Geologists could be looking at the oldest rocks on Earth in northern Quebec, along the eastern bank of Hudson Bay, where they uncovered possible evidence that the Earth’s crust is older that previously believed by several hundred million years. The bedrock is believed to have formed 4.28 billion years ago, not very long after our planet formed.

The report, which appears in Friday’s issue of the journal Science, reveals that the new samples are much older than those previously found in Canada, which were dated 4.03 billion years ago. Jonathan O’Neill of McGill University in Montreal, lead author of the study, explained that the rocks could be remnants of Earth’s crust.

The rocks were found 40 km south of Inukjuak, in the area known as Nuvvuagittuq greenstone belt. Jonathan O’Neill, together with Richard Carlson of the Carnegie Institution for Science in Washington, Don Francis, professor at the McGill University, Department of Earth and Planetary Sciences, and Ross K. Stevenson, professor at the University of Quebec reported the findings.

Some scientists continue to remain skeptical however, and advise us to do the same: University of Colorado’s Stephen J. Mojzsis explained that these rocks could just as well be younger sedimentary rocks that formed from pre-existing rocks.

Scientists have been working on establishing the age of the rocks by analyzing rare elements such as samarium and neodymium, but unfortunately they were unable to find any zircon crystals, which have also been identified in the rocks in Western Australia – there crystals have been dated back 4.38 billion years ago.

But while in Australia, geologists only found isolated zircon crystals, in Canada they found whole rocks that are extremely rare and are almost 300 million years older than those known as the Acasta Gneiss in the Northwest Territories.

If these rocks in northern Quebec are indeed the oldest on Earth, this means that the Earth, which is known to have formed 4.54 billion years ago, cooled down earlier than previously thought. If solid rocks were present on Earth 4.28 billion years ago, it means water was too, which suggests that the molten layer of the planet began to form the solid crust soon after the Earth was formed.

As Richard Carlson from the Carnegie Institution, co-author of the study, explained, the chemical composition of the newly found rocks resembles that of volcanic rocks in geologic settings where tectonic plates are crashing together. This will provide an unprecedented glimpse into the processes that led to the formation of the early crust.

 So far, it’s been almost impossible to find Earth’s oldest rocks due to the fact that the planet’s crust was melted and reformed by plate tectonics. But another issue that scientists are now concerned about is: if Earth offered water and the necessary elements for life to exist, was there life? The question remains unanswered for now, since scientists found no evidence of life forms in the analyzed rocks.