The extreme wet and dry periods Mongolia has experienced in the late 20th and early 21st centuries are rare but not unprecedented and future droughts may be no worse, according to an international research team that includes a University of Arizona scientist.

Kevin Anchukaitis (plaid shirt) and Oyunsanaa Byambasuren (orange chainsaw chaps) taking pieces of wood from dead trees on Mongolia's Uurgat lava field. The researchers use tree rings to create a record of Mongolia's droughts stretching two centuries into the past [Credit: Neil Pederson © 2013]

The research team developed a climate record stretching 2,060 years into Mongolia's past by using the natural archive of weather conditions stored in the annual rings of Siberian pines. The 10 researchers then combined that information on past climate with computer models that can project future regional climate.

The most recent extended drought in Mongolia lasted from 2000 to 2010 and resulted in major livestock die-offs and a massive migration of nomadic herders to the capital city.

"We were able to quantify how unusual this drought was," said co-author Kevin J. Anchukaitis, a University of Arizona associate professor of geography and development. "The drought was not unprecedented, but it has a 900-year return interval. It's a once-in-a-millennium drought."

Finding that future droughts would likely be no worse than those of the past was a surprise, said Anchukaitis, who led the modeling team. In other semi-arid regions of the world that he has studied such as California and the Mediterranean, global warming has already changed precipitation and temperature patterns and thereby increased the risk of long-term drought.

Mongolia, a landlocked country in central Asia, has long, cold winters and short summers. Much of the country is cold, semi-arid grasslands that resemble eastern Montana.

Lead author Amy Hessl of West Virginia University said, "You would expect, based on everything we've been thinking about and reading as climate scientists, that elevated temperatures are going to lead to more severe droughts in semi-arid regions. But the models did not project increased frequency or severity of droughts."

Researchers Kevin Anchukaitis and Amy Hessl walk across the Khorgo lava field in central Mongolia to collect cross-sections of dead trees. The researchers use tree rings to create a record of Mongolia's droughts stretching two centuries into the past [Credit: Neil Pederson © 2012]

The timing of the rainy season is the likely cause, the researchers said. Mongolia's rainy season is in the summer, the warmer time of the year, whereas California and the Mediterranean have winter rains and dry summers. As global temperatures increase, continental regions with summer rains may get more precipitation, offsetting the effects on plants of higher temperatures.

The team's research paper, "Past and Future Drought in Mongolia," has been published in Science Advances. A complete list of the authors is at the bottom of this release. National Geographic and the National Science Foundation funded the research.

Anchukaitis, who also has appointments in geosciences and in the UA Laboratory of Tree-Ring Research, is interested in how past and current civilizations dealt with drought and climate variability. This new research is an outgrowth of previous research he, Hessl and their colleagues conducted to figure out how past climate influenced the Mongol civilization.

Anchukaitis and his colleagues used their tree-ring record of past climate in Mongolia to reconstruct what the annual Palmer Drought Severity Index, or PDSI, would have been going back in time 2,060 years. The PDSI combines both temperature and precipitation to get a measure of soil moisture, one measure of how water-stressed a plant would be.

He and his colleagues combined the reconstruction of past annual PDSI measures with a set of climate model simulations called the Community Earth System Model to understand what influenced the Mongolian droughts for the period from 850 to 2100.

The Uurgat lava field with the Khangai Mountains in the background and the seasonal homes of nomadic herders in the lower right. An international team of researchers took wood samples of the Siberian pines growing on the lava field to construct a drought chronology reaching two centuries into the past [Credit: Scott Nichols]

The model incorporates information about past solar variability, volcanic eruptions, land use changes and carbon dioxide emissions. For projections to the end of the 21st century, the model uses the future emissions scenario called RCP 8.5, in which the rate of emissions of greenhouse gases continues to increase.

Even with the highest level of greenhouse gas emissions and rising global temperatures, the model simulations indicate that future droughts in Mongolia would be no more severe than those of the past.

"There's a tug of war between trends toward increased rainfall and more evaporative demand because of hotter temperatures. There's uncertainty about which will win this tug of war," Anchukaitis said.

"The simulations say that Mongolia dries between now and about 2050 because of higher temperatures, but then it turns around because of the increase in precipitation," he said.

