Location and grain-size analysis results of sediment samples collected in Nantucket Sound, Massachusetts, in May 2016 and May 2017 by the U.S. Geological Survey during field activities 2016-005-FA and 2017-022-FA (simplified point shapefile and CSV file)

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What does this data set describe?

Title:
Location and grain-size analysis results of sediment samples collected in Nantucket Sound, Massachusetts, in May 2016 and May 2017 by the U.S. Geological Survey during field activities 2016-005-FA and 2017-022-FA (simplified point shapefile and CSV file)
Abstract:
Two marine geological surveys were conducted in Nantucket Sound, Massachusetts, in May 2016 and May 2017 by the U.S. Geological Survey (USGS) as part of an agreement with the Massachusetts Office of Coastal Zone Management to map the geology of the sea floor offshore of Massachusetts. Samples of surficial sediment and photographs of the sea floor were collected at 76 sampling sites within the survey area, and sea-floor videos were collected at 75 of the sites. The sediment data and the observations from the photos and videos are used to explore the nature of the sea floor; in conjunction with high-resolution geophysical data, the observations are used to make interpretive maps of sedimentary environments and validate acoustic remote sensing data.
Supplemental_Information:
See the larger work citation to view the geotagged sea-floor photographs, location of bottom photographs, sea-floor videos, and location of bottom video tracklines collected during the surveys. For more information about these field activities, see https://cmgds.marine.usgs.gov/fan_info.php?fan=2016-005-FA and https://cmgds.marine.usgs.gov/fan_info.php?fan=2017-022-FA.
  1. How might this data set be cited?
    U.S. Geological Survey, 20201116, Location and grain-size analysis results of sediment samples collected in Nantucket Sound, Massachusetts, in May 2016 and May 2017 by the U.S. Geological Survey during field activities 2016-005-FA and 2017-022-FA (simplified point shapefile and CSV file): data release DOI:10.5066/P9UK5IOF, U.S. Geological Survey, Coastal and Marine Hazards and Resources Program, Woods Hole Coastal and Marine Science Center, Woods Hole, Massachusetts.

    Online Links:

    This is part of the following larger work.

