SPACE — A huge ocean floor lurks near the earth’s core. Seismic imaging has revealed its presence, which likely surrounds most, to say nothing of, the Earth’s core.
This thin, dense layer is nested roughly 2,000 miles (3,200 kilometers) below Earth’s surface, between the planet’s core and the planet’s middle layer, called the mantle. According to research published in the journal Science Advances on April 5, 2023, the ocean is thought to cover the entire core-mantle boundary.
To study Earth’s interior, seismologists measure earthquake waves as they travel through the planet, and then back toward Earth’s surface. By watching how these waves change after passing through various structures inside the Earth, the researchers created a map of what the Earth’s interior looks like.
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Previous studies identified several isolated pockets of dense marine crust near the core. These pockets are called ultra-low-velocity-zone structures (ULVZ), because seismic waves travel very slowly through them.
“Only (about) 20 percent of the previously investigated core-mantle boundary for ULVZ has not been identified (new research) at all of these locations. It is possible that this anomalous material covers the entire core,” said lead author of the study, Samantha Hansen, professor geology at The University of Alabama.
In the new study, scientists placed seismic equipment at 15 stations located in Antarctica and collected data over three years. The layers found are said to be extremely thin compared to Earth’s core which is 450 miles (724 km) wide, and the mantle which is roughly 1,800 miles (2,900 km) thick.
“The thickness (of the oceanic layer) varies, depending on location,” said Hansen. At some points it was 3.1 miles (5 km) thick and at others as much as 31 miles (50 km) thick.
These ancient oceanic layers likely developed as Earth’s tectonic plates shifted. That causes oceanic material to be carried into the planet’s interior in subduction zones, areas where two plates collide and force one plate to dive into the other. Over time, accumulations of subducted oceanic material accumulated along the core-mantle boundary and were propelled by slowly flowing rock within the mantle.
The researchers think the previously detected ULVZs are underground mountains that allow heat to escape from the Earth’s molten core. “The presence of this (ocean) layer can restrain the flow of heat across the core-mantle boundary, because temperature conditions in this part of the Earth have been shown to have a strong impact on the planet’s magnetic field,” said Hansen.
The research team plans to expand their study by examining data collected from all available seismic stations in Antarctica. Source: LiveScience
Also read:
Origin of Water Found, Not from Asteroid Collision
How Do We Know How Old the Earth is?
Why does the other side of the moon never face the earth?
Strange Radio Signals from Earth-like Planets Suspected Magnetic Fields Requirement for Life
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