Many people in Mongolia are nomadic pastoralists. They are particularly affected by the vagaries of weather and climate, because the combination of winter and summer temperatures plus rainfall controls the number of cattle the grassland can support.

"What to me stands out is this deep uncertainty about the future, particularly when you have a society that is so vulnerable to climate variability," he said, adding that uncertainty makes it hard to plan for coping with future climate change.

Anchukaitis said one of his next steps is translating the team's estimates of future soil moisture into estimates of the future productivity of Mongolia's grasslands.

Author: Mari N. Jensen | Source: University of Arizona [March 14, 2018]

The history and archaeology of Mongolia, most famously the sites associated with the largest land empire in the history of the world under Ghengis Khan, are of global importance. But they're facing unprecedented threats as climate change and looting impact ancient sites and collections.

Burial sites may contain treasures, or just old bones. And looters won’t know until they’ve destroyed them [Credit: Julia Kate Clark]

Climate change and looting may seem to be unrelated issues. But deteriorating climate and environmental conditions result in decreased grazing potential and loss of profits for the region's many nomadic herders. Paired with a general economic decline, herders and other Mongolians are having to supplement their incomes, turning to alternative ways of making money. For some, it's searching for ancient treasures to sell on the illegal antiquities market.

The vast Mongolian landscape, whether it be plains, deserts or mountains, is dotted with man-made stone mounds marking the burials of ancient peoples. The practice started sometime in the neolithic period (roughly 6,000-8,000 years ago) with simple stone mounds the size of a kitchen table. These usually contain a human body and a few animal bones.

Over time, the burials became larger (some over 400 metres long) and more complex, incorporating thousands of horse sacrifices, tools, chariots, tapestries, family complexes, and eventually treasure (such as gold, jewellery and gems).

For Mongolians, these remains are the lasting reminders of their ancient past and a physical tie to their priceless cultural heritage.

Mongolia has reasonably good laws regarding the protection of cultural heritage. But poor understanding of the laws, and the nearly impossible task of enforcing them in such a large space with relatively few people and meagre budgets keep those laws from being effective. And laws can't protect Mongolia's cultural heritage from climate change.

Looting losses

The looting of archaeological sites in Mongolia has been happening for a very long time. Regional archaeologists have shared anecdotes of finding skeletons with break-in tools made from deer antlers in shafts of 2,000 year old royal tombs in central Mongolia. These unlucky would-be thieves risked the unstable sands collapsing in the shafts above them for a chance at riches, not long after the royal leaders had been buried there.

While looters discard bones, they are invaluable to archaeologists’ research [Credit: Julia Kate Clark]

But many recent pits dug directly into burial sites around Mongolia, some that are more than 3,000 years old, suggest modern day looting is on the rise. For the untrained looter, any rock feature has the potential to contain valuable goods and so grave after grave is torn apart. Many of these will contain no more than human and animal bones.

Archaeologists' interest in these burials lie in the information they contain for research, but this is worthless on the black antiquities market. But to steer looters away from these burials would be to teach them which ones to target for treasure and so this strategy is avoided.

Archaeologists working in northern Mongolia in 2017 found hundreds of looted sites, including an 800 year old cemetery consisting of at least 40 burials. Each and every one of them had been completely destroyed by looters looking for treasure. Human remains and miscellaneous artefacts such as bows, arrows, quivers, and clothing were left scattered on the surface.

Having survived over 800 years underground, these priceless bows, arrows, cloth fragments and bones likely have less than a year on the surface before they're gone forever. This is not to mention the loss of whatever goods (gold, silver, gems) the looters decided was valuable enough to keep.

The mummy race

Archaeological teams are currently working against climate change, looters, and each other for the chance to unearth rare mummies in the region that are known to pique public interest within Mongolia and abroad. A 2017 exhibit at the National Museum of Mongolia featured two mummies and their impressive burial goods—one of which had been rescued from the hands of looters by archaeologists and local police. Though they appeared not to have been particularly high ranking individuals, their belongings displayed incredible variety, artistry and detail.

