Online Links:
Online Links:
Formal codeset | |
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Codeset Name: | Polygon |
Codeset Source: | ESRI |
Formal codeset | |
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Codeset Name: | Pz/Tcp/Qt - Undifferentiated Paleozoic bedrock, Late-Cretaceous or Tertiary coastal plain deposits, or Pleistocene glacial till or coarse drift deposits |
Codeset Source: | seismic interpretation |
Formal codeset | |
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Codeset Name: | Qd - Undifferentiated Pleistocene stratified glacial drift deposits. Commonly consists of vertically laminated, roughly horizontal to broadly undulating seismic reflectors or zone of near acoustic transparency. |
Codeset Source: | seismic interpretation |
Formal codeset | |
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Codeset Name: | Qfe - Holocene fluvial and estuarine deposits. The lowermost Holocene sedimentary deposit that fills the fluvial valleys incised into the surface of Qd. The surface is generally defined by the Holocene transgressive unconformity. |
Codeset Source: | seismic interpretation |
Formal codeset | |
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Codeset Name: | Qmn - Holocene nearshore marine deposits. Post-transgressive Holocene sediment deposits that are predominantly sand with varying proportions of gravel and mud and mostly restricted to the inner shelf area. |
Codeset Source: | seismic interpretation |
Formal codeset | |
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Codeset Name: | Qmd - Holocene deepwater marine deposits. Post-transgressive Holocene sediment deposits that are predominantly muddy with varying proportions of sand and are generally confined to portions of Cape Cod Bay that are deeper than 45 m. |
Codeset Source: | seismic interpretation |
Range of values | |
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Minimum: | 0.002 |
Maximum: | 237.146 |
Units: | Square Kilometers |
This data set describes sea-floor geology on the Massachusetts inner shelf between Nahant and Northern Cape Cod Bay. Polygons are used to indicate the areal distribution of sea-floor outcrop for sub-surface stratigraphic units interpreted in high-resolution seismic reflection data. These data are useful for assessing relations between geologic framework, sea-bed morphology, and sediment textural trends.
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Are there legal restrictions on access or use of the data?Access_Constraints: None
Use_Constraints: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 geologic mapping interpretations. Because of the scale (polygon editing was done at scales between 1:8,000 and 1:20,000, depending on the size of the outcrop area) and line spacing of the source seismic profiles, not all changes in seafloor geology are captured. The boundaries of polygons are inferred between seismic lines, and polygon boundaries should be considered an approximation of the location of a change in geology. Further, a constant seismic velocity of 1,500 m/s was assumed for all profiles in all sediment types, which may result in inaccurate depths of stratigraphic units.
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 polygons that define sea-floor geology from Nahant to Northern Cape Cod Bay, MA and the associated metadata in format Shapefile (version ArcGIS 9.3.1) Esri Polygon Shapefile Size: 0.25 |
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Network links: |
http://pubs.usgs.gov/of/2012/1157/GIS_catalog/SurficialGeology/SurfGeo.zip http://pubs.usgs.gov/of/2012/1157/html/GIS_catalog.html http://pubs.usgs.gov/of/2012/1157/ |
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.