New research strengthens case for age of ancient New Mexico footprints
A new line of evidence is providing further corroboration of the antiquity of fossilized footprints discovered at White Sands National Park in New Mexico that rewrite the history of humans in the Americas.
Researchers used a technique called radiocarbon dating to determine that organic matter in the remains of wetland muds and shallow lake sediments near the fossilized foot impressions is between 20,700 and 22,400 years old. That closely correlates to previous findings, based on the age of pollen and seeds at the site, that the tracks are between 21,000 and 23,000 years old.
The footprints, whose discovery was announced in 2021, indicate that humans trod the landscape of North America thousands of years earlier than previously thought, during the most inhospitable conditions of the last Ice Age, a time called the last glacial maximum.
The age of the footprints has been a contentious issue.
Asked how the new findings align with the previous ones, University of Arizona archaeologist and geologist Vance Holliday, the study leader, replied: "Spectacularly well."
Homo sapiens arose in Africa roughly 300,000 years ago and later spread worldwide. Scientists believe our species entered North America from Asia by trekking across a land bridge that once connected Siberia to Alaska. Previous archaeological evidence had suggested that human occupation of North America started roughly 16,000 years ago.
The hunter-gatherers who left the tracks were traversing the floodplain of a river that flowed into an ancient body of water called Lake Otero. The mud through which they walked included bits of semi-aquatic plants that had grown in these wetlands.
Radiocarbon dating is used to determine the age of organic material based on the decay of an isotope called carbon-14, a variant of the element carbon. Living organisms absorb carbon-14 into their tissue. After an organism dies, this isotope changes into other atoms over time, providing a metric for determining age.
"Three separate carbon sources - pollen, seeds and organic muds and sediments - have now been dated by different radiocarbon labs over the course of the trackway research, and they all indicate a last glacial maximum age for the footprints," said Jason Windingstad, a University of Arizona doctoral candidate in environmental science and co-author of the study published this week in the journal Science Advances.
The original 2021 study dated the footprints using radiocarbon dating on seeds of an aquatic plant called spiral ditchgrass found alongside the tracks. A study published in 2023 used radiocarbon dating on conifer pollen grains from the same sediment layers as the ditchgrass seeds.
But some scientists had viewed the seeds and pollen as unreliable markers for dating the tracks. The new study provides further corroboration of the dating while also giving a better understanding of the local landscape at the time.
"When the original paper appeared, at the time we didn't know enough about the ancient landscape because it was either buried under the White Sands dune field or was destroyed when ancient Lake Otero, which had a lot of gypsum, dried out after the last Ice Age and was eroded by the wind to create the dunes," Holliday said.
Today, the landscape situated just west of the city of Alamogordo consists of rolling beige-colored dunes of the mineral gypsum.
"The area of and around the tracks included water that came off the mountains to the east, the edge of the old lake and wetlands along the margins of the lake. Our dating shows that this environment persisted before, during and after the time that people left their tracks," Holliday said.
The area could have provided important resources for hunter-gatherers.
"We know from the abundant tracks in the area that at least mammoths, giant ground sloths, camels and dire wolves were around, and likely other large animals. Given the setting, there must have been a large variety of other animals and also plants," Holliday added.
The climate was markedly different than today, with cooler summers and the area receiving significantly more precipitation.
"It is important to note that this is a trackway site, not a habitation site," Windingstad said. "It provides us a narrow view of people traveling across the landscape. Where they were going and where they came from is obviously an open question and one that requires the discovery and excavation of sites that are of similar age in the region. So far, these have not been found."
