Grand Canyon Cliff Collapse Unearths Remarkable Find

By: Past Chronicles Staff | Published: Oct 31, 2023

The Grand Canyon is a fantastic attraction with so much beauty to see! In this deep canyon, you wouldn’t think that a boulder would be one of the most fascinating discoveries to explore. But one geologist found an incredible discovery in this seemingly common rock.

He decided to take a photograph of his findings. That casual image changed what we know about Arizona and the prehistoric life that used to reside there.

Where It All Began: The Bright Angel Trail

This story begins at Bright Angel Trail, the primary tourist starting point for exploring the Grand Canyon. This popular trail moves into the Canyon itself, while running parallel to the edge, lowering in elevation some 4,000 feet for eight miles.


Source: Inspired Imperfection

A cliff face along this trail collapsed and released a boulder which seemed all together unremarkable. It sat untouched for many years.


Seemed Like Your Typical Boulder

The boulder itself was no recent creation. The massive, compacted rock was easily dated by millions of years, well before the Grand Canyon ever reached the depths of its meandering caverns today.


U.S. Department of The Interior

However, the secrets of the boulder weren’t very apparent to folks in modern times until the photograph in this story was taken. Somehow, some way, the photograph triggered a question about what was captured in the image.

The Man Who Discovered It All

Allan Krill had been a trained geologist for years, studying the intricacies of rocks, soil, water, and the rest of the earth’s formations. However, he couldn’t have guessed that his vacation would lead to an amazing geological discovery.


Source: NTNU

Krill immediately spotted the boulder standing out amongst everything else in the Canyon and honed on its abnormality in the landscape. However, he also noticed something else too.

Rare Geological Discoveries

In the geology world, it’s hard to be the discoverer of something new, much less novel. So much of geology has been documented, surveyed, tracked, studied, and photographed that anything someone thinks they “found” turns out to be already thoroughly examined in one research paper or another.


Source: Mark A Paulda/Getty Images

So, when a geologist actually comes across a unique feature that is completely new, or has the potential to be unheard of until that moment, it’s the same as suddenly finding a chest of buried gold coins. It’s rare, usually scoffed at, but amazing when it does actually happen. For Krill, he had found the geologist’s treasure chest of gold coins on this Grand Canyon boulder.

The Discovery Predates Dinosaurs

The boulder itself was not the prize. Instead, what was preserved in the stone of the boulder was amazing and worth the world’s attention. Krill now just had to get others to confirm his suspicion was correct. If he was right, the find easily dated back deep into the era of the dinosaurs at least.

Source: American Rivers

The Grand Canyon’s geological history lies hidden within layers of rock. Compressive forces and high temperatures at first led to the formation of igneous and metamorphic rock. Next, sedimentary layers began to form. Each layer tells its own unique story. The ravine of the Grand Canyon didn’t begin to form until the end of the Cretaceous Period.


The Boulder Reveals Secrets

As so often happens, it took a number of coincidences and special circumstances for Krill’s discovery to even be visible by the geologist. The sequence of crumbling, cracking, gravity and falling in just the right exposed way made the difference in making the boulder’s secret see the light of day for Krill to “discover” it.

Source: torstenvelden/Getty Images

And it needed someone trained like Krill to see the significance. The average person was not likely to even notice the abnormality. In fact, had Krill not been the person to find the secret, the boulder would have kept silent about its gem for another century or longer.


Two Billion Years of History

The above said, the Grand Canyon has long been a repository of secrets. Inaccessible caves can be seen but not explored. Yet, as erosion cuts through the layers like a hot knife through cheese, the natural wonder is stuffed with geological finds.

Source: Living Image

By average estimates, the Canyon easily covers a history of two billion years or longer, with the same river slowly but methodically eating away at the innards of the region and creating the chasm people know today. And all of it is captured in the rock and soil information visible in the Canyon walls.


