These giant stones are in the Earth’s crust just above the mantle. We can see the results of the movement and brittleness around, from the formation of mountain ranges to earthquakes and volcanic activity.

The new research is based on new geochemical models of the early Earth using argon (Ar) as a measure. Because argon is too heavy to leave the atmosphere, we can use it as a way of studying back in time in the planet’s history.

Argon gas is released as part of continental growth caused by sinking (one plate pushes down to another), a major indicator of tectonic activity. As argon accumulates, it can be used to track the radioactive decay of potassium in the planet’s crust and coating, and then tectonic movements.

"Our model is the first to explore the full implications of the evolution of the crust on Earth’s degassing history," the researchers said.

The recycling of the Earth’s crust (where the eroded crust is then brought back underground) as well as the creation of a new continental crust is one of the important considerations for researchers. Their model shows that the tectonic network has been around for more than 4.4 billion years ago, far exceeding most previous estimates.

Assessing the geological history of the Earth is a difficult task. We are not sure exactly what is happening in terms of tectonic activity today, let alone billions of years ago. However, argon measurements may be our best option for moving tectonic plates.

"Due to the special characteristics of argon, we can deduce what happened to Earth by studying this atmospheric argon," said planetary scientist Jun Korenaga, from Yale University.

In fact, this is not the only evidence that comes to light that tectonic plates have existed for more than 3 billion years or longer. Studies have had similar estimates with ancient rocks in Australia and South Africa pushing back a period of several hundred million years.

The change from molten rock to solid crust is important not only for research on early Earth but also for early life forms.

"When plate tectonics research started on Earth has long been a fundamental problem, if we go back in time, we will have fewer geological records." Korenaga emphasized.