Hashtags
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
CNA
15 hours ago
- CNA
New research strengthens case for age of ancient New Mexico footprints
A new line of evidence is providing further corroboration of the antiquity of fossilized footprints discovered at White Sands National Park in New Mexico that rewrite the history of humans in the Americas. Researchers used a technique called radiocarbon dating to determine that organic matter in the remains of wetland muds and shallow lake sediments near the fossilized foot impressions is between 20,700 and 22,400 years old. That closely correlates to previous findings, based on the age of pollen and seeds at the site, that the tracks are between 21,000 and 23,000 years old. The footprints, whose discovery was announced in 2021, indicate that humans trod the landscape of North America thousands of years earlier than previously thought, during the most inhospitable conditions of the last Ice Age, a time called the last glacial maximum. The age of the footprints has been a contentious issue. Asked how the new findings align with the previous ones, University of Arizona archaeologist and geologist Vance Holliday, the study leader, replied: "Spectacularly well." Homo sapiens arose in Africa roughly 300,000 years ago and later spread worldwide. Scientists believe our species entered North America from Asia by trekking across a land bridge that once connected Siberia to Alaska. Previous archaeological evidence had suggested that human occupation of North America started roughly 16,000 years ago. The hunter-gatherers who left the tracks were traversing the floodplain of a river that flowed into an ancient body of water called Lake Otero. The mud through which they walked included bits of semi-aquatic plants that had grown in these wetlands. Radiocarbon dating is used to determine the age of organic material based on the decay of an isotope called carbon-14, a variant of the element carbon. Living organisms absorb carbon-14 into their tissue. After an organism dies, this isotope changes into other atoms over time, providing a metric for determining age. "Three separate carbon sources - pollen, seeds and organic muds and sediments - have now been dated by different radiocarbon labs over the course of the trackway research, and they all indicate a last glacial maximum age for the footprints," said Jason Windingstad, a University of Arizona doctoral candidate in environmental science and co-author of the study published this week in the journal Science Advances. The original 2021 study dated the footprints using radiocarbon dating on seeds of an aquatic plant called spiral ditchgrass found alongside the tracks. A study published in 2023 used radiocarbon dating on conifer pollen grains from the same sediment layers as the ditchgrass seeds. But some scientists had viewed the seeds and pollen as unreliable markers for dating the tracks. The new study provides further corroboration of the dating while also giving a better understanding of the local landscape at the time. "When the original paper appeared, at the time we didn't know enough about the ancient landscape because it was either buried under the White Sands dune field or was destroyed when ancient Lake Otero, which had a lot of gypsum, dried out after the last Ice Age and was eroded by the wind to create the dunes," Holliday said. Today, the landscape situated just west of the city of Alamogordo consists of rolling beige-colored dunes of the mineral gypsum. "The area of and around the tracks included water that came off the mountains to the east, the edge of the old lake and wetlands along the margins of the lake. Our dating shows that this environment persisted before, during and after the time that people left their tracks," Holliday said. The area could have provided important resources for hunter-gatherers. "We know from the abundant tracks in the area that at least mammoths, giant ground sloths, camels and dire wolves were around, and likely other large animals. Given the setting, there must have been a large variety of other animals and also plants," Holliday added. The climate was markedly different than today, with cooler summers and the area receiving significantly more precipitation. "It is important to note that this is a trackway site, not a habitation site," Windingstad said. "It provides us a narrow view of people traveling across the landscape. Where they were going and where they came from is obviously an open question and one that requires the discovery and excavation of sites that are of similar age in the region. So far, these have not been found."
CNA
2 days ago
- CNA
Nvidia-backed AI startup SandboxAQ creates new data to speed up drug discovery
SAN FRANCISCO :SandboxAQ, an artificial intelligence startup spun out of Alphabet's Google and backed by Nvidia, on Wednesday released a trove of data it hopes will speed up the discovery of new medical treatments by helping scientists understand how drugs stick to proteins. The goal is to help scientists predict whether a drug will bind to its target in the human body. But while the data is backed up by real-world scientific experiments, it did not come from a lab. Instead, SandboxAQ, which has raised nearly $1 billion in venture capital, generated the data using Nvidia's chips and will feed it back into AI models that it hopes scientists can use to rapidly predict whether a small-molecule pharmaceutical will bind to the protein that researchers are targeting, a key question that must be answered before a drug candidate can move forward. For example, if a drug is meant to inhibit a biological process like the progression of a disease, scientists can use the tool to predict whether the drug molecule is likely to bind to the proteins involved in that process. The approach is an emerging field that combines traditional scientific computing techniques with advancements in AI. In many fields, scientists have long had equations that can precisely predict how atoms combine into molecules. But even for relatively small three-dimensional pharmaceutical molecules, the potential combinations become far too vast to calculate manually, even with today's fastest computers. So SandboxAQ's approach was to use existing experimental data to calculate about 5.2 million new, "synthetic" three-dimensional molecules - molecules that haven't been observed in the real world, but were calculated with equations based on real-world data. That synthetic data, which SandboxAQ is releasing publicly, can be used to train AI models that can predict whether a new drug molecule is likely to stick to the protein researchers are targeting in a fraction of the time it would take to calculate it manually, while retaining accuracy. SandboxAQ will charge money for its own AI models developed with the data, which it hopes will get results that rival running lab experiments, but virtually. "This is a long-standing problem in biology that we've all, as an industry, been trying to solve for," Nadia Harhen, general manager of AI simulation at SandboxAQ, told Reuters on Tuesday. "All of these computationally generated structures are tagged to a ground-truth experimental data, and so when you pick this data set and you train models, you can actually use the synthetic data in a way that's never been done before."
