Abstract:
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 where the rift flank is offset along a transverse accommodation zone.
Purpose:
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.
Supplemental_Information: An aeromagnetic grid was created for the survey area. In addition, 65 gravity stations were collected in profile-form in the Skelton Neve region.
Quality
Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: The digital data are grids, which were created from helicopter magnetometer observations. Grid values represent the total intensity of the Earth's magnetic field after filtering to remove any anomalous noise, adjusting for ... the diurnal component of the magnetic field, and removal of the International Geomagnetic Reference Field (IGRF).
The data in the original grids have been processed using formulas and methods that are not usually documented but that represent industry standard practices for airborne data reduction.
Logical_Consistency_Report: 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 sq km. 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 fur 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.
Completeness_Report: Areas with no aeromagnetic data are flagged with dummy values, which are described for the grids in a readme.txt file.
Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: Flight Path Recovery - High-resolution horizontal position of the survey aircraft used to collect data were determined from differential positioning techniques based on Global Positioning System (GPS) satellites. Positioning data were recorded in-flight independently using a Trimble GPS receiver. For most flights GPS reference station data at either Skelton Neve Camp or McMurdo were available and a differential position was calculated. For gaps in differential positioning, original GPS Rover data were used, adjusted at both ends of any gap. Vertical_Positional_Accuracy: Vertical_Positional_Accuracy_Report: Flight Path Recovery - High-resolution vertical position of the survey aircraft used to collect data were determined from differential positioning techniques based on Global Positioning System (GPS) satellites. Positioning data were recorded in-flight independently using a Trimble GPS receiver. For most flights GPS reference station data at either Skelton Neve Camp or McMurdo were available and a differential position was calculated. For gaps in differential positioning, original GPS Rover data were used, adjusted at both ends of any gap.
U.S. Geological Survey, Geology Diviion
Box 25046, MS964
Denver Federal Center
City:
Denver
Province or State:
CO
Postal Code:
80225-0046
Country:
USA
Publications/References
MASLANYJ, M.P., & DAMASKE, D., 1986, Lessons regarding aeromagnetic surveying during magnetic disturbances in polar regions: British Antarctic Survey Bulletin, 73, 9-17.
DAMASKE, D., MARCINKOWSKI, V., MÖLLER, H.-D., in press, Aeromagnetic survey in central Dronning Maud Land, East Antarctica, during the GeoMaud expedition 1995/96: Lay-Out, Execution, and Data Processing: Geologisches Jahrbuch.