    Huntley, Emily C., Ackerman, Seth D., Brothers, Laura L., Blackwood, Dann S., Irwin, Barry J., and Pendleton, Elizabeth A., 2020, Sea-floor sediment and imagery data collected in Nantucket Sound, Massachusetts, 2016 and 2017: data release DOI:10.5066/P9UK5IOF, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    Suggested citation: Huntley, E.C., Ackerman, S.D., Brothers, L.L., Blackwood, D.S., Irwin, B.J., and Pendleton, E.A., 2020, Sea-floor sediment and imagery data collected in Nantucket Sound, Massachusetts, 2016 and 2017: U.S. Geological Survey data release, https://doi.org/10.5066/P9UK5IOF.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -70.173003
    East_Bounding_Coordinate: -70.037225
    North_Bounding_Coordinate: 41.435664
    South_Bounding_Coordinate: 41.320671
  3. What does it look like?
    https://www.sciencebase.gov/catalog/file/get/5f10fc3082ce21d4c40799ea/?name=2016-005-FA_and_2017-022-FA_samples_browse.jpg (JPEG)
    Map of sediment sample locations in the survey area in Nantucket Sound, Massachusetts.
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 02-May-2016
    Ending_Date: 04-May-2017
    Currentness_Reference:
    Data were collected on the following dates: 20160502, 20160503, 20160507, and 20170504
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: vector and 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 Vector data set. It contains the following vector data types (SDTS terminology):
      • Entity point (76)
    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 D_WGS_1984.
      The ellipsoid used is WGS_1984.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257224.
  7. How does the data set describe geographic features?
    2016-005-FA_and_2017-022-FA_samples
    Grain-size analysis results for sediment samples collected during USGS field activities 2016-005-FA and 2017-022-FA in Nantucket Sound, Massachusetts, in 2016 and 2017. These are the attributes for the CSV file. The shapefile is a simplified version of the CSV file with fewer attribute fields and two additional software-generated attributes, FID and Shape. Please see the entity and attribute overview section for a description of the shapefile attributes. (Source: U.S. Geological Survey)
    ANALYSIS_ID
    An identifier for the sample that is unique to the database. This identifier begins with the assigned multi-letter code GS-, which corresponds to the type of analysis performed on the sample (grain-size analysis), followed by a six-digit number assigned sequentially as samples are registered for analysis. (Source: U.S. Geological Survey) Character string.
    FIELD_NO
    The identification value assigned to the sample at the time of collection. This varies from field activity to field activity and the ID can contain any combination of letters and numbers. (Source: U.S. Geological Survey) Character string.
    PROJECT
    Name of project or project number under which samples were taken or data generated; sometimes project name indicates a more specific area. (Source: U.S. Geological Survey) Character sting.
    FA_ID
    The serial number assigned to the dataset field activity during which the sample was collected. This value is in the format YYYY-XXX-FA where YYYY is the year, XXX is the number assigned to the activity within the year, and FA indicates Field Activity. (Source: U.S. Geological Survey) Character string.
    CONTACT
    Name of Principal investigator or chief scientist responsible for data collection, or researcher submitting samples for analysis (usually first initial and last name). (Source: U.S. Geological Survey) Character string.
    AREA
    General geographic area of data collection. Name is general enough to easily locate area on a map. (Source: U.S. Geological Survey) Character string.
    LATITUDE
    Latitude coordinate, in decimal degrees (WGS 84), of sample location. South latitude is recorded as negative values. The attribute measurement resolution is 0.0000001 for 2016 and 0.000001 for 2017. (Source: U.S. Geological Survey)
    Range of values
    Minimum:41.3206708
    Maximum:41.435664
    Units:decimal degrees
    LONGITUDE
    Longitude coordinate, in decimal degrees (WGS 84), of sample location. West longitude is recorded as negative values. The attribute measurement resolution is 0.0000001 for 2016 and 0.000001 for 2017. (Source: U.S. Geological Survey)
    Range of values
    Minimum:-70.1730033
    Maximum:-70.037225
    Units:decimal degrees
    DEPTH_M
    Approximate depth of water in meters at the sample location acquired using the survey vessel's fathometer. (Source: U.S. Geological Survey)
    Range of values
    Minimum:9.0
    Maximum:17.0
    Units:meters
    Resolution:0.1
    T_DEPTH
    Top depth of the sample below the sediment-water interface in centimeters. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:0
    Units:centimeters
    B_DEPTH
    Bottom depth of the sample below the sediment-water interface in centimeters. (Source: U.S. Geological Survey)
    Range of values
    Minimum:2
    Maximum:2
    Units:centimeters
    DEVICE
    Sampling device used to collect the sample. (Source: U.S. Geological Survey) Character string.
    DATE_COLLECTED
    Calendar date based on UTC time indicating when the sample was collected in the format MM/DD/YYYY where MM is the numeric month, DD is the day of the month, and YYYY is the year. (Source: U.S. Geological Survey) Character string.
    ANALYSIS_COMPLETION_DATE
    Calendar date indicating when analyses on the sample were completed in the format MM/DD/YYYY where MM is the numeric month, DD is the day of the month, and YYYY is the year. (Source: U.S. Geological Survey) Character string.
    WEIGHT
