A new study published in Nature reveals that the first humans to colonize Europe arrived from the east 1.4 million years ago, much earlier than previously thought. The researchers used a novel dating method based on cosmic rays to date stone tools found at a site in western Ukraine called Korolevo.
The origin and evolution of early humans in Europe is a topic of great interest and debate among scientists and the public. When did the first humans arrive in Europe? Where did they come from? How did they adapt to the new environment? What was their relationship with later human groups? These are some of the questions that researchers try to answer using various sources of evidence, such as fossils, DNA, and artifacts.
One of the most important types of evidence is stone tools, which can provide clues about the culture, behavior, and technology of early humans. Stone tools are also more durable and abundant than fossils or DNA, which makes them easier to find and study. However, dating stone tools can be challenging, especially for very old sites that are beyond the range of conventional methods.
A new study, led by a team from the Czech Academy of Sciences and Aarhus University and published this week in Nature, reports the earliest human presence in Europe, at a site on the Tysa River in western Ukraine known as Korolevo. The researchers used a novel dating method based on cosmic rays to date stone tools found at the site, and found that they were 1.4 million years old, making them the oldest evidence of human presence in Europe.
The Oldowan Culture
The stone tools belong to the Oldowan culture, the most primitive form of tool-making, which originated in Africa and spread to other continents. The Oldowan culture is named after Olduvai Gorge in Tanzania, where the first tools of this type were discovered by Mary Leakey in 1959. The Oldowan tools consist of simple flakes and cores that were used for cutting, scraping, hammering, and digging.
The Oldowan culture is associated with the earliest members of the genus Homo, such as Homo habilis and Homo erectus. These early humans had larger brains and bodies than their ancestors, and were capable of making and using tools, controlling fire, and communicating with gestures and sounds. They also expanded their range from Africa to Asia and Europe, following environmental changes and resources.
The Korolevo Site
The Korolevo site was first discovered in 1974 by the Ukrainian archaeologist V. N. Gladilin, who noticed stone tools exposed by workers at a stone quarry. The site is located on a terrace of the Tysa River, which is a tributary of the Danube River. The site contains several layers of sediments and artifacts that span different periods of human occupation.
The researchers focused on the lowermost layer of stone tools, which was left on a river bed by the early humans who crafted them. The tools were later buried by river sediment and then by wind-blown dust, which preserved them from erosion and disturbance. The researchers excavated more than 200 stone tools from this layer, including choppers, flakes, cores, and scrapers.
The Dating Method
The researchers used a dating method called cosmogenic nuclide burial dating to determine the age of the stone tools and the surrounding sediments. This method relies on the fact that cosmic rays from outer space constantly bombard Earth’s surface and produce radioactive nuclides in rocks and soils. These nuclides accumulate over time until they are buried by other materials, which shield them from further exposure to cosmic rays.
By measuring the amount of radioactive nuclides in quartz grains from the tools and the sediments, the researchers could calculate how long they had been exposed to cosmic rays before being buried. This gave them an estimate of when the tools were made and left on the river bed by the early humans.
The researchers measured two different nuclides: aluminium-26 and beryllium-10. They found that the tools had been exposed to cosmic rays for about 1.4 million years before being buried by river sediment. This means that the tools were made around 1.4 million years ago, making them the oldest evidence of human presence in Europe.
The researchers also checked their results against other independent lines of evidence, such as magnetic polarity and fossil remains. They found that their results were consistent with these other sources of information. For example, they confirmed that the sediments containing the tools had a reversed magnetic polarity, indicating that they predated the last reversal of Earth’s magnetic field 0.8 million years ago.
The Implications
The study has important implications for our understanding of human evolution and migration in Europe. It shows that the first humans to colonize Europe arrived from the east 1.4 million years ago, much earlier than previously thought. Previous studies had suggested that the earliest human presence in Europe was around 1.2 million years ago, based on fossils and tools from sites in Spain and Italy.
The study also suggests that the first Europeans arrived during a warm period in Earth’s history, known as an interglacial, when glaciers retreated and new landscapes emerged. The early humans probably followed rivers and animal migrations across Asia and into Europe, where they encountered a Terra nullius unoccupied by other humans.
The study also sheds light on the evolution and migration of early humans, who may have belonged to the species Homo erectus or a closely related one. The researchers speculate that these early colonizers may have interbred with later arrivals, such as Homo heidelbergensis and Homo neanderthalensis, contributing to the genetic diversity of modern Europeans.
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