Latest news with #LastGlacialMaximum
Yahoo
25-06-2025
- Science
- Yahoo
Archaeologists Found 23,000-Year-Old Human Footprints Where They Shouldn't Exist
Here's what you'll learn when you read this story: Researchers determined that footprints in White Sands National Park in New Mexico are from the oldest migrants to North America. The footprints first made headlines after a study published in 2021 claimed that they were thousands of years older than the Clovis people of New Mexico, who had long been thought to be the first North American culture. Who these nomadic people were—or whether they stayed in New Mexico or moved on—is still unknown. An endless ocean of white sprawling across New Mexico's Tularosa Basin, White Sands National Park glitters with dunes of gypsum sand. From those sands have surfaced footprints that would rewrite human history. Found in ancient clay that had long since hardened to stone, the footprints were thought to be anywhere from 21,000 to 23,000 years old. Controversy surrounded the finding—if these tracks really were that ancient, it would mean that they were even older than the Clovis people from the late Pleistocene, whose name comes from a site in New Mexico that was thought to be the oldest known settlement in North America. Whether or not these tracks really did predate the Clovis culture would be debated for years until the investigation was reopened. Archaeologist and geologist Vance Holliday—now a professor emeritus at the University of Arizona—started researching the geologic strata of White Sands in 2012. In 2019, researchers from Bournemouth University in the UK teamed up with the U.S. National Park Service for the excavation that resulted in the discovery of the footprints, and some of Vance's data on the ages of seeds and pollen in the area was used to date the prints for a study published in 2021. If the age of the footprints was correct, that would make them 10,000 years older than the Clovis people. With doubts surrounding that study, Vance became determined to prove their age, and finally succeeded by dating the mud rock they were imprinted on. 'The issue of the arrival of the first Americans has long been contentious and the record from the White Sands locality generated considerable debate focused on the validity of the dating,' he said in a new study recently published in the journal Science Advances. The age of the footprints coincides with the final phase of the Pleistocene epoch, otherwise known as the Last Glacial Maximum. Ice sheets that blocked the Bering Land Bridge between Asia and North America made human migration impossible. This could potentially mean that the first people to settle in North America crossed over before Earth plunged into a deep freeze—a time period which aligns with the age of the footprints, as confirmed by Vance. What is now the Tularosa Basin was once the bottom of a paleolake called Lake Otero that formed after the snow and ice melted. Flows of melted snow brought dissolved gypsum to Lake Otero, which emerged as an expanse of white sand when the lake evaporated into a dry playa. Erosion may have erased some of this history forever, but beneath the sand, fossils of megafauna like mammoths and ground sloths were still preserved—alongside the controversial footprints. Whoever made these prints traveled through marshlands before Lake Otero formed and walked through gley—mud that is too waterlogged for oxygen to penetrate. Organisms in the mud instead turn to iron and manganese compounds in this mud to survive, chemically breaking down these compounds and turning the mud shades of blue, green, or gray. The gley was radiocarbon dated to anywhere between 20,700 and 22,400 years old, supporting previous findings that came close to that range. Before this, Vance had relied on pollen remnants and the seeds of the aquatic plant Ruppia cirrhosa (also known as spiral tasselweed or ditchgrass) to date the impressions. 'At the time that the human tracks were created […] there was an extensive body of standing but shallow water or wetlands in proximity to the trackways throughout the period of human activity,' Vance said. If this is proof of what could be the first humans who migrated to the Americas, then why did they only leave footprints? The absence of artifacts might be explained by nomadic life. Vance thinks that one of the trackways was easily walked over in only seconds, and hunter-gatherers might have only been passing through the basin while holding onto tools and supplies that were not easily replaced. Who these enigmatic people were remains a mystery burried in the sands of time. You Might Also Like The Do's and Don'ts of Using Painter's Tape The Best Portable BBQ Grills for Cooking Anywhere Can a Smart Watch Prolong Your Life?
