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The search for Earth’s hidden mountains

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The deep Earth contains vast mountain ranges with peaks up to four times the height of Everest. But no one knows why.

It was a glaring summer’s day in Antarctica. Through frozen eyelashes, Samantha Hansen blinked out at the featureless landscape: a wall of white, where up was the same as down, and ground blended seamlessly into sky. Amid these disorientating conditions, with temperatures of around -62C (-80F), she identified a suitable spot in the snow, and took out a spade.

Hansen was in the continent’s bleak interior – not the comparatively balmy, picturesque Antarctica of cruise ship tours, but an unforgiving environment rarely even braved by the local wildlife. As part of a team from the University of Alabama and Arizona State University, she was looking for hidden ‘mountain’ ranges – peaks that no explorer has ever set foot on, no sunlight has ever illuminated. These mountains occur deep within the Earth.

It was 2015 and the researchers were in Antarctica to set up a seismology station – equipment, half-buried in the snow, that would allow them to study the interior of our planet. In total, the team installed 15 across Antarctica.

The mountain-like structures they revealed are utterly mysterious. But Hansen’s team discovered that these ultra-low velocity zones or ULVZs, as they are known, are also likely to be almost ubiquitous – wherever you are in the world, they may be lurking far beneath your feet. “We found evidence for ULVZs kind of everywhere [we looked],” says Hansen. The question is – what are they? And what are they doing inside our planet?

A mystery history

The Earth’s strange interior mountains occur at a critical threshold: the one between the planet’s metallic core and the surrounding rocky mantle. This abrupt transition is, as Hansen’s team point out, even more drastic than the change in physical properties between solid rock and air. It has been tantalising experts for decades – as enigmatic as it is influential to the geology of the planet.

Though the ‘core-mantle boundary’ is thousands of kilometres from the Earth’s surface, there is a surprising amount of interchange between its unfathomable depths and our own world. It’s thought to be a kind of graveyard for ancient pieces of the ocean floor – and it may even be behind the existence of volcanoes in unexpected locations, such as Hawaii, by creating super-heated highways to the crust.

The story of the deep-Earth mountains began in 1996, when scientists explored the core-mantle boundary far beneath the central Pacific Ocean. They did this by studying seismic waves created by massive ground-shuddering events: usually earthquakes, though nuclear bombs can achieve the same effect. These waves pass right through the Earth, and can be picked up by seismic stations at other locations on its surface, sometimes more than 12,742 km (7,918 miles) away from where they started. By examining the paths the waves take as they travel through – such as the way they’re refracted by different materials – scientists can piece together an X-ray-like picture of the interior of the planet.

When researchers looked at waves generated by 25 earthquakes, they found they inexplicably slowed down when they reached a jagged patch on the core-mantle boundary. This vast, otherworldly mountain range was highly variable – some peaks stretched 40km (24.8 miles) up into the mantle, equivalent to 4.5 times the height of Everest. Meanwhile, others were just 3km (1.7 miles) high.

Since then, similar mountains have been found lurking at scattered locations all around the core. Some are particularly large: one monster specimen occupies a patch 910km (565 miles) across under Hawaii.

Yet to this day, no one knows how they got there, or what they’re made of.

Most of the Earth’s crust is made of basalt – and this might also be the material behind the mysterious deep-Earth mountains (Credit: Getty Images)

One idea is that the mountains are parts of the lower mantle that have been superheated due to their proximity with Earth’s incandescent core. While the mantle can reach 3,700C (6,692F), this is relatively mild – the core can achieve atom-bending highs of 5,500C (9,932F) – not far off the temperature at the surface of the Sun. The hottest parts of the core-mantle boundary, it is suggested, may become partially molten – and this is what geologists see as ULVZs.

Alternatively, the deep-Earth mountains could be made from a subtly different material to the surrounding mantle. Incredibly, it’s thought that they could be the remains of ancient oceanic crust which disappeared into its depths, eventually sinking down over hundreds of millions of years to settle just above the core.

