When Did Australia Become Its Own Continent? Exploring the History of Australia’s Continental Separation

Thursday, 28 December 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 its own continent?

Reported LIVE Techno from Live Science, 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 material known to come 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 in the journal Nature Geoscience.

Australia’s oldest parts are three continent-sized chunks of rock known as cratons: the North, South and West Australian cratons, Alan Collins, a geologist at the University of Adelaide in Australia, told Live Science. The younger eastern part of Australia consists of rocks that formed on the edge of the continent’s older areas over the last 500 million years.

Australia was once part of a much larger landmass known as Gondwana, which also included what is now Africa, South America, Antarctica, India and Madagascar. Gondwana itself was once part of the supercontinent Pangaea, which broke away about 200 million years ago, according to Monash University.

Gondwana began to break up about 180 million years ago, Collins said. Its eastern part – which includes Australia, Antarctica, India and Madagascar – is separated from its western part, which consists of Africa and South America, according to the Free University of Berlin.

Gondwana broke apart because oceanic crust subducted, or slid, beneath the southern and eastern margins of Asia, falling into the Earth, Collins explained. This oceanic crust drags along the rest of the tectonic plate, and Gondwana’s northern boundary is at the edge of this plate, he said.

East Gondwana, in turn, lost more and more parts over time. “Together as one block, Australia and Antarctica separated from Gondwana about 135 million years ago,” Patrice Rey, a geologist at the University of Sydney, told Live Science.

This block separated from Gondwana because the tectonic plate to the east of this block subducted beneath the block. “This subduction zone accommodates the eastward movement of the Australia-Antarctic block away from Gondwana,” said Rey.

New Zealand was also once part of this breakaway bloc. However, about 100 million years ago, the landmass that now includes New Zealand – a largely submerged continent nicknamed Zealandia – broke away from what is now eastern Australia in part due to massive volcanic activity.

Australia finally separated from Antarctica and became its own continent about 35 million years ago, when the former drifted northward away from the latter, Rey said. This event created the Southern Ocean that currently surrounds Antarctica, Collins said.

Australia is still moving. Shifting at 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 quickly – as fast as your fingernails grow,” Collins said.

In about 20 million to 30 million years, Australia “will likely crash into East Asia,” Collins added. Once Australia collides with Asia, its time as its own continent will end.

2023-12-28 04:08:02
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