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379 subglacial lakes have now been identified beneath the Antarctic continent.
This map, using data from Wright and Siegert 2012  shows that many are located in ice-stream onset zones as well as underneath slow-moving ice domes.
There are therefore density contrasts between meltwater and the main body of lake water, which results in circulation within the lake.Satellite images and airbourne radio echo-sounding have been used to identify flat regions on the ice-sheet surface.These flat areas have subglacial lakes beneath them.The largest is Lake Vostok in East Antarctica (240 km long, 50 km wide and hundreds of metres deep), which is of significant interest to researchers because of its potential to harbour life.Subglacial lakes have an ice-water interface that slopes eleven times more than the ice-surface gradient (but in the opposite direction and if they are in hydrostatic equilibrium).
It lies within a subglacial topographic basin, similar to a rift valley.