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An analysis of ancient genomes reveals an explosive geographical and demographic spread of modern domestic horses about 4,200 years ago. The findings counter the idea that horses accompanied and mobilized the mass migration of humans from the Eurasian steppes about 5,000 years ago.
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The Neolithic farmers and herders who built a massive stone chamber in southern Spain nearly 6,000 years ago possessed a good rudimentary grasp of physics, geometry, geology and architectural principles, finds a detailed study of the site.
Using data from a high-resolution laser scan, as well as unpublished photos and diagrams from earlier excavations, archaeologists pieced together a probable construction process for the monument known as the Dolmen of Menga. Their findings, published on 23 August in Science Advances1, reveal new insights into the structure and its Neolithic builders’ technical abilities.
Stonehenge’s enigmatic centre stone was hauled 800 kilometres from Scotland
The dolmen pre-dates the main stone circle at Stonehenge in the United Kingdom by about 1,000 years, but the construction process described in the study would have involved similar techniques and demanded a similar level of engineering.
“These people had no blueprints to work with, nor, as far as we know, any previous experience at building something like this,” says study co-author Leonardo García Sanjuán, an archaeologist at the University of Seville in Spain. “And yet, they understood how to fit together huge blocks of stone” with “a precision that would keep the monument intact for nearly 6,000 years”.
“There’s no way you could do that without at least a basic working knowledge of science,” he adds.
To construct the dolmen, its builders transported 32 giant stone blocks from a quarry around one kilometre away and used them to form the walls, pillars and roof of a massive chamber measuring around 28 metres long, 6 metres wide and 3.5 metres high. The largest of these blocks, one of the capstones that forms part of the roof, is 8 metres long and weighs an estimated 150 tonnes. By comparison, the biggest stone used to build Stonehenge weighs about 30 tonnes.
Transporting these huge slabs from the quarry to the site without breaking them would have required particular care, the researchers say, particularly with the soft sandstone used for the roof. They suggest that this could have been done using specially built wooden tracks to reduce friction as the stones were dragged along, much as the builders of Stonehenge are thought to have done.
The dolmen’s stones are fitted together with high precision, suggesting that the people who built the tomb understood principles of science and engineering.Credit: Album/Alamy
Another task that demanded precision and skill was finessing the upright slabs into sockets carved 1.5 metres deep into the bedrock. The laser scans revealed that the builders used counterweights and ramps to move the uprights carefully into the sockets, tilting them at precise, millimetre-scale angles. The stones were carved into facets that meant they locked against their neighbours when the weights and ramps were removed.
These ancient whittled logs could be the earliest known wooden structure
“I’ve always been amazed by the engineering skills needed to build this dolmen,” says Michael Parker Pearson, an archaeologist at University College London. “This paper reveals just how precisely that has to have been done, with an extraordinary eye on dimensions and angles. With such big stones, they could not have afforded to make mistakes when manoeuvring them into position. If even just one was a few centimetres out, that would have been hard to correct once an upright stone was set in its trench.”
Parker Pearson adds that the prehistoric engineers’ understanding of physics and geometry resulted in a ‘super-solid monument’. “It’s the sort of thing we see at Stonehenge a thousand years later, with the mortise and tenon joining of uprights and lintels.”
But unlike Stonehenge, the Dolmen of Menga is in a seismically active, earthquake-prone area. Despite this, after nearly 6,000 years, the stonework is still snug and secure, says García Sanjuán. “These people really knew what they were doing.”
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Nature, Published online: 20 August 2024; doi:10.1038/d41586-024-02666-1
The problems of political planning in 80 countries, and chemistry’s contributions to archaeology, in this week’s snippets from Nature’s archive.
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doi: https://doi.org/10.1038/d41586-024-02531-1
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The Xingu Indigenous Territory in the Amazon may contain over 900 square kilometres of dark earth
Leo F Freitas/Getty Images
Rich soil in the Amazon cultivated over centuries by Indigenous communities may store billions of tonnes of carbon, suggesting that the rainforest plays an even larger role in stabilising the global climate than previously thought.
