Pendleton, Elizabeth, 2015, Nahant_NH_sedcover: Sediment Texture Units of the Sea Floor from Nahant to Salisbury, Massachusetts (polygon shapefile, Geographic, WGS84): Open-File Report 2015-1153, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.This is part of the following larger work.Online Links:
Pendleton, E.A., Barnhardt., W.A., Baldwin, W.E., Foster, D.S., Schwab, W.C., Andrews, B.D., and Ackerman, S.D., 2015, Sea-Floor Texture and Physiographic Zones of the Inner Continental Shelf From Salisbury to Nahant, Massachusetts, Including the Merrimack Embayment and Western Massachusetts Bay: Open-File Report 2015-1153, U.S. Geological Survey, Reston, VA.Online Links:
This is a Vector data set. It contains the following vector data types (SDTS terminology):
Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.000001. Longitudes are given to the nearest 0.000001. 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.
Sequential unique whole numbers that are automatically generated.
Coordinates defining the features.
Value | Definition |
---|---|
Rg | The dominant texture (> 50%) Rock (R) is given the upper case letter and the subordinate texture (< 50%) gravel (g) is given a lower case letter. |
Gr | The dominant texture (> 50%) Gravel (G) is given the upper case letter and the subordinate texture (< 50%) rock (r) is given a lower case letter. |
Gs | The dominant texture (> 50%) Gravel (G) is given the upper case letter and the subordinate texture (< 50%) sand (s) is given a lower case letter. |
M | The end-member texture (~ 100%) Mud (M) is the primary texture. |
Ms | The dominant texture (> 50%) Mud (M) is given the upper case letter and the subordinate texture (< 50%) sand (s) is given a lower case letter. |
S | The end-member texture (~ 100%) Sand (S) is the primary texture. |
Sg | The dominant texture (> 50%) Sand (S) is given the upper case letter and the subordinate texture (< 50%) gravel (g) is given a lower case letter. |
Sm | The dominant texture (> 50%) Sand (S) is given the upper case letter and the subordinate texture (< 50%) mud (m) is given a lower case letter. |
Rs | The dominant texture (> 50%) Rock (R) is given the upper case letter and the subordinate texture (< 50%) sand (s) is given a lower case letter. |
Sr | The dominant texture (> 50%) Sand (S) is given the upper case letter and the subordinate texture (< 50%) rock (r) is given a lower case letter. |
Mg | The dominant texture (> 50%) Mud (M) is given the upper case letter and the subordinate texture (< 50%) gravel (g) is given a lower case letter. |
G | The end-member texture (~ 100%) Gravel (G) is the primary texture. |
N/A | There was not enough source input data to define sediment texture within this area. |
Value | Definition |
---|---|
sand | Sediment whose primary component (> 50%) is sand |
hardbottom | Sediment whose primary component is rock, boulder, cobble, or coarse gravel |
mud | Sediment whose primary component (> 50%) is silt and clay |
N/A | There was not enough source input data to define simple sediment texture within this area. |
Value | Definition |
---|---|
yes | bedforms are present within some part of the traced polygon in the source acoustic data |
no | bedforms are not present within any part of the traced polygon in the source acoustic data |
Value | Definition |
---|---|
coarse pebbles | sediment class whose phi size is between -5 and -4 |
coarse silt | sediment class whose phi size is between 4 and 5 |
coarse sand | sediment class whose phi size is between 0 and 1 |
cobble | sediment class whose phi size is between -6 and -8 |
fine pebbles | sediment class whose phi size is between -2 and -3 |
fine sand | sediment class whose phi size is between 2 and 3 |
