Oldest Rocks on Earth Discovered – They Are More Than 4 Billion Years Old

Greenstone – the oldest rock formation ever discovered. Image credit: Inuit Adventures
The Earth is about 4.54 billion years old, but most of its original crust has been recycled by plate tectonics and eroded by weathering. Finding the oldest rocks on Earth is a challenging task that requires careful dating techniques and rare geological conditions. One of the most promising sites for this quest is the Nuvvuagittuq Greenstone Belt (NGB), a sequence of metamorphosed volcanic and sedimentary rocks located on the eastern shore of Hudson Bay, 40 km southeast of Inukjuak, Quebec.

The NGB was first mapped in 1965 by the Quebec Ministry of Natural Resources, but it remained largely unexplored until the 2000s, when preliminary reports of uranium-lead dating on zircons found in granitic intrusions that cut portions of the belt gave an age of about 3.75 billion years. This was already remarkable, as it made the NGB one of the oldest known rock formations on Earth, but further studies suggested an even more astonishing possibility: some parts of the NGB could be as old as 4.28 billion years, making them the oldest known rocks on Earth.