Yahoo
19-06-2025
- Science
- Yahoo
Evidence is building that people were in the Americas 23,000 years ago
When you buy through links on our articles, Future and its syndication partners may earn a commission. The age of "rarely preserved" ancient human footprints dotting the landscape at White Sands National Park in New Mexico has been hotly debated for years. Now, a new study has found that these footprints really are around 23,000 years old — but the date isn't accepted by everyone. If the 23,000-year-old age is accurate, it would mean that humans were in North America around the peak of the Last Glacial Maximum, the coldest part of the last ice age — far earlier than archaeologists had previously thought. In the new study, the researchers radiocarbon-dated organic sediment in core samples from the site, which provided dates for the footprints as well as for the entire paleolake and river system that once existed there. The analysis was done in labs unaffiliated with earlier studies. "Our data supports the original data" that dated the site to 23,000 years ago, study first author Vance Holliday, a professor emeritus of anthropology and geosciences at the University of Arizona, told Live Science. "Plus, we now have an idea of what the landscape was like when people were out there." The saga of dating the roughly 60 footprints goes back to 2021, when a study reported the discovery of the footprints and dated them to between 21,000 and 23,000 years old. However, a 2022 rebuttal took issue with using the seeds of ditch grass (Ruppia cirrhosa), a water plant, for radiocarbon dating. Water plants get their carbon from underwater, which can be much older than carbon from the atmosphere. This can skew the levels of carbon 14, a radioactive version of the atom, in the samples, making the plants appear older than they really are. So, in 2023, researchers redated the site with optically stimulated luminescence (OSL) dating, which revealed when quartz or feldspar grains in the tracks were last exposed to sunlight, and radiocarbon dating of ancient conifer pollen from the footprint layer — which proved to be another way to use carbon 14 without relying on water plants. Related: The 1st Americans were not who we thought they were Again, the scientists found that the footprints were 21,000 to 23,000 years old. While some scientists called the results "very convincing," others, including those who wrote the 2022 rebuttal, were still wary of the results, saying the samples weren't taken from the right layer. Now, the new study offers more evidence that the footprints date to the Last Glacial Maximum, when the area was a vast wetland inhabited by ice age animals. The footprints likely came from hunter-gatherers who arrived in the Americas after traveling along the Bering Land Bridge, which connected Siberia and Alaska when sea levels were lower, research suggests. For decades, researchers thought the earliest Americans were the Clovis, who lived in North America around 13,000 years ago. But the footprint discovery and others are slowly revealing that Indigenous people reached the Americas much earlier than thought. Holliday has been working at White Sands since 2012, and some of his data was used in the original 2021 study, making him a co-author, he noted. This time, Holliday and his colleagues radiocarbon-dated mud cores from the site. They found that the trackways date to between 20,700 and 22,400 years ago, which closely matches the original dates. When added together, there are now a total of 55 radiocarbon-dated samples of mud, seeds and pollen from the footprint layer that support the 21,000- to 23,000-year-old dates, Holliday said. Ancient human footprints are "so rarely preserved," he said. And now, scientists have "dates on three different materials that all coincide" on a time for these tracks. "You get to the point where it's really hard to explain all this away," he said in a statement. "As I say in the paper, it would be serendipity in the extreme to have all these dates giving you a consistent picture that's in error." However, more work is needed to securely date the footprints at White Sands, said Michael Waters, director of the Center for the Study of the First Americans at Texas A&M University, who was not involved with the study. "Even with these new data, I remain concerned about the radiocarbon ages generated to date the footprints at White Sands," Waters told Live Science in an email. He reiterated the known Ruppia issue, saying the radiocarbon dates "are likely too old" because the plant got its carbon from the water. In fact, the same underwater carbon issues could have also affected the sediments dated in the new study, he said. "The new ages on bulk organic sediments presented in this paper are interesting, but it is unclear about the origin of the carbon being dated," Waters said. RELATED STORIES —13 of the oldest archaeological sites in the Americas —Ice age children frolicked in 'giant sloth puddles' 11,000 years ago, footprints reveal —How did humans first reach the Americas? Furthermore, Holliday and his colleagues acknowledge that their study doesn't address another hot-button issue: Where are the artifacts or settlements from these ice age people at White Sands? That question remains to be answered, Holliday said. But it's unlikely that hunter-gatherers would have left behind valuable items in the short time it took them to trek around the wetland. "These people live by their artifacts, and they were far away from where they can get replacement material," Holliday said in the statement. "They're not just randomly dropping artifacts. It's not logical to me that you're going to see a debris field."