Slow Changes Over Time

Back then, the world was amazingly different. Even the continents themselves were in different positions globally. What used to be clearly lush, heavy vegetation-covered land disappeared over time. The Arizona desert and arid conditions replaced the climate in the region to what we know today.

Source Christian Soldatke/ Eye Em/ Getty Images

Yet the signs of all that life and jungle are vivid and buried in the Canyon’s soil, captured as carbon layers between minerals. It’s likely, somewhere around the same era of two billion years ago, the boulder Krill ended up examining started to form.


History Continues To Be Written Within the Rocks

As every sedimentary layer was applied with time, it also became what geologists study intently as their version of history books. Not only the type of minerals and what was buried in them tell stories, but how the sedimentary layer was created and deposited makes a huge difference as well.

Source: Britannica

It can tell explicit details about ash fall, mud flows, water presence, and even life captured and fossilized in the minerals.


The Canyon Takes Shape

Long after all this activity came the Cretaceous Period. It was about this time that many experts agree the Grand Canyon likely started being formed, at least in terms of something becoming the gap in the Earth we know today. At that time it didn’t cover the 130,000 square miles the Canyon encompasses today.

Source: Britannica

Some 70 million years ago, geologists believe the first stage needed for the Canyon to exist happened as the earth’s tectonic movement shoved the Colorado Plateau upward in relation to the rest of the region. That movement of the Earth ultimately created a higher elevation point, providing the dynamics gravity would take advantage of later with water.


The Role Water Plays

Water came in the form of rainwater and ice that froze during cold periods. The Rocky Mountains became the watershed, generating much of the moisture and its build up. At first, the condensation factors had very little effect. However, with millennia to work with, water and time can do amazing things.

The Role Water PlaysThe Role Water Plays

Eventually, mere puddles became creeks and creeks became rivers, cutting deeper, wider, stronger and more consistently. No matter how hard the rock, water’s erosive nature as well as temperature takes a toll, wearing down even the strongest of granite.


Erosion Lead To The Geological Discovery

Erosion also has an abrasive effect. As water tears apart rock, it breaks it down, turning rock into boulders and boulders into stones and pebbles, all of which bang against the remaining rock and create multiple points of impact, some with significant force. Damage cascades into more damage and that in turn creates more erosion.


The result is the carving effect we now know as the Grand Canyon with the Colorado River flowing through it. Add in another two million years, ice ages, repeated cycles of freezing and melting, and more rock ends up being split, broken and deconstructed deeper.


A Global Geological Marvel

In modern times, the Grand Canyon enjoys National Park and Monument protection. Internationally, it is easily within the Seven Natural Wonders of the World. Even more interesting, the Canyon is not staying the same. While its current form was realized about 1.2 million years in the past, minuscule changes continue to occur that add up over time.

Source: Piriya Photography/Getty Images

A rock here, a fragment there, all add up to a continuing process of geological change still occurring. That kind of impact, including boulders leaving cliff walls and falling, led to Krill’s discovery.


The Canyon Used to Be Deeper

Interestingly, humans and the Canyon have a long history as well. Ancient peoples frequented the Canyon on a regular basis, easily noting its significance in the landscape by then, even though humanity was still a blip in the geological history range.

John Finney photography/Getty Images

By the time the first European arrivals walked upon the majesty of the Grand Canyon, it had already reached its deepest point 1 million years earlier.


Preserving the Grand Canyon

The Grand Canyon region was first designated a forest reserve in 1919, an early federal government predecessor to what would later become a National Park designation.

Source: Peter Cheung/Getty Images

President Benjamin Harrison made the declaration, and that became the genesis for hundreds of thousands visiting the area ever since. Today, the amount of tourism in the region dwarfs anything from the beginning of the 20th century. Six million people visit the Grand Canyon annually, with the only significant drop having occurred in 2020 due to the COVID pandemic.


Grounds for Tons of Research

Tourists aren’t the only ones visiting though; researchers spend an extensive amount of time in the Canyon on a regular basis. Studies and research have been on a steady diet in the area since before its designation, dating back to 1858.