Discovering mummies offers the opportunity to increase interest and tourism in Mongolia [Credit: The Center of Cultural Heritage of Mongolia]

The result of natural processes rather than intentional mummification as in ancient Egypt, some of these mummies are preserved by very dry environments protected in caves and rock shelters. Others are ice mummies, interred in burials that were constructed in such a way that water seeped in and froze—creating a unique preservation environment.

Both preservation environments produce artefacts that rarely survive such long periods of time. This includes human tissues like skin and hair, clothing and tapestries, wooden artefacts, and the remains of plants and animals associated with the burial.

As looters zero in on these sites, and climate change melts ice and changes the environmental conditions in other yet unknown ways, archaeologists are racing to locate, and preserve these finds. But with little infrastructure, small budgets and almost no specialised training in how to handle such remains, there's some concern about the long term preservation of even those remains archaeologists are able to rescue.

Efforts to provide training opportunities, international collaborations with mummy experts, and improved infrastructure and facilities are underway, but these collections are so fragile there is little time to spare.


What Mongolia can teach us

The situation in Mongolia could help us to understand and find new solutions to dealing with changes in climate and the economic drivers behind looting. Humans around the world in many different times have faced and had to adapt to climate change, economic strife and technological innovations.

There's truth represented by a material record of the "things" left by ancient peoples and in Mongolia, the study of this record has led to an understanding of the impact of early food production and horse domestication, the emergence of new social and political structures and the dominance of a nomadic empire.

Author: Julia Kate Clark | Source: The Conversation [March 12, 2018]

This article was originally published on The Conversation. Read the original article.

Researchers led by Nagoya University discover penetrative trace fossils from the late Ediacaran of western Mongolia, revealing earlier onset of the “agronomic revolution”.

This bedding surface was once the surface of the sea floor, which was densely colonized by unidentified animals that lived inside these burrows. The sizes of these openings range from a few millimeters to 1 cm, suggesting that these animals were relatively large [Credit: Tatsuo Oji]

In the history of life on Earth, a dramatic and revolutionary change in the nature of the sea floor occurred in the early Cambrian (541–485 million years ago): the “agronomic revolution.” This phenomenon was coupled with the diversification of marine animals that could burrow into seafloor sediments. Previously, the sea floor was covered by hard microbial mats, and animals were limited to standing on, resting on, or moving horizontally along those mats. In the agronomic revolution, part of the so-called Cambrian Explosion of animal diversity and complexity, vertical burrowers began to churn up the underlying sediments, which softened and oxygenated the subsurface, created new ecological niches, and thus radically transformed the marine ecosystem into one more like that observed today.

This event has long been considered to have occurred in the early Cambrian Period. However, new evidence obtained from western Mongolia shows that the agronomic revolution began in the late Ediacaran, the final period of the Precambrian, at least locally.

When a bed with burrows is cut perpendicular to the bedding plane, the burrows are 'U-shaped', with two openings toward the sea floor. The depth of the burrows reaches up to 4 cm. The animals that lived inside the burrows were  presumably elongated in shape, with the mouth at one end and the anus at the other. Animals with such active burrowing capability are inferred to have been bilaterians, and have not been clearly identified from the previous fossil record [Credit: Tatsuo Oji]

A team of researchers, primarily based in Japan, surveyed Bayan Gol Valley, western Mongolia, and found late Ediacaran trace fossils in marine carbonate rocks. They identified U-shaped, penetrative trace fossils, called Arenicolites, from 11 beds located more than 130 meters below the lowermost occurrence of Treptichnus pedum, widely recognized as the marker of the Ediacaran–Cambrian boundary. The researchers confirmed the late Ediacaran age of the rocks, estimated to be between 555 and 541 million years old, based on the stable carbon isotope record.

“It is impossible to identify the kind of animal that produced the Arenicolites traces,” lead author Tatsuo Oji says. “However, they were certainly bilaterian animals based on the complexity of the traces, and were probably worm-like in nature. These fossils are the earliest evidence for animals making semi-permanent domiciles in sediment. The evolution of macrophagous predation was probably the selective pressure for these trace makers to build such semi-permanent infaunal structures, as they would have provided safety from many predators.”