The soil, known as “terra preta” or “dark earth” for its distinctive colour, is formed by people spreading ash and other organic waste around settlements. It is more fertile than the region’s typically sandy, nutrient-poor soils, and stores around double the carbon. In some areas,…
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The culture that built Stonehenge suffered a mysterious population decline
Wirestock, Inc./Alamy
The Neolithic culture in Europe that produced megastructures such as Stonehenge went into a major decline around 5400 years ago. Now we have the best evidence yet that this was due to plague.
Sequencing of ancient DNA from 108 individuals who lived in northern Europe at this time has revealed that the plague bacterium Yersinia pestis was present in 18 of them when they died.
“We think that the plague did kill them,” says Frederik Seersholm at the University of Copenhagen in Denmark.
Around 5400 years ago, the population of Europe fell sharply, particularly in northern regions. Why this happened has long been a mystery.
Over the past decade, studies of ancient human DNA have revealed that local populations didn’t fully recover from the Neolithic decline. Instead, they were largely replaced by other people moving in from the Eurasian steppes. In Britain, by around 4000 years ago, for instance, less than 10 per cent of the population was derived from the people who built Stonehenge.
These studies of ancient humans also revealed several cases where the plague bacterium was present. This suggested a potential explanation – the plague might have wiped out Europe’s population, allowing the steppes people to move in with little opposition.
But not everyone agreed. Occasional sporadic plague cases are to be expected and aren’t evidence of a major pandemic, argued Ben Krause-Kyora at Kiel University in Germany in 2021. These early forms of Y. pestis were unlikely to cause a pandemic because their DNA shows they couldn’t survive in fleas, he and his colleagues wrote. Bites from infected fleas are the main way people contract bubonic plague, the form of the illness that killed people during the medieval Black Death.
So Seersholm and his colleagues set out to find more evidence of a plague pandemic. The 108 individuals whose DNA his team managed to sequence were buried in nine tombs in Sweden and Denmark. Most died between 5200 and 4900 years ago, and they represent several generations of four families.
There seem to have been three separate outbreaks of the plague over these generations. The last outbreak was caused by a strain with reshuffled genes that might have been much more dangerous.
“It’s present in a lot of individuals,” says Seersholm. “And it’s all the same version, which is exactly what you would expect if something spreads very quickly.”
The plague DNA was found mainly in teeth, which shows that the bacterium entered the blood and caused serious illness, and was probably the cause of death, he says. In some cases, closely related individuals were infected, implying person-to-person spread.
The team suggests this could be a result of Y. pestis infecting the lungs and spreading via droplets – a form of the illness known as pneumonic plague. Recent studies also indicate that human lice can cause bubonic plague, not just fleas, so it is possible that plague bacteria spread by this route.
“Of course, it’s worth noting that all of these individuals were buried properly,” says Seersholm, so society hadn’t broken down at this time. “If there was in fact an epidemic, we only see the very beginning of it.”
After about 4900 years ago, the megalithic tombs seem to have been abandoned for centuries. But 10 of the sequenced individuals were buried in them much later, most between 4100 and 3000 years ago. These individuals were of steppes origin, unrelated to those who built the tombs.
“It is 100 per cent complete replacement,” says Seersholm. “Five thousand years ago, these Neolithic people disappear. And now we show that plague was widespread and abundant at exactly the same time.”
The researchers aren’t claiming their findings are definitive, but they do bolster the case that plague caused the Neolithic decline, says Seersholm.
“I would say that we’ve definitely shown that it had the potential to spread within humans, and that it had the potential to kill an entire family, for example.”
Krause-Kyora accepts that the findings show the plague was highly prevalent in this particular place and time. “Our previous explanation needs to be revised somewhat, and we can’t just talk about isolated cases,” he says.
But there is no evidence of high prevalence in other regions, he says. And he thinks the normal burials show there was no deadly epidemic. “The results could even suggest that the Yersinia infection was more of a chronic disease over a long period of time.”
Seersholm and his team will now look for more evidence elsewhere in Europe. But the only way to know for sure how deadly the reshuffled strain was would be to bring it back to life, he says, and that is far too risky to attempt.
“I think that this paper will convince many colleagues who were skeptical about our previous work,” says Nicolás Rascovan at the Pasteur Institute in Paris, whose team proposed in 2018 that the plague was responsible for the Neolithic decline after finding it in two individuals from the period.
