Changes of earth until 2.4 billion years ago
Geologists from University of Oregon uncovers that, 2.4 billion years ago the Earth was simply a substantial waterway. Later, land rapidly rose out of the ocean and triggered dramatic changes in life and atmosphere.
According to researchers, the earth’s crust made of different types of rocks which form continents, and Earth’s interior close to the shores. But, one major mystery remains how old the crust is?
To solve this mysterious science study, geologists tested the sample of Earth’s most common sedimentary rock, shale, and analyzed the triple-isotopes of oxygen inside the rock. The isotopes contain the traces of rainwater that caused weathering of land from 3.5 billion years back.
Earth’s first super continent
Also, the chemical signatures in the shale rock pointed to a rapid rise of land. When land started to emerge from the water, the Earth’s first super continent, Kenorland is formed.
While, the previous studies proposed a slow development of land about 1.1 and 3.5 billion years ago. But, isotopic changes recorded from the shale sample point to a rapid rise of land above the ocean 2.4 billion years ago.
Lead author Ilya Bindeman, said, the crust layer should be thick to stand out of the water. The thickness depends on its amount and on thermal regulation and the viscosity of the mantle. At the point the Earth was hot, and the mantle was soft, large, tall mountains couldn’t upheld. Our information demonstrated that this changed exponentially 2.4 billion years ago. The cooler mantle could bolster expansive swaths of land above sea level.
The present land exposed to weathering by chemical processes at 2.4 billion years ago and began to consume CO2 from the atmosphere. The timing also coincides with the change of life from basic prokaryote in the Archean Eon to the eukaryotes, such as algae, plants and parasites in Proterozoic Eon.
