The Earth was a world of water, it was covered by a single global ocean without or with very little land, about 3.2 billion years ago: this is the interesting conclusion reached by a team of researchers from the Iowa State University.
The geologists have in fact analyzed the exposed oceanic crust, dating back precisely to this period in the history of the Earth, present in Australia and have realized a model which indicates that, in this distant period, the primordial Earth had all its continents submerged.
This approach could also have important consequences for the origin of life on Earth. If this condition was in fact present even when life on earth was born, the very origin of life itself should be reassessed and some of the most accepted models today could be set aside.
“Without continents and land above sea level, the only place where the first ecosystems would have evolved would have been in the ocean,” the researchers report.
The pieces of oceanic crust analyzed by the researchers date back to the Archean eon, a period of the Earth between 4 and 2.5 billion years ago.
Benjamin Johnson, along with colleagues including Boswell Wing, analyzed the oxygen isotopes of these rocks and the temperature values he found suggest that seawater in this ancient period was enriched with about 4 parts per thousand more than water in today’s seas with a heavy oxygen isotope.
Finding that the ratio between two different isotopes of oxygen trapped in rocks was very different 3.24 billion years ago, researchers came to the conclusion that there were no emerged continents.
Today, in fact, the mainland absorbs heavier oxygen isotopes from the water through atmospheric agents, something that does not seem to have happened in that distant period.
According to geologists, that is, it can be explained in the fact that there was not enough land to suck up these isotopes. That doesn’t mean that there wasn’t any land area in the world. There may have been, for example, microcontinents during this period, but they were not large enough to absorb heavy oxygen isotopes from the seas as they do today.
The question then arises: when did the action of Earth’s tectonics bring forth the first true continents? Interesting question here the same researchers promise to answer through new analyses of old oceanic crusts in other areas of the world.
Latest posts by Eduardo Vera (see all)
- Drug prices rose three times faster than inflation in the US - June 25, 2020
- Everlywell - June 12, 2020
- Dietary drinks consumed with carbohydrate-rich meals can have adverse effects - June 9, 2020