Gas mapped within Holocene unit, u1: Hudson Shelf Valley

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Frequently-anticipated questions:


What does this data set describe?

    Title: Gas mapped within Holocene unit, u1: Hudson Shelf Valley
    Abstract:
    These data represent gas found within the upper most mappable unit wtihin the Hudson Shelf Valley; Holocene unit, u1. These data were mapped based CHIRP seismic-reflection records collected May, 1996. See Allison, 1997; Lanier, 1999; Lotto, 2000.

  1. How should this data set be cited?
    Denny, Jane F. , 2002, Gas mapped within Holocene unit, u1: Hudson Shelf Valley: US Geological Survey, Woods Hole, MA.

     

    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: -74.06
    East_Bounding_Coordinate: -71.8000
    North_Bounding_Coordinate: 41.26
    South_Bounding_Coordinate: 40
  3. What does it look like?

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

    Beginning_Date: 01-May-1996
    Ending_Date: 30-May-1996
    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 6378137.0000000.
      The flattening of the ellipsoid used is 1/298.26.

      Vertical_Coordinate_System_Definition:
      Altitude_System_Definition:
      Altitude_Datum_Name: North American Vertical Datum of 1988
      Altitude_Resolution: 1
      Altitude_Distance_Units: Meters
      Altitude_Encoding_Method:
      Explicit elevation coordinate included with horizontal coordinates
      Depth_System_Definition:
      Depth_Datum_Name: Mean sea level
      Depth_Resolution: 0.1
      Depth_Distance_Units: Meters
      Depth_Encoding_Method: Explicit depth coordinate included with horizontal coordinates
  7. How does the data set describe geographic features?


Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

  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


Why was the data set created?

In 1995, the U.S. Geological Survey (USGS), in cooperation with the U.S. Army Corps of Engineers (USACE), began a program to generate reconnaissance maps of the sea floor offshore of the New York - New Jersey metropolitan area and within the southern Long Island nearshoe area. Our methods include high-resolution sidescan sonar and subbottom profiling techniques, along with surface grab and vibracore sampling to verify the geophysical interpretations. The goal of the investigation is to provide a regional synthesis of the sea-floor environment, to determine regional-scale availability of sand as a resource for beach nourishment programs, and to investigate the role that inner-shelf morphology and geologic framework have in the evolution of the coastal region within the New York Bight Apex and southern Long Island. Maps derived from interpretation of the subbottom profiles show information on the geometry and distribution of the Quaternary sediments and the underlying coastal-plain unconformity. This seismic stratigraphy yields a regional framework on which explanations of present (and past) sediment movement, dispersal, and erosion processes are based.


How was the data set created?

  1. From what previous works were the data drawn?

    Hudson Shelf Valley (source 1 of 5)
    Allison, M.A., Lotto, L.L, Brink, Buchholtz ten , and Schwab, W.C., 1997, Formation and geologic evolution of the Hudson Shelf Valley, New York Bight(abstract):: Geological Society of America, Abstracts with Programs vol.29, p.27, Geological Society of America, Unknown.

    Type_of_Source_Media: map
    Source_Contribution:
    This reference definees the Pleistocene channels mapped within the Hudson Shelf Valley.

    Lanier (source 2 of 5)
    Lanier, D.L, Allison, M.A., Schwab, W.C., Thieler, E.R., and Butman, B., 1999, Effects of Holocene transgression on the stratigraphy of the NY Bight inner continental shelf: American Geophysical Union, Ocean Sciences Meeting Supplement OS203, unknown, unknown.

    Type_of_Source_Media: map
    Source_Contribution:
    This reference was used in the interpretation of the Pleistocene channels within the Hudson Shelf Valley.

    Seismic Stratigraphy of New York Bight (source 3 of 5)
    Lotto, L.L, 2000, Seismic stratigrpahy and Quaternary evolution of the New York Bight inner continental shelf: Texas A&M University, unpublished M.S. Thesis, College Station, TX, 79p and 16 sheets.: Masters of Science Thesis unknown, Texas A&M University, College Station, Texas.

    Type_of_Source_Media: online
    Source_Contribution:
    The well log data compiled within this thesis were used to generate a gridded data set of the depth to coastal-plain Unconformity and Quaternary thickness onshore Long Island, NY.

    MapInfo Pleistocene Channel, r6 (source 4 of 5)
    Lanier, D.L, and Allison, M.A., 2002, rednew: MapInfo vector file MapInfo vector file.

    Other_Citation_Details: See Allison, 1999; Lanier, 1997.
    Type_of_Source_Media: digital raster grid
    Source_Contribution:
    This MapInfo vector file contain contours of a Pleistocene channel mapped within the Hudson Shelf Valley based on 15 cubic inch water gun and CHIRP seismic-reflection data, gas and structure wtihin the channels, and gas within an upper seismic facies. The MapInfo file was converted to ArcView vector format. The areas containing gas and structure were extracted and converted to individual ArcView shapefiles for display within ArcView 3.2.

    Pleistocene channel, r5 (source 5 of 5)
    Lanier, D.L., and Allison, M.A., 2002, bluenew: MapInfo vector data MapInfo vector data.

    Other_Citation_Details: See Allison, 1997; Lanier, 1999.
    Type_of_Source_Media: digital raster grid
    Source_Contribution:
    This MapInfo vector file contain contours of a Pleistocene channel mapped within the Hudson Shelf Valley based on 15 cubic inch water gun and CHIRP seismic-reflection data, gas and structure wtihin the channels, and gas within an upper seismic facies. The MapInfo file was converted to ArcView vector format. The areas containing gas and structure were extracted and converted to individual ArcView shapefiles for display within ArcView 3.2.

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

    Date: 2000 (process 1 of 1)
    MapInfo vector data, rednew and bluenew, were converted into ArcView 3.2 shapefiles using the Universal Translator within MapInfo 5.5. Polygons within the original files defining the location of gas within the upper most mappable unit within the Hudson Shelf Valley; Holocene unit, u1. These data were converted to shapefile:

    gas_u1.shp

    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?


How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?

    These data are derived from 2D seismic reflection profiles that are spaced approximately 1.3 km apart in the cross track-direction. Shore perpendicular track lines were spaced about 3-4 km apart. Along track samples of the seismic profiles are approximately 1 meter assuming a ship speed of 2 meters/second. The data were downsampled in the along-track direction at an interval of about 30 meters.

  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). The horizontal positioning 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.

  3. How accurate are the heights or depths?

    Vertical positioning accuracy of the offshore data is based on the seafloor reference used.

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

    complete

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

    The Pleistocene channels and gas and structure found within these channels, were mapped by Allison(1997) and Lanier(1999).


How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints: none
Use_Constraints: none

  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?

    gas and clinoform definition, HSV

  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?


Who wrote the metadata?

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 Content Standards for Digital Geospatial (FGDC-STD-001-1998)


Generated by mp version 2.7.17 on Tue Apr 16 10:18:47 2002