In the substrate attribute, weight percents described in the domain value definitions may not add to 100 due to rounding of values. Also in the geo_substr attributes, the mean weight percents for the units, sand is divided into two composite grades: fine-grained sand (fgS; 0.062 to <0.25 mm) and coarse-grained sand (cgS; 0.25 to <2mm). Gravel is also divided into two composite grades: Gravel1 (G1; w to <8 mm) and Grave2(Gs; 8 to <64 mm). This G1 and G2 are not to be confused with the geologic substrate units G1 i_mfgS and G2 i_mfgS.
In addition to the shapefile, there is an accompanying Excel spreadsheet (SIM3341_table4.xlsx). The spreadsheet has the original column headings as described in SIM 3341, table 5:
http://dx.doi.org/10.3133/sim3341. Additional information regarding abbreviations is at the top of the spreadsheet.
That following information included here as column: column heading: description.
Column A: USGS SBNMS Sta No.: Station number for samples collected during this project in the Stellwagen Bank National Marine Sanctuary region offshore of Boston, Massachusetts
Column B: Substrate unit symbol: Symbol of substrate shown on maps
Column C: Substrate unit name: Combination of substrate unit symbol and abbreviation of substrate descriptive name (see column AV)
Column D: Photos: Collected (TRUE) or did not collect (FALSE) seabed photographs at the station
Column E: Video: Collected (TRUE) or did not collect (FALSE) video imagery at the station
Column F: Sample: Collected (TRUE) or did not collect (FALSE) sediment sample at the station
Column G: USGS-DBID: USGS sediment grain size analysis database identification; n.d., no data
Column H: Longitude west, decimal degrees: Longitude west in decimal degrees
Column I: Latitude north, decimal degrees: Latitude north in decimal degrees
Column J: WHCMSC field activity (cruise) no.: USGS Woods Hole Coastal and Marine Science Center field activity (cruise) number. Example ANDR95036. ANDR is vessel name code (Peter W. Anderson), 95 is last two digits of year, and 036 is the 36th field activity of the year.
Column K: Sample collection water depth, m: Water depth at which sample was taken, in meters
Column L: Sample collection year: Year sediment sample was collected
Column M: Sample collection date, DDD:HH:MM:SS GMT: Date expressed as Julian Day (DDD) and time as HOUR:MINUTES:SECONDS Greenwich Mean Time (GMT) at which sample was collected (GMT same as UTC, Universal Coordinated Time, and ZULU, military time)
Column N: Quad: Quadrangle number in SBNMS region in which sample was collected
Column O: Sampler used: Sediment sample collected by a USGS modified Van Veen (VV) grab sampler
http://woodshole.er.usgs.gov/operations/sfmapping/seaboss.htm
Column P: Sediment sample top, cm below seabed surface: Top of sediment sample is the seabed surface (0 cm)
Column Q: Sediment sample bottom, cm below seabed surface: Bottom of sediment sample is 2 cm below the seabed surface
Column R: Dry sediment sample mass, g: Mass of dry sediment used for grain-size analysis in grams
Column S: Sand, wt percent: Weight percent of sand in sample
Column T: Gravel, wt percent: Weight percent of gravel in sample
Column U: Clay, wt percent: Weight percent of clay in sample
Column V: Silt, wt percent: Weight percent of silt in sample
Column W:Mud (clay+silt), wt percent: Weight percent of mud (combined clay and silt) in sample
Column X: Median grain size, phi units: Median grain size of sample in phi units
Column Y: Mean grain size, phi units: Mean grain size of sample in phi units
Column Z: Standard deviation of grain sizes, phi units: Standard deviation of the distribution of phi grain size units in a sample, in phi units
Column AA: 11-phi-size class (clay), wt percent: Weight percent of 11-phi-size sediment in sample
Column AB: 10-phi-size class (clay), wt percent: Weight percent of 10-phi-size sediment in sample
Column AC: 9-phi-size class (clay), wt percent: Weight percent of 9-phi-size sediment in sample
Column AD: 8-phi-size class (very fine silt), wt percent: Weight percent of 8-phi-size sediment in sample
Column AE: 7-phi-size class (fine silt), wt percent: Weight percent of 7-phi-size sediment in sample
Column AF: 6-phi-size class (medium silt), wt percent: Weight percent of 6-phi-size sediment in sample
Column AG: 5-phi-size class (coarse silt), wt percent: Weight percent of 5-phi-size sediment in sample
Column AH: 4-phi-size class (very fine sand), wt percent: Weight percent of 4-phi-size sediment in sample
Column AI: 3-phi-size class (fine sand), wt percent: Weight percent of 3-phi-size sediment in sample
Column AJ: fine-grained sand (fgS) (4 + 3 phi), wt percent: Weight percent of combined 3-phi- and 4-phi-size sediment in sample
Column AK: 2-phi-size class (medium sand), wt percent: Weight percentage of 2-phi-size sediment in sample
Column AL: 1-phi-size class (coarse sand), wt percent: Weight percent of 1-phi-size sediment in sample
Column AM: 0-phi-size class (very coarse sand), wt percent: Weight percent of 0-phi-size sediment in sample
Column AN: coarse-grained sand (cgS) (2 + 1 + 0 phi), wt percent: Weight percent of combined 2-phi-, 1-phi-, and 0-phi-size sediment in sample
Column AO: -1-phi-size class (granule), wt percent: Weight percent of -1-phi-size sediment in sample
Column AP: -2-phi-size class (pebble), wt percent: weight percent of -2-phi-size sediment in sample
Column AQ: Gravel 1 (G1) (-1 + -2 phi), wt percent: G subscript 1 weight percent of combined -1-phi- and -2-phi-size sediment in sample
Column AR: -3-phi-size class (pebble), wt percent: Weight percent of -3-phi-size sediment in sample
Column AS: -4-phi-size class (pebble), wt percent: Weight percent of -4-phi-size sediment in sample
Column AT: -5-phi-size class (pebble), wt percent: Weight percent of -5-phi-size sediment in sample
Column AU: Gravel 2 (G2) (-3 + -4 + -5 phi), wt percent: G subscript 2 weight percent of combined -3-phi-, -4-phi-, and -5-phi-size sediment in sample
Column AV: Substrate unit name translation: Describes the mobility, texture, and layering of the sediment substrate
Column AW: Comment: Explanatory notes for selected stations.
