[ad_1]
Planet Earth
(Stockli Challenge / NASA Goddard Space Flight Center)
Researchers have revealed that Earth’s tectonic plates began to move more than 3.2 billion years ago, much earlier than originally thought, and just over 1.3 billion years after Earth formed. 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 magazine. Scientific advances, Harvard University researchers searched for clues in ancient rocks (more than 3 billion years old) from Australia and South Africa, and discovered that these plates were moving at least 3.2 billion years ago on early 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, plate tectonics appears to be a much more likely process to have occurred on early Earth, and that argues in favor of an Earth that looks much more like today’s than most people think.” , said. investigator of the study Alec Brenner of the University of Harvard 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 researchers took these samples back to the laboratory in Cambridge, where they placed the samples 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 the data from other researchers who have 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 say they couldn’t rule out a phenomenon called “true polar shift.” 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.
