7 Mysterious Geological Formations That Still Baffle Scientists

bennymarty/iStock via Getty Images
bennymarty/iStock via Getty Images

Earth is covered with incredible geological structures, from volcanos to crystal-encrusted caves to awe-inspiring canyons. While some of our planet’s mysteries have been solved, some of its formations defy easy explanation. Here are a few that continue to baffle scientists.

1. The Eye of the Sahara // Mauritania

The Richat Structure, a.k.a. the Eye of the Sahara
ISS Crew Earth Observations Facility and Earth Science and Remote Sensing Unit, Johnson Space Center, NASA // Public Domain

The Eye of the Sahara, also known as the Richat Structure, is a 28-mile-wide site of huge concentric circles found in the western African nation of Mauritania. Geologists initially thought the site was created by an asteroid impact, but there isn’t enough melted rock among the rings to support this theory. Similarly, there’s no evidence to suggest a volcanic eruption. New Age enthusiasts hint that the Eye of the Sahara could represent the remains of the mythical sunken island of Atlantis, based on Plato’s allegory.

More recently, geologists have proposed that the Eye of the Sahara could be an eroded, collapsed geological dome, formed some 100 million years ago when the supercontinent Pangea broke up. Bolstering this theory are ancient rocks found on the surface, which originated as much as 125 miles beneath the Earth’s crust and before life existed on Earth. Research continues.

2. Lake Hillier // Australia

Pink Lake Hillier in Western Australia
Kurioziteti123, Wikimedia Commons // CC BY-SA 4.0

This small, saltwater lake on an island off Western Australia is only one-third of a mile long, but its bubblegum-pink color makes it especially striking. The lake was documented in 1802 by British explorer Matthew Flinders, who took a sample of its waters but failed to understand how it got its startling hue. Tourists can visit only by helicopter, though it is safe to swim in the waters.

Scientists today suspect the color is due to the presence of a pink alga, Dunaliella salina, and/or a pink bacterium, Salinibacter ruber. But unlike other pink lakes around the world, such as Lake Retba in Senegal, Lake Hillier’s color doesn’t fluctuate with temperature or sunlight—so the investigation goes on.

3. The Great Unconformity // United States

Great Unconformity at the Grand Canyon
Alex Demas, USGS // Public Domain

The Great Unconformity is a huge gap in the geological record: Layers of rock dating from about 1.2 billion to 250 million years ago are completely missing from certain areas around the globe. This enormous chunk of lost time can be seen clearly in the stratigraphy of the Grand Canyon in Arizona. Geologists studying the anomaly there have noted that there is plenty of rock, full of fossils, from the Cambrian period (540 million years ago) but the layer beneath it is basement rock, formed roughly 1 billion years ago and empty of fossils. So, what happened to the stuff in between?

An emerging theory—"Snowball Earth”— may explain where the rock disappeared to. Around 700 million years ago, Earth was encased in snow and ice. Moving glaciers peeled off the planet’s crust with the help of lubricating sediments, pushing it into oceans, where it was reabsorbed by subducting tectonic plates. Many questions remain unanswered, though—such as the multimillion-year gap between the end of Snowball Earth, around 635 million years ago, and the start of the Cambrian period.

4. Nastapoka Arc // Canada

Aerial view of Hudson Bay
Jeff Schmaltz, MODIS Land Rapid Response Team, NASA GSFC, Wikimedia Commons // Public Domain

In the southeast corner of Hudson Bay, Canada, lies a near-perfect arc. The mysterious half-circle, also known as the Hudson Bay Arc, was first thought to be an impact crater from a meteorite. But none of the usual confirming evidence, such as shatter cones or unusual melted rocks, has been found in the vicinity.

The most commonly accepted theory for the arc, based on geological evidence collected in the 1970s and later, is that it is a boundary formed when one shelf of rock was pushed under another other. That doesn’t explain how or why is it’s so perfectly round—so the Nastapoka Arc remains subject to ongoing study.

5. Mima Mounds // United States

Mima Mounds in Washington
zrfphoto/iStock via Getty Images

The Mima Mounds are mysterious, uniform undulations in the grasslands of Washington State near Olympia, ranging from 10 to 164 feet in diameter and up to 6.5 feet tall. When American explorer Charles Wilkes set eyes on them in 1841, he believed they were human-made burial mounds and had three of them excavated, only to find them filled with loose stones. Similar mounds are found from California to Colorado and have puzzled naturalists for years.

Scientists suggest that some of the mounds may be 30,000 years old, which makes decoding them complex; humans are believed to have arrived in North America several thousand years later than that. Many theories about their cause—glacial flooding, whirlpools, and even wind-blown sediment clumping around vegetation—have been dismissed. The current leading theory, based on computer modelling, is that pocket gophers created the mounds. Yet doubts remain: No one has ever witnessed a pocket gopher building one.

6. Fairy Circles // Namibia

Fairy circles in Namibia
demerzel21/iStock via Getty Images

Up close, the fairy circles in the Namib Desert are just circular patches of bare red earth, surrounded by tufts of grass. But from a bird’s-eye view, these spots stretch endlessly across the arid landscape, creating a regular polka-dot pattern. Folktales claim the spots are the gods’ footprints, but scientists have searched for an evidence-based explanation.

