    Units:milliCelsius per meter
    Resolution:0.1
    3-4 Gradient (milliC/m)
    Thermal gradient in milliCelsius per meter between thermistors 3 and 4, with 1 being the deepest penetrating thermistor. (empty cell) for no value. (Source: Producer Defined)
    Range of values
    Minimum:26.4
    Maximum:104.4
    Units:milliCelsius per meter
    Resolution:0.1
    3-5 Gradient (milliC/m)
    Thermal gradient in milliCelsius per meter between thermistors 3 and 5, with 1 being the deepest penetrating thermistor. This gradient is used when thermistor 4 is malfunctioning. (empty cell) for no value. (Source: Producer Defined)
    Range of values
    Minimum:34.9
    Maximum:62.9
    Units:milliCelcius per meter
    Resolution:0.1
    4-5 Gradient (milliC/m)
    Thermal gradient in milliCelsius per meter between thermistors 4 and 5, with 1 being the deepest penetrating thermistor. (empty cell) for no value. (Source: Producer Defined)
    Range of values
    Minimum:47.4
    Maximum:82.9
    Units:milliCelsius per meter
    Resolution:0.1
    1-2 Conductivity (mcal/(cm-s-C))
    Thermal conductivity in millicalorie per (centimeter-second-degree Celsius) measured on the benchtop (not in the seafloor) in the sediment core section recovered between thermistors 1 and 2. Thermistor 1 is the deepest penetrating thermistor. (empty cell) for no value. (Source: Producer Defined)
    Range of values
    Minimum:1.94
    Maximum:3.60
    Units:millicalorie per (centimeter-second-degree Celsius)
    Resolution:0.01
    1-3 Conductivity (mcal/(cm-s-C))
    Thermal conductivity in millicalorie per (centimeter-second-degree Celsius) measured on the benchtop (not in the seafloor) in the sediment core section recovered between thermistors 1 and 3. Thermistor 1 is the deepest penetrating thermistor. Only used when Thermistor 2 was malfunctioning.(empty cell) for no value. (Source: Producer Defined)
    Range of values
    Minimum:2.37
    Maximum:3.07
    Units:millicalorie per (centimeter-second-degree Celsius)
    Resolution:0.01
    2-3 Conductivity (mcal/(cm-s-C))
    Thermal conductivity in millicalorie per (centimeter-second-degree Celsius) measured on the benchtop (not in the seafloor) in the sediment core section recovered between thermistors 2 and 3. Thermistor 1 is the deepest penetrating thermistor. (empty cell) for no value. (Source: Producer Defined)
    Range of values
    Minimum:1.58
    Maximum:3.49
    Units:millicalorie per (centimeter-second-degree Celsius)
    Resolution:0.01
    2-4 Conductivity (mcal/(cm-s-C))
    Thermal conductivity in millicalorie per (centimeter-second-degree Celsius) measured on the benchtop (not in the seafloor) in the sediment core section recovered between thermistors 2 and 4. Thermistor 1 is the deepest penetrating thermistor. Column only used when Thermistor 3 was malfunctioning. (empty cell) for no value. (Source: Producer Defined)
    Range of values
    Minimum:2.14
    Maximum:3.3
    Units:millicalorie per (centimeter-second-degree Celsius)
    Resolution:0.01
    3-4 Conductivity (mcal/(cm-s-C))
    Thermal conductivity in millicalorie per (centimeter-second-degree Celsius) measured on the benchtop (not in the seafloor) in the sediment core section recovered between thermistors 3 and 4. Thermistor 1 is the deepest penetrating thermistor. (empty cell) for no value. (Source: Producer Defined)
    Range of values
    Minimum:2.13
    Maximum:3.41
    Units:millicalorie per (centimeter-second-degree Celsius)
    Resolution:0.01
    3-5 Conductivity (mcal/(cm-s-C))
    Thermal conductivity in millicalorie per (centimeter-second-degree Celsius) measured on the benchtop (not in the seafloor) in the sediment core section recovered between thermistors 3 and 5. Thermistor 1 is the deepest penetrating thermistor. Column only used when Thermistor 4 was malfunctioning. (empty cell) for no value. (Source: Producer Defined)
    Range of values
    Minimum:2.79
    Maximum:3.22
    Units:millicalorie per (centimeter-second-degree Celsius)
    Resolution:0.01
    4-5 Conductivity (mcal/(cm-s-C))
    Thermal conductivity in millicalorie per (centimeter-second-degree Celsius) measured on the benchtop (not in the seafloor) in the sediment core section recovered between thermistors 4 and 5. Thermistor 1 is the deepest penetrating thermistor. (empty cell) for no value. (Source: Producer Defined)
    Range of values
    Minimum:2.76
    Maximum:3.56
    Units:millicalorie per (centimeter-second-degree Celsius)
    Resolution:0.01
    Heat flow (HFU)
    Heat flow in heat flow units (HFU) calculated by taking the product of the average thermal gradient and average thermal conductivity; 1 HFU = 41.8 milliWatt/m^2. (Source: Producer Defined)
    Range of values
    Minimum:0.71
    Maximum:2.86
    Units:Heat Flow Units
    Resolution:0.01
    Average % Deviation
    Percentage uncertainty in heat flow measurement (empty cell means no value reported) (Source: Producer Defined)
    Range of values
    Minimum:0.15
    Maximum:39.35
    Units:percentage
    Resolution:0.01
    Max. Heat Flow Deviation (HFU)
    Maximum uncertainty in heat flow value in heat flow units (HFU). 1 HFU = 41.8 milliWatts/m^2. (Source: Producer Defined)
    ValueDefinition
    empty cellNo average percentage deviation given for heat flow measurement and therefore no absolute value of heat flow deviation
    Range of values
    Minimum:0.01
    Maximum:1.8
    Units:HFU
    Resolution:0.01