    Weight of initial sample in grams. (Source: U.S. Geological Survey)
    Range of values
    Minimum:101.3429
    Maximum:252.3198
    Units:grams
    Resolution:0.0001
    GRAVEL_PCT
    Gravel content in percent dry weight of the sample. Gravel consists of particles with nominal diameters greater than 2 mm (-1 phi and larger). (Source: U.S. Geological Survey)
    Range of values
    Minimum:0.022
    Maximum:56.845
    Units:weight percent
    Resolution:0.001
    SAND_PCT
    Sand content in percent dry weight of the sample. Sand consists of particles with nominal diameters less than 2 mm, but greater than or equal to 0.0625 mm (0 phi through 4 phi, inclusive). (Source: U.S. Geological Survey)
    Range of values
    Minimum:17.454
    Maximum:99.920
    Units:weight percent
    Resolution:0.001
    SILT_PCT
    Silt content in percent dry weight of the sample. Silt consists of particles with nominal diameters less than 0.0625 mm, but greater than or equal to 0.004 mm (5 phi through 8 phi, inclusive). (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:52.877
    Units:weight percent
    Resolution:0.001
    CLAY_PCT
    Clay content in percent dry weight of the sample. Clay consists of particles with nominal diameters less than 0.004 mm (9 phi and smaller). (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:34.107
    Units:weight percent
    Resolution:0.001
    CLASSIFICATION (Shepard)
    Sediment classification based on a rigorous definition (Shepard [1954] as modified by Schlee and Webster [1967], Schlee [1973], and Poppe and others [2005]). In the definitions below, gravel is defined as particles with nominal diameters greater than 2 mm; sand consists of particles with nominal diameters less than 2 mm, but greater than or equal to 0.0625 mm; silt consists of particles with nominal diameters less than 0.0625 mm, but greater than or equal to 0.004 mm; and clay consists of particles with nominal diameters less than 0.004 mm. (Source: U.S. Geological Survey)
    ValueDefinition
    clayey sandSediment whose main phase is sand, but with significant clay.
    gravelSediment whose main phase is gravel.
    gravelly sedimentSediment whose main phase is gravel, but with significant other sediment. Gravel greater than 10 percent.
    sandSediment whose main phase is sand.
    sand silt claySediment with significant (over 20 percent) sand, silt, and clay.
    sandy siltSediment whose main phase is silt, but with significant sand.
    silty sandSediment whose main phase in sand, but with significant silt.
    MEDIAN
    Diameter at which 50% of the sample mass is comprised of sediment particles with a diameter less than this value and 50% is larger; middle point in the grain-size distribution in phi units. (Source: U.S. Geological Survey)
    Range of values
    Minimum:-3.032
    Maximum:5.275
    Units:phi
    Resolution:0.001
    MEAN
    Average value in the grain-size distribution in phi units. (Source: U.S. Geological Survey)
    Range of values
    Minimum:-0.910
    Maximum:5.678
    Units:phi
    Resolution:0.001
    STDEV
    Standard deviation (root mean square of the deviations) of the grain-size distribution in phi units (sorting). (Source: U.S. Geological Survey)
    Range of values
    Minimum:0.398
    Maximum:4.837
    Units:phi
    Resolution:0.001
    SKEWNESS
    Skewness (deviation from symmetrical form) of the grain-size distribution in phi units. (Source: U.S. Geological Survey)
    Range of values
    Minimum:-1.456
    Maximum:6.724
    Units:phi
    Resolution:0.001
    KURTOSIS
    Kurtosis (degree of curvature near the mode) of the grain-size distribution in phi units. (Source: U.S. Geological Survey)
    Range of values
    Minimum:1.191
    Maximum:93.942
    Units:phi
    Resolution:0.001
    PHI_11
    Weight percent of the sample in the 11-phi fraction and smaller (nominal diameter of particles less than 0.001 mm); fine clay. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:3.841
    Units:weight percent
    Resolution:0.001
    PHI_10
    Weight percent of the sample in the 10-phi fraction (nominal diameter of particles greater than or equal to 0.001 mm, but less than 0.002 mm); medium clay. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:13.669
    Units:weight percent
    Resolution:0.001
    PHI_9
    Weight percent of the sample in the 9-phi fraction (nominal diameter of particles greater than or equal to 0.002 mm, but less than 0.004 mm); coarse clay. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:16.597
    Units:weight percent
    Resolution:0.001
    PHI_8
    Weight percent of the sample in the 8-phi fraction (nominal diameter of particles greater than or equal to 0.004 mm, but less than 0.008 mm); very fine silt. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:13.235
    Units:weight percent
    Resolution:0.001
    PHI_7
    Weight percent of the sample in the 7-phi fraction (nominal diameter of particles greater than or equal to 0.008 mm, but less than 0.016 mm); fine silt. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:14.671
    Units:weight percent
    Resolution:0.001
    PHI_6
    Weight percent of the sample in the 6-phi fraction (nominal diameter of particles greater than or equal to 0.016 mm, but less than 0.031 mm); medium silt. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:15.236
    Units:weight percent
    Resolution:0.001
    PHI_5
    Weight percent of the sample in the 5-phi fraction (nominal diameter of particles greater than or equal to 0.031 mm, but less than 0.0625 mm); coarse silt. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:24.816
    Units:weight percent
    Resolution:0.001
    PHI_4
