H11250G_GEOL: Interpretive Data Layer Showing the Framework Geology of NOAA Survey H11250 (Geographic)

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Frequently-anticipated questions:

What does this data set describe?

Title:
H11250G_GEOL: Interpretive Data Layer Showing the Framework Geology of NOAA Survey H11250 (Geographic)
Abstract:
The U.S. Geological Survey, in cooperation with the National Oceanic and Atmospheric Administration and the Connecticut Department of Environmental Protection, has produced detailed geologic maps of the sea floor in Long Island Sound, a major East Coast estuary surrounded by the most densely populated region of the United States. These studies have built upon cooperative research with the State of Connecticut that was initiated in 1982. The current phase of this research program is directed toward studies of sea-floor sediment distribution, processes that control sediment distribution, nearshore environmental concerns, and the relation of benthic community structures to the sea-floor geology. Acoustic data collected during hydrographic surveys provide valuable base maps for marine geological interpretations. These maps help define the geological variability of the seafloor (one of the primary controls of benthic habitat diversity); improve 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 provide a detailed framework for future research, monitoring, and management activities. This shapefile represents the geologic interpretation of features influencing the bathymetry of study area H11250, The Race. Sharing of multibeam bathymetric data (NOAA Ship Thomas Jefferson, October 2003 survey H11250) between NOAA's Atlantic Hydrographic Branch and the State of Connecticut/USGS Geologic Mapping Cooperative has yielded a new geologic perspective on approximately 94 km2 of the sea floor in the vicinity of The Race, an area where the Orient Point-Fishers Island segment of the Harbor Hill-Roanoke Point-Orient Point-Fishers Island-Charlestown Moraine marks the dividing line between easternmost Long Island Sound and northwestern Block Island Sound. The detailed bathymetry collected by NOAA has been examined in relation to seismic data collected concurrently, as well as archive data collected as part of a long-standing geologic mapping partnership between the State of Connecticut and the U.S. Geological Survey (USGS). These new data reveal previously unknown details of the physical character of the sea floor such as bedforms, moraines, and ship wrecks. These features have been mapped as interpretive GIS data layers that can be used in conjunction with the multibeam grid H11250G or related shaded relief graphics (h11250gcolhs.tif).
Supplemental_Information:
Original bathymetric data was collected via a Simrad EM1002 multibeam system mounted on the hull of the Thomas Jefferson which acquired over 560 km of survey lines from the deeper water (>20 m) parts of the study area. Two 29-foot launches with hull-mounted Reson systems were deployed from the ship and were used to acquire an additional 637 km of survey lines from the shallower areas.
  1. How should this data set be cited?

    Poppe, L.J., and DiGiacomo-Cohen, M.L., 2007, H11250G_GEOL: Interpretive Data Layer Showing the Framework Geology of NOAA Survey H11250 (Geographic): Open-File Report 2007-1012, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, MA.

    Online Links:

    This is part of the following larger work.

    Poppe, L.J., DiGiacomo-Cohen, M.L., Doran, E.F., Smith, S.M., Stewart, H.F., and Forfinski, N.A., 2007, Geologic Interpretation and Multibeam Bathymetry of the Sea Floor in the Vicinity of the Race, Eastern Long Island Sound: Open-File Report 2007-1012, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, MA.

    Online Links:

    Other_Citation_Details: 1 DVD-ROM

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -72.150490
    East_Bounding_Coordinate: -71.996559
    North_Bounding_Coordinate: 41.270111
    South_Bounding_Coordinate: 41.190006

  3. What does it look like?

    <http://pubs.usgs.gov/of/2007/1012/data/interpretation/geologic/h11250g_geol.gif> (GIF)
    Thumbnail image showing the distribution of geologic features withi NOAA survey H11250

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

    Calendar_Date: 2003
    Currentness_Reference: ground condition

  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 (24)
      • Label point (24)
      • GT-polygon composed of chains (24)
      • Point (4)

    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 0.000001. 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.

      Vertical_Coordinate_System_Definition:
      Depth_System_Definition:

  7. How does the data set describe geographic features?

    h11250g_geol

    FID
    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    Shape
    Feature geometry. (Source: ESRI)

    Coordinates defining the features.

    AREA
    Area of feature in internal units squared. (Source: ESRI)

    Positive real numbers that are automatically generated.

    PERIMETER
    Perimeter of feature in internal units. (Source: ESRI)

    Positive real numbers that are automatically generated.

    INTERP
    geologic interpretation of features influencing the bathymetry (Source: compiler)

    Value Definition
    delta glacial lake deltaic deposits
    delta/gas gas-charged marine deposits of Holocene age
    lake glacial lake-bottom deposits
    moraine moraine deposits
    reworked over lake reworked marine deposits (includes bedforms and lag deposits) over glacial lake-bottom deposits
    bedrock Paleozoic bedrock
    drumlin glacial drumlin
    coastal plain semi-consolidated Cretaceous coastal plain deposits
    no data gaps in the original data

    ICODE
    code for geologic features influencing the bathymetry (Source: compiler)

    Value Definition
    D delta
    M moraine
    R/L reworked over lake
    K/m coastal plain
    L lake
    Pz bedrock
    M/F moraine/fan?
    K/d drumlin
    TR thick reworked over lake
    HG Holocene/gas
    0 no data

    Entity_and_Attribute_Overview:
    Polygons are interpreted to represent the geologic features which influence the bathymetry such as bedrock, moraines, drumlins, glacial lake deposits, coastal plain and Holocene deposits.