fine silt | sediment class whose phi size is between 6 and 7 |
granules | sediment class whose phi size is between -1 and -2 |
medium pebbles | sediment class whose phi size is between -3 and -4 |
medium sand | sediment class whose phi size is between 2 and 1 |
medium silt | sediment class whose phi size is between 5 and 6 |
very coarse pebbles | sediment class whose phi size is between -5 and -6 |
very coarse sand | sediment class whose phi size is between 0 and -1 |
very fine sand | sediment class whose phi size is between 3 and 4 |
very fine silt | sediment class whose phi size is between 7 and 8 |
N/A | sediment class whose phi size could not be determined from grain size data or there were no samples with laboratory analyzed grain size statistics within the polygon |
Value | Definition |
---|---|
1 | Sediment texture regions that were defined based on the highest resolution bathymetry (5m) and backscatter (1m), bottom photos, sediment samples, and seismic interpretations were given the highest data interpretation confidence value of 1 (very high confidence). |
2 | Areas where sediment texture was defined based on bathymetry of 30m resolution, backscatter of 1m resolution, bottom photos, and sediment samples were given an interpretation confidence value of 2 (high confidence). |
3 | A confidence value of 3 (moderate confidence) was given to areas with lidar and sediment samples, but no bottom photos or high density seismic interpretations. |
4 | The lowest confidence values (4) were given to areas where only sample and aerial photography data were available. |
Range of values | |
---|---|
Minimum: | 0 |
Maximum: | 169 |
Units: | count |
Resolution: | 1 |
Range of values | |
---|---|
Minimum: | 0 |
Maximum: | 97.9 |
Units: | percent |
Resolution: | 0.1 |
Range of values | |
---|---|
Minimum: | 2 |
Maximum: | 100 |
Units: | percent |
Resolution: | 0.01 |
Range of values | |
---|---|
Minimum: | 0 |
Maximum: | 67.2 |
Units: | percent |
Resolution: | 0.1 |
Range of values | |
---|---|
Minimum: | 0 |
Maximum: | 48.0 |
Units: | percent |
Resolution: | 0.1 |
Range of values | |
---|---|
Minimum: | -5.2 |
Maximum: | 7.5 |
Units: | phi |
Resolution: | 0.01 |
508-548-8700 x2259 (voice)
508-457-2310 (FAX)
ependleton@usgs.gov
These sea-floor sediment cover data were created from geophysical and sample data collected from Nahant to Salisbury, and are used to characterize the sea floor in the area. Sediment type and distribution maps are important data layers for marine resource managers charged with protecting fish habitat, delineating marine boundaries, and assessing environmental change due to natural or human impacts.
Barnhardt, W.A., Andrews, B.D., and Butman, Bradford, 2006, High-Resolution Geologic Mapping of the Inner Continental Shelf: Nahant to Gloucester, Massachusetts: Open-File Report 2005-1293, U.S. Geological Survey, Reston, VA.Online Links:
Barnhardt, W.A., Andrews, B.D., Ackerman, S.D., Baldwin, W.E., and Hein, C.J., 2009, High-Resolution Geologic Mapping of the Inner Continental Shelf: Cape Ann to Salisbury Beach, Massachusetts: Open-File Report 2007-1373, U.S. Geological Survey, Reston, VA.Online Links:
Butman, B., Valentine, P.C., Middleton, T.J., and Danforth, W.W., 2007, A GIS Library of Multibeam Data for Massachusetts Bay and the Stellwagen Bank National Marine Sanctuary, Offshore of Boston, Massachusetts: Digital Data Series 99, U.S. Geological Survey, Reston, VA.Online Links:
Ford, K.H., Huntley, E.C., Sampson, D.W., and Voss, S., Unpublished Material, Massachusetts Sediment Database:,.
U.S. Army Corps of Engineers, Joint Airborne LiDAR Bathymetry Center of Expertise, 2008, Massachusetts LiDAR Grid Data in Coastal Areas: Fugro Pelagos, Inc, San Diego, CA.
