Oldest evidence of a moving tectonic plate found in Australia

[FfFfFfFF 58,135]

 In the desolate landscape of western Australia, a rocky outcrop that formed more than three billion years ago is giving geologists an unprecedented look at the early churnings of our planet. These rocks—among the most ancient in the world—contain what may be the oldest direct evidence of the movement of tectonic plates.

The rocks formed when magma oozed up from beneath Earth’s surface into a now-vanished ocean, cooling and hardening into a bulbous mass. As detailed in a new study in Science Advances, magnetic signatures preserved in the rock suggest the region was inching across the planet 3.2 billion years ago at similar speeds to tectonic plates today—nearly half a billion years earlier than previous evidence of such movement.

The team compared the calculated position of the Honeyeater basalt to a previously analyzed outcrop of rock nearby, which is slightly older and contains an earlier magnetic signature. The analysis revealed that the crust was shifting about 2.5 centimeters each year at the time these rocks formed. 

By understanding the origins of plate tectonics, “you can try to nail down timing of events that were crucial for the development of life on this planet,” says geochemist Val Finlayson from the University of Maryland, who was not part of the study.

To do that, scientists are continuing to scour the earth for more signs of ancient movement. Brenner says: “We are actually, as we speak, running through the data analysis for another [rock] unit."

 

Source: https://www.nationalgeographic.com/science/2020/04/oldest-direct-evidence-plate-tectonics-found-australia/