In the past, geologists have looked to a second puzzle for clues. The deep-Earth mountains tend to be found near other mystery structures: enormous blobs, or large low-shear velocity provinces (LLSVPs). There are just two: an amorphous lump called “Tuzo” beneath Africa, and another known as “Jason” beneath the Pacific. They are thought to be truly primeval, possibly billions of years old. Again, no one knows what they are, or how they got there. But their close proximity to the mountains has led to the belief that they’re somehow linked.

One way to explain this association is that it did indeed all begin with tectonic plates slipping down into the Earth’s mantle, and sinking to the core-mantle boundary. These then slowly spread out to form an assortment of structures, leaving a trail of both mountains and blobs. This would mean both are made from ancient oceanic crust: a combination of basalt rock and sediments from the ocean floor, albeit transformed by the intense heat and pressure.

But the existence of deep-Earth mountains below Antarctica could contradict this, Hansen suggests. “Most of our study region, the southern hemisphere, is pretty far away from those larger structures.”

A frigid quest

To install their Antarctic seismology stations, Hansen and her team flew out to suitable locations in helicopters and small planes, placing the equipment in waist-deep snow – some near the coast, under the curious gaze of resident penguins, others inland.

It only took a matter of days to get the first results. The instruments can detect earthquakes almost anywhere on the planet – “If it’s big enough, we can see it,” Hansen says – and there are plenty of opportunities. The US National Earthquake Information Center records around 55 across the globe every day.

While identifying deep-Earth mountain ranges had been done before, no one had ever checked for them below Antarctica. It’s not near either of the mystery blobs, or close to where any tectonic plates have recently fallen. Yet to the team’s surprise they found them at every site they sampled.

Previously the mountains were thought to be scattered near places occupied by blobs. But Hansen’s  results suggest they may form a continuous blanket that wraps around Earth’s core.

Testing this idea will require a lot more investigation: before the Antarctic study, just 20% of the core-mantle boundary had been checked. “But we’re hoping to fill that gap,” says Hansen, who explains it’s also dependent on the development of new techniques for identifying smaller structures. In some regions, the ULVZ structures are more like slim plateaus than mountains, so it’s not possible to see the entire layer just yet – they don’t show up on seismographs, if they are there at all.

However, if the mountains really are that widespread, it would have implications both for what they are made of and how they’re linked to the larger blob structures. Could the smaller, mountain-sized remains of tectonic plates really have ended up scattered that far away from the larger blobs?

Whatever we discover, it’s oddly fitting that the frigid, alien landscape of Antarctica has given us clues to the strange, super-heated mountains of the deep Earth.

 

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Here’s how Helene and other storms dumped a whopping 40 trillion gallons of rain on the South

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More than 40 trillion gallons of rain drenched the Southeast United States in the last week from Hurricane Helene and a run-of-the-mill rainstorm that sloshed in ahead of it — an unheard of amount of water that has stunned experts.

That’s enough to fill the Dallas Cowboys’ stadium 51,000 times, or Lake Tahoe just once. If it was concentrated just on the state of North Carolina that much water would be 3.5 feet deep (more than 1 meter). It’s enough to fill more than 60 million Olympic-size swimming pools.

“That’s an astronomical amount of precipitation,” said Ed Clark, head of the National Oceanic and Atmospheric Administration’s National Water Center in Tuscaloosa, Alabama. “I have not seen something in my 25 years of working at the weather service that is this geographically large of an extent and the sheer volume of water that fell from the sky.”

The flood damage from the rain is apocalyptic, meteorologists said. More than 100 people are dead, according to officials.

Private meteorologist Ryan Maue, a former NOAA chief scientist, calculated the amount of rain, using precipitation measurements made in 2.5-mile-by-2.5 mile grids as measured by satellites and ground observations. He came up with 40 trillion gallons through Sunday for the eastern United States, with 20 trillion gallons of that hitting just Georgia, Tennessee, the Carolinas and Florida from Hurricane Helene.