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Carolyn D. Ruppel
    • Deborah R. Hutchinson
    • Arthur H. Lachenbruch
  2. Who also contributed to the data set?
    Dataset originally compiled by Lachenbruch and others (2019)--see cross-reference. Digital dataset formulated through manual rekeying, optical character recognition, and quality control at the Woods Hole Coastal and Marine Science Center in 2016.
  3. To whom should users address questions about the data?
    Carolyn Ruppel
    U.S. Geological Survey, Woods Hole Coastal and Marine Science Center
    Research Geophysicist
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    (508) 548-8700 x2339 (voice)
    (508) 457-2310 (FAX)
    cruppel@usgs.gov

Why was the data set created?

To provide a digital version of the original data table recording the T-3 thermal gradients, thermal conductivity values, and heat flow for the 356 successful stations.

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: 31-Dec-1974 (process 1 of 4)
    This process step gives an overview of the acquisition of the original data. Details about the operations to acquire the data are given in Lachenbruch and others (2019)--see cross-reference. Summary information about procedures is also provided in the other cross-referenced publications, , particularly the Journal of Geophysical Research paper by Ruppel and others (2019). The heat flow measurements were made once a day or once every several days (occasionally two per day) during USGS occupation of the T-3 ice island. The measurements were made through a permanent hole in the ice (moonpool) maintained under the protection of a hut near the Colby Bay portion of the T-3 ice island. The apparatus consisted of a corer with attached thermistors (four thermistors during the first few years of the operation and then five thermistors on a slightly longer core barrel during subsequent years). The thermistor closest to the bottom of the core barrel was designated as #1. Thermistor accuracy was 0.001 degrees Celsius based on Lachenbruch and others(2019).
    The corer with attached thermistors was lowered to the seafloor on a winch system. The probe remained in the bottom sediments long enough for the frictional heat pulse associated with sediment penetration to decay to the conductive part of the curve so that an equilibrium temperature could be determined for each thermistor during post-analysis. Thermal conductivity was not measured in situ in the seafloor. The probe was recovered with sediments in the corer. Far more sediment cores were recovered than heat flow measurements taken (for example, refer to the information in the University of Wisconsin NCEI dataset at https://doi.org/10.7289/v51834g7 for selected information about USGS T-3 sediment cores). It is unknown whether heat flow measurements were not attempted on every coring run or whether the heat flow probe or recording instrumentation suffered frequent problems. The consistent recovery of sediment cores indicates that the probe penetrated the sediments at many locations, meaning that a heat flow measurement was in theory possible at those locations as well.
    After completion of a measurement, data would have been analyzed to determine an equilibrium temperature for each thermistor. These equilibrium temperature data have been lost, as have the bottom water temperature data recorded during the surveys and information about the penetration depth of the probe. For Ruppel and others (2019)--see cross-reference, attempts were made to use the lengths of recovered cores as an indicator of the probe's penetration depth to assist in determination of equilibrium thermal gradients, but this analysis was unsuccessful. The reported data from the heat flow measurements are thermal gradients between adjacent thermistors. For a 4-thermistor penetration with all 4 thermistors operational, the dataset provides thermal gradient values between thermistors 1 and 2, 2 and 3, and 3 and 4. If one thermistor were not functioning (for example, thermistor #2), the reported gradients would be between thermistors 1 and 3 and 3 and 4.
