Sydney, Oct 27 (IANS/EFE): The discovery of fragments of Australia in the subsoil of the volcanic Vanuatu island in the South Pacific raises new questions on how continents are formed, an Australian university said Monday.

A study by the James Cook University has found tiny crystals of zircon belonging to Australia in the subsoil dating back to up to three billion years that "shouldn't be there", according to one of the authors, Carl Spandler.

Geologists had so far believed that Vanuatu island had no continental influences.

"The age of the zircon crystals of Vanuatu is almost the same as the age of rocks that make up northern Australia," said the study's co-author in a statement.

According to the study, the fragments must have separated from Australia 100 million years ago, prior to the Cenozoic era in which the continents came to occupy their current positions and when Australia and New Guinea broke off from Gondwana and Antarctica was situated on the South Pole.