New research by analyzing ancient fragments of our planet's rocks provides some of the strongest evidence that Earth's crust at least
New research by analyzing ancient fragments of our planet's rocks provides some of the strongest evidence that Earth's crust at least <3.25 billion years ago, it was being compressed and stretched in a manner similar to today's plate tectonics. The study also provides the first evidence of when our planet's magnetic north and south poles switched positions. These two results are actually clues as to how such Geological changes could have led to a more favorable environment for the evolution of life on planet Earth.
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This research is led by "Alec Brenner" and "Roger Fu" (Harvard University geologists, whose results It was published in the Proceedings of the National Academy of Sciences of the United States of America (PNAS), on a part of the Pilbara Craton in Western Australia, which is one of the oldest and most stable parts of the Earth's crust. It was focused. Using new techniques and equipment, researchers have shown that some of the earliest parts of the Earth's surface moved at a rate of 6.1 cm per year and 0.55 degrees per 1 million years.
This speed is more than It is twice the speed of the ancient crust that was shown in the previous study by the same researchers. Both the speed and the direction of this transverse thrust, consider plate tectonics as the most logical and strongest explanation for this issue.
Brenner said in this context. : "Many studies show that, contrary to today's situation, in the early history of the Earth, plate tectonics, during which the internal heat of the planet is released through the movement of plates, was not the dominant method. This evidence helps us more confidently reject explanations that do not involve plate tectonics."
For example, these results contradict theories called "True Polar Wander" and " 'Stagnant Lid Tectonics', both of which can cause land surface movement, but are not part of modern-style plate tectonics. The results lean more toward plate tectonic movement, the newly discovered higher speed, which is inconsistent with aspects of the other two processes.
In this paper, scientists also present what is believed to be the oldest evidence of It is described as the time when the earth was reversing its geomagnetic fields. During periods of Earth's history, the position of the magnetic north and south poles has changed. According to NASA, this type of shift is a common occurrence in Earth's geological history, and in the past 83 million years, the magnetic poles have reversed 183 times, and perhaps several hundred times in the past 160 million years.
This information reversal It tells a lot about the planet's magnetic field 3.2 billion years ago. The key to these events is that the magnetic field was probably stable and strong enough to prevent the solar wind from eroding the atmosphere. This view, together with the results of plate tectonics, gives clues as to what the ideal conditions were for the emergence of early life forms.
Brenner pointed out: "These results paint the picture of the early Earth." which has been really mature in terms of geodynamics. Many similar dynamic processes have been going on and ultimately resulted in an Earth that had fundamentally more stable environmental and surface conditions and made the evolution and development of life more possible. or plates are formed that hold the continents and oceans of the planet. Over the millennia, the plates moved closer and further apart. In this way, they formed new continents and mountains and exposed new rocks to the atmosphere, which led to new chemical reactions and stabilized the temperature of the Earth's surface over billions of years.
The plates of the earth's crust
Credit: Earth How
From the beginning of plate tectonics Earth, evidence is hard to come by because the oldest pieces of crust are pushed into the Earth's inner crust and never resurface. Only 5% of rocks on Earth are older than 2.5 billion years, and no surface rocks are older than 4 billion years.
Overall, this study adds to the research. There is a growing body of evidence that suggests a relatively early tectonic movement in Earth's 4.5-billion-year history led to the emergence of early life forms in a more temperate environment.
Members of this project in 2018 Visit the Pilbara craton, which stretches for about 480 km, and collect samples by drilling on the primary slab and thick crust. used magnetometers, demagnetization equipment, and a quantum diamond microscope, which images the magnetic fields of a sample and precisely identifies the nature of the magnetized particles, using new techniques. created to determine the age and method of magnetization of the samples. This will allow them to understand how, when, and in what direction the crust, as well as the effect of the Earth's magnetic poles, have shifted. (EPS) and Faculty of Physics has been built. For future studies, Fu and Brenner will keep their focus on the Pilbara shell, while also exploring other ancient shells from around the world. They hope to find older evidence of modern plate motion and when the Earth's magnetic poles rotated.
Fo pointed out: "Being able to reliably read these very ancient rocks opens up many opportunities to observe a It opens up a period of time that is often known based on theory rather than real data. He added: Finally, we'll have a good picture of not only when the tectonic plates started to move. , but to reconstruct the way they change in motion and therefore change the Earth's internal processes over time."
Cover photo: A graphic design of the Earth's magnetic field
Credit: Alec Brenner