Thermogravimetric Analysis of rock samples from the Escanaba Trough (Gorda Ridge)

Frequently anticipated questions:

• What does this data set describe?
  1. How might this data set be cited?
  2. What geographic area does the data set cover?
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
  5. What is the general form of this data set?
  6. How does the data set represent geographic features?
  7. How does the data set describe geographic features?
• Who produced the data set?
  1. Who are the originators of the data set?
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
• Why was the data set created?
• How was the data set created?
  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
  3. What similar or related data should the user be aware of?
• How reliable are the data; what problems remain in the data set?
  1. How well have the observations been checked?
  2. How accurate are the geographic locations?
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
  5. How consistent are the relationships among the data, including topology?
• How can someone get a copy of the data set?
  1. Are there legal restrictions on access or use of the data?
  2. Who distributes the data?
  3. What's the catalog number I need to order this data set?
  4. What legal disclaimers am I supposed to read?
  5. How can I download or order the data?
• Who wrote the metadata?

What does this data set describe?

1. How might this data set be cited?
   Shapiro, Isabelle M., Phan, Kha C., and Gartman, Amy, 20260520, Thermogravimetric Analysis of rock samples from the Escanaba Trough (Gorda Ridge): data release DOI:10.5066/P13WN2F7, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

   Online Links:

   • https://doi.org/10.5066/P13WN2F7

   Other_Citation_Details:

   Suggested Citation: Shapiro, I.M., Phan, K.C., and Gartman, A., 2026, Thermogravimetric Analysis of rock samples from the Escanaba Trough (Gorda Ridge): U.S. Geological Survey data release, https://doi.org/10.5066/P13WN2F7.

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -127.5358
   East_Bounding_Coordinate: -127.4463
   North_Bounding_Coordinate: 41.0820
   South_Bounding_Coordinate: 40.6957
   

3. What does it look like?
4. Does the data set describe conditions during a particular time period?

   Beginning_Date: 24-May-2022

   Ending_Date: 17-Mar-2026

   Currentness_Reference:

   ground condition at the time data were collected through when last process step was completed

5. What is the general form of this data set?

   Geospatial_Data_Presentation_Form: comma-delimited text
   

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. It contains the following vector data types (SDTS terminology):
      • Point (382070)
   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 D_WGS_1984.
      The ellipsoid used is WGS_1984.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257222101.
      
7. How does the data set describe geographic features?

   TN403_TGA.csv

   Comma-delimited file containing results from thermogravimetric analyses of bulk marine mineral samples. The accompanying table TN403_Location.csv includes corresponding location and depth information about each sample. (Source: Producer defined)

   Sample_name

   The sample ID for each sample (Source: Producer defined) The sample ID of each sample. Samples follow a similar pattern of Dive #-rock number-composition-Sample Purge Gas-run number. For example, j2-1418-r03-bulk-n2s1sf is a size fractionated sample (sf) of rock number 3 from Jason 2 dive number J2-1418, with bulk composition, and the first run (s1) using nitrogen gas (n2) as the sample purge gas. Variations from this name scheme are when the sample name is modified with 5deg and 10deg, which show that this sample was run with the temperature ramp of 5 or 10 degrees Celsius per minute instead of the standard 15. Some sample names also include "parta" or "partb" which refer to the original rock subsample taken from a larger rock during sampling.

   Sample_purge_gas

   The gas that was in the chamber while the sample was run. (Source: Producer defined)

   Value	Definition
   N2	this sample was run in nitrogen gas
   air	this sample was run in air.

   Rate

   This is the rate that the temperature increases by, in degrees Celsius per minute (Source: producer defined)

   Range of values
   Minimum:	5
   Maximum:	15
   Units:	Degrees C per min
   Resolution:	5

   Time

   This is the time of the run for each sample. (Source: producer defined)

   Range of values
   Minimum:	0.00000
   Maximum:	56.98350
   Units:	minutes
   Resolution:	0.00001

   Program_Temperature

   This is the temperature of the chamber. (Source: producer defined)

   Range of values
   Minimum:	30.009
   Maximum:	599.992
   Units:	degrees Celsius
   Resolution:	0.001

   Sample_Temperature

   This is the internal temperature of the sample. (Source: producer defined)

   Range of values
   Minimum:	29.232
   Maximum:	595.372
   Units:	degrees Celsius
   Resolution:	0.001

   Sample_Purge_Flow

   This is the pressure at which the sample gas entered the chamber. (Source: producer defined)

   Range of values
   Minimum:	16.45
   Maximum:	20.03
   Units:	pounds per square inch (PSI)
   Resolution:	0.01

   System_Purge_Flow

   This is the pressure at which the gas not entering the chamber was cycled through the instrument. Where the system purge flow is zero, the flow was not functioning but should not impact the quality of the reported data. (Source: producer defined)

   Range of values
   Minimum:	0.00
   Maximum:	40.06
   Units:	pounds per square inch (PSI)
   Resolution:	0.01

   Unsubtracted_Weight

   This is the weight of the sample. (Source: producer defined)

   Range of values
   Minimum:	0.9234
   Maximum:	12.4293
   Units:	mg
   Resolution:	0.0001

   TN403_Location.csv

   Comma-delimited file containing longitude, latitude, and depth information for the samples in the associated data file TN403_TGA.csv. (Source: Producer defined)

   Sample_name

   The sample ID for each sample (Source: Producer defined) The sample ID of each sample. Samples follow a similar pattern of Dive #-rock number-composition-Sample Purge Gas-run number. For example, j2-1418-r03-bulk-n2s1sf is a size fractionated sample (sf) of rock number 3 from Jason 2 dive number J2-1418, with bulk composition, and the first run (s1) using nitrogen gas (n2) as the sample purge gas. Variations from this name scheme are when the sample name is modified with 5deg and 10deg, which show that this sample was run with the temperature ramp of 5 or 10 degrees Celsius per minute instead of the standard 15. Some sample names also include "parta" or "partb" which refer to the original rock subsample taken from a larger rock during sampling.