    Weight percent of the sample in the 4-phi fraction (nominal diameters of particles greater than or equal to 0.0625 mm, but less than 0.125 mm); very fine sand. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0.009
    Maximum:63.699
    Units:weight percent
    Resolution:0.001
    PHI_3
    Weight percent of the sample in the 3-phi fraction (nominal diameter of particles greater than or equal to 0.125 mm, but less than 0.25 mm); fine sand. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0.550
    Maximum:95.325
    Units:weight percent
    Resolution:0.001
    PHI_2
    Weight percent of the sample in the 2-phi fraction (nominal diameter of particles greater than or equal to 0.25 mm, but less than 0.5 mm); medium sand. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0.319
    Maximum:63.740
    Units:weight percent
    Resolution:0.001
    PHI_1
    Weight percent of the sample in the 1-phi fraction (nominal diameter of particles greater than or equal to 0.5 mm, but less than 1 mm); coarse sand. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0.045
    Maximum:59.165
    Units:weight percent
    Resolution:0.001
    PHI_0
    Weight percent of the sample in the 0-phi fraction (nominal diameters of particles greater than or equal to 1 mm, but less than 2 mm); very coarse sand. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0.002
    Maximum:17.892
    Units:weight percent
    Resolution:0.001
    PHI_-1
    Weight percent of the sample in the -1-phi fraction (nominal diameter of particles greater than or equal to 2 mm, but less than 4 mm); very fine pebbles (granules). (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:4.433
    Units:weight percent
    Resolution:0.001
    PHI_-2
    Weight percent of the sample in the -2-phi fraction (nominal diameter of particles greater than or equal to 4 mm, but less than 8 mm); fine pebbles. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:4.414
    Units:weight percent
    Resolution:0.001
    PHI_-3
    Weight percent of the sample in the -3-phi fraction (nominal diameter of particles greater than or equal to 8 mm, but less than 16 mm); medium pebbles. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:51.633
    Units:weight percent
    Resolution:0.001
    PHI_-4
    Weight percent of the sample in the -4-phi fraction (nominal diameter of particles greater than or equal to 16 mm, but less than 32 mm); coarse pebbles. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:0
    Units:weight percent
    Resolution:0.001
    PHI_-5
    Weight percent of the sample in the -5-phi fraction and larger (nominal diameter of particles greater than or equal to 32 mm); very coarse pebbles, cobbles, and boulders. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:0
    Units:weight percent
    Resolution:0.001
    ANALYST
    Name (usually first, middle, and last initials) of person who performed the grain-size or physical properties analysis. (Source: U.S. Geological Survey) Character string.
    PHI-1_SHELLPCT
    Percent of shell or carbonate material in the -1-phi fraction (nominal diameter of particles greater than or equal to 2 mm, but less than 4 mm) for the 2016 samples. No data value is -9999 for the 2017 samples. (Source: U.S. Geological Survey)
    Range of values
    Minimum:20
    Maximum:100
    Units:percent
    Resolution:1
    PHI-2_SHELLPCT
    Percent of shell or carbonate material in the -2-phi fraction (nominal diameter of particles greater than or equal to 4 mm, but less than 8 mm) for the 2016 samples. No data value is -9999 for the 2017 samples. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:100
    Units:percent
    Resolution:1
    PHI-3_SHELLPCT
    Percent of shell or carbonate material in the -3-phi fraction (nominal diameter of particles greater than or equal to 8 mm, but less than 16 mm) for the 2016 samples. No data value is -9999 for the 2017 samples. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:100
    Units:percent
    Resolution:1
    Entity_and_Attribute_Overview:
    The shapefile is a simplified version of the CSV file with fewer attribute fields. Specifically, STDEV, SKEWNESS, KURTOSIS, the individual phi measurements (e.g., PHI_11), and the percentages of shell or carbonate material in the coarse phi fractions (e.g., PHI-1_SHELLPCT) were removed. The shapefile also has two additional attributes, FID and Shape, which have the following descriptions:
    Attribute: Attribute Label: FID Attribute Definition: Internal feature number. Attribute Definition Source: Esri Attribute Domain Values: Unrepresentable Domain: Sequential unique whole numbers that are automatically generated.
    Attribute: Attribute Label: Shape Attribute Definition: Feature geometry. Attribute Definition Source: Esri Attribute Domain Values: Unrepresentable Domain: Coordinates defining the features.
    All the other attributes in the shapefile have the same definitions as the CSV file attributes. Please note that some of the field names were truncated since a shapefile field name can only contain up to 10 characters. The following fields are included in the shapefile: FID, Shape, ANALYSIS_I (truncated field name for ANALYSIS_ID), FIELD_NO, PROJECT, FA_ID, CONTACT, AREA, LATITUDE, LONGITUDE, DEPTH_M, T_DEPTH, B_DEPTH, DEVICE, DATE_COLLE (truncated field name for DATE_COLLECTED), ANALYSIS_C (truncated field name for ANALYSIS_COMPLETION_DATE), WEIGHT, GRAVEL_PCT, SAND_PCT, SILT_PCT, CLAY_PCT, CLASSIFICA (truncated field name for CLASSIFICATION), MEDIAN, MEAN, and ANALYST.
    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)
    • U.S. Geological Survey
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    Seth Ackerman
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    508-548-8700 x2315 (voice)
    508-457-2310 (FAX)
    sackerman@usgs.gov

