Citation:
Citation_Information:
Originator: U.S. Geological Survey and the Department of Interior
Publication_Date: 2012
Title: Airborne geophysical survey: Spencer, Maine
Geospatial_Data_Presentation_Form: analog contour map
Online_Linkage:
Description:
Abstract:
Aeromagnetic data were collected along flight lines by instruments in an
aircraft that recorded magnetic-field values and locations. In the earlier
days of surveying, the only way to represent this data was to generate an
analog map with contour lines. This dataset is a representation of the
digitized contour lines either by following the lines or by choosing the
intersection of the contour and flight-line to create a value of the magnetic
field. The values presented are latitude, longitude, and map magnetic-field
values.
Purpose:
Aeromagnetic surveys are used for geophysical prospecting. Some variations in
magnetic measurements are caused by rocks that contain significant amounts of
magnetic minerals (magnetite being the most common). These anomalies reflect
variations in the amount and type of magnetic material and the shape and depth
of the body of rock. The features and patterns of aeromagnetic anomalies can
also be used to delineate details of subsurface geology including the locations
of buried faults and the thickness of surficial sedimentary rocks.
Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 19580911
Ending_Date: 19580930
Currentness_Reference: ground condition
Status:
Progress: complete
Maintenance_and_Update_Frequency: none planned
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -70.50
East_Bounding_Coordinate: -70.25
North_Bounding_Coordinate: 45.50
South_Bounding_Coordinate: 45.25
Data_Set_G-Polygon:
Data_Set_G-Polygon_Outer_G-Ring:
G-Ring:
-70.50 45.50, -70.25 45.50, -70.25 45.25,
-70.50 45.25, -70.50 45.50
Keywords:
Theme:
Theme_Keyword_Thesaurus: USGS Metadata Identifier
Theme_Keyword: USGS:4aa16df7-2456-4920-a831-49b7b040539b
Theme:
Theme_Keyword_Thesaurus: none
Theme_Keyword: geophysical surveys
Theme_Keyword: aeromagnetic data
Theme_Keyword: airborne surveys
Theme_Keyword: magnetic surveys
Theme_Keyword: residual magnetic field
Theme_Keyword: total field
Theme_Keyword: magnetic
Theme:
Theme_Keyword_Thesaurus: USGS Thesaurus
Theme_Keyword: geophysics
Theme_Keyword: geospatial datasets
Theme_Keyword: magnetic field (earth)
Theme_Keyword: aeromagnetic surveying
Theme_Keyword: field monitoring stations
Place:
Place_Keyword_Thesaurus: none
Place_Keyword: United States
Place_Keyword: Maine
Place_Keyword: ME
Place_Keyword: Spencer
Place:
Place_Keyword_Thesaurus: Common Geographic Areas
Place_Keyword: f23007 = Franklin
Place_Keyword: f23025 = Somerset
Access_Constraints: none
Use_Constraints:
none. Acknowledgement of the U.S. Geological Survey would be appreciated
in products derived from these data.
Browse_Graphic:
Browse_Graphic_File_Name:
Browse_Graphic_File_Description:
Reduced-size image depicting the data, 1118 x 1303 pixels, 86,296 bytes
Browse_Graphic_File_Type: JPEG
Data_Set_Credit:
These USGS employees contributed to reformatting and archiving these data:
Viki Bankey, Pat Hill, Holly Hindle,
Bob Kucks, Sarah Shearer, Esther Castellanous
Cross_Reference:
Citation_Information:
Originator: U.S. Geological Survey
Publication_Date: 1963
Title:
Aeromagnetic map of the Spencer Lake Quadrangle, Franklin
and Somerset counties, Maine
Geospatial_Data_Presentation_Form: map
Series_Information:
Series_Name: U.S. Geological Survey Geophysical Investigations Map
Issue_Identification: GP-331
Publication_Information:
Publication_Place: Denver, CO
Publisher: U.S. Geological Survey
Other_Citation_Details:
by R.W. Bromery others
map scale 1:62,500