the giant block is estimated to cover an area of roughly 6,000sqkm,that's about a quarter the size of wales.
a us satelite observed the berg on wednesday while passing over a region known as the larson ice shelf.scientists were expecting it.they 'd been following the development of a large crack in larsen's ice for more than a decade.
the rift's propagation had accelerated since 2014,making an imminent calving ever more likely.
the more than 200m-thick tabular berg will not move very far,very fast in the short term.but it will need to be monitored.currents and winds might eventually push it north of the atlantic where it could become a hazard to shipping.
an infrared sensor on the american space agency's aqua satelite spied clear water in the rift between the shelf and the berg on wednesday.the water is warmer relative to the surrounding ice and air-both of which are sub-zero.
''the rift was barely visible in these data in recent weeks,but the signature is so clear now that it must have opened considerably along its whole length'',explained prof adrian luckman,whose project midas at swansea university has followed the berg's evolution most closely.
the new larsen berg is probably in the top 10 biggest ever recorded.
the largest observed in the satelite era was an object called b-15.it came away from the ross ice shelf in 2000 and measured some 11,000sqkm six years later,fragments of this super-berg still persisted and passed by new zealand.