World’s oldest volcanic rocks found near Inukjuak

ODILE NELSON

Inukjuak is poised to become a geological hotspot after a scientific team announced this week they have discovered the world’s oldest volcanic rocks in a nearby cove.

Researchers from the University of Montreal, the Quebec Ministry of Natural Resources and Simon Fraser University in British Columbia discovered the rocks — estimated to be more than 3.82 billion years old — 30 kilometres outside Inukjuak during routine mapping last year.

But it was not until this spring, after geologists had conducted repeated tests of the rock’s radioactive isotopes to discover their precise age, that geologists recognized their find’s significance.

Most volcanic rocks in the Inukjuak area are between 2.7 billion and three billion years old.

The world’s oldest known volcanic rocks, discovered in the 1980s in Isua, Greenland, date back 3.82 billion years.

“It’s not the discovery of diamonds. It’s not the discovery of gold. But researchers have been going back to Isua since the rocks were discovered 20 years ago,” Dr. Ross Stevenson of the University of Quebec’s department of earth and atmospheric sciences, said this week. “I suspect people will be going back for years to come. It’s part of an intriguing puzzle about the Earth’s history.”

The Inukjuak volcanic rocks could give a little more shape to this immense puzzle. They could help geologists learn more about the formation of the Earth’s crust and mantle layers billions of years ago and they could also help determine when life on Earth started.

According to Dr. Stevenson, before scientists discovered the Isua rocks, geologists had no proof life existed on earth 3.82 billion years ago. But the Isua rocks suggest that bacteria may have been present when the rocks first formed.

If the Inukjuak rocks display similar evidence, Dr. Stevenson said, the Isua finding would be supported.

Scientists currently estimate the Earth is 4.6 billion years old. Older non-volcanic rocks have been discovered previously by geologists in the Northwest Territories. They were estimated to be 3.96 billion years old.