Very recently, scientists have just discovered volcanic rocks under Baffin islands in the Canadian Arctic that suggests these are the oldest type of rock discovered on Earth thus far. This geochemical evidence suggests that the mantle beneath these islands is a region that has escaped the billions of years of melting and geological churning that has affected the rest of the planet. After more research, geochemists believe that this discovery reveals clues to the early chemical evolution of the Earth. The new recently discovered rock is referred to as mantle “reservoir.” It is shown that this rock dates back to just a few tens of millions of years after the Earth was assembled. This volcanic rock reservoir represents a composition of the mantle shortly after the formation of Earth’s core.
Extended research then confirmed that the reservoir dates between 4.55 and 4.45 billion years old, which is only slightly younger than the Earth itself. This evidence proves that this rock has existed before melting of the mantle began to create the magma’s that formed Earth’s crust today. It also implies that this reservoir of rock formed before plate tectonics began.
I think it’s incredible that researchers are still able to find and date types of rocks all the way back to plate tectonics. Hopefully this new information will lead to more discoveries and possibly help on research of the formation of the core and mantle.