The geological world is buzzing with news that the oldest rocks on Earth are sitting on a windswept, barren shore in northern Quebec. An international team is reporting the rocks date back almost 4.3 billion years to when the infant Earth was being pummeled by meteors, comets and asteroids. There are also intriguing signs the rocks may carry the “biosignature” of the earliest life to emerge from the primordial seas. “It really puts Canadian geology back on the map,” says geoscientist Boswell Wing, at McGill University, who suspects rusty rock at the site may prove to be evidence of ancient microbial life. But for now it is the rocks’ antiquity that is making headlines. Researchers at McGill, the Universite du Quebec and the Carnegie Institution in Washington report Friday in the journal Science that rock found on the remote eastern shore of Hudson Bay is 4.28 billion years old. “This would make them the oldest rocks ever found on the surface of the Earth,” says McGill’s Jonathan O’Neil, lead author of the report. He has spent the last five summers exploring the Hudson Bay outcropping and hauling chunks of the ancient bedrock back to his Montreal lab.
Rocks from Earth’s early days are extremely rare, and the Quebec find is expected to see plenty of researchers swarm north for a look. “Anything from the first three-quarters of a billion years (of Earth’s history) attracts geologists like flies to dead fish,” says Roger Buick, at the University of Washington in Seattle, who specializes in the planet’s early evolution. He says he would love to get a closer look at the Hudson Bay rocks. The Earth is said to have formed from a cloud of cosmic dust and debris about 4.567 billion years ago. Until now weathered granite in the Northwest Territories, dating back about four billion years, has held the title of the world’s oldest rock. The Hudson Bay rocks appear to be about 300 million years older and scientists say they should provide clues about not just early geological processes, but also Earth’s early atmosphere, and perhaps even the microbes that are thought to have interacted with iron in the early oceans to create rusty sediments. Mike Carroll, general manager for the Pituvik Landholding Corporation that oversees use of the land for the Inuit, says the scientists gave the community the heads-up about the discovery when they passed through Inukjuak this summer. The corporation’s board of directors is now mulling over how best to manage the site. Everything from a “possible moratorium” on visitors to prevent abuse of the geological treasure, to incorporating a visit to the ancient rocks as part of a tourism package are up for discussion, says Carroll. (Source: Canwest News Service)