    Thermal conductivity values were measured on the laboratory benchtop on recovered sediment cores using needle probes. The reported values correspond to core sections between each of the working thermistors. For example, if a gradient is reported for the interval between thermistors 2 and 3, then the dataset gives a corresponding thermal conductivity determination in that interval from the corresponding core. The original thermal conductivity data have been lost, but it is suspected that far more thermal conductivity measurements were completed than are compiled or averaged to generate the values in the dataset. Ruppel and others (2019)--see cross-reference-- analyzes some of the thermal conductivity data in this dataset. Heat flow was calculated by multiplying average thermal gradient and average thermal conductivity. Uncertainties are reported on a subset of the values as a percentage of the heat flow. A maximum heat flow uncertainty is also provided by for heat flow values to which a percentage deviation was assigned. Process date likely spanned the duration of the experiment and is reported below as the last day of 1974, which is the approximate date of the USGS report provided in Lachenbruch and others (2019)--see cross-reference Data sources used in this process:
    • Lachenbruch and others (2019)--see cross-reference
    Date: 2019 (process 2 of 4)
    This process step details how the original table was digitized and quality checked. The original table was available only as a PDF scan of Table 2 from Lachenbruch and others (2019). In 2016, Carolyn Ruppel manually keyed most of this table. Subsequently, technical staff (B. Clark and M. Arsenault) at the USGS Woods Hole Coastal and Marine Science Center conducted optical character recognition on parts of the scanned file. The two inputs were combined, and then Deborah Hutchinson conducted quality control on the resulting table. This process identified entries that were partially illegible in the original PDF scan of the report, positions that had been improperly keyed, and one position (station FL-532) that did not plot on the T-3 navigation track obtained through independent means and released with this dataset as "T-3 Ice Island One Hour Navigation: May 14, 1962 to September 15, 1974." Values were corrected in the table based on this analysis. It is expected that some errors likely remain in the transfer of the original PDF scan to the digital data file. It is not believed that any of the possible errors affect the subsequent outcome or analysis in any significant way. The initial digital files and the accompanying scanned portions of the original data table are provided in the following images included in this dataset: Table2_2to66.jpg, Table2_71to146.jpg, Table2_147to231.jpg, Table2_233to287.jpg, Table2_288to340.jpg, Table2_341to386.jpg, Table2_387to441.jpg, Table2_442to552.jpg, Table2_556to584.jpgj. The range of numbers in the title of each plot refer to heat flow stations. Also provided is a file to explain error checking: digitizationoftable.txt Person who carried out this activity:
    U.S. Geological Survey
    Attn: Carolyn Ruppel
    Research Geophysicist
    384 Woods Hole Road
    Woods Hole, Massachusetts
    USA

    508-548-8700 x2263 (voice)
    508-457-2310 (FAX)
    cruppel@usgs.gov
    Date: 21-Jun-2019 (process 3 of 4)
    The Excel 2013 XLSX file was written in CSV format using "save as". Person who carried out this activity:
    U.S. Geological Survey
    Attn: Carolyn Ruppel
    Research Geophysicist
    384 Woods Hole Road
    Woods Hole, Massachusetts
    USA