Clark did the calculations independently and said the 40 trillion gallon figure (151 trillion liters) is about right and, if anything, conservative. Maue said maybe 1 to 2 trillion more gallons of rain had fallen, much if it in Virginia, since his calculations.

Clark, who spends much of his work on issues of shrinking western water supplies, said to put the amount of rain in perspective, it’s more than twice the combined amount of water stored by two key Colorado River basin reservoirs: Lake Powell and Lake Mead.

Several meteorologists said this was a combination of two, maybe three storm systems. Before Helene struck, rain had fallen heavily for days because a low pressure system had “cut off” from the jet stream — which moves weather systems along west to east — and stalled over the Southeast. That funneled plenty of warm water from the Gulf of Mexico. And a storm that fell just short of named status parked along North Carolina’s Atlantic coast, dumping as much as 20 inches of rain, said North Carolina state climatologist Kathie Dello.

Then add Helene, one of the largest storms in the last couple decades and one that held plenty of rain because it was young and moved fast before it hit the Appalachians, said University of Albany hurricane expert Kristen Corbosiero.

“It was not just a perfect storm, but it was a combination of multiple storms that that led to the enormous amount of rain,” Maue said. “That collected at high elevation, we’re talking 3,000 to 6000 feet. And when you drop trillions of gallons on a mountain, that has to go down.”

The fact that these storms hit the mountains made everything worse, and not just because of runoff. The interaction between the mountains and the storm systems wrings more moisture out of the air, Clark, Maue and Corbosiero said.

North Carolina weather officials said their top measurement total was 31.33 inches in the tiny town of Busick. Mount Mitchell also got more than 2 feet of rainfall.

Before 2017’s Hurricane Harvey, “I said to our colleagues, you know, I never thought in my career that we would measure rainfall in feet,” Clark said. “And after Harvey, Florence, the more isolated events in eastern Kentucky, portions of South Dakota. We’re seeing events year in and year out where we are measuring rainfall in feet.”

Storms are getting wetter as the climate change s, said Corbosiero and Dello. A basic law of physics says the air holds nearly 4% more moisture for every degree Fahrenheit warmer (7% for every degree Celsius) and the world has warmed more than 2 degrees (1.2 degrees Celsius) since pre-industrial times.

Corbosiero said meteorologists are vigorously debating how much of Helene is due to worsening climate change and how much is random.

For Dello, the “fingerprints of climate change” were clear.

“We’ve seen tropical storm impacts in western North Carolina. But these storms are wetter and these storms are warmer. And there would have been a time when a tropical storm would have been heading toward North Carolina and would have caused some rain and some damage, but not apocalyptic destruction. ”

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Follow AP’s climate coverage at https://apnews.com/hub/climate

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Follow Seth Borenstein on Twitter at @borenbears

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Associated Press climate and environmental coverage receives support from several private foundations. See more about AP’s climate initiative here. The AP is solely responsible for all content.

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‘Big Sam’: Paleontologists unearth giant skull of Pachyrhinosaurus in Alberta

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It’s a dinosaur that roamed Alberta’s badlands more than 70 million years ago, sporting a big, bumpy, bony head the size of a baby elephant.

On Wednesday, paleontologists near Grande Prairie pulled its 272-kilogram skull from the ground.

They call it “Big Sam.”

The adult Pachyrhinosaurus is the second plant-eating dinosaur to be unearthed from a dense bonebed belonging to a herd that died together on the edge of a valley that now sits 450 kilometres northwest of Edmonton.

It didn’t die alone.

“We have hundreds of juvenile bones in the bonebed, so we know that there are many babies and some adults among all of the big adults,” Emily Bamforth, a paleontologist with the nearby Philip J. Currie Dinosaur Museum, said in an interview on the way to the dig site.

She described the horned Pachyrhinosaurus as “the smaller, older cousin of the triceratops.”

