In a new study, scientists have found that the first continents on the planet were unstable and
Many observations of cratons show thatthey are much more complex and heterogeneous than modern lithosphere. However, scientists did not know what caused the differences or how they formed. The study shows that parts of the cratonic lithospheric mantle still exist in the mantle as dispersed, depleted heterogeneities at different scales that may persist for billions of years.
Rocks at the core of continents—cratons are more than three billion years old. They formed on the early Earth and store information about how the continents and the planet changed over time.
To "extract" this data, scientists usedhigh-throughput computational modeling to simulate the evolution of the planet over its first billion years. They discovered that the first continents were unstable and were being recycled in the Earth's mantle. In other words, the ancient planet “chewed” them.
Once the early continental blocks werein the mantle, they melted and mixed until they disappeared. In addition, the researchers found that parts of the original rocks may remain in the mantle for billions of years.
Over time, recycled "pieces" of the continent can accumulate under the new lithosphere, making it more buoyant and strong enough to stop further "recycling."
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Cover photo: CC0 Public domain