U.S. Geological Survey

Central West Antarctica Aeromagnetic Compilation

The aeromagnetic data presented here are one data set collected as a National Science Foundation (NSF) project entitled, "Lithospheric controls on the behavior of the West Antarctic ice sheet." This is a multi-institutional project that includes the Institute for Geophysics of the University of Texas (UTIG) at Austin, the Lamont-Doherty Earth Observatory (LDEO), and the U. S. Geological Survey (USGS). The scientific objective of this program is to understand the lithospheric framework across the West Antarctic rift system in order to determine the geological controls on the dynamics of the West Antarctic ice sheet. The Support Office for Aerogeophysical Research (SOAR) collected the data.

These data show variations in the Earth's magnetic field caused primarily by the uneven distribution of the mineral magnetite in the rocks that make up the upper part of the Earth's crust. The features and patterns of the maps reveal details of subsurface geology including the locations of buried faults and magnetite-bearing rocks, which include Cenozoic magmatic rocks, and non-magnetic sedimentary and granitic rocks.

The aeromagnetic data were collected in 5 separate field seasons covering 4 geographic regions (IRE, BSB, WAZ, TKD). Each survey made simultaneous measurements of radar ice soundings, laser altimetry, gravity (Bell and others, 1999), and magnetics. The transects flown in all regions were separated by 5.3 kilometers in both the flight-line and orthogonal tie-line directions. The magnetic field observations are accurate to one nT. High-resolution horizontal and vertical positions were obtained from differential positioning techniques based on Global Positioning System (GPS) satellites. When GPS satellite positioning was unavailable, the laser altimetry was corrected using attitude information from an inertial navigation system, and a digital pressure transducer was used to recover vertical positions and accelerations. The latitudes of the final composite map ranged from approximately -77.8 to -84.5 degrees; the longitudes from approximately -103.9 to -153.3 degrees. A data index plot gives an overview of the names and locations of the geographic regions. A data table summarizes the survey specifications, including dates flown and original flight elevations. A list of data processing steps details the procedures used to produce the final maps.

HPGL plot files can be downloaded for plotting at a 1:1,000,000 scale for the composite IRE/BSB, WAZ/TKD, and IRE/BSB/WAZ/TKD maps, and at a 1:750,000 scale for the individual WAZ and TKD maps. GIF and page-sized color postscript plot files can be downloaded for all maps. All maps are also available for screen viewing.

This project was supported by National Science Foundation Grant OPP-9319877 and by the Mineral Resources Team, the Global Change and Climate History Team, and the Coastal and Marine Geology Team, all of the USGS. The authors wish to thank our USGS colleagues Richard Saltus and Kim Oshetski for their assistance in preparing this report, and Robert Arko of LDEO for his assistance with the data processing.

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U.S. Department of the Interior
U.S. Geological Survey

This page is <URL: https://greenwood.cr.usgs.gov/pub/open-file-reports/ofr-99-0420/cwantarctica.html>
Maintained by: Gene Ellis
Last Modified Thursday, 19-Nov-1998 11:19:34 MST
For more information about this report contact: Ronald Sweeney