The St. Olaf College contribution to the US-ITASE 2 program is a deep-penetrating 3 MHz radio echo-sounding system that can measure the bedrock surface beneath the ice as well as internal layers that have unique electrical properties. Total ice thickness data is useful to researchers who develop ice-flow models of the ice sheet. The immense size of the ice sheet makes it difficult to obtain high-accuracy thickness measurements over the entire continent. The long distance traverses of the US-ITASE program make it an ideal platform for ground-based radar measurements.
Internal ice reflections are usually related to deposition of volcanic debris (acids or ash) or dust layers. These layers give researchers a window into the accumulation and flow history of the ice sheet. Changes in the layer thickness along the traverse routes may be attributed to changes in snow accumulation due to climate or geographic changes (crossing a drainage divide, for example). Changes in the ice flow velocity due to bumps in the bedrock or changes in the bedrock character cause the ice to thicken or thin as the ice decelerates or accelerates.
We plan to resurvey a number of radar profiles recorded at Taylor Dome by David Morse and Howard Conway from the Univ. of Washington prior to the Taylor Dome Ice Core project in the early 1990's. These profiles will help us establish a baseline for the reflectivity of bedrock frozen to the ice sheet and also provide dates for internal ice layers. Once the traverse departs Taylor Dome we will record radar profiles along the entire traverse route to establish dating control of the internal stratigraphy that can be traced back to the Taylor Dome core. We plan to collect radar profiles on a number of side-traverses that will parallel ice flow in order to examine the influence of basal conditions on flow dynamics. In addition we hope to gain access to a number of the ridges separating the large outlet glaciers that drain the East Antarctic Ice Sheet through the Transantarctic Mountains to examine the stability of ice flow into the glaciers. Finally we will visit a number of interesting glaciological features along the route including Titan Dome, large zones of wind erosion, and perhaps the edges of the Mega-dunes region. Our 3 MHz radar system has been upgraded to collect data closer to the ice surface so we hope to correlate our internal ice stratigraphy with that collected by Steve Arcone's 400 MHz shallow radar system. Upon reaching the South Pole in Year 2 of this project we will connect our radar stratigraphy to the data collected in West Antarctica during the first phase of US-ITASE (1999-2003) that also finished at South Pole.
Map of the proposed traverse corridor for US-ITASE 2 starting at Taylor Dome and ending at South Pole. Click the map for a full-size image.
