Holocene Silty Deposits

Frequently-anticipated questions:

• What does this data set describe?
  1. How should this data set be cited?
  2. What geographic area does the data set cover?
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
  5. What is the general form of this data set?
  6. How does the data set represent geographic features?
  7. How does the data set describe geographic features?
• Who produced the data set?
  1. Who are the originators of the data set?
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
• Why was the data set created?
• How was the data set created?
  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
  3. What similar or related data should the user be aware of?
• How reliable are the data; what problems remain in the data set?
  1. How well have the observations been checked?
  2. How accurate are the geographic locations?
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
  5. How consistent are the relationships among the data, including topology?
• How can someone get a copy of the data set?
  1. Are there legal restrictions on access or use of the data?
  2. Who distributes the data?
  3. What's the catalog number I need to order this data set?
  4. What legal disclaimers am I supposed to read?
  5. How can I download or order the data?
• Who wrote the metadata?

Title: Holocene Silty Deposits

Abstract:

These data orginate from interpretations of seismic reflection and sidescan-sonar data. The derivative data are in an ESRI shapefile, polygon vector format and are intended to represent the distribution of Holocene silty deposits throughout the inner-continental shelf within the New York Bight. These data are helpful in understanding the stratigraphic evolution of the inner-continental shelf, the regional sediment transport system, and the influence of the inner-shelf framework on coastal processes.

1. How should this data set be cited?

   USGS, Woods Hole Field Center, 2002, Holocene Silty Deposits: USGS, USGS, Woods Hole Field Center.

    

   This is part of the following larger work.

   Schwab, William C., Denny, Jane F., Foster, David S., Lotto, Linda L., Allison, Mead A., Uchupi, Elazar, Swift, B. Ann, Danforth, William W., Thieler, Robert E., and Butman, Bradford, 2002, High-Resolution Quaternary seismic stratigraphy of the New York Bight Continental Shelf: Open-File Report OFR02-152, U.S. Geological Survey, Woods Hole, MA.

    

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -74.3

   East_Bounding_Coordinate: -73.2

   North_Bounding_Coordinate: 40.65

   South_Bounding_Coordinate: 40.15

3. What does it look like?

4. Does the data set describe conditions during a particular time period?

   Beginning_Date: 13-May-1995

   Ending_Date: 13-Oct-1999

   Currentness_Reference: Publication Date

5. What is the general form of this data set?

   Geospatial_Data_Presentation_Form: vector 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):

      • G-polygon

   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 0.000089992. Longitudes are given to the nearest 0.000089992. Latitude and longitude values are specified in Decimal degrees.

      The horizontal datum used is WGS84.
      The ellipsoid used is WGS84.
      The semi-major axis of the ellipsoid used is 6378137.
      The flattening of the ellipsoid used is 1/298.257223563.
      

7. How does the data set describe geographic features?

1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
   • USGS, Woods Hole Field Center

2. Who also contributed to the data set?

3. To whom should users address questions about the data?

   Jane F. Denny
   US Geological Survey
   Geologist
   384 Woods Hole Road
   Woods Hole, MA 02543
   USA
   

   508-457-2311 (voice)
   508-457-2310 (FAX)
   jdenny@usgs.gov
   

A focus for the U.S. Geological Survey (USGS) Coastal and Marine Geology Program is reconnaissance mapping of the shallow Exclusive Economic Zone (EEZ), with initial emphasis on the heavily utilized areas of the sea floor offshore of major metropolitan centers. The objective is to develop a detailed understanding of the sea-floor geology that will provide information for a wide range of management decisions and form a basis for further process-oriented investigations. In 1995, the USGS, in cooperation with the U.S. Army Corps of Engineers (USACOE), New York District, began a program designed to generate reconnaissance maps of the sea floor offshore of the New York - New Jersey metropolitan area), one of the most populated coastal regions within the United States. This mapping effort differs from previous studies of this area by obtaining digital, sidescan-sonar images that cover nearly 100 percent of the sea floor.

