[Capriole]

Why are these lakes warm enough to remain unfrozen when everything else in the neighborhood is frozen to the depth of 4km?

[Strategerist]

Why are these lakes warm enough to remain unfrozen when everything else in the neighborhood is frozen to the depth of 4km?

Heating from below; areas where the crust is thinner and you've got magma nearer the surface.

[reg45]

If the pressure is high enough, water can remain liquid even below the standard freezing point.

[PapaBear3625]

Why are these lakes warm enough to remain unfrozen when everything else in the neighborhood is frozen to the depth of 4km?

Antarctica has volcanoes, hot springs, etc, from an underground magma hot spot. The red dots below are volcanoes.

Notice how that side of Antarctica has a lot less ice cover than the other side?