A massive iceberg, measuring 78 kilometres long and 39 kilometres wide, has calved from the Mertz Glacier in the Australian Antarctic Territory.

The iceberg has a surface area of 2500 square kilometres and broke off the glacier after another 97 kilometre-long iceberg (B9B) collided with the tongue of the glacier.

The calving event was detected recently by Australian and French researchers who have been studying the Mertz Glacier since 2007.

The tongue has had major rift in it from opposite sides for many years and the piece that has broken off is about half the length of the tongue.