Reconstruction of the late Ediacaran (ca. 550 million years ago) sea floor with burrows of a worm-like animal. This was the first discovery of such deeply penetrating burrows [Credit: Nagoya University]

These Arenicolites also reached unusually large sizes, greater than one centimeter in diameter. The discovery of these large-sized, penetrative trace fossils contradicts the conclusions of previous studies that small-sized penetrative traces emerged only in the earliest Cambrian.

“These trace fossils indicate that the agronomic revolution actually began in the latest Ediacaran in at least one setting,” co-author Stephen Dornbos explains. “Thus, this revolution did not proceed in a uniform pattern across all depositional environments during the Cambrian radiation, but rather in a patchwork of varying bioturbation levels across marine seafloors that lasted well into the early Paleozoic.”

The findings are published in Royal Society Open Science.

Source: Nagoya University [March 12, 2018]

The simple story says that during the last ice age, temperatures were colder and ice sheets expanded around the planet. That may hold true for most of Europe and North America, but new research from the University of Washington tells a different story in the high-altitude, desert climates of Mongolia.

The Gobi-Altai mountain range in western Mongolia is in a very dry region but ice can accumulate on mountaintops, such  as Sutai Mountain, the tallest peak in the range. In the picture, friends of Jigjidsurengiin Batbaatar descend this mountain after helping to install a weather station [Credit: Jigjidsurengiin Batbaatar/University of Washington]

The recent paper in Quaternary Science Reviews is the first to date ancient glaciers in the high mountains of Mongolia's Gobi Desert. It compares them with glacial records from nearby mountains to reveal how glaciers behave in extreme climates.

On some of the Gobi mountain ranges included in the study, glaciers started growing thousands of years after the last ice age ended. In contrast, in slightly wetter parts of Mongolia the largest glaciers did date from the ice age but reached their maximum lengths tens of thousands of years earlier in the glacial period rather than at its culmination, around 20,000 years ago, when glaciers around most of the planet peaked.

Both trends differ from the typical chronology of glacier growth during an ice age.

"In some of the Gobi mountains, the largest glaciers didn't happen during the last ice age," said first author Jigjidsurengiin Batbaatar, a UW doctoral student in Earth and Space Sciences. "Some of these glaciers were starving for precipitation then. Our measurements show that they actually shrank as cold, dry conditions of the ice age became more intense. Then they grew when the warming climate of the Holocene brought more moist air, feeding the glaciers with more snow."

Batbaatar and co-author Alan Gillespie, a UW research professor emeritus in Earth and Space Sciences, collected samples from moraines, which are long ridges of rocky debris dropped at a glacier's edge. They used a dating technique perfected in the last 20 years that measures elemental changes in the rock that occur when the rock gets bombarded by cosmic rays after the glacier's retreat.

"We were expecting to find rocks exposed for 20,000 years, the date of the peak of the last ice age, but these moraines were much younger. That means that these glaciers were smaller when the climate was the coldest," Batbaatar said. "The results were so surprising that we went back to double check."

At a moraine, a band of boulders left by a retreating glacier, co-author Ari Matmon collects rock samples with his son. This site is in the Khangai Mountains in Mongolia [Credit: Jigjidsurengiin Batbaatar/University of Washington]

The study was possible both because of advances in the cosmic-ray dating method, and political changes that allow more access to Central Asia.

"After the fall of the Soviet Union, Russia opened up, China opened up, and Mongolia opened up to Western researchers with these novel dating techniques. And we see a very different pattern of glacial advances compared to North America and Europe," Batbaatar said.

The data collected in 2007 and 2010 confirm a theoretical study by Summer Rupper, a former UW doctoral student now at the University of Utah, and UW faculty member Gerard Roe. In very cold and dry environments, where rain and snow are scarce, it predicted that temperature would not always be the main factor driving a glacier's growth.

"Because the melting is so dominant a process, and the melting is mostly controlled by temperature, people think of glaciers as thermometers. But we all know that precipitation plays a role," Batbaatar said.

The new study confirms that so-called "starving glaciers" in dry, high-altitude environments are indeed controlled by precipitation. They grow so slowly that they seldom reach the lower altitudes where melting is possible. Instead, they shrink when sunlight hits the surface and transforms ice into water vapor, a process called sublimation. These glaciers are thus less sensitive to temperature shifts, but very sensitive to precipitation amounts.

