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)
Value | Definition |
clayey sand | Sediment whose main phase is sand, but with significant clay.
|
gravel | Sediment whose main phase is gravel.
|
gravelly sediment | Sediment whose main phase is gravel, but with significant other sediment. Gravel greater than 10 percent.
|
sand | Sediment whose main phase is sand.
|
sand silt clay | Sediment with significant (over 20 percent) sand, silt, and clay.
|
sandy silt | Sediment whose main phase is silt, but with significant sand.
|
silty sand | Sediment 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