At first, some proposed that the circles are created when plants compete for water: The root systems of the successful vegetation dominate the ground, while smaller plants are unable to compete, leaving bare patches of desert. In 2017, a promising new theory appeared in the journal Nature. Excavations of several circles revealed termite nests under each one, implying the circles were created by the termites eating the vegetation above their territory, allowing desert grasses to flourish only between each nest. Ecologists modeled both the plant-competition and hungry-termite theories, and found that both supported conditions conducive to fairy circles. But with such a complex ecosystem, scientists say more research is needed.

7. Yamal Craters // Russia

Aerial view of the Yamal Peninsula, Siberia
Jesse Allen, Earth Observatory, NASA // Public Domain

In 2014, a helicopter pilot flying over the Yamal Peninsula in Siberia, which juts into the Kara Sea, noticed an enormous hole in the permafrost. Scientists rushed to analyze the nearly 100-foot-wide crater and determine its origin. A meteorite impact, a natural gas explosion, or alien interference were all floated as possible causes.

Tests of the air at the bottom of the crater revealed very high levels of methane, pointing to an explosion—possibly brought on by several unusually warm summers that destabilized the permafrost. But an equally likely explanation, according to some researchers, is that the crater represents a slow, long-term collapse of the permafrost itself rather than a recent explosion. Since then, more craters have been discovered. Further study is needed, but the treacherous permafrost makes research difficult.

Not-So-Fancy Feast: Your Cat Probably Would Eat Your Rotting Corpse

Tycson1/iStock via Getty Images
Tycson1/iStock via Getty Images

Cat enthusiasts often cite the warmth and companionship offered by their pet as reasons why they’re so enamored with them. Despite these and other positive attributes, cat lovers are often confronted with the spurious claim that, while their beloved furry pal might adore them when they’re alive, it won’t hesitate to devour their corpse if they should drop dead.

Though that’s often dismissed as negative cat propaganda spread by dog people, it turns out that it’s probably true. Fluffy might indeed feast on your flesh if you happened to expire.

A horrifying new case study published in the Journal of Forensic Sciences offers the fresh evidence. The paper, first reported by The Washington Post, documents how two cats reacted in the presence of a corpse at Colorado Mesa University’s Forensic Investigation Research Station, or body farm, where the deceased are used to further forensic science for criminal investigations.

The study’s authors did not orchestrate a meeting between cat and corpse. The finding happened by accident: Student and lead author Sara Garcia was scanning surveillance footage of the grounds when she noticed a pair of cats trespassing. The cats, she found, were interested in the flesh of two corpses; they gnawed on human tissue while it was still in the early stages of decomposition, stopping only when the bodies began leaching fluids.

The cats, which were putting away one corpse each, didn’t appear to have a taste for variety, as they both returned to the same corpse virtually every night. The two seemed to prefer the shoulder and arm over other body parts.

This visual evidence joins a litany of reports over the years from medical examiners, who have observed the damage left by both cats and dogs who were trapped in homes with deceased owners and proceeded to eat them. It’s believed pets do this when no other food source is available, though in some cases, eating their human has occurred even with a full food bowl. It’s something to consider the next time your cat gives you an affectionate lick on the arm. Maybe it loves you. Or maybe it has something else in mind.

[h/t The Washington Post]

Wolf Puppies Play Fetch, Too, Study Finds

Christina Hansen Wheat
Christina Hansen Wheat

It took thousands of years of selective breeding for wolves to become the Golden Retrievers you see at dog parks today. Domesticated dogs are very different from their wild counterparts, but according to a new study, they may have a surprising trait in common. Researchers found that some wolf puppies are willing to play fetch with total strangers, suggesting that following human commands is intrinsic to canines.

For their study in the journal iScience, researchers from Stockholm University in Sweden set out to find how domestication affects behaviors in young wolves. They raised litters of wolf and dog pups separately from 10 days old and placed them in various scenarios.

When the scientists tested how the wolf puppies would respond to a game of fetch, they expected to be ignored. Chasing a ball and bringing it back requires understanding human commands and obeying them—abilities that were thought to only have emerged in dogs post-domestication.

The first two wolf groups met expectations by showing little interest in the toy, but something different happened with the third set. Three eight-week old pups went after the ball and brought it back when they were encouraged to do so. This was the case even when the person giving the commands was someone they had never met before.

Even though most of the puppies didn't play fetch, the fact that those who did belonged to the same litter indicates a "standing variation" for a retrieving trait in wolves. "When you talk about a specific trait in the context of standing variation, it means that there is variation for the expression of this trait within a given population," co-author Christina Hansen Wheat tells Mental Floss. "For our study it suggests that, while probably rare, standing variation in the expression of human-directed behavior in ancestral populations could have been an important target for early selective pressures exerted during dog domestication." In other words, ancient people seeking to domesticate wolves might have focused on some wolves' innate ability to follow human commands.

The first dogs were domesticated as far back as 33,000 years ago. Over millennia, humans have selected for traits like loyalty, friendliness, and playfulness to create the modern dog, but these new findings could mean that the dog's earliest canine ancestors were genetically predisposed toward some of these behaviors.

"All three litters were brought up under identical and standardized conditions across years," Hansen says of the pups in the study. "With this significant effort to control the environmental conditions, it is likely that the differences in behavior across litters to some extent have a genetic basis."

After raising the dog and wolf litters for three years and completing that part of their study, the researchers will continue to analyze their data to see if there are any other adorable (or weird) traits the two groups share.

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