"Generally, people have assumed from well-documented North American and European records that the largest glaciers should have come in the peak of the last ice age," Batbaatar said. "But in Mongolia, our results show that this was not the case. Glacier behavior there was different from the better-studied areas of the Alps or the Sierra Nevada in the U.S. Even within Mongolia we observe very different behavior from range to range."

Jigjidsurengiin Batbaatar chisels rock from the surface of a boulder dropped by a glacier in the Gobi-Altai range in  Mongolia. The elemental traces of exposure to cosmic rays show that this glacier reached its maximum size 7,500 years ago, much later than the last ice age [Credit: Alan Gillespie/University of Washington]

The conditions at the Gobi-Altai mountain range are extreme, with precipitation at the five research sites Batbaatar established there ranging from roughly 50 to 300 millimeters (2 inches to 1 foot) per year. Nearby mountains in Mongolia with more precipitation have more typically behaving glaciers. But other extreme climates, for example the driest parts of Tibet or the Andes, can produce glaciers with similar paradoxical trends.

"Even in this current warming climate, some mountains are so high that the temperatures are still below freezing, and the warming ocean may provide more precipitation to drive some of the glaciers to advance," Batbaatar said.

He is now working to interpret more measurements collected from a wider geographic area in Central Asia.

"Batbaatar has shown that glaciers growing in cold, arid, desert mountains may be out of sync with those in wetter, warmer environments such as the Alps," Gillespie said. "His findings move us toward a more complete understanding of how glaciers advance and retreat in response to climatic fluctuations."

Source: University of Washington [March 06, 2018]

Scientists once could reconstruct humanity's distant past only from the mute testimony of ancient settlements, bones, and artifacts.

The use of stylized bell-shaped pots like this one from Sierentz, France spread across Europe beginning about 4,700 years ago. DNA analysis show that this so-called Bell Beaker culture was brought to Britain by people who largely replaced the island's existing inhabitants  [Credit: Anthony Denaire]

No longer. Now there's a powerful new approach for illuminating the world before the dawn of written history - reading the actual genetic code of our ancient ancestors. Two papers published in the journal Nature, more than double the number of ancient humans whose DNA has been analyzed and published to 1,336 individuals - up from just 10 in 2014.

The new flood of genetic information represents a "coming of age" for the nascent field of ancient DNA, says lead author David Reich, a Howard Hughes Medical Institute investigator at Harvard Medical School - and it upends cherished archaeological orthodoxy. "When we look at the data, we see surprises again and again and again," says Reich.

Together with his lab's previous work and that of other pioneers of ancient DNA, the Big Picture message is that our prehistoric ancestors were not nearly as homebound as once thought. "There was a view that migration is a very rare process in human evolution," Reich explains. Not so, says the ancient DNA. Actually, Reich says, "the orthodoxy - the assumption that present-day people are directly descended from the people who always lived in that same area - is wrong almost everywhere."

Instead, "the view that's emerging - for which David is an eloquent advocate - is that human populations are moving and mixing all the time," says John Novembre, a computational biologist at the University of Chicago.

Stonehenge's Builders Largely Vanish

In the first new Nature paper, Reich and a cast of dozens of collaborators chart the spread of an ancient culture known by its stylized bell-shaped pots, the so-called Bell Beaker phenomenon. This culture first spread between Iberia and central Europe beginning about 4,700 years ago. By analyzing DNA from several hundred samples of human bones, Reich's team shows that only the ideas - not the people who originated them - made the move initially. That's because the genes of the Iberian population remain distinct from those of the central Europeans who adopted the characteristic pots and other artifacts.

But the story changes when the Bell Beaker culture expanded to Britain after 4,500 years ago. Then, it was brought by migrants who almost completely supplanted the island's existing inhabitants - the mysterious people who had built Stonehenge - within a few hundred years. "There was a sudden change in the population of Britain," says Reich. "It was an almost complete replacement."

For archaeologists, these and other findings from the study of ancient DNA are "absolutely sort of mind-blowing," says archaeologist Barry Cunliffe, a professor emeritus at the University of Oxford. "They are going to upset people, but that is part of the excitement of it."