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?

    Source data were acquired during National Oceanic and Atmospheric Administration (NOAA) survey H11250. Please acknowledge NOAA as the originator of the dataset from which this dataset was derived.

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

    U.S. Geological Survey
    c/o Larry Poppe
    Geologist
    384 Woods Hole Road
    Woods Hole, MA 02543-1598
    USA

    508-548-8700 x2314 (voice)
    508-457-2310 (FAX)
    lpoppe@usgs

Why was the data set created?

To release interpretations the geologic features based on data collected during NOAA survey H11250 in easternmost Long Island Sound and westernmost Block Island Sound, in geographic. This GIS layer serves a starting point for a geologic study of the area in that it shows the geologic units that subcrop and influence the bathymetry and geometry of the Race, Long Island Sound. The detailed bathymetic data 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 bathymetric data models 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.

How was the data set created?

  1. From what previous works were the data drawn?

    h11250g (source 1 of 1)
    U.S. Geological Survey, National Oceanic and Atmospheric Administration, and Connecticut Department of Environmental Protection, 2004, h11250g: Long Island Sound Resource Center.

    Type_of_Source_Media: computer program
    Source_Scale_Denominator: 2 m resolution grid
    Source_Contribution:
    Multibeam bathymetric grid with 2 m resolution. This data (and other source and derivative data products) was visually interpreted.

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

    Date: 2004 (process 1 of 2)
    The multibeam bathymetric data (in grid, contour, and shaded relief formats) was examined in conjunction with sub-bottom seismic profiles (collected concurrently as well as previous studies: AST90-1, AST82-3, AST81-2), unit contacts were first sketched/interpreted on large scale plots with seismic cruise navigation overprints, then digitized on screen using Arc Edit. A study area boundary line was digitized and added, polygons cleaned and attributed.

    Person who carried out this activity:

    Mary DiGiacomo-Cohen
    U.S. Geological Survey
    Geologist / GIS Analyst
    Long Island Sound Resource Center
    Groton, CT 06340

    (860) 405-9210 (voice)
    mdicohen@usgs.gov

    Data sources used in this process:
    • h11250g

    Data sources produced in this process:

    • h11250geoi

    Date: 2006 (process 2 of 2)
    Coverage was projected to geographic coordinates and converted to shapefile format

    Person who carried out this activity:

    Mary DiGacomo-Cohen
    U.S. Geological Survey
    Geologist / GIS Analyst
    Long Island Sound Resource Center
    Groton, CT 06340

    860-405-9210 (voice)
    mdicohenusgs.gov

    Data sources used in this process:
    • h11250geoi

    Data sources produced in this process:

    • h11250g_geol

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

    Poppe, L.J., DiGiacomo-Cohen, M.L., Smith, S.M., Stewart, H.F., and Forfinski, N.A., 2006, Seafloor character and sedimentary processes in eastern Long Island Sound and Western Block Island Sound: Geo-Marine Letters v. 26, p. 59-68.

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

  1. How well have the observations been checked?

    The attribute values represent interpreted features; accuracy has been checked by the compilers.

  2. How accurate are the geographic locations?

    Navigation was by differential GPS; positional accuracy to less than 10 m. Interpreted polygons are accurately located given the nature and scale of the features. Previously collected seismic data used to aid the interpretation of the multibeam data was collected by ship navigated by Loran C which is less positional accuracy than GPS.

  3. How accurate are the heights or depths?

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

    The interpretation is considered complete for the data/area provided. There are gaps in the bathymetric source data in areas inaccessible to the survey vessels (shallow water surrounding islands).

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

    The interpretation is topologically consistent. There are gaps in the bathymetric source data in areas inaccessible to the survey vessels (shallow water surrounding islands).

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:
Public domain data are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey (USGS) and the Connecticut Department of Environmental Protection (CTDEP) as the originators of this dataset.

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

    U.S. Geological Survey
    c/o Larry Poppe
    Geologist
    384 Woods Hole Road
    Woods Hole, MA 02543-1598
    USA

    508-548-8700 x2314 (voice)
    508-457-2310 (FAX)
    lpoppe@usgs.gov

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

    Downloadable Data - H11250G_GEO - ArcGIS shapefile

  3. What legal disclaimers am I supposed to read?

    Although this data set has been used by the U.S. Geological Survey (USGS), Connecticut Department of Environmental Protection (CTDEP) and the National Oceanic and Atmospheric Administration (NOAA), no warranty, expressed or implied, is made by the USGS, CTDEP or NOAA 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, CTDEP or NOAA 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.

  4. How can I download or order the data?

  5. What hardware or software do I need in order to use the data set?

    These data are available in Environmental Systems Research Institute (ESRI) shapefile format. The user must have ArcGIS or ArcView 3.0 or greater software to read and process the data file. In lieu of ArcView or ArcGIS, the user may utilize another GIS application package capable of importing data. A free data viewer, ArcExplorer, capable of displaying the data is available from ESRI at www.esri.com.

Who wrote the metadata?

Dates:
Last modified: 06-Apr-2007
Metadata author:
U.S. Geological Survey
c/o Larry Poppe
Geologist
384 Woods Hole Road
Woods Hole, MA 02543-1598
USA

508-548-8700 x2314 (voice)
lpoppe@usgs.gov

Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
Metadata extensions used:

Generated by mp version 2.8.6 on Fri Apr 06 08:41:25 2007