Why was the data set created?

This dataset provides access to the locations and grain-size analysis results of surficial sediments collected with a modified Van Veen grab on the Mini SEABed Observation and Sampling System (MiniSEABOSS) aboard the Research Vessel (R/V) Rafael during USGS field activity 2016-005-FA (May 2 to May 7, 2016) and aboard the R/V Tioga during USGS field activity 2017-022-FA (May 4, 2017). These data were collected to characterize the sea floor by identifying sediment texture and to ground-truth acoustic data collected during USGS field activity 2013-003-FA (Ackerman and others, 2016).

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: 04-May-2017 (process 1 of 9)
    Step 1: Collected data.
    Two marine geological surveys were conducted in Nantucket Sound, Massachusetts, in May 2016 and May 2017. The survey vessel occupied one of the target sites and the MiniSEABOSS was deployed off the vessel's starboard side in 2016 and off the vessel's stern in 2017. The MiniSEABOSS was equipped with a modified Van Veen grab sampler, two GoPro HERO4 Black digital cameras, an oblique downward-looking SeaViewer 6000 HD Sea-Drop video camera with a topside feed, and a dive light to illuminate the sea floor for video and photograph collection. The elements of this particular MiniSEABOSS system were held within a stainless-steel frame that measured ~1 x 1 meter. The frame had a stabilizer fin that oriented the system as it drifted over the seabed. The winch operator lowered the sampler until the sea floor was observed in the topside live video feed. Generally, the vessel and sampler drifted with wind and current for up to a few minutes to ensure a decent photo with a clear view of the sea floor was acquired. Bottom video was also recorded during the drift. Then, the winch operator lowered the Van Veen sampler until it rested on the sea floor. When the system was raised, the Van Veen sampler closed and collected a sample as it was lifted off the sea floor. Times for the sampler retrieval, which would later be used to derive the sample locations, were manually recorded in the survey log when the sampler was lifted off the seabed. The sampler was recovered to the deck of the survey vessel where a subsample was taken for grain-size analysis at the sediment laboratory at the USGS Woods Hole Coastal and Marine Science Center. A total of 76 sites were occupied with the MiniSEABOSS: 55 sites were occupied aboard the R/V Rafael in May 2016 during field activity 2016-005-FA, and 21 sites were occupied aboard the R/V Tioga in May 2017 during field activity 2017-022-FA. Sediment samples were collected at all 76 sites. Person who carried out this activity:
    Seth Ackerman
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    508-548-8700 x2315 (voice)
    508-457-2310 (FAX)
    sackerman@usgs.gov
    Data sources produced in this process:
    • Sediment samples
    • Survey logs
    Date: 2017 (process 2 of 9)
    Step 2: Acquired and processed navigation.
    During field activity 2016-005-FA, DGPS navigation from a Hemisphere DGPS receiver was logged through HYPACK navigation software and a DataBridge data logger. The DGPS was set to receive fixes at a 2-second interval in geographic coordinates (WGS 84). Dates and times were recorded in Coordinated Universal Time (UTC). Log files for each MiniSEABOSS deployment were saved in text format and then combined for each Julian day. An AWK script (awkseth.gprmc.16005.awk) was used to parse the GPRMC navigation string from the log files and create ASCII Comma Separated Values (CSV) text files. The output files were merged and then reformatted using an AWK script (nav_time_reformat.awk), creating a processed navigation CSV text file for the survey (2016-005-FA_OdysseyAudioStamp_nav_ALL.csv). For field activity 2017-022-FA, a GPS log file in text format for the R/V Tioga was provided by the Woods Hole Oceanographic Institution. The navigation was collected at a 1-second interval in geographic coordinates (WGS 84), and dates and times were recorded in UTC. An AWK script (awksethTioga.gprmc.17022.awk) was used to parse the GPRMC navigation string from the log file, creating a processed navigation CSV text file for the survey (2017022FA_TiogaShip_nav.csv). Person who carried out this activity:
    Seth Ackerman
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    508-548-8700 x2315 (voice)
    508-457-2310 (FAX)
    sackerman@usgs.gov
    Data sources produced in this process:
    • Processed navigation files
    Date: 2017 (process 3 of 9)
    Step 3: Assembled sample information for sediment laboratory.
    The sediment sample times (as recorded in the survey logs) were used to parse GPS positions for each sediment sample from the logged GPS data. Approximate depths for each sample, which had been acquired using the ship's fathometer, were extracted from the HYPACK target file for the 2016 samples and the captain's log for 2017. This information was then provided to the sediment laboratory at the USGS Woods Hole Coastal and Marine Science Center with the sample analysis request form for each survey. Person who carried out this activity:
    Seth Ackerman
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    508-548-8700 x2315 (voice)
    508-457-2310 (FAX)
    sackerman@usgs.gov
    Data sources used in this process:
    • Survey logs
    • Processed navigation files
    • 2016-005-FA HYPACK target file
    • 2017-022-FA captain's log
    Data sources produced in this process:
