Oldest Evidence of Plate Tectonics Discovered

via ScienceDaily.

Some of the oldest rock formations on the planet, discovered in the 1960s in Greenland and dating back to 3.8 billion years ago, and long been known to contain the oldest known living organisms, have yielded new secrets. A recent new analysis of these formations show that they also contain evidence that proves conclusively that Plate tectonic processes were already acting on the Earth at that time, over a billion years earlier than previously thought. The formation was originally part of the Atlantic ocean seafloor, and shows evidence of basalt lava flows from the same mid-ocean ridge that still flows today, responsible for the volcanic activity in Iceland.

"The study focuses on an area near the southwestern coast of Greenland where there is a rare outcrop of ancient rock, called the Isua Supracrustal Belt, which have been dated at 3.8 billion years old. The Isua rocks are ophiolites, which have a green hue from the chlorite minerals within them and are found in all major mountain belts, usually located in areas associated with volcanism and plate tectonics."

The importance of the new analysis is that the same geologic processes that operate today, like seafloor spreading and ocean crust formation, have been operating since very early in Earth's history and that such formations accrete to continental landmasses. In addition, these formations are also helping to settle a scientific dispute regarding the oxygen content of ancient seawater, which appears to be very similiar or just a bit heavier than current oceans. Both the oxygen content of the oceans and the geologic processes underway at such early dates have serious implications for other scientists theorizing on the origins of life on Earth.