Ancient stones show the earliest evidence of tectonic activity on earth

Ancient stones show the earliest evidence of tectonic activity on earth

The Pilbara CRATON in Western Australia is made up of few stones 3.5 billion years old

Elizabeth czitryyyi / offering

Australian stones preserve evidence that land crust plates operate in 3.5 billion years ago, a search that turns the beginning of the plate tectonics in hundreds of millions.

Today, about eight wide, tight stone plates over the planet, plus some small plates, pulled or pushed by a soft stone layer at the bottom. If the edges of these plates fall or slide each other, the sudden geological events can occur, such as earthquakes, as well as slower processes, such as many mountain processes.

But geologists don’t agree with how many plates there once, when they start moving and how they act. Some researchers claim to have found evidence from distance returns As 4 billion Years ago, if the planet is hotter, while others say the strongest evidence is newer, from 3.2 billion years ago.

Most of this evidence involves indications from the chemical composition of the rocks, which can be used by geologists to undermine how the stones were transferred. However, there is a small record of how to move to each other’s first plates, which are found to be strongest evidence of tectonic plate moves.

Now, Alec Brenner On Yale University and his colleagues say they found the odd evidence of relatives of the plate mome of 8,5 billion years ago in the eastern CRATON in Western Australia. Researchers tracked how the magnetic field of stones, consistent with the magnetic field of the land, which lasted several hours, which a compass was transferred to the stone that the earth was transferred.

Brenner and his team first dated stones by analyzing radioactive isotopes they attached, then confirmed the magnetization of rocks that were not reset. By tracking how this magnetisation is moving, they can show that the entire rock region migrated over time, at a rate of ten centimeters a year. Then they compare it with the rocks dated and tracked with the same way with the Barberton Greenstone belt in South Africa, with no action.

“It means that there is a type of plate border between these two (regions) to take care of Renthmid Geochemte, Czech Republic, on 9 July.

“The pill, about 3.8 billion years ago, moving from the middle of the high latitude, within the geomagnetic area today, in a few million years. While Barberton was just sitting in the same.

“If the two plates act relative to each other, there must be a terrible many things going in between,” as Robert Hack At Carnegie institution for the science of Washington DC. “It can’t be a different thing.”

But there is a scale for different interpretations of what is caused by that movement, as Herrapit. This is a part because there is widespread uncertainty how strong the plate moves, and data can fit in many different theories of what the world looks at that time.

At least, the search means the existence of a tectonic border, as Michael Brown at the University of Maryland. However, he says the motion of rocks can be seen differently than what we understand as plate tectonics today. “Cause, the pilbara (plate) goes through a higher latitude and stops dead, which is not usually in any context of the plate tectonic.”

The brown arguments that apply to a theory that the crust of the earth at that time is made up of many small plots in the columns of hot stone, called columns of hot stone, which are called the plumes, which are called the plumes, which are called the plumes, which fluttered from the mostly molten mantles. The surviving remnants of these smaller plates, which in this view brenner and his team would have sampled from, are useful to indicate that there was motion, but because they are only a small proportion of the crust, they might be moving, say brown.

Brenner and his team also found evidence that the magnetic direction of land moves 3.46 billion years ago, which is 200 million years before the most recent flip. Unlike the magnetic field, turning away every 1 million years, the magnetic field previously appears to be less frequent, in a million millions of years. It can mean that “different underwater driving energy and mechanisms”, as Brenner.

What population of the earth looks like that point in its development is also the warm debate, as Herrarit, in part because of the lack of magnetic data. “I think it moves the bar,” he said. “It’s an important search for a change early. It tells you something about geodynamics at the core not crucified.”

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