Three billion years ago, the Earth was completely covered by the ocean

What did Earth look like 3.2 billion years ago? Recent evidence indicates that it was entirely covered in ocean and there was not a single continent on it.

According to researchers from the Universities of Iowa and Colorado, the continents later appeared when tectonic movements pushed massive masses of land upwards until they rose above the ocean's surface.

Evidence of this early Earth history was found in the petrified portion of the ocean floor in northwestern Australia.

4.5 billion years ago, our planet was formed as a result of collisions of dust particles and rocks orbiting the sun that had just been formed. Initially it was only a hot, melted magma ball, thousands of kilometers deep. Over time, 1,000 - 1,000,000 years later, the first minerals formed in the cooling magma.

Water could come to Earth with comets from outer regions of the Solar System and with dust filling the surroundings of the young Sun.

When the Earth was still covered with a hot ocean of magma, water vapor and gases could be in the atmosphere of the emerging planet. As the surface temperature decreased, the water gradually condensed on the surface.

We cannot say what was the source of water on Earth, but we point out that, regardless of the source, the water was present in the atmosphere while the magma ocean was still floating on the surface, '' says Benjamin Johnson of the Department of Geological and Atmospheric Sciences at the State University of Iowa.

In his latest research, Johnson and colleagues focused on the unique Australian outback landscape. It is there that traces of the hydrothermal system from 3.2 billion years ago and layers of the oceanic crust reaching from the surface to the heat source that fueled the circulation are preserved.

It is there that the different layers of the ocean floor contain different oxygen isotopes. The change in the ratio of the number of individual isotopes over time allows scientists to reproduce the temperature changes of the former oceans and climate on Earth.

During the analysis of over 100 sediment samples, the scientists came across something unexpected.

It turned out that 3.2 billion years ago, the oceans had more oxygen-18 than oxygen-16 (now the opposite is true). Computer models indicate that on a global scale, continental masses are sucking oxygen-18 from oceans. However, if there were no continents, there would be more of this isotope in the ocean. The ratio of the abundance of these two isotopes of oxygen indicates that there were no continents on Earth more than three billion years ago.

These values ​​differ from modern ones so much that they can be easily explained by the total absence of continents - adds Johnson.

Other scientists also pointed out earlier that perhaps the Earth was once completely covered with water. The studies described above provide us with real geochemical limitations on the number of lands above sea level.

The possibility that the Earth was once a water world puts in a completely new light the question of where the first life forms on Earth originated and how they evolved.

There are two main currents of thinking about the creation of life on Earth: hydrothermal chimneys and water tanks on land. If the research published now is confirmed, it means that there was very little space for life on land before 3.2 billion years ago.

Three billion years ago, the Earth was completely covered by the ocean