Thousands of kilometres long old crust discovered floating under Australia.

A section of the Earth’s crust that is four million years old and the size of Ireland has been discovered floating beneath Western Australia.

The crust is ‘tens of kilometres’ deep and covers an area of at least 38,610 square miles (100,000 square kilometres), according to research that was published online in the journal Terra Nova on June 17.

The crustal fragment is one of the oldest on Earth at 4.54 billion years old, making the entire planet 4.54 billion years old.

According to Space, the oldest rocks are those of the Canadian Shield, which are found on the eastern shore of Hudson Bay and are 4.3 billion years old.

The majority of Earth’s rocky surface was developed within the last few billion years as a result of plate tectonics, which frequently stirs up and pushes the planet’s crust back into the mantle.

Near Australia’s Jack Hills, where zircons, tiny minerals with an estimated age of 4.4 billion years, are also present, researchers have found evidence of the crust. They are the oldest materials ever discovered on Earth as a result.