Earth Was Once the Water World

Earth's land is surrounded by water. But the landmass was once beneath a global ocean, and it was a Waterworld.

The Earth has not always been like it is today. Many million years ago, when it was young, it had a different look. It had massive landmasses where we live now. As a result of tectonic movements, the landmasses dispersed.  

But before that, there were little or no landmasses on Earth! At that time, the Earth was nothing but a soggy water world. New research confirms the Earth's state.

Our world is 4.5 billion years old. According to the geologic records, the Earth was covered with a vast global ocean 3.2 billion years ago.

It is an important finding that can resolve many emerging questions on how life started 3.5 billion years ago. It will also clarify whether life started in freshwater, landmasses or salty seas. The question remains valid if there are no landmasses to hold freshwater. 

Boswell Wing, a geobiologist from the University of Colorado Boulder says, "The history of life on Earth tracks available niches. If you've got a water world, a world covered by ocean, then dry niches are just not going to be available."

The ever-evolving question on the temperature of the early Earth seemed challenging to solve. So, the research team started examining that. It is not clear whether it was warmer, cooler or just like the same temperature as it is today in consideration to life emerging. 

There are two isotopes in oxygen that occurs because of the variation of the element. This variation in these isotopes molecular weights may have a link with the temperature of the Earth's ocean in ancient time. The study shows that water with a lower temperature contains a higher amount of oxygen-16 in comparison to oxygen-18. The order alters in water with a higher temperature. 

It is nearly impossible for the researchers to find out 3.2 billion years old seawater to continue proper analyze. But they had rocks of that period beneath the ancient oceans. For example, they collected rocks from the Panorama District in the Pilbara region in Western Australia. The stones are essential elements as they contain the chemical history of the oceans. 

With this rock, researchers reconstructed the 3.2 billion years old temperature profile. But after this, they found that oxygen-18 was present in a number that exceeds their earlier expectation. The amount was 3.3 percent, that is 4 percent more in comparison to today's relatively ice-free ocean. It is much higher than it was thought previously.   

A similar study held back in 2012 shows the same results—the presence of oxygen-18 in oceans 3.8 billion years ago. The range of that time was 0.8 to 3.8 percent.

Though the differences are small, they can influence landmass as molecular weight fluctuations are sensitive to the landmass. Large land areas like the continent-sized ones do slurping jobs. The soil of that area can slurp oxygen-18 from the water.

The team opines after completing their model that rock samples with different ratios are the result of a lack of continents. It also clarifies the Earth was not entirely wet at that time. Instead, it could have been much, much soggier than Earth is right now.

Wing continues, "There's nothing in what we've done that says you can't have teeny, micro-continents sticking out of the oceans. We just don't think that there was a global-scale formation of continental soils like we have today."

The team published the research in Nature Geoscience. With answering one question, they now face another. Now they need to find out when the continents started to emerge with the movement of tectonic plates. They need further research for this. For this, the team now focuses on the younger rock formations.