Australia is not only the smallest continent but also the largest island on earth. But the land below is not always isolated; It was once part of a larger supercontinent. So when did Australia become its own continent?
Australia's Continental Land Activities About 2,300 miles (3,700 km) from north to south and 2,485 miles (4,000 km) from east to west. Within its 2.97 million square miles (7.69 million square kilometers), Australia is home to the oldest terrestrial resource on Earth: zircon crystals from the Jack Hills region of Western Australia, some 4.4 billion years old. According to a 2014 study in the journal Nature Geoscience.
Australia's oldest regions are three continental-scale rock fragments called 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 is made up of rocks formed on the edge of older parts of the continent over the past 500 million years.
Australia was once part of a much larger land mass called Gondwana, which now includes Africa, South America, Antarctica, India and Madagascar. Gondwana was once part of the supercontinent MiracleIt split about 200 million years ago. According to Monash University.
Gondwana began to split about 180 million years ago, Collins said. Its eastern part – which includes Australia, Antarctica, India and Madagascar – separates from its western part, which is made up of Africa and South America. According to the Free University of Berlin.
Related: Is Africa splitting into two continents?
Gondwana broke up as the oceanic crust plunged deeper under the southern and eastern margins of Asia. Earth, Collins explained. This oceanic crust dragged the rest of it away Tectonic plate Along with that, the northern edge of Gondwana was at the other end of this plate, he said.
East Gondwana lost more and more areas over time. „As a single block, Australia and Antarctica separated from Gondwana about 135 million ago.” Patrice Raygeologist at the University of Sydney, told Live Science.
This block was separated from Gondwana because a tectonic plate east of the block was subducted under the block. “This sub zone allowed the eastward movement of the Australia-Antarctica block from Gondwana,” Ray said.
New Zealand was once part of this breakaway bloc. However, about 100 million years ago, the landmass that now includes New Zealand — often called the submerged continent of Zealandia — Now separated from Eastern Australia Due to major volcanic activity.
Australia eventually separated from Antarctica and became its own continent about 35 million years ago, when the former moved north from the latter, Ray said. This event created the Southern Ocean that currently surrounds Antarctica, Collins said.
Australia is still moving. Australia is the planet's fastest-moving tectonic plate, oscillating about 2.75 inches (7 centimeters) per year, wrote Australian scientists Chris Risos and Donald Grant. A 2017 piece on the conversation.
„Australia is moving north very fast – as fast as your fingernails grow,” Collins said.
Collins added that in about 20 million to 30 million years, Australia „is likely to bypass East Asia”. Once Australia collided with Asia, the era of its own continent would end.