TAMDEF: Transantarctic Mountains Deformation Network, GPS Measurements of Rock and Ice Motions in South Victoria Land, Antarctica

The TAMDEF (TransAntarctic DEFormation) GPS network consists of an array of 25 primary sites located in the Transantarctic Mountains of southern Victoria Land and on islands in the adjacent Ross Sea. Ohio State University and the USGS Antarctic Mapping group jointly carried out installation and surveying of the TAMDEF array between 1996 and 2001. Willis et al., (In press; BPRC Report No. 20) provide detailed information on field methods, data processing, and site characterization for the TAMDEF network. Steel pins sunk directly into bedrock were used for monuments. Fixed-height forced-centered level mounts were used to accurately re-center the GPS antenna at each site each year. Dorne-Margolin T style choke-ring antennae were exclusively used to reduce signal interference. All measurements were made at approximately the same time of year to minimize possible seasonal fluctuations in the monument positions or atmospheric conditions. Large multi-day data sets were collected. To be certain that local periglacial processes did not contaminate the average motion of a site, we installed a micro-footprint array consisting of at least 3 other GPS monuments around each primary pin. Short, highly accurate baselines were recorded back to the central pin at least twice over the 4-year period. The raw data from the TAMDEF project are available from the UNAVCO archive at &http://facility.unavco.org/data/data.html& under &Campaign Data Holdings& and the &Antarctic Support& links. The data are also available via a web site established at the Ohio State University &http://www.geology.ohio-state.edu/~willis/&, contact Michael Willis ([e-mail]) or Terry Wilson ([e-mail]) for data details and access information.