Anthropogenic wastes, toxic chemicals, and changes in land-use patterns resulting from residential, commercial, and recreational development have stressed the environment of the Sound, causing degradation and potential loss of benthic habitats (Koppelman and others, 1976; Long Island Sound Study, 1994). Detailed maps of the sea floor are needed to help evaluate the extent of adverse impacts and to help manage resources wisely in the future. Therefore, in a continuing effort to better understand Long Island Sound, we have constructed and interpreted sidescan sonar mosaics (complete-coverage acoustic images of the sea floor) within specific areas of special interest (Poppe and Polloni, 1998; fig. 1). The mosaic presented herein covers a 41.1 km square area of the sea floor in north-central Long Island Sound off Branford, Connecticut.
The mosaics and their interpretations serve many purposes, including: (1) defining the geological variability of the sea floor, which is one of the primary controls of benthic habitat diversity; (2) improving our understanding of the processes that control the distribution and transport of bottom sediments and the distribution of benthic habitats and associated infaunal community structures; and (3) providing a detailed framework for future research, monitoring, and management activities. The sidescan sonar mosaics also serve as base maps for subsequent sedimentological, geochemical, and biological observations, because precise information on environmental setting is important for selection of sampling sites and for accurate interpretation of point measurements.
Poppe, Lawrence J. , 2003, SEDENVIRON: interpretation of the distribution of sedimentary environments of the sidescan sonar mosaic of NOAA survey H11043 off Branford, Connecticut: U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, MA.Online Links:
L.J.Poppe, Paskevich, V.F., Moser, M.S., DiGiacomo-Cohen, M.L., and Christman, E.B., 2004, Sidescan Sonar Imagery and Surficial Geologic Interpretation of the Sea Floor off Branford, Connecticut: Open-File Report 2004-1003, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, MA.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 0.000000. Longitudes are given to the nearest 0.000000. 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.
Range of values | |
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Minimum: | 0 |
Maximum: | 0 |
Value | Definition |
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Erosion or Nondeposition | High energy environment not permitting the accumulation of recent sediments |
Sorting or Reworking | Moderate energy environment that separates fine-grained sediments from coarser ones by winnowing. |
Deposition | Lower energy environment allowing the accumlation of modern sediments |
Lawrence J. Poppe, U.S. Geological Survey, must be referenced as the originator of the dataset in any future products or research derived from these data.
U.S. Geological Survey
c/o Lawrence J. Poppe
Geologist
U.S. Geological Survey
Woods Hole, MA 02543
USA
(508) 548-8700 x2314 (voice)
(508) 457-2310 (FAX)
lpoppe@usgs.gov
This GIS overlay is a component of the Branford Survey, Long Island Sound, ArcView GIS database and shows the distribution of sedimentary environments within the study area.
Person who carried out this activity:
U.S. Geological SurveyData sources used in this process:
c/o Lawrence J. Poppe
Geologist
U.S. Geological Survey
Woods Hole, MA 02543
USA
(508) 548-8700 x2314 (voice)
(508) 457-2310 (FAX)
lpoppe@usgs.gov
Data sources produced in this process:
Interpretations are based on tonal changes on a sidescan sonar mosaic that was navigated with differential GPS; positional accuracy to less than 10 m.
Interpretations of the sedimentary environments across the sidescan sonar mosaic were completed using tonal changes and all available textural data.
All polygons were constructed in a consistent manner. No additional checks for topological consistency were performed on this data.
Are there legal restrictions on access or use of the data?
- Access_Constraints: None
- Use_Constraints:
- Public domain data are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey (USGS) as the originator of this dataset.
U.S. Geological Survey
c/o Lawrence J. Poppe
Geologist
U.S. Geological Survey
Woods Hole, MA 02543
USA
(508) 548-8700 x2314 (voice)
(508) 457-2310 (FAX)
lpoppe@usgs.gov
Downloadable Data
Although this data set has been used by the USGS, NOAA, and the State of Connecticut, no warranty, expressed or implied, is made by the USGS, NOAA, or the State of Connecticut as to the accuracy of the data and/or related materials. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS, NOAA, or the State of Connecticut in the use of these data or related materials.
Data format: | Five files: sedenviron.shp, sedenviron.shx, sedenviron.dbf, sedenviron.avl, sedenviron,prj in format ArcView shapefile (version 3.3) ESRI golygon shapefile Size: 0.209 |
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Media you can order: |
CD-ROM
(Density 650
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(format ISO9660)
Note: The user must have a CD-ROM capable of reading an ISO9660 standard CD-ROM
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The data are available in the ESRI shapefile format. The user must have Environmental Systems Research Institute's (ESRI) ArcView 3.0 or greater or ArcGIS software to read and process the data file. In lieu of Arcview, the user may utilize another GIS application package capable of importing the data. A free GIS data viewer, ArcExplorer, is available from the ESRI website at www.esri.com/software/arcexplorer/download4.htmlAccess to the data and information contained on this CD-ROM was developed using the HyperText Markup Language (HTML) utilized by the World Wide Web (WWW) project. Development of the CD-ROM documentation and user interface in HTML allows a user to access the information by using a variety of WWW information browsers to facilitate browsing and locating information and data. To access the information contained on this disk with a WWW client browser, open the file 'index.htm' at the top level directory of this CD-ROM with your selected browser.
This CD-ROM should be readable by a variety of operating systems including Windows 95/98/NT, Macintosh and UNIX.
U.S. Geological Survey
c/o Lawrence J. Poppe
Geologist
U.S. Geological Survey
Woods Hole, MA 02543
USA
(508) 548-8700 x2314 (voice)
(508) 457-2310 (FAX)
lpoppe@usgs.gov