    508-548-8700 x2263 (voice)
    508-457-2310 (FAX)
    cruppel@usgs.gov
    Data sources used in this process:
    • T3heatflow_originaltable.xlsx
    Date: 06-Aug-2020 (process 4 of 4)
    Added keywords section with USGS persistent identifier as theme keyword. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
  3. What similar or related data should the user be aware of?
    Lachenbruch, Arthur H., Marshall, B. Vaughn, and Ruppel, C.D., 2019, Post-expedition report for USGS T-3 Ice Island heat flow measurements in the High Arctic Ocean, 1963-1973: data release DOI:10.5066/P91XQ3IS, U.S. Geological Survey, Coastal and Marine Hazards and Resources Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

    Online Links:

    Other_Citation_Details:
    This dataset is Table 2 in: Lachenbruch, A.H., Marshall, B.V., and Ruppel, C.D., 2019, Post-expedition report for USGS T-3 Ice Island heat flow measurements in the High Arctic Ocean, 1963-1973: U.S. Geological Survey data release, https://doi.org/10.5066/P91XQ3IS.
    Ruppel, Carolyn D., Lachenbruch, Arthur H., Hutchinson, Deborah R., Munroe, Robert, and Mosher, David C., 2019, Heat Flow in the Western Arctic Ocean (Amerasian Basin): Journal of Geophysical Research DOI:10.1029/2019JB017587, American Geophysical Union, Washington, D.C..

    Online Links:

    Other_Citation_Details:
    Ruppel, C.D., Lachenbruch, A.H., Hutchinson, D.R., Munroe, R., and Mosher, D.C., 2019, Heat flow in the Western Arctic Ocean (Amerasian Basin), J. Geophysical Research.
    University Of Wisconsin-Madison Department Of Geoscience, 2016, Archive of information about the Ice Island T3 piston core collection: NOAA National Centers for Environmental Information, n/a.

    Online Links:

    Lachenbruch, Arthur H., and Marshall, B. Vaughn, 1966, Heat flow through the Arctic Ocean floor: The Canada Basin-Alpha Rise Boundary: Journal of Geophysical Research vol. 71, issue 4, American Geophysical Union (AGU), Washington, D.C..

    Online Links:

    Other_Citation_Details: pp. 1223– 1248
    Lachenbruch, Arthur H., and Marshall, B. Vaughn, 1969, Heat Flow in the Arctic: Arctic Institute of North America, Calgary, Alberta, Canada.

    Online Links:

    • www.jstor.org/stable/40507641

    Other_Citation_Details: pp. 300–311
    Langseth, Marcus G., Lachenbruch, Arthur H., and Marshall, B. Vaughn, 1990, Geothermal observations in the Arctic region: Geological Society of America, Boulder, CO.

    Online Links:

    Other_Citation_Details:
    In: The Arctic Ocean Region, edited by A. Grantz, L. Johnson and J. F. Sweeney, Decade of North American Geology, Vol. L, Geological Society of America, pp. 133-152.