CNA
6 days ago
- CNA
That cup of coffee may have a surprising perk – a healthier, longer life
Most people who drink coffee appreciate the quick jolt of energy it provides. But in a new study, presented at the annual meeting of the American Society for Nutrition, scientists have found that coffee may offer the much longer-term benefit of healthy ageing. The study has not been peer-reviewed or published, but it was rigorous and included a large number of women who were followed for many years. It also adds to a large body of evidence linking coffee to longer lives and various health advantages, including lower risks of certain chronic diseases – though all of these studies had limitations, including that they were observational and could not prove cause and effect. Still, the results linking coffee to healthier ageing were not surprising, said Fang Fang Zhang, a professor of nutritional epidemiology at Tufts University who was not involved with the study. 'The data is quite consistent that coffee consumption is actually beneficial,' she said. WHAT DID THE NEW RESEARCH FIND? In the study, researchers followed more than 47,000 female nurses for several decades beginning in the 1970s. Every few years, the women answered detailed questions about their diets, including how much coffee, tea and cola (like Coca-Cola or Pepsi) they typically drank. Then, the scientists looked at how many of the women were still alive and met their definition of 'healthy ageing' in 2016. Just over 3,700 women met that criteria: They were 70 or older; reported good physical and mental health, with no cognitive impairment or memory problems; and were free of 11 chronic diseases such as cancer, Type 2 diabetes, heart disease, kidney failure, Parkinson's disease and multiple sclerosis. The researchers found a correlation between how much caffeine the women typically drank (which was mostly from coffee) when they were between 45 and 60 years old and their likelihood of healthy ageing. After adjusting for other factors that could affect aging, such as their overall diet, how much they exercised and whether they smoked, those who consumed the most caffeine (equivalent to nearly seven eight-ounce cups of coffee per day) had odds of healthy ageing that were 13 per cent higher than those who consumed the least caffeine (equivalent to less than one cup per day). Drinking tea or decaffeinated coffee was not associated with healthy ageing, the researchers found. That may be because the study participants generally consumed less tea and decaffeinated coffee overall, so perhaps there were fewer chances for the researchers to find benefits linked to them, said Sara Mahdavi, an adjunct professor of nutritional sciences at the University of Toronto who led the study. Tea and decaf coffee also have less caffeine, and tea has different plant compounds from regular coffee, so that may explain the results, too, she added. Drinking cola, another potential source of caffeine, was associated with significantly decreased odds of healthy ageing. Dr Mahdavi cautioned that while drinking up to seven small cups of coffee per day was associated with healthy ageing in her study, that doesn't necessarily mean that drinking that much will benefit everyone, nor that it is healthy to do so. Research in other groups of people suggests that the health benefits of coffee may plateau or even dip when they drink more than three to four cups per day. WHAT DOES OTHER RESEARCH SUGGEST? Many other studies have linked drinking coffee regularly to a lower risk of early death. In a study of more than 46,000 US adults published in May, Dr Zhang and her colleagues found that those who consumed one to three cups of coffee per day were about 15 percent less likely to die within the next nine to 11 years than those who didn't drink coffee. That benefit disappeared, though, for people who said they typically added more than about a half teaspoon of sugar to their coffee and for people who added more than one gram of saturated fat (equivalent to about one tablespoon of half-and-half or 3.5 tablespoons of whole milk) per cup of coffee. Research has also suggested that people who drink coffee regularly have lower risks of heart disease, Type 2 diabetes, Parkinson's disease, liver disease, osteoporosis and some types of cancer. These kinds of studies can't prove cause and effect, said Aladdin Shadyab, an associate professor of public health and medicine at the University of California, San Diego. But because the benefits associated with coffee have been so consistent, it's unlikely that they are entirely explained by other aspects of a person's life, Dr Zhang said. If anything, drinking coffee is often associated with unhealthy habits, like smoking and less exercise. The fact that you see benefits after accounting for these differences means that coffee is probably helping, Dr Zhang said. HOW MIGHT COFFEE PROTECT YOUR HEALTH? Researchers aren't entirely sure why coffee may be beneficial. 'It's a bit of a mystery,' said Marilyn Cornelis, an associate professor of preventive medicine at Northwestern Feinberg School of Medicine. Studies in mice have found that caffeine may improve memory and protect brain cells from damage. And human studies have found links between regular (not decaffeinated) coffee and a reduced risk of Parkinson's disease. Both regular and decaf coffee contain hundreds of chemical compounds, including many that may lower inflammation and prevent cell damage, Dr Mahdavi said. While the new study didn't find a benefit associated with decaf coffee, other research has linked it, along with regular coffee, to lower rates of Type 2 diabetes and other conditions, Dr Cornelis said. Tea also contains many beneficial compounds, and drinking it has been associated with better heart health and a longer life. WHAT'S THE TAKEAWAY? If you drink coffee regularly, consider the new findings and others like it as good news that it may benefit your health – so long as you don't add too much cream or sugar, Dr Zhang said. But if you don't enjoy coffee, Dr Mahdavi added, there's no need to start drinking it. It can interfere with sleep or make some people feel anxious or jittery.