   Latitude

   This is the latitude of the sample. (Source: producer defined)

   Range of values
   Minimum:	40.6957
   Maximum:	41.0820
   Units:	Decimal degrees
   Resolution:	0.0001

   Longitude

   This is the longitude of the sample. (Source: producer defined)

   Range of values
   Minimum:	-127.5358
   Maximum:	-127.4463
   Units:	Decimal degrees
   Resolution:	0.0001

   Depth_meters

   This is the depth of the sample. (Source: producer defined)

   Range of values
   Minimum:	3198
   Maximum:	3284
   Units:	meters
   Resolution:	1

   Entity_and_Attribute_Overview:

   This data release includes 2 comma separated values (CSV) data files containing thermogravimetric analyses of bulk marine mineral samples (TN403_TGA.csv) and the associated location information (TN403_Location.csv). The first line of the csv file is a header line. The "Sample_name" field can be used to join the two data files.

   Entity_and_Attribute_Detail_Citation: U.S. Geological Survey
   

Who produced the data set?

1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
   • Isabelle M. Shapiro
   • Kha C. Phan
   • Amy Gartman
2. Who also contributed to the data set?
3. To whom should users address questions about the data?
   U.S. Geological Survey, Pacific Coastal and Marine Science Center

   Attn: PCMSC Science Data Coordinator

   2885 Mission Street

   Santa Cruz, CA
   

   831-427-4747 (voice)

   pcmsc_data@usgs.gov

Why was the data set created?

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: 13-Jun-2022 (process 1 of 4)

   Rock samples were collected on the R/V Thomas G. Thompson between May 24, 2022, and June 13, 2022, during the TN403 Escanaba Trough expedition, which was led and staffed by USGS employees. Rocks were collected from the seafloor using the ROV Jason's manipulator arm at water depths between 3192 and 3319 meters. Rock samples were frozen immediately upon recovery from the ROV, stored frozen, and shipped on ice to the USGS Pacific Coastal and Marine Science Center in Santa Cruz, CA.

   Date: 24-Aug-2023 (process 2 of 4)

   In the USGS Pacific Coastal and Marine Science Center Global Seabed Mineral Resources Lab, rock samples were subsampled, freeze dried, and then ground to a powder using a shatterbox and ceramic-lined bowls and ceramic pucks. Ceramic-lined bowls and pucks were cleaned thoroughly with quartz powder and detergents between samples to avoid cross-contamination.

   Date: 30-Sep-2025 (process 3 of 4)

   Powdered samples were sifted to isolate a size fraction of 75 to 150 microns, then loaded into a PerkinElmer Pyris TGA 9 thermogravimetric analysis system. Small aliquots of each sample were run in triplicate with ultra-high purity compressed nitrogen flowing through the chamber, and in triplicate with compressed laboratory air with an in-line filter, with samples being disposed of after each run. Samples were run with pre-programed temperature ramp from 30 to 300 degrees Celsius at either 5, 10, or 15 degrees Celsius per minute. Data sources produced in this process:

   • results

   Date: 17-Mar-2026 (process 4 of 4)

   Results from the Thermogravimetric analyses were combined into a comma-delimited text values document (TN403_TGA.csv). Data sources used in this process:

   • results

3. What similar or related data should the user be aware of?

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

1. How well have the observations been checked?
   Thermogravimetric analyzer is calibrated to weight and temperature by instrument manufacturers.
2. How accurate are the geographic locations?
   The location of rock samples were determined using ROV Jason's ultra-short baseline (USBL) navigation. Accuracy for this depth is approximately 6-26 meters. A formal accuracy assessment of the horizontal positional information in the dataset has not been conducted.
3. How accurate are the heights or depths?
   Vertical accuracy was determined with ROV Jason's altimeter, which is accurate to less than 1 m. No formal positional accuracy tests were conducted.
4. Where are the gaps in the data? What is missing?
   Dataset is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details.
5. How consistent are the relationships among the observations, including topology?
   Each sample was run in triplicate to verify consistency across sample runs.

How can someone get a copy of the data set?

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? These data are available in .csv format contained in a single file accompanied by CSDGM FGDC-compliant metadata.
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?
   • Availability in digital form:

     Data format:	File contains table in .csv format in format comma-delimited text (version Microsoft Excel 16.16.17 for Mac) Size: 1.77
     Network links:	https://doi.org/10.5066/P13WN2F7

   • Cost to order the data: None.

5. What hardware or software do I need in order to use the data set?
   These data can be viewed with Microsoft Excel or any text reader.

Who wrote the metadata?

Dates:

Last modified: 20-May-2026

Metadata author:

U.S. Geological Survey, Pacific Coastal and Marine Science Center

Attn: PCMSC Science Data Coordinator

2885 Mission Street

Santa Cruz, CA

831-427-4747 (voice)

pcmsc_data@usgs.gov

Metadata standard:

Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)