Melbourne: A fragment of ancient Australia under Vanuatu has been found out by researchers, raising questions about how continents are formed.
A team of scientists at James Cook University believed Vanuatu's geological basement contains ancient material from northern Australia, AAP news agency reported.
The team found that volcanic rocks from Vanuatu contained tiny crystals of zircon, carried up in magma from the depths by the volcanic plumbing systems.
It was thought that volcanic Vanuatu islands, about 2200km east of Townsville, were isolated from continental influences.
With the help of the state-of-the-art radiometric dating techniques, the crystals were dated at up to three billion years old and the range of ages of those crystals closely matches the age of rocks that make up northern Australia.
Carl Spandler, one of the study's author said the zircon "shouldn't be there", and its presence has major implications for how scientists understand continents are made, the report said.
"There is nothing else like it in the south west Pacific," Spandler said adding "Just because island chains or land masses may be far removed from each other today, doesn't mean that they always were. This calls for a rethink of how we calculate the rates and processes of generating new crust on Earth."
The fragment of Australian crust now under Vanuatu is believed to have separated from the mainland prior to the Cenozoic Era, around 100 million years ago, the report said.