Yahoo
19-06-2025
- Science
- Yahoo
Scientists Just Proved That All Life on Earth Follows One Simple Rule
"Hearst Magazines and Yahoo may earn commission or revenue on some items through these links." Here's what you'll learn when you read this story: The organization of life on Earth follows a simple, hidden rule known as 'core-to-transition organization.' Hypothesized by biogeographers for centuries, a new study finally finds empirical evidence of this phenomenon using geographic dispersion data across five separate taxa. This shows how a majority of species originate from 'core regions,' but those species suitable to heat and drought often colonize areas beyond those regions. The Earth is home to incredibly remarkable and diverse biomes that host millions of species worldwide. (George Lucas managed to create an entire galaxy far, far away for Star Wars using just the natural wonders mostly found in the state of California.) Although life appears relatively well-distributed across countries and continents—barring Antarctica, of course—a new study suggests that biodiversity isn't so much an evenly distributed blanket across the planet as it is a 'core-to-transition' organization. This is the insight gleaned from a new article—published earlier this month in the journal Nature Ecology & Evolution—analyzing how organisms are divided into biogeographical regions, or bioregions, across the planet's surface. An international team of scientists from Sweden, Spain, and the U.K. examined the global distribution maps of species across a variety of limbs on the tree of life, including amphibians, birds, dragonflies, mammals, marine rays, reptiles, and even trees. Because of this vast swath of differing types of life, the researchers expected that species distribution would vary wildly due to environmental and historical factors. However, what they discovered is that life all around the world proliferates through a very similar process. First, there is a core area where life appears to flourish, and from there, species tend to radiate outward—hence 'core-to-transition' organization. 'In every bioregion, there is always a core area where most species live,' Rubén Bernardo-Madrid, a co-author of the study from Umeå University, said in a press statement. 'From that core, species expand into surrounding areas, but only a subset manages to persist. It seems these cores provide optimal conditions for species survival and diversification, acting as a source from which biodiversity radiates outward.' These 'core' regions are immensely important, as they only cover about 30 percent of the world's surface but contain more biodiversity than the other 70 percent. These regions likely evolved because they were originally refuges from the devistation brought on by past climatic events, such as the Last Glacial Maximum. The study also shows that overall species must be well adapted for heat and drought to colonize new areas beyond these core bioregions. 'The predictability of the pattern and its association with environmental filters can help to better understand how biodiversity may respond to global change,' Joaquín Calatayud, co-author of the study from Rey Juan Carlos University, said in a press statement. Of course, this core-to-transition organization idea isn't a new one. Biogeographers have largely illustrated this phenomenon over the centuries, but this is the first time that empirical evidence has confirmed these long-standing suspicions. Understanding the relationship between life and these bioregions can help inform conservation decisions while predicting how certain species may respond to a new type of climatic uncertainty—anthropogenic climate change. 'Our core-to-transition hypothesis and results,' the authors wrote, 'show that global variations in species richness can be better understood by unravelling the genesis of regional hotspots and the subsequent filtering of species to the rest of the biogeographical region.' You Might Also Like The Do's and Don'ts of Using Painter's Tape The Best Portable BBQ Grills for Cooking Anywhere Can a Smart Watch Prolong Your Life?