Source: Laura Hedien/Getty Images

Krill himself studied the area frequently as he developed his skills as a geologist. It’s this very research that confirms the portfolio of geological elements and formations in the area.


Isis Temple

The Grand Canyon easily gains recognition in photographs and films for some of its more famous locations. Created by an assortment of water movements, wind, arid conditions, and erosion, a number of locations within the National Park have become go-to spots for tourists from around the world.

Source: Martin Kovács/Getty Images

The Isis Temple, for example, sits out in the landscape prominently, reaching as much as 7,000 feet above the sea level elevation. Additionally, the Granite Gorge gets a lot of views, photographs and traffic being one of the iconic towering wall areas that the Colorado River moves through incessantly. And it’s because of that river movement that new things appear every couple of years.


A Controversial New Study

In 2014, researchers pushed out an academic paper which said that the majority view of how the Colorado River formed the Canyon seemed to be incorrect. Instead, the River’s behavior had moved in a very different way.

Source: The Social Stories

In short, the University of New Mexico study, led by geologist Karl Karlstrom, posited that original assumptions about the Canyon’s age were overstated. In fact, they believed the Canyon was younger, likely starting formation only 5 to 6 million years ago instead of the conventional view of 70 million years. No surprise, the argument generated a lot of academic discussion and controvery.


Fossilized Evidence

Fossils are mineral leftovers from organic life. They can be created either by animals or plants. Under the right circumstances, the organic material gets preserved and replaced by minerals.


These minerals then take the form of an organism that eventually deconstructs and breaks down to carbon. When the minerals form in the same shape, a fossil is created. Interestingly, fossils can be created from impressions as well.


A Discovery Older Than Dinos

That was the case with a 2019 Grand Canyon discovery announced by the National Park Service involving the footprints of a tetrapod, a four-legged creature older than ordinary dinosaurs.


This particular species, an Ichniotherium, was never previously known to have lived in a desert region. Yet, if the area had already reached its arid state, the finding would rewrite history about where this species could have lived.


Krill’s Historic Hike

Krill’s discovery proved that no amount of research can compare to time spent out in the field and walking the ground still tends to be the best way to understand the geology of the Grand Canyon. Despite how much research has already been collected, discoveries still pop up.


So, when Krill was leading a team of students through the Canyon in 2016, the last thing he was expecting was to make a great geological discovery himself. The team set off to hike on the Bright Angel Trail, and soon enough Krill was busy taking in the sights and looking at things with a geologist’s eye.


The Strange, Misplaced Rock

The out of place boulder was easy enough to spot, making it a natural attractant to an observer on the trail. However, for Krill, there was a lot more going on, and he wanted a closer look at the boulder’s story. His eye caught an aberration in the stone’s surface that didn’t look right and definitely didn’t look geological.

Source: Simon McGill/Getty Images

Instead, the boulder’s surface had a pattern on it that looked like it was created. In addition, the boulder’s composition gave away its source; the rock type was a clear match to the Manakacha Formation, higher up on the trail’s cliff wall.


The Manakacha Formation

For geologists, the Manakacha Formation is a geology playground. Originally mud and soft Earth in its original form millions of years ago, the mudstone and limestone now tends to be a treasure trove of fossils and captured material preserved in the ancient mud.

Source: AZ Central

As it dried out, the layer turned to rock, and that in turn erodes and breaks apart over time, creating the boulder.


Krill Finds Footprints

What caught Krill’s eye on the boulder’s surface was a marking that looked like a footprint. And, there was more than one. In fact, he discovered a pattern of footprints fossilized in the boulder. Krill took a number of photographs and then sent one of them to a paleontologist for confirmation.

Source: PLOS

Upon examination, Krill’s discovery was dead on; the geologist had indeed discovered a unique and actual specimen of a fossilized footprint track. The finding was confirmed two years later in peer-reviewed academic research by the Society of Vertebrate Paleontology.


