Transantarctic Mountain Aerogeophysical Research Activities

Project Description
The Transantarctic Mountains (TAM) rift-flank uplift has developed along the ancestral margin of the East Antarctic craton, and forms the boundary between the craton and the thinned lithosphere of the West Antarctic rift system. Geodynamic processes associated with the exceptionally large-magnitude uplift of the mountain belt remain poorly constrained, but may involve interaction of rift-related mechanical and thermal processes and the inherited mechanical elements of the cratonic lithosphere. The Transantarctic Mountain Aerogeophysical Research Activities (TAMARA) program proposes to document the regional structural architecture of a key segment of the Transantarctic Mountains in the region around the Royal Society Range (Fig. 1) where the rift flank is offset along a transverse accommodation zone. In December through January, 1998, the TAMARA group flew a helicopter aeromagnetic survey and collected ground gravity station data. These data will be integrated with other geologic and geophysical information from the region in order to map the large-scale structures along the TAM where relations between longitudinal and transverse structures along the rift flank can be resolved.

During the 1997-1998 field season, the TAMARA project collected about 14,100 line-km of helicopter magnetic data, covering an area just a little less than 30,000 km2 (Fig. 2). One hundred twenty-five hours of helicopter time were used to complete the survey. Relative to the initial plans, 92.5% of line-kilometers, or 95% of the planned area, was covered.

Magnetic base stations established in McMurdo and the Skelton Neve field camp recorded the daily variations of Earth's magnetic field for removal from the total-field observed from the helicopter. The position of a cesium magnetometer carried in a bird slung 30 m below the helicopter was accomplished with Trimble 4000 GPS receivers. Barometric altitudes were also recorded. The data from each flight were quality controlled.

The crew for the aeromagnetic helicopter-borne program consisted of 3 helicopter support personnel (including 2 pilots and an engineer) and 6 scientific staff (geophysicists, engineers, and quality control specialists). Bundesanstalt für Geowissenschaften und Rohstoffe (BGR) contributed a geophysicist, an engineer, and a quality control specialist. Three additional scientists were from the USGS and Ohio State University. A general assistant for camp operations and a mountaineer were supported by the National Science Foundation (NSF).

In addition to the aeromagnetic data, 65 gravity stations were collected in profile-form in the Skelton Neve region.

This material is based upon work supported by the National Science Foundation under Grant No. 9618568.

Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.

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