Melbourne: Scientists have found a
geological mechanism which caused New Zealand to separate from
Australia -- and other continents, including the Indian sub-
continent, to form.
Using a mathematical model, a team at University of
Sydney has calculated the immense forces of nature that tore
New Zealand away from Australia nearly 100 million years ago,
the `Nature Geoscience` journal reported.
According to the scientists, Australia was once part
of a much larger land mass called Gondwana, which included the
modern continents of Africa, South America, Antarctica and the
Indian subcontinent.
However, Gondwana was torn apart - with connections
between Africa and South America broken first, followed by New
Zealand`s and New Caledonia`s shift away from the eastern edge
of the Australian plate, say the scientists.
Professor Patrice Rey and Professor Dietmar Miller
from the University`s School of Geosciences have explained for
the first time the mechanism responsible for East Gondwana`s
disintegration into micro continents.
Between 105 million and 90 million years ago,
Australia and NZ were joined with Antarctica, but the Pacific
tectonic plate dived under the supercontinent`s east coast at
the rate of 7cm to 8cm a year, about the same rate it now
sinks beneath South America, they say.
As the plates slowed down, the friction between the
two plates (Pacific and Gondwana) got smaller and smaller and
the mountain belt along East Gondwana began to collapse,
spreading under its own weight.
PTI