    • Sediment sample locations CSV files
    Date: 13-Oct-2017 (process 4 of 9)
    Step 4: Analyzed sediment samples.
    The samples from each survey were analyzed in the sediment laboratory at the USGS Woods Hole Coastal and Marine Science Center using the Beckman Coulter Multisizer 3 and sieving of the >= 4-phi fraction. The samples were assigned unique analysis identifiers (ANALYSIS_ID), and a macro-enabled Microsoft Excel data entry spreadsheet (GrainSizeWorksheet_xxxx.xlsm, where xxxx is the batch number assigned to the sample submission) was created for each survey to record the measurement data. About 50 grams of wet sediment were placed in a pre-weighed beaker, weighed, oven dried at 100 degrees Celsius, and reweighed to correct for salt. The dried sample was wet sieved through a 0.062 mm (No. 230) sieve. The coarse fraction remaining in the sieve was oven dried at 100 degrees Celsius (until completely dried) and weighed. The fine fraction in water was collected in a plastic Nalgene bottle and sealed with a screw lid (stored for no longer than one week). The coarse fraction was dry sieved to determine the individual weights of the 4- to -5-phi fractions, and the weights were recorded in the data entry spreadsheet. For the 2016 samples, shell and shell fragments were manually removed from the -1-phi and coarser fractions and weighed, and their weights were recorded in the data entry spreadsheet (this was not done for the 2017 samples). The fine fraction was run and combined using the 200-micron and 30-micron Coulter analyses using the Multisizer 3 software to get the fine fraction grain-size distribution for each survey. The fine fraction distribution data were added to the data entry spreadsheet for each survey. The spreadsheet for each survey was used to calculate a continuous phi class distribution from the original fractions. Person who carried out this activity:
    Allison Paquette
    U.S. Geological Survey
    Integrated Statistics contractor to the U.S. Geological Survey
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    508-548-8700 (voice)
    508-457-2310 (FAX)
    Data sources used in this process:
    • Sediment samples
    • Sediment sample locations CSV files
    Data sources produced in this process:
    • Data entry spreadsheets
    Date: 13-Oct-2017 (process 5 of 9)
    Step 5: Calculated grain-size classification and statistical analyses.
    A continuous phi class distribution from the original fractions was transposed to the "results" tab in the macro-enabled Microsoft Excel data entry workbook (GrainSizeWorksheet_xxxx.xlsm, where xxxx is the identifier assigned to the sample submission) for each survey. Macros in the workbook ("GS_statistics" and "sedimentname") were run to calculate grain-size classification and statistical analyses and finish processing the data. Sample, navigation, and field identifiers, along with continuous phi class distribution data, grain-size classification, and statistical analysis results, were copied and pasted into a final Microsoft Excel spreadsheet (xxxx_GS-MS_results.xlsx, where xxxx is the batch number assigned to the sample submission) for each survey. The processed data were quality control checked and assigned a quality grade based on the examination of the analytical data. Processed data were released to the submitter and incorporated into the laboratory's database. All raw analytical data generated by the samples were archived in the sediment analysis laboratory. Person who carried out this activity:
    Brian Buczkowski
    U.S. Geological Survey
    Physical Scientist
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    508-548-8700 x2361 (voice)
    508-457-2310 (FAX)
    bbuczkowski@usgs.gov
    Data sources used in this process:
    • Data entry spreadsheets
    Data sources produced in this process:
    • Final Microsoft Excel spreadsheets (LB3_GS-MS_results.xlsx and SA9_GS-MS_results.xlsx)
    Date: Dec-2019 (process 6 of 9)
    Step 6: Interpolated to create 1-second navigation.
    The navigation fixes were interpolated to create 1-second navigation. This was done because the application used to geotag the bottom photos would have interpolated between fixes; therefore, the navigation was interpolated so that the sediment and imagery data could be mapped using the same 1-second navigation. To interpolate the 2016 navigation data, first, a column of the original source filename was deleted from the processed navigation CSV text file (2016-005-FA_OdysseyAudioStamp_nav_ALL.csv). Next, a shapefile was created from the CSV file in Esri ArcGIS (version 10.3.1) and projected to WGS 84 UTM Zone 19N so that the distance in meters between the navigation fixes could be calculated. Then, the Generate Near Table tool was run using the planar method with the input and output features set to the UTM navigation shapefile and with the option checked to find only the closest feature. The output table was used to identify erroneous fixes, and two erroneous fixes were deleted from the navigation CSV text file. A Jupyter Notebook Python script (Interp_NAV_Dec2019_for_Nantucket2016-005-FA.ipynb) was run to interpolate and create a CSV text file of 1-second navigation. The original 2-second fixes were logged only when the video was recorded, so the script also interpolated between the end point of a video trackline and the start point of the next trackline. To create a final file of 1-second navigation, the points between the video trackline start and end times were