Gutierrez, B.J., Butman, Bradford, and Blackwood, D.S., 2000, Photographs of the Sea Floor in Western Massachusetts Bay, Offshore of Boston, Massachusetts, July, 1999: Open-File Report 00-427, U.S. Geological Survey, Reston, VA.Online Links:
U.S. Geological Survey, 2009, MassGIS Data - USGS Color Ortho Imagery (2008/2009): Massachusetts Office of Geospatial Information, Boston, MA.Online Links:
Pendleton, E.A., Baldwin, W.E., Barnhardt, W.A., Ackerman, S.D., Foster, D.S., Andrews, B.D., and Schwab, W.C., 2013, Shallow Geology, Seafloor Texture, and Physiographic Zones of the Inner Continental Shelf from Nahant to Northern Cape Cod Bay, Massachusetts: Open-File Report 2012-1157, U.S. Geological Survey, Reston, VA.Online Links:
Oldale, R.N., and Bick, Jennifer, 1987, Maps and seismic profiles showing geology of the inner continental shelf, Massachusetts Bay, Massachusetts: Miscellaneous Field Studies Map 1923, U.S. Geological Survey, Reston, VA.Online Links:
Oldale, R.N., and Wommack, L.E., 1987, Maps and seismic profiles showing geology of the inner continental shelf, Cape Ann, Massachusetts to New Hampshire: Miscellaneous Field Studies Map 1892, U.S. Geological Survey, Reston, VA.Online Links:
Hein, C.J., FitzGerald, D.M., Barnhardt, W.A., and Stone, B.D., 2013, Onshore-Offshore Surficial Geologic Map of the Newburyport East and Northern Half of the Ipswich Quadrangles, Massachusetts: Geologic Map GM-13-01, Massachusetts Geological Survey, Amherst, MA.Online Links:
Oldale, R.N., Knebel, H.J., and Bothner, M.H., 1994, Submerged and Eroded Drumlins off Northeastern Massachusetts: Geomorphology 9, Elsevier, Philadelphia, PA.
Person who carried out this activity:
508-548-8700 x2259 (voice)
508-457-2310 (FAX)
ependleton@usgs.gov
Person who carried out this activity:
508-548-8700 x2259 (voice)
508-457-2310 (FAX)
ependleton@usgs.gov
Person who carried out this activity:
(508)-548-8700 x2259 (voice)
(508)-457-2310 (FAX)
ependleton@usgs.gov
Kelley, J.T., Barnhardt, W.A., Belknap, D.F., Dickson, S.M., and Kelley, A.R., 1996, The Seafloor Revealed: The Geology of the Northwestern Gulf of Maine Inner Continental Shelf: Maine Geological Survey Open-File Report 96-6, Maine Geological Survey, Natural Resources Information and Mapping Center, Augusta, ME.
Shepard, F.P., 1954, Nomenclature Based on Sand-Silt-Clay Ratios: Journal Sedimentary Petrology volume 24, Society for Sedimentary Geology, Tulsa, OK.
Barnhardt, W.A., Kelley, J.T., Dickson, S.M., and Belknap, D.F., 1998, Mapping the Gulf of Maine with Side-scan Sonar: a New Bottom-type Classification for Complex Seafloors: Journal of Coastal Research volume 14(2), Coastal Education and Research Foundation, Inc., Royal Palm Beach, FL.
Wentworth, C.K., 1922, A Scale of Grade and Class Terms for Clastic Sediments: Journal of Geology vol. 30, University of Chicago Press, Chicago, IL.
McMullen, K.Y, Paskevich, V.F., and Poppe, L.J., 2012, USGS East-coast Sediment Analysis: Procedures, Database, and GIS Data: Open File Report 2005-1001, U.S. Geological Survey, Reston, VA.Online Links:
Ford, K.H., and Voss, S.E., 2010, Seafloor Sediment Composition in Massachusetts Determined Using Point Data: Massachusetts Division of Marine Fisheries Technical Report TR-45, Massachusetts Division of Marine Fisheries, New Bedford, MA.Online Links:
Blackwood, D.S., and Parolski, K.F., 2000, "SeaBOSS": an elegantly simple image and sample collecting system: Proceedings, 6th Annual International Conference on Remote Sensing for Marine Environments Volume 1, Veridian ERIM International, Charleston, SC.
