(ORDO NEWS) — Plate tectonics on Earth began about 3.25 billion years ago, according to a new study published in the scientific journal PNAS.
The researchers also found the oldest evidence of the event when the north and south magnetic poles of the Earth switched places.
These two discoveries point to how such geological changes have created a planet with a more favorable environment for the emergence of life.
The study was carried out in the Pilbara Craton region of Western Australia by Harvard geologists Alec Brenner and Roger Fu. This region contains one of the oldest and most stable parts of the earth’s crust.
Using innovative methods, including magnetometers, degaussing tools, and a quantum diamond microscope, geologists have been able to figure out how, when, and in what direction the crust moved, as well as the magnetic influence emanating from the Earth’s magnetic poles.
They found that part of Earth’s oldest surface was moving at a rate of 6.1 centimeters per year and 0.55 degrees every million years.
The researchers argue that plate tectonics is the most logical and convincing explanation for the speed and direction of this movement.
“There is a lot of work that suggests that early in Earth’s history, plate tectonics was not really the dominant way the planet’s internal heat was released, as it is today, through plate shifting,” said Alec Brenner.
According to NASA, the Earth’s magnetic poles have reversed 183 times in the last 83 million years and possibly several hundred times in the last 160 million years, a phenomenon that is quite typical of the Earth’s geological history .
3.2 billion years ago, the magnetic field was most likely stable and strong enough to prevent solar winds from destroying Earth’s atmosphere. This gives an idea of the conditions under which the earliest forms of life arose.
The latest study shows that tectonic movement began relatively early in Earth’s history. It also supports the hypothesis that the earliest forms of life on Earth evolved under more temperate conditions.
Currently, the earth’s crust consists of about 15 mobile plates that form modern continents and oceans. In ancient times, the plates moved, forming new mountains, continents and rocks.
Because the oldest fragments of the Earth’s crust are forced into the inner mantle and never come to the surface, it’s hard for geologists to figure out exactly when plate tectonics began.
Thus, no rock is older than 4 billion years, and only 5 percent of all rocks on Earth are older than 2.5 billion years.
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