Vast Migration from the Steppe

Consider the unexpected movement of people who originally lived on the steppes of Central Asia, north of the Black and Caspian seas. About 5,300 years ago, the local hunter-gatherer cultures were replaced in many places by nomadic herders, dubbed the Yamnaya, who were able to expand rapidly by exploiting horses and the new invention of the cart, and who left behind big, rich burial sites.

DNA from people from the Bell Beaker culture (illustration of one man shown) reveal that they descended from nomadic herders who migrated from the steppes of Central Asia [Credit: Manuel Rojo-Guerra/Luis Pascual-Repiso]

Archaeologists have long known that some of the technologies used by the Yamnaya later spread to Europe. But the startling revelation from the ancient DNA was that the people moved, too - all the way to the Atlantic coast of Europe in the west to Mongolia in the east and India in the south. This vast migration helps explain the spread of Indo-European languages. And it significantly replaced the local hunter-gatherer genes across Europe with the indelible stamp of steppe DNA, as happened in Britain with the migration of the Bell Beaker people to the island.

"This whole phenomenon of the steppe expansion is an amazing example of what ancient DNA can show," says Reich. And, adds Cunliffe, "no one, not even archeologists in their wildest dreams, had expected such a high steppe genetic content in the populations of northern Europe in the third millennium B.C."

This ancient DNA finding also explains the "strange result" of a genetic connection that had been hinted at in the genomes of modern-day Europeans and Native Americans, adds Chicago's Novembre. The link is evidence from people who lived in Siberia 24,000 years ago, whose telltale DNA is found both in Native Americans, and in the Yamnaya steppe populations and their European descendants.

New Insights from Southeastern Europe

Reich's second new Nature paper, on the genomic history of southeastern Europe, reveals an additional migration as farming spread across Europe, based on data from 255 individuals who lived between 14,000 and 2,500 years ago. It also adds a fascinating new nugget - the first compelling evidence that the genetic mixing of populations in Europe was biased toward one sex.

Hunter-gatherer genes remaining in northern Europeans after the influx of migrating farmers came more from males than females, Reich's team found. "Archaeological evidence shows that when farmers first spread into northern Europe, they stopped at a latitude where their crops didn't grow well," he says. "As a result, there were persistent boundaries between the farmers and the hunter-gatherers for a couple of thousand years." This gave the hunter-gatherers and farmers a long time to interact. According to Reich, one speculative scenario is that during this long, drawn-out interaction, there was a social or power dynamic in which farmer women tended to be integrated into hunter-gatherer communities.

So far that's only a guess, but the fact that ancient DNA provides clues about the different social roles and fates of men and women in ancient society "is another way, I think, that these data are so extraordinary," says Reich.

Advanced Machines

These scientific leaps forward have been fueled by three key developments. One is the dramatic cost reduction (and speed increase) in gene sequencing made possible by advanced machines from Illumina and other companies. The second is a discovery spearheaded by Ron Pinhasi, an archaeologist at University College Dublin. His group showed that the petrous bone, containing the tiny inner ear, harbours 100 times more DNA than other ancient human remains, offering a huge increase in the amount of genetic material available for analysis. The third is a method implemented by Reich for reading the genetic codes of 1.2 million carefully chosen variable parts of DNA (known as single nucleotide polymorphisms) rather than having to sequence entire genomes. That speeds the analysis and reduces its cost even further.

The new field made a splash when Svante Pääbo of the Max Planck Institute for Evolutionary Anthropology, working with Reich and many other colleagues, used ancient DNA to prove that Neanderthals and humans interbred. Since then, the number of ancient humans whose DNA Reich has analyzed has risen exponentially. His lab has generated about three-quarters of the world's published data and, included unpublished data, has now reached 3,700 genomes. "Every time we jump an order of magnitude in the number of individuals, we can answer questions that we couldn't even have asked before," says Reich.

Now, with hundreds of thousands of ancient skeletons (and their petrous bones) still to be analyzed, the field of ancient DNA is poised to both pin down current questions and tackle new ones. For example, Reich's team is working with Cunliffe and others to study more than 1,000 samples from Britain to more accurately measure the replacement of the island's existing gene pool by the steppe-related DNA from the Bell Beaker people. "The evidence we have for a 90 percent replacement is very, very suggestive, but we need to test it a bit more to see how much of the pre-Beaker population really survived," explains Cunliffe.

