Australia: The Land Where Time Began

A biography of the Australian continent 

Indo-Australian Plate

The Indo-Australian Plate is a large crustal plate that includes the continent of Australia and the sub-continent of India. The Indian Plate and the Australian Plate fused about 43 Ma, stretching from Antarctica in the south to the Himalayas, the Indonesian Islands and New Guinea in the north, and to New Zealand in the east.  It is currently moving to the north-east at about 7 cm/year, considered to be a rapid rate in plate tectonics, though the upper mantle, that is believed to at least partially drive plate movements, is apparently moving at a slower rate. The other driving force believed to be moving the Indo-Australia Plate is the subduction along the northern margins of the plate as it is subducted along the highly volcanic band known as the Pacific "Ring if Fire". In the case of the subduction of the plate, it is being pulled down along the subduction zone by gravity.

There are a number of geological features of the Australian continent that hint at a more complex process than passively drifting to the northeast. According to Mike Sandiford of the University of Melbourne, included in these features are tilted parts of the coast of South Australia, the lack of large carbonate deposits in northern Australia, and in southern Victoria, the shape of volcanic provinces. Sandiford has suggested these features, that are manifestations of motion, are instabilities resulting from difference of the speed of travel between the crust, the lithosphere, and the aesthenosphere, the upper mantle. He has also suggested that the differential rates of motion of the crust and the upper mantle may eventually lead to a splitting of the Australian continent.

see Drifting Direction Change

Sources & Further reading

1. Catchpole, Heather, Oct/Nov 2010, Cosmos Magazine

Links

AESC 2010