Only 800 million years after the formation of the Earth, the first land masses have already appeared.
We know that the Earth formed about 4.5 billion years ago. Between 4.4 and 4.2 billion years ago, the first oceans appeared that covered the entire crust of the Earth. But when did the Earth first rise above sea level? Dutch researchers are now lifting a corner of the veil.
The first land masses
In the new study, published in Nature Geoscience, geologists examined the emergence of the first important land masses. This leads to a surprising result. For example, it seems that the first country on Earth appeared about 3.7 billion years ago. That was a billion years earlier than thought. Moreover, this means that the first state appeared only 800 million years after the creation of the Earth.
Researchers rely on analyzes of ancient rocks. “We cannot look back in time to the first country,” researcher Paul Mason explains. But we can find traces of it stored in ancient rocks. We have examined the minerals that were deposited from seawater and have stored information about those first bits of exposed land.”
Scientists believe that the first mountain ranges on Earth may have been formed primarily of granite rocks. Granite has a relatively low density, as it easily rises above other rocks on the sea floor. So the researchers explained in this matter. Granite is rich in rubidium, which can make a new isotope of strontium through radioactive decay. “We can then see from the ratio of strontium isotopes in seawater whether it comes from exposed granite rocks,” explains research leader Desiree Roerdink. “In other words, from land above sea level.”
However, it is no longer possible to trace the composition of seawater from the past. Therefore, in their study, the researchers used an indirect method of analyzing seawater billions of years ago. They studied barite, which is formed at the bottom of the sea. Barite captures strontium from seawater and thus contains a fingerprint of isotopes that were originally washed out from those first land masses.
The research led to the startling discovery that the first Earth on Earth arose much earlier than was thought. The minerals under investigation, which were found in present-day South Africa, India and Australia, were subsequently preserved unchanged for 3.5 billion years.
Earth’s oldest traces
But Mason has an important caveat. “Note that we are talking about the oldest traces of Earth that have been recovered here,” Nuances. “This does not mean that there was no land above sea level before. There may have been islands in the oceans more than 3.7 billion years ago, but they were simply too small to leave traces after they eroded and disappeared.”
In addition, the results also do not indicate that present-day South Africa, India, and Australia are the oldest land masses. “Only those areas contain traces of those ancient rocks,” Rordink says. “Earth’s crust is constantly changing. Continents are moving or disappearing or emerging. And a piece of rock that you now find somewhere may have formed on the other side of the Earth.”
In addition to re-establishing the history of the first country on our planet, the study also provides important information about the origin of life, Rordink emphasizes. “Erosion of the rocks has provided the oceans with essential nutrients, such as phosphorous,” she says. “Thus the geological and biological evolution on the early Earth were inextricably linked.”
Zombie specialist. Friendly twitter guru. Internet buff. Organizer. Coffee trailblazer. Lifelong problem solver. Certified travel enthusiast. Alcohol geek.