1. From what previous works were the data drawn?

2. How were the data generated, processed, and modified?

   Date: 2000 (process 1 of 1)

   These data are interpreted and based on acquired high-resolution seismic-reflection, sidescan-sonar, surficial sediment core and grab sample data. These various data types were placed within a Geographic Information System (ESRI ArcView 3.2) within which the interpretations were made. The final interpretations are stored as a polygon ArcView 3.2 shapefile.

   Person who carried out this activity:
   

   Jane F. Denny
   US Geological Survey
   Geologist
   384 Woods Hole Road
   Woods Hole, MA 02543
   USA
   

   508-457-2311 (voice)
   508-457-2310 (FAX)
   jdenny@usgs.gov
   

3. What similar or related data should the user be aware of?

1. How well have the observations been checked?

   These data are interpretative. They are accurate according to geologic interpretations made by scientists at the USGS, Woods Hole Field Center. These interpretations were based on acquired high-resolution seismic reflection, sidescan-sonar, and surficial core and sample information.

2. How accurate are the geographic locations?

   DGPS is assumed to be accurate within 1-2 meters. Standard GPS is assumed accurate within 5-10 meters. 99% of the positional data is DGPS. Unless noted, all GPS/DGPS data is referenced to WGS84 (NAD83). Slant-range distance is recorded between the sidescan-sonar tow vehicle and a sidemount rigged with an acoustic transponder. Offset between the sidemount and GPS antennae is measured. Basic trigonomic calculations use the slant-range offset to calculate a 'fish' (tow-vehicle) navigation. An assumption in these calculations is that the tow-vehicle is traveling directly behind the vessel; movement to port or starboard is not accounted for within 'fish' navigation. Thus, the horizontal accuarcy of the sidescan-sonar tow-vehicle is +/- 15 meters. The horizontal positioning of the seismic systesm did not account for source and receiver offsets and offset the GPS antennae and the boomer source and streamer. It is estimated that these offsets could lead to inaccuracies of about 30 m.

   Interpretive products are based on the evaluation of sidescan-sonar, seismic-reflection, and sample data. Therefore, the horizontal accuracies of these systems will carry through to the interpretive products. As such, the horizontal accuracy of these data is assumed to be within +/- 30 meters.

3. How accurate are the heights or depths?

4. Where are the gaps in the data? What is missing?

   These data are complete. These data were published within USGS Open-File Report 00-295.

5. How consistent are the relationships among the observations, including topology?

   These data are associated with high-resolution seismic reflection, sidescan-sonar, and surficial sediment core and sample data. They are consistent within their assocations with these data.

Are there legal restrictions on access or use of the data?

Access_Constraints:

None

Use_Constraints:

Please recognize the USGS as the source of these data.

1. Who distributes the data set? (Distributor 1 of 1)

   Jane F. Denny
   US Geological Survey
   Geologist
   384 Woods Hole Road
   Woods Hole, MA 02543
   USA
   

   508-457-2311 (voice)
   508-457-2310 (FAX)
   jdenny@usgs.gov
   

2. What's the catalog number I need to order this data set?

   holosilt.shp

3. What legal disclaimers am I supposed to read?

   Altough this data set and its lineage have been used by the USGS, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and/or it's related materials. 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 items. Users must assume responsibility for the proper use of this data. This data should not be used at resolutions for which it is not intended. This data has no been reviewed for conformity with US Geological Survey editorial standards, or the North American Strigraphic code. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the US Government.

4. How can I download or order the data?

Dates:

Last modified: 19-Jan-2002
Last Reviewed: 2002

Metadata author:

Jane F. Denny
US Geological Survey
Geologist
384 Woods Hole Road
Woods Hole, MA 02543
USA

508-457-2311 (voice)
508-457-2310 (FAX)
jdenny@usgs.gov

Metadata standard:

FGDC Metadata_Standard_Version: FGDC 19940608 (FGDC-STD-001-1998)