An iceberg the size of Luxembourg has smashed into another vast slab of ice that juts out from Antarctica.
B15A (right) broke off a 5km-long section of Drygalski
The 115km-long B-15A iceberg broke off a 5km-long section of the Drygalski ice tongue when it collided with the prominence in the Ross Sea.
The iceberg itself so far appears unaffected by the smash-up.
More of the B-15A iceberg still has to pass by Drygalski, so the ice tongue may be in for even more punishment in the coming days, experts have said.
The European Space Agency's Earth-observation platform Envisat has returned some remarkable images of the collision.
From January, the iceberg has been on a collision course with the 70-km-long Drygalski ice tongue in McMurdo Sound in the Ross Sea.
In the last month, prevailing currents have been slowly edging B-15A along past the northern edge of Drygalski.
The iceberg could cause yet more problems. It appears to be rotating into Terra Nova Bay, where it could cause problems for penguins trying to feed and for the Italian Mario Zuchelli research base which is located there.
B-15A has an area exceeding 2,500 sq km and is the largest remaining section of the even bigger B-15 iceberg that broke off from the Ross Ice Shelf in March 2000.
About the same size as Jamaica, B-15 had an initial area of 11,655 sq km but subsequently broke up into smaller pieces.
Experts first noticed the berg was on a collision course in January
Since then, B-15A has drifted its way to McMurdo Sound, where its presence blocked ocean currents and led to a build-up of sea ice.
Because penguins had to swim greater distances to reach open waters and food, this prompted fears that many chicks could starve.
The Drygalski ice tongue stretches out into McMurdo Sound as an extension of the land-based David Glacier, which flows through the coastal mountains of Victoria Land.
It is large and permanent enough to feature in Antarctic atlases, which may now have to be amended.