Australia: The Land Where Time Began

A biography of the Australian continent 

Totten Glacier, East Antarctica - Ocean Access to a Cavity Beneath it

The largest rate of thinning in East Antarctica is occurring at the Totten Glacier, which is the primary outlet for the Aurora Subglacial Basin (Flament & Rémy, 2012; Pritchard et al., 2009). According to Greenbaum et al. thinning may be driven by enhanced melting at the base as a result of ocean processes (Pritchard, 2012), that are modulated by polynya activity (Gwyther et al., 2012; Khazender et al., 2013). Warm modified Circumpolar Deep Water, which has been linked to glacier retreat in West Antarctica (Jenkins et al., 2010), has been observed in summer and winter on the nearby continental shelf beneath 400-500 m of cool Antarctic Surface Water (Bindoff, Rosenberg & Warner, 2000; Williams et al., 2011). In this paper Greenbaum et al. derived a bathymetry of the sea floor in the region (Parker, 1973) by the use of gravity data and magnetics data (Aitken et al., 2014) as well as measurements of ice thickness (Young et al., 2011). They identified entrances to the ice shelf cavity below depths of 400-500 m that could allow warm water to intrude if the vertical flow is similar to nearby observations. It was revealed by radar sounding that an inland trough, that had not previously been known, connects the main ice shelf cavity to the ocean. They suggest that if thinning trends continue a larger water body over the trough could potentially allow warm water to enter the cavity which may eventually result in destabilisation of the low-lying region between Totten Glacier and the glacier, that is similarly deep, that flows into the Reynolds Trough. Greenbaum et al. estimate that at least 3.5 m of eustatic sea level potential drains through the Totten Glacier, therefore coastal processes in this area could result in global consequences.

Sources & Further reading

1. Greenbaum, J. S., D. D. Blankenship, D. A. Young, T. G. Richter, J. L. Roberts, A. R. A. Aitken, B. Legresy, D. M. Schroeder, R. C. Warner, T. D. van Ommen and M. J. Siegert (2015). "Ocean access to a cavity beneath Totten Glacier in East Antarctica." Nature Geosci 8(4): 294-298.