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

  1. How well have the observations been checked?
    This is a legacy dataset collected between 1963 and 1973. To determine accuracy of the original data: Carolyn Ruppel attempted to locate original records at the USGS Menlo Park office and among Arthur Lachenbruch's scientific papers, which are in the possession of Barbara Lachenbruch of Corvalis, Oregon. Lacking the original records (logs, records of heat flow equilibration curves, records of benchtop thermal conductivity measurements), it is impossible to determine whether the derived information reported in this dataset is accurate. The dataset is assumed to be accurate based on material in Lachenbruch and others (2019)--(see cross-reference), which discusses calibrations, internal checks, and other measures taken to ensure that the collected data (geothermal gradients and thermal conductivity values) were of high quality and accuracy. The dataset includes percentage uncertainties on reported heat flow measurements for most of the heat flow stations. It is assumed that these uncertainties are propagated errors from the thermal gradients and thermal conductivities combined. Another accuracy issue concerns the quality of the transfer from the hardcopy table to the digital version. The data were first manually keyed by Carolyn Ruppel in 2016. Subsequently, the data were optically scanned to PDF format and a subset of the data were subjected to optical character recognition by B. Clark and M. Arsenault. The manually keyed and optically-character-recognized data were then quality controlled by Deborah Hutchinson, who made notes about parts of the table that were not legible in the scans and best determinations about the appropriate values. Hutchinson also identified locations that did not confirm to the known T-3 navigation track. The dataset contains JPEG graphics showing the initially digitized table beside the scanned PDF portion of the table, with identified problems marked.
  2. How accurate are the geographic locations?
    Background on navigation is summarized in: Hunkins, K., and W. Tiemann (1977), Geophysical data summary for Fletcher's Ice Island (T-3), 1962-1974, Technical Report, Lamont-Doherty Survey of the World Ocean Rep. CU-1-77, 219 pp, Lamont-Doherty Geological Observatory and in the cross-referenced Journal of Geophysical Research paper (Ruppel and others, 2019) associated with this release. See also "T-3 Ice Island One Hour Navigation: May 14, 1962 to September 15, 1974" within this data release. Before 1967, navigation relied on theodolite fixes of the sun (summer) and stars (winter) coupled with a chronometer that was frequently checked for accuracy via radio. Hunkins and Tiemann [1977] estimate a positional error of up to 1 km during the summer and 0.5 km in the winter for this period. Starting in 1967, satellite data from the Navy Navigation Satellite System provided positional fixes, and Hunkins and Tiemann [1977] estimate that positions were known within 250 m. Based on the years of the island's occupation, the horizontal datum is assumed to be NAD27.
  3. How accurate are the heights or depths?
    The water depths reported in the data table accompanying the Lachenbruch and others (2019) report (see cross-reference) are apparently line-out depths for the heat flow apparatus. No additional information with regards to depth measurements is indicated, and no vertical coordinate system is specified. Note that Hunkins and Tiemann (1977) also collected depth measurements using seismic and subbottom profiling systems and these are reported in "T-3 Ice Island One Hour Navigation: May 14, 1962 to September 15, 1974" as part of this data release. It is not known whether these depth measurements were adopted for the heat flow and radiogenic heat datasets.
  4. Where are the gaps in the data? What is missing?
    complete. When data were illegible in the original photocopy, a best guess was used as the entry. No stations or individual values of data recorded at the stations were excluded.
  5. How consistent are the relationships among the observations, including topology?
    Positions of measurements were checked to confirm that they lie on the known navigational track for T-1 as provided in this data release as part of the dataset "T-3 Ice Island One Hour Navigation: May 14, 1962 to September 15, 1974." Station FL-532 was correctly digitized but does not lie on the T-1 navigational track. The point was retained. Thermal gradients, thermal conductivity, and heat flow values are all positive and physically plausible.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints: None. Please see 'Distribution Info' for details.
Use_Constraints:
Not to be used for navigation. Users are advised to read the dataset's metadata thoroughly to understand appropriate use and data limitations.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey - ScienceBase
    Denver Federal Center, Building 810, Mail Stop 302
    Denver, CO

    1-888-275-8747 (voice)
    sciencebase@usgs.gov
  2. What's the catalog number I need to order this data set? The dataset contains the data in both Excel XLSX format and CSV format (T3heatflow_originaltable.xlsx, T3heatflow_originaltablerelease.csv), browse graphic of data locations (T3heatflowgraphic.jpg), images of the comparison of the original tables and the Excel spreadsheet(Table2_2to66.jpg, Table2_71to146.jpg, Table2_147to231.jpg, Table2_233to287.jpg, Table2_288to340.jpg, Table2_341to386.jpg, Table2_387to441.jpg, Table2_442to552.jpg, Table2_556to584.jpg), the explanation of the table images (digitizationoftable.txt), and CSDGM metadata in XML, TXT, and HTML formats.
  3. What legal disclaimers am I supposed to read?
    Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty.
  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 06-Aug-2020
Metadata author:
Carolyn Ruppel
U.S. Geological Survey, Northeast Region
Research Geophysicist
384 Woods Hole Road
Woods Hole, MA
United States

508-548-8700 x2339 (voice)
cruppel@usgs.gov
Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/whcmsc/SB_data_release/DR_P97EPU2F/T3_originalheatflow.faq.html>
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