Ice tongues -- the laws of physics still apply

These are three satellite images of ice tongues in Antarctica.  The top one shows Drygalski Ice Tongue, the middle one shows the Erebus Ice Tongue, and the third is at a location I haven't been able to identify.  These are very strange features -- essentially they are glaciers afloat, but not constrained by valley sides, so they just keep on pushing out from the coast, sometimes with the rate of forward progress faster than the rate of wastage or breakage, and sometimes being dramatically shortened if there is a major collision with a broken chunk of ice shelf or tabular berg.  Open water can have a similar effect, with tides and storm waves causing a fragmentation of the ice tongue tip, with huge tabular bergs then floating away.

These features seem to defy the laws of physics, since one would expect them simply to break up on reaching the coast, as is the case with most of the tidewater glaciers of Greenland and Alaska, for example.  The difference here is that there is a constraining medium -- sea ice or shelf ice which holds the glacier tongue in place.  So the glacier simply retains its shape, pushing out to sea in a relatively unchanged form although it is afloat and therefore vulnerable to breakup.

Such features are very rare in the northern hemisphere, although the Petermann Gletscher and other north Greenland glaciers do sometimes create tongues in situations where there is thick and persistent sea ice on the fringes of the Arctic Ocean.

The laws of physics still apply -- but don't ask me to try and explain in simple terms the strange serrated edges of the Erebus Ice Tongue...........