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A hoard of Roman gold coins found below the floor of a Roman house in Corbridge, UK
World History Archive/Alamy
After the Romans conquered Britain in AD 43, the technologies and laws they introduced led to centuries of economic growth of a kind once thought to be limited to modern industrial societies. That is the conclusion of an analysis of thousands of archaeological finds from this time.
“Over that period of about 350 years, you’re looking at roughly a two and a half [fold] increase in productivity per capita,” says Rob Wiseman at the University of Cambridge.
It has long been believed that economic growth in the ancient world depended on having more people and more resources, says Wiseman: to increase food production, say, required more land and more farm workers. This kind of growth is known as extensive growth.
By contrast, economic growth today is driven mainly by increased productivity, or intensive growth. Thanks to mechanisation and better breeds of plants and animals, for instance, more food can be produced from the same area of land with fewer workers.
Some recent studies have challenged the idea that intensive growth occurred only after the industrial age began, inspiring Wiseman and his colleagues to look at growth in Roman Britain from AD 43 to 400.
The team’s research was made possible by UK laws requiring archaeological investigations to be done when a site is developed, says Wiseman. “The result is there’s been tens of thousands of archaeological excavations done in this country. And, moreover, that data is publicly accessible.”
By looking at how the number of buildings changed over time, the researchers were able to get an idea of how the population of Roman Britain grew. There is a strong relation between the number of buildings and population size, says Wiseman.
To get an idea of economic growth, the team looked at three measures. One was the size of buildings, rather than the number of them. As people grow richer, they build bigger houses, says Wiseman.
Another measure was the number of lost coins found in digs. “These are things that have fallen through the floorboards, or they’ve been lost in the baths, or something like that,” he says.
The idea is that the more coins are in circulation, the more are likely to be lost. The team didn’t count hidden hoards of coins, as these reflect instability rather than growth.
The third measure was the proportion of crude pottery, such as cooking pots and storage pots, to more ornate pottery like decorated plates. Economic growth requires people to interact more and socialise more, which means “showing off” when guests are present, says Wiseman.
Based on these measures, the team found that economic growth exceeded that expected from population growth alone. They estimate that per capita growth was around 0.5 per cent between AD 150 and 250, slowing to around 0.3 per cent between AD 250 and 400.
“What we’re able to show is yes, after the Romans arrived, there was definitely intensive growth,” says Wiseman. The pace of growth rather than the kind of growth is what probably distinguishes the modern world from the ancient one, he says.
The researchers think that this growth was driven by factors such as the roads and ports built by the Romans, the laws they introduced making trading safer, and their technologies, such as more advanced grain mills and better breeds of animals for ploughing.
The higher growth between AD 150 and 250 may be a result of Britain catching up with the rest of the Roman world, says Wiseman. “You’re moving from a small tribal society where there’s not a lot of interaction going on to a world-spanning economy.”
What isn’t clear is whether this economic development made people happier or healthier. “Just because the productivity is going up doesn’t automatically mean that the welfare of Britons who were invaded and colonised was better under Rome,” says Wiseman. “That’s an open question.”
To investigate this, the researchers now plan to look at human remains to work out things such as how long people lived.
“I am convinced that they are right and that, indeed, intensive growth took place in Roman Britain,” says Alain Bresson at the University of Chicago, Illinois.
“A lot of archaeologists have noted compelling evidence for economic growth in Roman Britain, but this paper adds a welcome formal theoretical dimension to the discussion,” says Ian Morris at Stanford University, California.
However, Morris suspects that the lower average growth rate from AD 250 to 400 actually reflects high growth followed by rapid decline as the Roman empire began to break up. Further studies will resolve this, he says.
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The people of Easter Island built hundreds of monolithic statues called moai
Stephanie Morcinek via Unsplash
The widespread claim that the ancient people of Easter Island experienced a societal collapse due to overexploitation of natural resources has been thrown into fresh doubt. Instead, there was a small and stable population that lived sustainably for centuries before the arrival of Europeans, an analysis of historical farming practices suggests.
Famous for its towering stone statues, Easter Island – also known as Rapa Nui – in the Pacific Ocean is thought to have been inhabited by Polynesians since around AD 1200. At that time, its 164-square kilometres were covered in palm forests, but these were quickly destroyed, probably by a combination of rats and over-harvesting.
