One idea is that mountains are parts of the lower mantle It was very heated Because of its proximity to the Earth’s glowing core. While the mantle can reach 3,700°C (6,692°F), this is relatively mild – the core can reach an atom-bending high of 5,500°C (9,932°F) – not far from hot. on the surface of the sun. the hottest parts From the core-mantle boundary, it is suggested, they may become partially molten—that’s what geologists see as ULVZs.
Alternatively, the Earth’s deep mountains could be made of a subtly different material than the surrounding mantle. Incredibly, it is believed that they may be remnants of ancient oceanic crust that, in its depths, eventually disappeared sinking down over hundreds of millions of years to settle above the core.
In the past, geologists have looked to a second mystery for clues. Deep mountains tend to be found near other mysterious structures: massive bubbles, or large low shear velocity provinces (LLSVPs). There are only two: an amorphous mass called “Tuzo” under Africa, and another known as “Jason” under the Pacific Ocean. They are believed to be really primitive, possibly billions of years old. Again, no one knows what they are, or how they got there. But their proximity to the mountains has led to the belief that they are related in some way.
One way to explain this connection is that it actually began with tectonic plates sliding down into the Earth’s mantle, and then sinking to the core-mantle boundary. These then slowly spread out to form a variety of structures, leaving behind a series of mountains and blobs. This means that both are made of ancient oceanic crust: a mixture of basalt rock and sediment from the ocean floor, though it was transformed by intense heat and pressure.
Hansen suggests that the presence of mountains deep in the ground below Antarctica could counter this. “Most of our study area, the Southern Hemisphere, is very far away from those larger structures.”
rigid task
To install the Antarctic seismology stations, Hansen and her team flew to suitable sites in helicopters and small planes, placing the equipment in waist-deep snow—some near the coast, under the gaze of resident penguins, others inland.
It only took a few days to get the first results. Instruments can detect earthquakes almost anywhere on the planet—”if they’re big enough, we can see them,” Hansen says—and there are plenty of opportunities. US National Earthquake Information Center records About 55 worldwide every day.
While mountain ranges deep within the Earth have been identified before, no one has verified them below Antarctica. It’s nowhere near any of the fuzzy spots, or anywhere near where any tectonic plates have fallen off recently. However, the team was surprised to find it at every site they sampled.
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Previously it was believed that the mountains were scattered near the places occupied by the points. But Hansen’s results indicate that it may form a continuous mantle that wraps around Earth’s core.
Testing this idea will require further investigation: prior to the Antarctic study, only 20% of the core-mantle boundary had been examined. “But we hope to fill this gap,” says Hansen, explaining that it also depends on developing new techniques to identify smaller structures. In some areas, the ULVZ’s structures look more like thin plateaus than mountains, so the entire layer can’t be seen yet — it doesn’t show up on seismometers, if it exists at all.
However, if mountains are truly widespread, it has implications for both their components and how they relate to large point structures. Could remnants of smaller, mountain-sized tectonic plates actually end up that far away from the big blobs?
Whatever we discover, bizarrely, the frozen and bizarre landscapes of Antarctica have given us clues to strange, superheated mountains deep within the Earth.
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