extracted (which removed the interpolated positions during the transits between the video tracklines) and were saved as a CSV text file (out_interp_2016Nantucket_sel_for_gpx.csv). Finally, the CSV file was reorganized and formatted to have fields of the latitude, longitude, hours, minutes, seconds, Julian day, year, field activity ID, and Julian day and time. For the 2017 survey, navigation data were logged for the full Julian day, including when the survey vessel was at the dock and when it was transiting to, from, and between the sampling sites. First, the navigation data from 13:30:00 to 19:14:59 were extracted from the processed navigation CSV text file (2017022FA_TiogaShip_nav.csv) to remove the navigation logged at, departing, and returning to the dock. Next, columns of the original source filename and time (the hours, minutes, and seconds were listed individually in other columns) were deleted from the CSV text file, and leading spaces were deleted as needed. Then, a shapefile was created from the CSV file in Esri ArcGIS (version 10.3.1) and projected to WGS 84 UTM Zone 19N so that the distance in meters between the navigation fixes could be calculated. The Generate Near Table tool was run using the planar method with the input and output features set to the UTM navigation shapefile and with the option checked to find only the closest feature. The output table was used to identify erroneous fixes, but no erroneous fixes were identified. The navigation data, however, were noisy. To smooth the data, the coordinates were rounded from seven to six decimal places and every fourth fix was extracted. A Jupyter Notebook Python script (Interp_NAV_Dec2019_for_Nantucket2017-022-FA.ipynb) was run to interpolate and create a CSV text file of 1-second navigation (2017022FA_TiogaShip_nav_4secint_round6_interp_for_gpx.csv). Finally, the CSV file was reorganized and formatted to have fields of the latitude, longitude, hours, minutes, seconds, Julian day, year, field activity ID, and Julian day and time to create a final CSV file of 1-second navigation for the survey. This process step and the subsequent process steps were performed by the same person, Emily Huntley. Person who carried out this activity:
    Emily Huntley
    U.S. Geological Survey
    Geographer/Database Specialist
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    508-548-8700 (voice)
    508-457-2310 (FAX)
    ehuntley@contractor.usgs.gov
    Data sources used in this process:
    • Processed navigation files
    Data sources produced in this process:
    • Final processed navigation files
    Date: Jan-2020 (process 7 of 9)
    Step 7: Checked and updated sediment sample locations.
    The sediment sample times (as recorded in the survey logs) were checked by viewing the sea-floor videos to see when the sampler was lifted off the sea floor at each site and updated with more precise times as appropriate. The new sample times were matched to the corresponding times in the final interpolated navigation files to update the latitude and longitude of each sample in the sediment grain-size analysis results spreadsheets in Microsoft Excel 2016 for Mac. Data sources used in this process:
    • Sea-floor videos
    • Final Microsoft Excel spreadsheets (LB3_GS-MS_results.xlsx and SA9_GS-MS_results.xlsx)
    • Final processed navigation files
    Data sources produced in this process:
    • Final Microsoft Excel spreadsheets with updated coordinates
    Date: Jan-2020 (process 8 of 9)
    Step 8: Created final sediment grain-size analysis results CSV file.
    The sediment grain-size analysis results spreadsheets for each survey were merged in Microsoft Excel 2016 for Mac and then edited to remove some fields, format fields, and add a no data value (-9999) to empty attributes as needed. The Microsoft Excel spreadsheet was then saved as a CSV file. Data sources used in this process:
    • Final Microsoft Excel spreadsheets with updated coordinates
    Data sources produced in this process:
    • Final sediment grain-size analysis results CSV file
    Date: Jan-2020 (process 9 of 9)
    Step 9: Created a simplified sediment grain-size analysis results shapefile.
    The sediment grain-size analysis results CSV file was copied and edited to create a simplified version of the CSV file with fewer attribute fields (specifically, STDEV, SKEWNESS, KURTOSIS, the individual phi measurements [e.g., PHI_11], and the percentages of shell or carbonate material in the coarse phi fractions [e.g., PHI-1_SHELLPCT] were removed). A shapefile was created using the simplified version of the CSV file in Esri ArcGIS (version 10.3.1), and XTools Pro (version 12.0) for Esri ArcGIS was used to modify some field parameters in the point shapefile (Table Operations - Table Restructure). Please note that this metadata file represents the CSV file; users should access the CSV file for the full sediment grain-size analysis results. Data sources used in this process:
    • Final sediment grain-size analysis results CSV file
    Data sources produced in this process:
    • Final simplified sediment grain-size analysis results shapefile
  3. What similar or related data should the user be aware of?
    Ackerman, Seth D., Brothers, Laura L., Foster, David S., Andrews, Brian D., Baldwin, Wayne E., and Schwab, William C., 2016, High-resolution geophysical data from the inner continental shelf: South of Martha’s Vineyard and north of Nantucket, Massachusetts: Open-File Report 2016–1168, U.S. Geological Survey, Reston, VA.