How Old Was This Creature?

While Krill’s eye had made the original discovery, the depth of the finding took another year or two to be fully understood. Paleontologists who studied the boulder and formation intently detailed their findings in the fall of 2020, again crediting Krill with a major find. As it turned out, the footprints involved were far older than previous conclusions.

Source: Ballista

Instead, based on the rock formations and material the prints were found in, the prints were estimated to be as old as 313 million years, far earlier than previously known for this type of creature to have existed, much less in the Grand Canyon region. It was a unique find that rewrote the history books, literally.


An Incredible Discovery That Changed History

Scientists concluded that, while they couldn’t identify the creature, it was definitely reptilian and living in an arid location.

Source: PLOS

The tracks are some of the oldest examples of life on Earth based on dating and research, and it was a definite vertebrate type of creature moving on four legs.


A Mysterious Reptile We Didn't Know Existed

For today’s reader, it’s a bit hard to understand how dinosaurs long depicted being in jungles ended up in the desert arid regions of Arizona. Part of the perspective problem comes from the fact that today we think of the world as it is, not as it was.


The continents were far closer together and compacted, with the area that became Arizona being a lot closer to the equator at the time. Somewhere during that time period, a pair of reptiles that were big moved over the mud area that ultimately became frozen in time and preserved as a fossil.


Perfectly Preserved Prints

It’s likely that instead of eroding flat, the tracks were subsequently covered up by water and more mud, which caked and preserved their form.

Source: AFP/Getty Images

That turned into rock over the ages and became fossils in the Manakacha Formation. These footprints were naturally preserved, just waiting to be discovered to reveal the interesting history of the past.


Analyzing the Clues

A lot of the academic debate continues to rage back and forth whether the reptiles tracked through the area are the same time or were separate tracks. Were there two separate reptiles or only one?

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No one really knows for sure since nobody was alive to observe anything at the time that this creature roamed the earth. All we have to go by is the fossilized evidence found in the stones. From there, it’s up to geologists and historians to infer what happened.


How the Creature Walked

However, all accounts do agree that there are two distinct sets of footprint tracks preserved in the boulder. And the mechanics of the walk pressure, impression, gait, and depth of the print say a lot about the type of creature that caused it.

Source: Greg Willis

For example, some of the research pointed out that the direction the reptile walked was in a lateral form versus moving directly forward, like a crab on the sand moving sideways.


The Great Geological Debate

Yet, despite all the academic research published since Krill’s discovery, the boulder and its secret are still being hotly debated. Much of the disagreement centers around exactly what kind of reptile made the tracks, how they were made, and what one should infer from their shape and presence.


It got to the point that many of the academics often have to start off by pointing out that multiple opinions exist and continue to gyrate.


An Ancient Secret Hidden in Plain Sight

As for the rest of the world, those hiking down the Bright Angel Trail just see a big boulder that stands out as a visible shop to stop and catch one’s breath.

Source: Wirepec/Getty Images

That said, visiting geologists, paleontologists and other researchers regularly make a point to stop at the boulder to get a closer look at Krill’s discovery and prints. If folks aren’t looking for it, the majority of hikers walk right past without even realizing what they have just missed.


A Discovery that Will Go Down in History

However, for the scientists, the prints might as well have a blazing neon sign posted over them, enticing all to come visit and check it out. The boulder is truly that exciting of a find and geologists love to visit with its history.

Source: Posnov/Getty Images

And for Krill, his discovery literally makes a print for his name in recorded history, at least in the geology world that will be there long after he has retired from the field.


You Can See The Boulder For Yourself!

It’s incredible that discoveries like this from millions of years ago can still be made today. We’re fortunate that geologists with keen eyes, like Krill spend the time studying to be able to identify these discoveries which help inform us of life before we roamed the earth.

Researchers still debate the prints discovered in the boulder. But, if you want to see them for yourself, the boulder is now a tourist attraction that hikers and geologists alike can visit and enjoy.