Tuesday, May 28, 2024

There are two giant blobs lurking deep within the Earth, but why?

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Maria Gill
Maria Gill
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Volcanoes and earthquakes are among the most dynamic and interesting forces on Earth, but their origins have remained somewhat elusive. Plate tectonics is the result of a cosmic collision about 4.5 billion years ago, when a Mars-sized body collided with Earth. The collision left behind some strange blobs inside our planet that may have created tectonic plates, according to new computer modeling research. This new hypothesis is described in A A study published May 7 in the journal Geophysical Research Letters.

What are these mysterious dots?

In the eightiesGeophysicists have discovered for the first time two continent-sized blobs of unusual material located near the Earth’s center. One point falls Under the Pacific Ocean The other is Under the African continent. Both are twice the size of our moon. It is so large that if placed on the surface of the earth it would form a rough layer 60 miles thick Around the planet.

Officially known as Large, low-speed counties (LLVPs), they are also likely built with different proportions of elements than the mantle that surrounds them. to 2023 papers published in the journal nature He suggested they were the remains of an ancient planet called Theia that collided with Earth in the same massive impact that created the Moon. The study suggests that most of Theia was absorbed into our young planet, forming LLVP points. The remaining debris formed the moon.

[Related: Earth’s first continent? Probably a giant continental crust.]

“The Moon appears to contain material representing both the pre-impact Earth and Theia, but any remnants of Theia in the Earth were thought to have been erased and homogenized by billions of years of dynamics (e.g., mantle convection) within the Earth,” physicist An astronomer at Arizona State University and co-author of the book nature Study by Stephen Desch He said in a statement. “This is the first study to prove that distinct ‘chunks’ of Theia still exist within Earth, at the core-mantle boundary.”

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The study posits that these same blobs created our planet’s tectonic plates, allowing life to flourish.

A new look at some very old metals

this New paper It builds on that study. Using computer modeling, they determined that about 200 million years after the collision with Theia, submerged LLVPs may have helped form hot plumes inside the Earth that disrupted the surface. They broke through the flat crust and allowed the circular plates to sink in a process called subduction.

According to the teamThis may explain why Earth’s oldest minerals are zircon crystals that appear to have undergone subduction more than 4 billion years ago and may have contributed to plate tectonics.

[Related: How old is Earth? It’s a surprisingly tough question to answer.]

“The giant impact is not only the reason for the existence of our moon, if so, it also determines the initial conditions of our Earth,” said Caltech geologists and study co-author Qian Yuan. Tell Washington Post.

The form is uploaded Many questions for some outside geologists, including whether or not the collision would result in recycling of the entire Earth’s crust rather than plate tectonics. This process likely occurred on our sister planet Venus billions of years ago. There are also some geochemical inconsistencies that cast doubt on the planet theory as a whole, according to some scientists.

Is plate tectonics really necessary for life?

Although they can be devastating to both property and life, some scientists believe that plate tectonics helps the Earth maintain its activity. Carbon cycle. this process Carbon is transferred between microbes, plants, minerals, animals and the Earth’s atmosphere. The fourth most abundant element in the universe, carbon can also form complex molecules on Earth such as DNA and proteins. These building blocks of carbon make life on Earth possible.

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but, Another study published last year in nature It is assumed that moving plate tectonics was not occurring on Earth until about 3.9 billion years ago when the first traces of life appeared on Earth.

[Related: Your ancestors might have been Martians.]

“We found that there were no tectonic plates when life was first thought to have arisen, and that there were no tectonic plates for hundreds of millions of years afterward,” said University of Rochester paleogeologist John Tarduno. He said in a statement. “Our data suggest that when we search for exoplanets that harbor life, the planets do not necessarily need tectonic plates.”

What is clear is that concrete answers to the question of how, when and why life first appeared on our planet and what role moving plates did or did not play will continue to exist.

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