Seismic waves transmitted through the Earth’s interior by earthquakes change speed and direction as they travel through various materials. Rock type, density, and temperature all change the progression of these waves, so scientists are gradually building a complete picture of the Earth’s crust and mantle, including rising plumes of hot mantle material and cooler debris. You will be able to discover. A plate that fell off the surface of the Earth in the distant past.
However, some of these images are difficult to explain. Deep in the Earth’s mantle, there are two regions where seismic waves slow down, called large-slow regions. This decrease in velocity is consistent with a higher density of the material, so it is not too surprising that the material is closer to the core. But that doesn’t explain why there are two distinct regions or why they appear to contain material that has been there since the formation of the solar system.
Now, a team of scientists has linked the existence of these two regions to a catastrophe early in the solar system’s history: a giant collision with a Mars-sized planet that eventually formed the moon.
difficult to explain
Various explanations have been offered for such large, slow regions, but none are entirely satisfactory. One idea is that they are leftovers from the separation of Earth’s interior into a crust-mantle-core structure. But that material should have been thoroughly stirred up when a Mars-sized object named Theia crashed into the early Earth, leaving enough debris in orbit to form the moon. Ta.
Other suggestions include the idea that they may be the remains of plates that have sunk to unusual depths in the mantle. But this does not explain what this material looks like when a mantle plume brings some of it to the surface through volcanic activity. Once sampled, the isotope ratios in the gases trapped in this material are similar to those expected to exist in the early solar system and different from those found in the Earth’s crust today.
The team behind the new paper suggests that an entirely different source could explain the strange properties of these large slow regions. Compared to Earth, the Moon contains more iron oxide, suggesting that Theia also had large amounts of this material. Iron oxide is denser than many other mantle materials, which could explain the properties of large-scale slow-velocity regions. Additionally, the collision is thought to have occurred early in the solar system’s history, potentially explaining why the isotopic ratio is so primordial.
The big problem with this idea is that material from Theia would also have been stirred up after the impact, making it difficult to understand how it would form separate layers inside the Earth. So researchers modeled Earth’s interior during and after the impact to better understand how things work.