“This species of dinosaur is endemic to the Grand Prairie area, so it’s found here and nowhere else in the world. They are … kind of about the size of an Indian elephant and a rhino,” she added.

The head alone, she said, is about the size of a baby elephant.

The discovery was a long time coming.

The bonebed was first discovered by a high school teacher out for a walk about 50 years ago. It took the teacher a decade to get anyone from southern Alberta to come to take a look.

“At the time, sort of in the ’70s and ’80s, paleontology in northern Alberta was virtually unknown,” said Bamforth.

When paleontogists eventually got to the site, Bamforth said, they learned “it’s actually one of the densest dinosaur bonebeds in North America.”

“It contains about 100 to 300 bones per square metre,” she said.

Paleontologists have been at the site sporadically ever since, combing through bones belonging to turtles, dinosaurs and lizards. Sixteen years ago, they discovered a large skull of an approximately 30-year-old Pachyrhinosaurus, which is now at the museum.

About a year ago, they found the second adult: Big Sam.

Bamforth said both dinosaurs are believed to have been the elders in the herd.

“Their distinguishing feature is that, instead of having a horn on their nose like a triceratops, they had this big, bony bump called a boss. And they have big, bony bumps over their eyes as well,” she said.

“It makes them look a little strange. It’s the one dinosaur that if you find it, it’s the only possible thing it can be.”

The genders of the two adults are unknown.

Bamforth said the extraction was difficult because Big Sam was intertwined in a cluster of about 300 other bones.

The skull was found upside down, “as if the animal was lying on its back,” but was well preserved, she said.

She said the excavation process involved putting plaster on the skull and wooden planks around if for stability. From there, it was lifted out — very carefully — with a crane, and was to be shipped on a trolley to the museum for study.

“I have extracted skulls in the past. This is probably the biggest one I’ve ever done though,” said Bamforth.

“It’s pretty exciting.”

This report by The Canadian Press was first published Sept. 25, 2024.

The Canadian Press. All rights reserved.

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The ancient jar smashed by a 4-year-old is back on display at an Israeli museum after repair

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TEL AVIV, Israel (AP) — A rare Bronze-Era jar accidentally smashed by a 4-year-old visiting a museum was back on display Wednesday after restoration experts were able to carefully piece the artifact back together.

Last month, a family from northern Israel was visiting the museum when their youngest son tipped over the jar, which smashed into pieces.

Alex Geller, the boy’s father, said his son — the youngest of three — is exceptionally curious, and that the moment he heard the crash, “please let that not be my child” was the first thought that raced through his head.

The jar has been on display at the Hecht Museum in Haifa for 35 years. It was one of the only containers of its size and from that period still complete when it was discovered.

The Bronze Age jar is one of many artifacts exhibited out in the open, part of the Hecht Museum’s vision of letting visitors explore history without glass barriers, said Inbal Rivlin, the director of the museum, which is associated with Haifa University in northern Israel.

It was likely used to hold wine or oil, and dates back to between 2200 and 1500 B.C.

Rivlin and the museum decided to turn the moment, which captured international attention, into a teaching moment, inviting the Geller family back for a special visit and hands-on activity to illustrate the restoration process.

Rivlin added that the incident provided a welcome distraction from the ongoing war in Gaza. “Well, he’s just a kid. So I think that somehow it touches the heart of the people in Israel and around the world,“ said Rivlin.

Roee Shafir, a restoration expert at the museum, said the repairs would be fairly simple, as the pieces were from a single, complete jar. Archaeologists often face the more daunting task of sifting through piles of shards from multiple objects and trying to piece them together.

Experts used 3D technology, hi-resolution videos, and special glue to painstakingly reconstruct the large jar.

Less than two weeks after it broke, the jar went back on display at the museum. The gluing process left small hairline cracks, and a few pieces are missing, but the jar’s impressive size remains.

The only noticeable difference in the exhibit was a new sign reading “please don’t touch.”

The Canadian Press. All rights reserved.

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