These data were produced qualitatively from acoustic and sample data with varying resolutions. Horizontal uncertainty associated with sample collection especially, can be quite high (100's of meters), much higher than positional uncertainty associated with acoustic data (usually less than <10's of meters). The date of sample collection and ship station positioning all contribute to sample position uncertainty. These qualitatively derived polygons outlining sea floor features are estimated to be within 50 meters, horizontally, but locally may be higher when sediment texture delineation is based on sample information alone.
Although there is a field for mean water depth, there is no assumption of vertical accuracy. The depth value is an average of all grid cells within each polygon (gridded data from Pendleton and others (2013)). In many cases the mean depth value covers a range of depths from near zero to < -30 meters, and as such should not be used for navigation or taken as an absolute depth value within a polygon.
These sediment cover data are defined for areas where source data exists. In general, gaps in the coverage coincide with gaps in the source data. However, some small data gaps were interpreted through extrapolation. Areas of lower data quality and incomplete coverage are noted in a data confidence attribute field.
These data were drawn and vetted for accuracy using the source input rasters and point sample data described in the processing steps and source contributions. Overlapping features and unintentional gaps within the survey area were identified using the topology checker in ArcMap (version 10.2) and corrected or removed.
Are there legal restrictions on access or use of the data?
- Access_Constraints: None
- Use_Constraints:
- Not to be used for navigation. Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey (USGS) as the source of this information. Additionally, there are limitations associated with qualitative sediment mapping interpretations. Because of the scale of the source geophysical data and the spacing of samples, not all changes in sea floor texture are captured. The data were mapped between 1:8,000 and 1:25,000, but the recommended scale for application of these data is 1:25,000. Features below 5,000 m2 or less than 50 m wide were not digitized due to positional uncertainty, lack of sample information, and the often ephemeral nature of small-scale sea floor features. Not all digitized sea floor features contained sample information, so often the sea floor texture is characterized by the nearest similar feature that contains a sample. Conversely, sometimes a digitized feature contained multiple samples and not all of the samples within the feature were in agreement (of the same texture). In these cases the dominant sediment texture was chosen to represent the primary texture for the polygon. Samples from rocky areas often only consist of bottom photographs, because large particle size often prevents the recovery of a sediment sample. Bottom photo classification can be subjective, such that determining the sediment type that is greater than 50% of the view frame is estimated by the interpreter and may differ among interpreters. Bottom photo transects often reveal changes in the sea floor over distances of less than 100 m and these changes are often not observable in acoustic data. Heterogeneous sea floor texture can change very quickly, and many small-scale changes will not be detectable or mappable at a scale of 1:25,000. The boundaries of polygons are often inferred based on sediment samples, and even boundaries that are traced based on amplitude changes in geophysical data are subject to migration. Polygon boundaries should be considered an approximation of the location of a change in texture.
508-548-8700 x2259 (voice)
508-457-2310 (FAX)
ependleton@usgs.gov
USGS open file report 2015-1153 Sediment Texture from Nahant to NH. The zip file contains a shapefile (Nahant_NH_sedcover), a browse graphic (sedcover_browse.png) and FGDC CSDGM metadata files in four standard formats.
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 U.S. Geological Survey 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.
Data format: | WinZip (v 14.5) file contains qualitatively derived polygons that define sea floor texture and distribution from Nahant to Salisbury, MA and the associated metadata in format Shapefile (version ArcGIS 10.2) Esri Polygon Shapefile Size: 930 KB |
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Network links: |
<https://pubs.usgs.gov/of/2015/1153/GIS_catalog/SedimentTexture/SedCover.zip> <https://pubs.usgs.gov/of/2015/1153/html/ofr20151153_GIS_catalog.html//> <https://pubs.usgs.gov/of/2015/1153/> |
These data are available in Environmental Systems Research Institute (Esri) shapefile format. The user must have software capable of importing and processing this data type.
508-548-8700 x2259 (voice)
508-457-2310 (FAX)
ependleton@usgs.gov