Thursday, December 28, 2023 – 11:08 WIB
Australia – Australia is not only the smallest continent, but also the largest island in the world. However, this country, known as Kangaroo Country, is not isolated, because it was once part of a larger super continent. So when did Australia become a continent in its own right?
Reported Live technology from Science liveAs of Thursday, December 28, 2023, the Australian continent measures approximately 2,300 miles (3,700 kilometers) from north to south and 2,485 miles (4,000 km) from east to west. With an area of 2.97 million square miles (7.69 million square kilometers).
Australia is home to the oldest known material from land on Earth, namely zircon crystals from the Jack Hills region of Western Australia, which date back 4.4 billion years, according to a 2014 study published in the journal Nature Geoscience.
The oldest parts of Australia are three continent-sized pieces of rock known as cratons: the North, South and West Australian cratons, Alan Collins, a geologist at the University of Adelaide in Australia, told LiveScience. The younger eastern part of Australia is made up of rocks that formed on the edges of older areas of the continent over the last 500 million years.
Australia was once part of a much larger territory known as Gondwana, which also included what is now Africa, South America, Antarctica, India and Madagascar. According to Monash University, Gondwana itself was once part of the supercontinent Pangea, which broke away about 200 million years ago.
Gondwana began breaking up about 180 million years ago, Collins said. Its eastern part – which includes Australia, Antarctica, India and Madagascar – is separate from its western part, which includes Africa and South America, according to the Free University of Berlin.
Gondwana broke up because oceanic crust subducted, or slipped, under the southern and eastern edges of Asia and fell into the Earth, Collins explained. This oceanic crust drags along the rest of the tectonic plate, and the northern boundary of Gondwana lies on the edge of this plate, he said.
Eastern Gondwana, in turn, lost more and more parts over time. “Together as a single block, Australia and Antarctica separated from Gondwana about 135 million years ago,” Patrice Rey, a geologist at the University of Sydney, told LiveScience.
This block separated from Gondwana because the tectonic plate east of this block subducted beneath the block. “This subduction zone accommodates the eastward movement of the Australia-Antarctic block away from Gondwana,” Rey said.
New Zealand was also part of this breakaway bloc. However, about 100 million years ago, the landmass that now comprises New Zealand – a largely submerged continent nicknamed Zealandia – broke away from what is now eastern Australia, partly due to massive volcanic activity.
Australia finally separated from Antarctica and became a continent of its own about 35 million years ago, when the former drifted northward from the latter, Rey said. This event created the Southern Ocean that currently surrounds Antarctica, Collins said.
Australia is still on the move. Moving about 2.75 inches (7 cm) per year, Australia is the fastest-moving tectonic plate on the planet, Australian scientists Chris Rizos and Donald Grant wrote in a 2017 article for The Conversation.
“Australia is moving north quite fast, as fast as fingernails grow,” Collins said.
In about 20 or 30 million years, Australia “will probably crash into East Asia,” Collins added. Once Australia collides with Asia, its time as a continent will end.
2023-12-28 04:08:02
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