Time of India
19-06-2025
- Science
- Time of India
Who really were the first Americans? New study debunks earlier theory
A new study has reignited debate over the age of human footprints discovered at White Sands National Park in New Mexico. These ancient tracks, first revealed in 2021, were initially dated to between 21,000 and 23,000 years ago — suggesting humans lived in North America during the peak of the last Ice Age, far earlier than previously thought. To verify these findings, researchers led by Vance Holliday of the University of Arizona conducted fresh radiocarbon dating on organic sediments from core samples at the site. Their results aligned with the earlier estimates, placing the footprints firmly within the Last Glacial Maximum. The analysis, conducted in independent labs, adds weight to the theory that humans occupied the region around 23,000 years ago. "Our data supports the original data" that dated the site to 23,000 years ago, study first author Vance Holliday, a professor emeritus of anthropology and geosciences at the University of Arizona, told Live Science. "Plus, we now have an idea of what the landscape was like when people were out there." by Taboola by Taboola Sponsored Links Sponsored Links Promoted Links Promoted Links You May Like Access all TV channels anywhere, anytime Techno Mag Learn More Undo The footprints, likely left by Ice Age hunter-gatherers, suggest early migration via the Bering Land Bridge from Asia to North America. If confirmed, this would challenge the long-held belief that the Clovis people — who arrived around 13,000 years ago — were the first inhabitants of the Americas. Dating the tracks has proven controversial. In 2022, skeptics argued that radiocarbon dating of ditch grass (a water plant) may have yielded misleadingly old results due to underwater carbon contamination. To address this, researchers later used optically stimulated luminescence (OSL) and pollen-based radiocarbon methods, which again confirmed the original timeline. Live Events The latest study brings the total number of radiocarbon-dated samples from the footprint layer to 55, including mud, seeds, and pollen. 'It would be extreme serendipity for all these independent dates to be wrong,' Holliday said. Still, some experts remain cautious. Michael Waters of Texas A&M told Live Science that the source of the organic carbon is unclear and could still be affected by old water-derived carbon. He also pointed out the absence of associated artifacts or tools, though Holliday argues this is consistent with mobile hunter-gatherer behavior. Despite lingering doubts, the growing body of evidence points to a much earlier human presence in North America than previously accepted — a discovery that may reshape our understanding of the continent's earliest settlers.
Yahoo
08-06-2025
- Health
- Yahoo
Bed Bugs May Have Been The First Urban Pest to Ever Plague Humans
Humans were letting the bed bugs bite long before beds existed, and while they do live on other species, we're the main reason this notorious parasite is still going strong. In fact, bed bugs might have been the first pest to plague our cities – earlier than the black rat, for instance, which joined us in urban life about 15,000 years ago, and even the German cockroach, which only got the memo about 2,100 years ago. Researchers think the blood-sucking pests – Cimex lectularius – first jumped from their bat hosts onto a passing human some 50,000 years ago, a move which would change the course of the insect species forever. Human bed bugs, it turns out, have boomed since the Last Glacial Maximum about 20,000 years ago. But it's a different story for those populations that continued living on bats. "Initially with both populations, we saw a general decline that is consistent with the Last Glacial Maximum; the bat-associated lineage never bounced back, and it is still decreasing in size," says entomologist Lindsay Miles, from Virginia Tech. "The really exciting part is that the human-associated lineage did recover and their effective population increased." The researchers were able to track this evolution because the human bed bugs have a much narrower genetic diversity, since only a few 'founders' probably came with us when we abandoned life in caves. But our move into cities around 12,000 years ago is what really kicked off the human bed bug boom. This was only briefly interrupted when DDT was invented in the 1940s. Populations crashed, humans slept sweetly, and then five years later, the bed bugs were back. Since then, bed bugs have travelled around the world with us, and even become resistant to our pesticides. For now, it seems, bed bugs are here to stay. It's been a long-term relationship, after all. The research is published in Biology Letters. Your Brain Wrinkles Are Way More Important Than We Ever Realized Something Strange Happens to Your Eyes When You're Sexually Aroused 2-Year-Old Prodigy Joins 'High IQ' Club Mensa as Youngest Member Ever
