It is difficult to understand what Earth might have looked like in the early years before life appeared. Geological explorers have now gained ample evidence that the ancient Earth was very different from the one we live in today. According to a new analysis of the characteristics of the Earth’s mantle over its long history, our entire world has been submerged by a vast ocean, with little or no land mass.
So where has all the water on Earth gone? According to a team of researchers led by Harvard-led planetary scientist Junjie Dong, minerals deep inside the crust are slowly eroding the oceans of ancient Earth and leaving behind what we are available today.
“We calculated the capacity to store water in the solid mantle of the Earth,” the researchers wrote in the article. We found that the water storage capacity in the early mantle may be less than the amount of water the Earth’s mantle currently contains, so additional water in the current mantle would exist on the Earth’s surface. , ancient and forming larger oceans. Our results suggest the long-held hypothesis that the volume of surface oceans which is nearly constant over geological time may need to be reassessed.
It is believed that large amounts of groundwater are stored as compounds of the hydroxy group – made up of oxygen and hydrogen atoms. In particular, water is stored in two high pressure forms of the volcanic mineral olivine, hydrated wadsleyite and ringwoodite. Wadsleyite samples deep underground may contain about 3% H2O by weight; ringwoodite about 1%.
Previous research on two minerals has placed them under the high pressure and temperature of the current earth’s crust to find this storage capacity. Dong and his team saw another possibility. They compiled all the physical data on the available minerals and quantified the water storage capacity of wadsleyite and ringwoodite over a wider temperature range. The results showed that both minerals have a lower storage capacity at higher temperatures. Because the Earth is small, formed 4.54 billion years ago, the interior is much warmer than it is today (and its internal heat is still decreasing, very slowly and completely unrelated to its external climate. It), which means that the water storage capacity of the Earth’s mantle is now higher than it was before.
Additionally, as more and more olivine minerals crystallize in the earth’s magma, the mantle’s water storage capacity will also increase in this way. Overall, the difference in water storage capacity would be significant, although the team was careful in their calculations. The large water storage capacity of the Earth’s solid mantle was significantly affected by the temperature-dependent storage capacity of the constituent minerals, the researchers wrote.
The researchers found that if the amount of water stored in the current mantle was greater than its capacity in the Archean Aeon 2.5 to 4 billion years ago, then the world could end up in a state of distress, flooding, the researchers found.
This finding is consistent with an earlier study which found, based on an abundance of certain oxygen isotopes stored in the geological records of the early oceans, that the Earth is 3.2 billion years old. There was less land in the past than today.
If so, it could help us answer some scathing questions about other aspects of Earth’s history, such as where life first appeared around 3.5 billion years ago. There is an ongoing debate as to whether life first formed in saltwater oceans or freshwater ponds on land; if the entire planet were submerged by the ocean, it would solve this mystery.
In addition, the results can also help us search for extraterrestrial life. Evidence suggests that ocean-covered planets are abundant in our Universe, so finding signs of these “soggy” planets could help us identify the planets. There could be life.
