Earth is the only known planet with plate tectonics today. The continuous movement of these huge slabs of rock over the planet’s magma creates continents – and may have also helped in making life.
Today, in a newspaper published in Nature, colleagues and I reveal the mysteries of the Earth’s crust 4.5 billion years ago. In this process, we also provide a new way to contact one of the largest permanent scientific secrets: when did the plate tectonics begin?
Intimately related to the development of life
The Earth is about 4.5 billion years old. Some scientists argue that in its early form, the planet had a lack of plate tectonics and may be characterized by a stable crust (imagining a certain lid) instead – similar to one on Mars.
Others say that it may be characterized by episodic, stop-start tectonics. The latter may have been triggered by major meteorite effects that were generally common, but the number declined over time.
The plate is intimately connected to the composition of the tectonics oceans and the atmosphere as the continuous movement of the plates also moves carbon and other elements. It is also associated with how the heat is released from the Earth’s interior.
Because of this, plate tectonics are also considered associated with the development of life on earth.
A specific chemical fingerprint
The movement of tectonic plates produces volcanic activity on their borders. But in island arcs, such as the so -called ring of fire that surrounds the Pacific Ocean, this volcano has a specific chemical fingerprint similar to today’s average continental crust. For example, the relative element of rare earth elements is the lack of nyobium.
Because of this, scientists have long thought that when the plate tectonics started, the key to determine is to find the first appearance of this fingerprint in ancient rocks.
Unfortunately, the actions of plate tectonics also compress, melts and reproduce the rocks of the earth’s crust. As a result, the ancient rocks are very rare and perhaps there is no remaining from the Hadian Eon (4.5–4 billion years ago).
Interestingly, despite a lot of effort in several decades, the results of such efforts to determine the time of the onset of plate tectonics have resulted in the estimate of age from 800 million to 4.5 billion years.
Such a large range suggests a major problem in the approach.
A new approach
In early 2024, the research team I led tried a new approach. Team was composed of Oxford University, Curtin University, University of Technology, Queensland University and four other researchers at Leon University.
We used mathematical models to simulate the period of the time when the Earth’s core was still being formed and its surface included a ocean of bubbling, melted rock. In particular, we examined the degree of melting of the behavior of chemical elements during the Earth’s early mental – and during this process.
Our results showed the oldest crust of the Earth – known as a polechrust – which is formed during Hudian Eon, will have a chemical composition that is similar to the modern average continental crust.
For example, nyobium is extracted in metal and removed into the Earth’s core, while rare earth elements grow on the surface in magma that are crystallized to create crusts.
Chemical fingerprint was always
The main implications of this discovery are how we think about the early history of the Earth. This means that the specific chemical fingerprint of the Continental crust was always – and was recycled only in island arcs.
It is as follows that this signature cannot be used to determine when the plate tectonics started, explaining why the previous studies could not reach any consensus.
Although the major meteorite effects would have been motivated to melt and reproduce the crust as soon as possible, such procedures would have recycled only the continental chemical fingerprints, not created.
Some of these early major impacts may also have introduced periodic sub -groups – downwards and side -to -tectonic plates, which we eventually fell into the constant, self -sufficient patterns that we finally seen today. However, our study shows when this infection took place, determining it is more complex than the long -term idea and will require new research methods.
There is a need to better understand modeling ahead of the Earth’s initial crust when it has become unstable and began to subdue. So there is a revaluation of its implications for the development of the Earth and the final development of life.
This task also gives us a new way to think about how the continent and life can become on other rocky planets.
(Author: Simon Turner, Professor, School of Natural Sciences, McConi University
(Disclaimer statement: Simon Turner does not work, consults or receives for funding from any company or organization benefiting from this article, and will benefit from this article, and has not disclosed any relevant affiliation beyond their educational appointment.)
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