Glaciology of Blue Ice Areas in Antarctica
Our main objective for this project is to contribute to the glaciological understanding of blue ice areas in Antarctica. Most of the Antarctica Ice Sheet has a snow/firn cover of ~100m that overlies the ice. In blue ice areas, the ice is on the surface and there is no blanket of snow. This is because wind and sublimation remove more snow than is accumulated by snowfall, causing a negative mass balance. Typically, blue ice areas form where mountains obstruct ice flow and high winds transport a lot of snow. These conditions cause ice to flow upwards, towards the surface (Figure 1). By walking in the direction of the Allan Hills in Figure 1, we are essentially walking back in time over older and older ice. As a result, we can obtain long records by collecting a ‘horizontal ice core’ as opposed to a vertical one (Figure 2).
We will investigate the ice dynamics of two blue ice areas – Mt. Moulton and the Allan Hills.
Below is a brief list of techniques that we will use. We’ll explain them in more detail in our logbook:
- GPS (Global Positioning System): Both field sites have a pre-existing network of velocity markers. We will determine the displacement of these markers to update our velocity measurements.
- Radar: Radar profiles will be collected in order to map the bedrock topography and assess how well ice layers are preserved as they pass over bedrock bumps.
- ECM (Electrical Conductivity Measurements): ECM profiling is a way to delineate ice layers while in the field. Conductivity measurements vary depending on sea salt concentrations, volcanic tephras, etc.
- Shallow Ice Cores: Outside of the blue ice area, shallow firn cores will be collected to determine accumulation rates.
- Meteorite Dating: The ice dynamics of blue ice areas make them the primary collection zones for meteorites. These meteorites help us date the surrounding ice (through the radioactive decay of cosmogenic nuclides).
Visit our Expedition Page to read about our field work.