Geologists have shed new light on how continents formed


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An international research team found that the first continents were unstable and were recycled into the Earth’s interior, in the mantle.

Research published today in Proceedings of the National Academy of Sciences (PNAS), is important because it provides important clues about how planets formed.

“The rocks in the cores of the continents, called kratons, are more than three billion years old,” explains lead study author Professor Fabio Capitanio of Monash University’s School of Earth, Atmosphere and Environment.

“They were formed at the beginning of the Earth and they hold the secret of how the continents and planet have changed over time.”

Researchers used high performance Computer modeling to simulate the evolution of the first billions of years on the planet.

They found that the first continents were unstable and recycled into the Earth’s mantle.

Once the early continental masses were in the mantle, they were melted, stirred, and mixed until they disappeared.

Researchers have found that some pieces of the original rock can remain in the mantle for billions of years but eventually return.

“Our work is important in two respects,” said Associate Professor Capitanio.

“First of all, kraton is where important minerals and other minerals are stored/found.

“And second, they tell us how planets formed and changed in the past, including how continents arose and how they supported life, and how the atmosphere formed and changed as a result of planetary tectonics.”

Over time, the recycled pieces of continent It can build up under the new lithosphere, making it more buoyant and strong enough to stop further recycling.

The study is unique because it explains how the continents are grouped together.

Numerous observations of ancient continental cores, called cratons, show that they are much more complex and heterogeneous than today’s lithosphere. However, scientists did not know what caused the differences or how they formed.

The study shows that parts of the CLM remain in the mantle as diffuse and depleted heterogeneities at multiple levels that can persist for billions of years.

The conversion works best at high degrees of depletion and cloak Temperatures similar to those of the early Earth. This results in the upsurge and reduction of large amounts of faltering CLM, which is referred to as massive regional relocation (MRR).

MRR explains the complex source, age, and depleted heterogeneity found in ancient CLM. This suggests that this may have been an essential part of building the continents in the early Earth.

Study finds devastation-prone continents in their infancy

more information:
Accumulation of cratonic mantle lithosphere via massive regional relocation, Proceedings of the National Academy of Sciences (2022).

Introduction of
Monash University

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