    Online Links:

    Shepard, F.P., 1954, Nomenclature based on sand-silt-clay ratios: Journal of Sedimentary Petrology v. 24, no. 3., p. 151-158.

    Schlee, J.S., and Webster, J., 1967, A computer program for grain-size data: Sedimentology v. 8, no. 1., p. 45-53.

    Schlee, J.S., 1973, Atlantic continental shelf and slope of the United States—sediment texture of the northeastern part: Professional Paper 529-L, U.S. Geological Survey, Reston, VA.

    Online Links:

    Poppe, L.J., McMullen, K.Y., Williams, S.J., and Paskevich, V.F., 2014, USGS east-coast sediment analysis: Procedures, database, and GIS data: Open-File Report 2005-1001, U.S. Geological Survey, Reston, VA.

    Online Links:


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

  1. How well have the observations been checked?
    All attributes were evaluated during data processing as standard quality control to ensure attributes contain accurate and relevant information and values. Due to rounding, the sum of the aggregate class percentages (e.g., GRAVEL_PCT, SAND_PCT, etc.) and the sum of the phi fraction percentages (e.g., PHI_11, PHI_10, etc.) may not always add up to exactly 100.000%. One sample (site 2017-022-020) had negative values for the silt percentage, clay percentage, and phi fraction percentages for 11 phi through 5 phi; once these attributes were rounded to three decimal places, they were all equal to zero.
  2. How accurate are the geographic locations?
    Navigation for field activity 2016-005-FA used a Differential Global Positioning System (DGPS). The DGPS was set to receive fixes at a 2-second interval in geographic coordinates (World Geodetic System of 1984 [WGS 84]). The fixes were later interpolated to get 1-second navigation. For field activity 2017-022-FA, navigation data for the R/V Tioga from a Global Positioning System (GPS) were provided by the Woods Hole Oceanographic Institution. The 2017 navigation was collected at a 1-second interval in geographic coordinates (WGS 84); however, the navigation data were noisy, so a fix every 4 seconds was extracted and then interpolated to get smoother 1-second navigation. The recorded position of each sediment sample is the position of the DGPS/GPS antenna on the survey vessel, located on the aft port side of the R/V Rafael's cabin just off the centerline in 2016 and on the forward center of the R/V Tioga's wheelhouse in 2017, not the location of the MiniSEABOSS. The MiniSEABOSS was deployed approximately 2 meters to the starboard side of the DGPS antenna in 2016 and approximately 13 meters aft the GPS antenna in 2017. No layback or offset was applied to the recorded position. In addition, the sampler may drift away from the survey vessel when deployed to the sea floor. Based on the various sources of horizontal offsets, a conservative estimate of the horizontal accuracy of the sediment sample locations is 2-4 meters in 2016 and 13-15 meters in 2017. Navigation was not recorded for one site (site 2016-005-043), so the sample from this site was mapped at the closest available fix, which was shortly after the MiniSEABOSS was lifted off the sea floor at the site.
  3. How accurate are the heights or depths?
    The depths recorded for each sample are approximate and were acquired using the ship's fathometer. These depths are generally within 1 meter of actual referenced depths from previous bathymetry surveys.
  4. Where are the gaps in the data? What is missing?
    Physical sediment samples were collected at all 76 sites occupied during field activities 2016-005-FA and 2017-022-FA. Each site usually had only one deployment of the sampler; however, four sites (sites 2016-005-001, 2016-005-053, 2017-022-004, and 2017-022-008) had two separate deployments because a sediment grab was not successfully collected during the first deployment. The sediment sample locations for these four sites are from the second deployment when a grab sample was successfully collected. Navigation and video were not recorded for one site (site 2016-005-043), so the sample and a bottom photograph from this site were mapped at the closest available fix, which was shortly after the MiniSEABOSS was lifted off the sea floor at the site.
  5. How consistent are the relationships among the observations, including topology?
    The sediment samples were all collected with the same modified Van Veen grab sampler mounted on the MiniSEABOSS. The sediment samples were usually collected at the end of the video trackline, but some samples were collected at the start of the transect (sites 2016-005-013, 2016-005-016, 2016-005-028, 2016-005-044, 2016-005-046, 2016-005-049, 2016-005-050, 2016-005-052) or middle (site 2016-005-023).

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints: None
Use_Constraints:
Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey as the originator of the dataset.
  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
    USA

    1-888-275-8747 (voice)
    sciencebase@usgs.gov
  2. What's the catalog number I need to order this data set? Location and grain-size analysis results of sediment samples collected in Nantucket Sound, Massachusetts, in May 2016 and May 2017 by the U.S. Geological Survey during field activities 2016-005-FA and 2017-022-FA. This dataset contains the following files: a CSV file of the sediment sample locations and grain-size analysis results (2016-005-FA_and_2017-022-FA_samples.csv); a simplified shapefile of the sediment sample locations and grain-size analysis results (2016-005-FA_and_2017-022-FA_samples.shp); a browse graphic of sediment sample locations (2016-005-FA_and_2017-022-FA_samples_browse.jpg); and a Federal Geographic Data Committee (FGDC) Content Standard for Digital Geospatial Metadata (CSDGM) metadata file (2016-005-FA_and_2017-022-FA_samples_meta.xml).
  3. What legal disclaimers am I supposed to read?
    Neither the U.S. Government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
  4. How can I download or order the data?
  5. What hardware or software do I need in order to use the data set?
    This dataset contains data available as a CSV file and a point shapefile. The CSV file can be read with a text editor. The user must have software capable of reading shapefile format to use the point shapefile.

Who wrote the metadata?

Dates:
Last modified: 16-Nov-2020
Metadata author:
Emily Huntley
U.S. Geological Survey
Geographer/Database Specialist
384 Woods Hole Rd.
Woods Hole, MA
USA

508-548-8700 (voice)
508-457-2310 (FAX)
ehuntley@contractor.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_P9UK5IOF/2016-005-FA_and_2017-022-FA_samples_meta.faq.html>
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