clustered about the vents.

The former Larsen A region, which was the farthest north and was just outside the Antarctic Circle, had previously broken up in the middle of the present interglacial and reformed only about 4,000 years ago. The former Larsen B, by contrast, had been stable for at least 10,000 years. The ice of the shelf is renewed on a much shorter time-scale and the oldest ice on the current shelf dates from only two hundred years ago. The speed