Studying samples of the chemical element europium embedded in zircon crystals is a curious way to find out what the Earth’s crust looked like millions of years ago .
Thanks to a new study that takes this approach, we can deduce that our planet was mostly flat, that the crust was thinner than now, that there were probably not even mountains.
But how do we know about the crust by studying a single chemical element? Because the amount of europium found in such crystals can be used to reveal the thickness of the earth’s crust at the time of crystal formation. The more europium in the crystal, the more pressure was exerted from above, suggesting a thicker crust.
They found evidence to suggest that during Earth’s middle period, the crust was thinner, more uniform than it is now .
So the planet was covered by oceans and flat land masses. Such conditions suggest that tectonic activity must have drastically decreased or stopped altogether for about a billion years. The researchers also point out that the tectonic activity that pushes the mountains towards the sky and the consequent erosion would have enriched the environment in the oceans, making the evolution of life possible.
Without such cycles, evolution would have slowed drastically, which previous research has shown occurred during Earth’s mean period.
Previous research has suggested that roughly 1.8 billion years ago , the Earth went through a lull in which the evolution of life slowed dramatically. In this new effort, the researchers suggest that the reason for the slowdown was the absence of tectonic activity.