Beyond that, ancient DNA offers the promise of studying not only the movements of our distant ancestors, but also the evolution of traits and susceptibilities to diseases. "This is a new scientific instrument that, like the microscope when it was invented in the seventeenth century, makes it possible to study aspects of biology that simply were not possible to examine before," explains Reich. In one example, scientists at the University of Copenhagen found DNA from plague in the steppe populations. If the groups that migrated to Britain after 4,500 years ago brought the disease with them, that could help explain why the existing population shrank so quickly.

With the possibility of many such discoveries still ahead, "it is a very exciting time," says Cunliffe. "Ancient DNA is going to revitalize archeology in a way that few of us could have guessed even ten years ago."

Source: Howard Hughes Medical Institute [February 21, 2018]

The Khermen Tal site is located in Ogiinuur Sum, Arkhangai Province, Mongolia. The site is attributed to the Xiongnu, a nomadic tribe that made its first appearance in northern Eurasia in the third century BC, migrating westward in the second century before vanishing in the fifth century. As one of the best preserved and largest ancient city groups in Mongolia, it contained three walled enclosures the remains of which lie side by side from east to west and have the same layout. Hence the site's name: 'Hudgiyn Denj' or 'Three Interconnected Cities'.

Aerial photo of the 'Hudgiyn Denj' site [Credit: Archaeology Press IA CASS]

From 2014 to 2016, a Sino-Mongolian joint archaeological team from the Inner Mongolian Institute of Cultural Relics and Archaeology and International College of Nomadic Culture of Mongolia conducted an archaeological survey, while also undertaking research, exploration and mapping of the site.

Some features of the site were also cleared. The Central platforms of the Western and Middle Cities, the Eastern Gate of the Western City and the earthen platform in the southwest of the Middle City were uncovered during the excavations. The eastern wall, a moat and path in the Western City were sectioned.

Very few artefacts were recovered from the various features and deposits. Only several broken pottery shards were unearthed, as well as a copper nail, a copper knife and an iron knife.

Aerial photo of the Middle City [Credit: Archaeology Press IA CASS]

From July to October in 2017, the joint archaeological team cleared up the central platform located in the middle of the walled enclosure (numbered IIA). This platform consisted of a covered cone-shaped platform, a sloping step-road in the west and a north-south oriented sloping step-road in the east.

The platform was oriented north-south and each side was 35.8m long. Around the platform, 36 large post-holes were discovered, most of which were round in shape with a 0.75~1.05m diameter and 0.80~1.00m depth. In their bottoms, there were flat stones used as plinths. Around the large post-holes, there are also small post-holes with a 0.15~0.30m diameter and a 0.30~0.60m depth distributed regularly.

According to the results of excavations, there was probably a grid-like structure consisting of 100 large posts, probably supporting a large ritual platform 9 rooms wide and 9 rooms deep. A sloping step road in the west connected with the middle part of the west end of the platform. The step road is 14.4m long and 4.2m wide.

The earthern platforms IIA and IIB [Credit: Archaeology Press IA CASS]

The sloping step road in the east was 2.6~2.9m wide and 64m long, oriented north-south, and was located next to a small earth platform (IIB) to the left of IIA. This smaller platform is likewise oriented north-south and is square in plan. It’s 13.6m long from east to west and 12.8m wide from north to south. Regularly distributed small post holes were also discovered around this platform.

'Hudgiyn Denj' belongs to the Xiongnu period based on stratigraphic, typological analysis and the results of C14 dating, between the third century BC to the first century AD. Written historical books in ancient China recorded that the Xiongnu used to build religious sites along the basin of the Orhon River for their religious conventions, such as offering sacrifices to the god of heaven three-times-a-year. Later, the chief of the Xiongnu also convened meetings on state affairs at the sites by the opportunity of these religious ceremonies, with horse racing and camel riding as an amusement.

The central platform of the Middle City of 'Hudgiyn Denj' is the first large platform base of a building constructed from packed earth and wood that has been completely uncovered in Mongolia and is therefore of significant historical value for research in the field of Xiongnu archaeology.

Source: The Institute of Archaeology, Chinese Academy of Social Sciences (IA CASS) [January 23, 2018]