A few interesting theories exist about how the first humans found their way into North America after dispersing from Africa and Asia. But we may finally have some concrete evidence to make valid scientific claims and discard other assumptions.
The most significant attempt at determining when humans first walked across North America was made a few years back. In 2021, a group of researchers published a study with a stunning discovery that shed light on an intriguing mystery: When did humans first arrive in North America after migrating from Asia and Africa?
In their findings, they discovered fossilized footprints in New Mexico that indicate early humans were walking across North America around 23,000 years ago. The footprints were detected in a dry lake bed in White Sands National Park in 2009.
To determine the approximate age of these footprints, scientists at the U.S. Geological Survey then analyzed the seeds stuck in them and stated the approximate age to be between 22,800 and 21,130 years. Based on the footprint sizes, the scientists noted that some were made by children and teenagers who were part of the last ice age population.
“These findings confirm the presence of humans in North America during the Last Glacial Maximum, adding evidence to the antiquity of human colonization of the Americas and providing a temporal range extension for the coexistence of early inhabitants and Pleistocene megafauna,” the study concluded.
However, these findings were met with skepticism in the scientific world.
In what can be called a strong confirmation of the 2021 findings by the same researchers, a new study published in the journal Science has confirmed that humans indeed walked the landscape of North America much earlier than we previously believed.
The study employed two additional dating approaches to confirm what was previously known about the age of the fossilized footprints discovered in New Mexico. Optically stimulated luminescence and radiocarbon dating techniques revealed that the footprints date to about 21,000 to 23,000 years ago.
“Every dating technique has strengths and weaknesses, but when three different techniques all converge on the same age range, then the resulting ages are exceptionally robust,” explained Jeff Pigati, a research geologist at the U.S. Geological Survey (USGS) in Denver and co-lead author of the paper.
The findings of their 2021 studies “were controversial,” thus necessitating an independent evaluation of the seed ages to develop community confidence in them.
Using radiocarbon dating on conifer pollen isolated from the same sediment layers as the ditch grass seeds, the scientists found that the pollen age statistically matched the seed age. They also used optically stimulated luminescence dating to estimate the age of the quartz grains in the footprint-bearing sediments.
Matthew Bennett is a co-author of the study and a professor of environmental and geographical sciences at Bournemouth University in England. He explained that “the work confirms the chronology set out in 2021 for the site using independent methods, labs, and approaches.”
The new dates confirm the imagery of a once lush landscape at White Sands. Over 20,000 years ago, the area was home to giant sloths, mammoths, and camels living near a lake. The human footprints suggest that modern humans also lived in White Sands National Park during the last ice age. How they got there is still a mystery.
With the study further supporting the presence of humans in North America during the last ice age, the global scientific community can finally put other theories to rest.
Cynthia Liuktus-Pierce, a Geologist at the Appalachian State University, shared similar sentiments. “This is exciting and will certainly have scientists rethinking how humans interacted with the North American environment during the [Last Glacial Maximum],” she remarked.
The last Ice Age, an era that grips the imagination, played a pivotal role in shaping the modern world. Let’s dive into this frigid period and explore its features, causes, and lasting impact.
Often called the Last Glacial Maximum (LGM), it peaked around 21,000 years ago. During this period, vast ice sheets covered significant portions of North America, Europe, and Asia.
Several factors contributed to the onset of the Ice Age. Orbital changes, known as Milankovitch cycles, altered the amount and distribution of solar energy reaching Earth’s surface.
These factors impacted global temperatures, initiating periods of cooling. Additionally, volcanic activity, shifting ocean currents, and fluctuations in greenhouse gas levels played roles in driving the Earth into a prolonged cold phase.
Life adapted to these chilly conditions. Woolly mammoths, saber-toothed cats, and giant ground sloths roamed the icy landscapes.
Humans, too, showed resilience. They crafted specialized tools, developed new hunting strategies, and wore animal skins to stave off the cold. These adaptations not only ensured survival but also fostered innovation and creativity.
The Ice Age didn’t end abruptly. As Earth’s orbit began to allow more sunlight to hit the northern hemisphere, temperatures slowly rose.
The ice sheets began to retreat, carving valleys, forming lakes, and reshaping landscapes in the process. The meltwater also contributed to rising sea levels, creating the coastlines we recognize today.
The Ice Age left an indelible mark on the planet. Glacial valleys, moraines, and fjords showcase the power and movement of these ancient ice masses. The melting glaciers also filled basins, creating the Great Lakes of North America. Moreover, as humans migrated and adapted to changing environments, new cultures and ways of life emerged.
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