According to a narrative popularised by the historian Jared Diamond, the unsustainable use of resources led to runaway population growth and a subsequent collapse before Europeans arrived in 1722.
The islanders mainly supported themselves through rock gardening, a form of agriculture that has been widely practised in places where soils are poor or the climate harsh. Stones are scattered around fields to create microhabitats and wind breaks, preserve moisture and supply important minerals.
Previous studies have suggested that as much as 21 square kilometres of Rapa Nui was covered in rock gardens, supporting a population of up to 16,000 people.
To find out more, Carl Lipo at Binghamton University in New York and his colleagues used satellite imagery combined with machine learning models trained with ground surveys to generate an island-wide estimate of rock gardening sites.
This found that the maximum area of the stone gardens was only 0.76 square kilometres. The researchers estimate that such a system wouldn’t have been able to support more than 4000 people – roughly the population estimated to live there when Europeans arrived. In other words, the team argues, the population remained remarkably stable.
Researcher Robert DiNapoli, from Binghamton University in New York, inspects a rock garden
Carl Lipo
Lipo says that those who continue to use Easter Island as a case study of degradation and collapse need to look at the empirical evidence. “The results we produce continue to support our hypothesis that the island never… [had] a massive population that overconsumed its resources,” he says. “Overall, we do not see evidence in the archaeological record of a population collapse before European arrival.”
Instead, there is growing weight behind the suggestion that islanders transformed their environment in ways that allowed them to live sustainably for generations, says Lipo. “Small populations and low-density, dispersed settlement patterns enabled the communities to reliably produce sufficient food for more than 500 years until the arrival of Europeans.”
Dale F. Simpson at the University of Illinois says more work is needed to evaluate whether the precision and accuracy of the model calculations used in the research fit the archaeological record.
“Overall, this [study] highlights that although the Rapa Nui [people] are often portrayed as a collapsed culture bounded by socio-political competition, ecological overexploitation and megalithic overproduction, the discussion would be better served if it recognised the Rapa Nui as a Polynesian island culture of adaptation and survival that has thrived for almost a millennium,” says Simpson.
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The 2000-year-old wine found in a Roman tomb in Carmona, Spain
Juan Manuel Román/University of Cordoba
A reddish liquid found in a 2000-year-old Roman mausoleum in Spain is the oldest known liquid wine in existence, a chemical analysis has revealed.
“I was surprised and full of disbelief,” says José Rafael Ruiz Arrebola at the University of Cordoba in Spain. “It seemed impossible that a liquid could have remained in this state for 2000 years.”
Until now, a sealed vessel found near Speyer, Germany, and believed to be about 1700 years old, was thought to contain the oldest known wine, but it has never been opened.
The Spanish tomb, accidentally discovered in 2019 in Carmona, near Seville, dates from the 1st century AD and belonged to a wealthy family. Eight burial niches, carved in its walls, held six urns made from limestone, sandstone or glass. Half of them contained the cremated remains of women and the other half those of men. Two urns bore the names of the deceased: Hispanae and Senicio.
One of the glass urns, encased in a lead shell, contained bone remnants of a 45-year-old man, a gold ring bearing the image of the two-faced Roman god Janus, and approximately 5 litres of liquid.
Ruiz Arrebola and his team studied the composition of the reddish liquid by various methods, including liquid chromatography-mass spectrometry. They found that it had a pH of 7.5 – much more alkaline than normal for wine, indicating strong decay.
Its mineral profile was similar to that of modern sherry and fino wines from Spain. It also contained seven polyphenols, natural antioxidant compounds, exclusively found in wine.
The entrance to the mausoleum in Carmona where the wine was found
Juan Manuel Román/University of Cordoba
The absence of syringic acid, a compound produced when the main pigment in red wines decomposes, confirmed its identity as a white wine. The wine was probably meant for the deceased to drink on their voyage into the afterlife.
“The discovery of a 2000-year-old liquid presumed to be wine in a Roman urn is rare and significant, providing unique insights into Roman burial practices,” says Davide Tanasi at the University of South Florida. “It demonstrates the continuity between ancient and contemporary wine production.”
Ruiz Arrebola plans to carry out further tests to identify any remains of microbes such as bacteria or yeasts that might be present in the wine.
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