Archaeologists recently discovered a set of mysterious ‘ghost footprints’ in the salt flats of the Utah desert that became visible after it rained. The rain had caused the footprints to become moist and darken in color, but they later dried out in the sun and became hard to spot once again.
These unusual ancient tracks get their creepy name not because they are from an ethereal realm, but due to their earthly composition. They were accidentally discovered by researchers in early July as they drove to another nearby archaeological site at Hill Air Force Base in Utah’s Great Salt Lake Desert.
The Salt Lake Desert was once covered by a large, salty lake similar to the nearby Great Salt Lake, the largest saltwater lake in the Western Hemisphere which the desert is named after.
It slowly dried up due to changes in Earth’s climate triggered by the end of the last ice age, which left behind the salts that were once dissolved in the water. But during the transition from lake to dry salt flats, the area was briefly a large wetland that was occupied by humans up until ten thousand years ago, according to the statement.
The team initially only found a handful of footprints, but a thorough sweep of the surrounding area using ground-penetrating radar (GPR) revealed at least eighty-eight individual footprints belonging to a range of adults and children, potentially as young as five years old.
Anya Kitterman, the cultural resource manager at Hill Air Force Base who oversaw the archaeological work, said in a statement: “The discovery of so many ancient footprints is a ‘once-in-a-lifetime discovery’, We found so much more than we bargained for.”
The discovery, however, has not yet been published in a peer-reviewed journal because researchers are still analyzing the footprints.
Ghost footprints identified to be left by bare human feet
10,000 years ago, when the Utah desert was still a vast wetland, it is believed that the ghostly prints were left by bare human feet although researchers suspect that the tracks could date back as far as 12,000 years ago during the final stretch of the last ice age during the Pleistocene epoch (2.6 million to 11,700 years ago).
Maintain that during this time, the conditions would have been perfect to create the ghost footprints, the researchers said.
“People appear to have been walking in shallow water, with the sand rapidly in-filling their print behind them, much as you might experience on a beach,” lead researcher Daron Duke, an archaeologist with Far Western Anthropological Research Group, a private firm that specializes in cultural resources management, said in the statement. “But under the sand was a layer of mud that kept the print intact after infilling.”
Duke added that the footprints have since been filled in with salt as the wetlands dried out, making them indistinguishable from the surrounding landscape when they’re dry.
The Utah desert region is a hotspot for ancient human trackways. In September 2021, a study revealed that sixty human footprints in White Sands National Park in New Mexico dated to between 21,000 and 23,000 years ago, making them the oldest “unequivocal evidence” of humans in the Americas. These footprints were also discovered using GPR.
A previous research group uncovered a hunter-gatherer camp dating to 12,000 years ago, less than a mile (1.6 kilometers) away from where the tracks were uncovered. It is believed that some sort of settlement might have existed there.
Archaeological finds at the site included an ancient fireplace, stone tools used for cooking, a pile of more than two thousand animal bones, and charred tobacco seeds, which are the earliest evidence of tobacco use in humans.
Ghost Footprints exposed due to rains in the Utah Desert
Normally, when it rains, the water is quickly absorbed deep into the surrounding sediment, which means the ground quickly returns to its normal color. However, when the rain falls on top of the hidden muddy footprints, the water gets trapped, creating patches of dark and wet sediment that stand out from their surroundings.
Researchers involved with the new finding have collected some of the footprints in order to determine the exact age. According to the statement, using radiocarbon dating, researchers will be able to analyze small pieces of organic material. It may possibly be material that could have been trapped in the sediment after having been left behind by whomever it was that had walked that path so many years ago.
Thomas Urban, an archaeologist at Cornell University who developed the GPR survey technique used at White Sands and, more recently, at the Hill Air Force Base, said in a statement that they “have long wondered whether other sites like White Sands were out there and whether GPR would be effective for imaging footprints at other locations…the answer to both questions is yes.”
Duke said “there is an immediate human connection to seeing human footprints, [and] to see them from a distant past, especially so much different than it looks today, can be impactful.”
Researchers maintain that these types of discoveries are important because they are direct evidence of human settlement in the area and are much more visceral than other nearby archaeological discoveries.