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New York, April 23 (IANS) Earth’s tectonic plates began to move more than 3.2 billion years ago, just over 1.3 billion years after Earth first formed and earlier than originally thought, the researchers revealed.
To date, some researchers theorized that it happened about four billion years ago, while others thought it was close to a billion.
According to the study, published in the journal Science Advances, researchers at Harvard University searched for clues in ancient rocks (over 3 billion years old) in Australia and South Africa, and found that these plates were moving at least 3.2 billion years ago. on primitive Earth.
In a portion of the Pilbra Craton in Western Australia, one of the oldest pieces of the Earth’s crust, scientists found a latitudinal drift of about 2.5 centimeters a year and dated the movement 3.2 billion years ago.
The researchers believe this change is the first evidence that the modern plate movement occurred two to four billion years ago. It is added to the growing research that tectonic motion occurred on early Earth.
“Based on the evidence we find, it seems that plate tectonics is a much more likely process to have occurred on early Earth and that it advocates an Earth that looks much more like today’s than most people think,” the study said. researcher Alec Brenner from Harvard University in the United States.
For the study, project members traveled to the Pilbara Craton in Western Australia. A craton is a thick, very stable primordial bark. They are usually found in the middle of tectonic plates and are the ancient hearts of Earth’s continents.
This makes them the natural place to study early Earth. The Pilbara Craton stretches about 300 miles wide, covering approximately the same area as the state of Pennsylvania. Rocks were formed there 3.5 billion years ago.
In 2017, researchers took samples from a portion called the Honeyeater Basalt. They drilled into the rocks there and collected core samples about an inch wide.
The samples were taken to the Cambridge laboratory, where they were placed on magnetometers and demagnetization equipment. These instruments told them the magnetic history of the rock. Hopefully the oldest and most stable part of that story is when the rock formed. In this case, it was 3.2 billion years ago.
The team then used their data and those of other researchers, who demagnetized rocks in nearby areas, to date when the rocks changed from point to point. They found a drift of 2.5 centimeters a year.
The researchers used the novel Quantum Diamond Microscope to confirm their findings from 3.2 billion years ago. The microscope takes pictures of the magnetic fields and particles in a sample. It was developed in collaboration between researchers at Harvard and MIT.
In the study, the researchers note that they couldn’t rule out a phenomenon called “true polar wandering.” It can also cause the Earth’s surface to shift.
Their results are more inclined towards plate tectonic movement due to the time interval of this geological movement.
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