LONDON: A big rift on the Antarctic ice shelf has grown an additional 17 kilometres in last six days, say scientists who suggest that a massive iceberg is now at the brink of breaking off.The rift tip is now within 13 kilometres of breaking all the way through to the ice front. The break off will produce one of the largest ever recorded icebergs at the South Pole.In the largest jump since January, the rift in the Larsen C Ice Shelf has grown an additional 17 kilometres between May 25 and May 31.The rift tip appears also to have turned significantly towards the ice front, indicating that the time of calving is probably very close.The rift has now fully breached the zone of soft 'suture' ice originating at the Cole Peninsula and there appears to be very little to prevent the iceberg from breaking away completely, according to scientists of the Project MIDAS based at is based at Swansea University and Aberystwyth University in the UK.Larsen C Ice Shelf is about 350 metres thick and floats on the seas at the edge of West Antarctica, holding back the flow of glaciers that feed into it.When it calves, the ice shelf will lose more than 10 per cent of its area to leave the ice front at its most retreated position ever recorded. The event will fundamentally change the landscape of the Antarctic Peninsula."We have previously shown that the new configuration will be less stable than it was prior to the rift, and that Larsen C may eventually follow the example of its neighbour Larsen B, which disintegrated in 2002 following a similar rift-induced calving event," researchers said.