New clues emerge about the earliest known Americans

Stone tools, cooked animal and plant remains and fire pits found at the Monte Verde site in southern Chile provide greater interdisciplinary evidence that the earliest known Americans--a nomadic people adapted to a cold, ice-age environment--were established deep in South America more than 15,000 years ago. The research, led by Tom Dillehay, Rebecca Webb Wilson University Distinguished Professor of Anthropology, appears in the Nov. 18 issue of PLOS ONE. 

A very small faceted basalt wedge. Basalt is a local material. This tool, also found at MVI, was made 15,000-16,000 years ago. It would have been used for woodworking.

CREDIT

(Courtesy Tom Dillehay)

In 2013, at the request of Chile's National Council of Monuments, Dillehay and an international team of archaeologists, geologists and botanists performed an archaeological and geological survey of Monte Verde to better define the depth and breadth of the site, which is protected by the Chilean government. 

It's familiar ground for Dillehay, who has worked there since 1977, and it's there that Dillehay found evidence that fundamentally contributed to a new understanding of how and when humans first arrived in the Americas. 

Until about 40 years ago, the prevailing understanding was that the Americas first began to be populated 13,000 years ago by big-game hunters from Asia who used a distinctive type of fluted stone projectile point called Clovis points. Dillehay's work at Monte Verde, however, has yielded a wide variety of scientific evidence of a small human settlement using a different stone tool technology that predated the Clovis people by about 1,500 years at a site called MVII. He also uncovered possible, though not conclusive, evidence of a much earlier human presence at a nearby site called MVI. Subsequent excavations at sites in both North and South America have also yielded evidence supporting this earlier human migration through the Americas. 

On this visit, Dillehay's team explored key areas around MVI and MVII. Though it was not intended to be a comprehensive reexamination of the site, their findings did yield new insights. "We began to find what appeared to be small features--little heating pits, cooking pits associated with burned and unburned bone, and some stone tools scattered very widely across an area about 500 meters long by about 30 or 40 meters wide," said Dillehay. 

The stone tools discovered by the team were similar to what Dillehay had previously found at Monte Verde. Many were simple unifacial tools--meaning they were worked on only one side of the stone, to create a sharp edge--though some of the younger tools and projectile points indicate bifacial technologies. "One of the curious things about it that is that unlike what we found before, a significant percentage, about 34 percent, were from non-local materials. Most of them probably come from the coast but some of them probably come from the Andes and maybe even the other side of the Andes," said Dillehay. Prior research had revealed evidence of Andean plants in the area, providing further support for a highly mobile population. 

Stones, bones, plants and fires

The team recovered a total of 39 stone objects and 12 small fire pits associated with bones and some edible plant remains, including nuts and grasses. The bones tended to be small fragments, broken and scorched, indicating that the animals had been cooked. They often came from very large animals, like prehistoric llamas or mastodons, as well as smaller creatures like prehistoric deer and horses. The Monte Verde site was unlikely to have been able to support the kind of vegetation that those animals needed to eat, so they were likely killed and butchered elsewhere. The objects were radiocarbon dated and most were found to range in age from more than 14,000 to almost 19,000 years old. 

The wide scattering suggests that the people who created these features were nomadic hunter-gatherers who might have camped for only a night or two before moving on. "Where they're going, we don't know, and where they're coming from, we don't know, but this would have been a passageway from the coast to the foothills of the Andes," Dillehay said. Dillehay believes that they may have come through Monte Verde because the terrain was more walkable than the surrounding bogs and wetlands, and because it provided access to stone to make tools.

Rain, ice, soil and ash

A key goal during this visit was to better understand the geological and environmental context of the site. At the end of the last ice age, Monte Verde was a sandur plain--a runoff area situated about six kilometers away from a glacier, crisscrossed by a network of shallow streams and brooks fed by rain washing off the glacier, as well as melting snow. It was also a time marked by volcanic activity and a gradually warming climate, as the last glaciers began to retreat.

"It appears that these people were there in the summer months," Dillehay said. "Each one of these [burned] features and the bones and stones associated with them is embedded in thin, oxidized tephra"--a type of geological layer formed by airborne ash particles from nearby volcanoes that only form in rainy, warmer temperatures. But though the glaciers had begun to retreat by 19,000 to 17,000 years ago, it was still an extremely challenging environment, Dillehay said. "We're looking at people living in some really cold, harsh areas, even in the summer months." Only later, around 15,000 years ago, did the climate warm enough to support the kind of longer-term settlement found at MVII. 

New questions

Put together, these findings support the paradigm shift toward an earlier peopling of the Americas, although questions inevitably remain about how the hemisphere was settled. It also underscores the importance of long-term interdisciplinary research. "We now realize that the geology and the climate and the archaeology are much more complex than we ever calculated," said Dillehay.

'Fourth strand' of European ancestry originated with hunter-gatherers isolated by Ice Age

  

IMAGE: DNA WAS EXTRACTED FROM THE MOLAR TEETH OF THIS SKELETON, DATING FROM ALMOST 10,000 YEARS AGO AND FOUND IN THE KOTIAS KLDE ROCKSHELTER IN WESTERN GEORGIA.

CREDIT: EPPIE JONES

The first sequencing of ancient genomes extracted from human remains that date back to the Late Upper Palaeolithic period over 13,000 years ago has revealed a previously unknown "fourth strand" of ancient European ancestry. 

This new lineage stems from populations of hunter-gatherers that split from western hunter-gatherers shortly after the 'out of Africa' expansion some 45,000 years ago and went on to settle in the Caucasus region, where southern Russia meets Georgia today. 

Here these hunter-gatherers largely remained for millennia, becoming increasingly isolated as the Ice Age culminated in the last 'Glacial Maximum' some 25,000 years ago, which they weathered in the relative shelter of the Caucasus mountains until eventual thawing allowed movement and brought them into contact with other populations, likely from further east. 

This led to a genetic mixture that resulted in the Yamnaya culture: horse-borne Steppe herders that swept into Western Europe around 5,000 years ago, arguably heralding the start of the Bronze Age and bringing with them metallurgy and animal herding skills, along with the Caucasus hunter-gatherer strand of ancestral DNA - now present in almost all populations from the European continent. 

The research was conducted by an international team led by scientists from Cambridge University, Trinity College Dublin and University College Dublin. The findings are published today in the journal Nature Communications. 

"The question of where the Yamnaya come from has been something of a mystery up to now," said one of the lead senior authors Dr Andrea Manica, from Cambridge's Department of Zoology. 

"We can now answer that as we've found that their genetic make-up is a mix of Eastern European hunter-gatherers and a population from this pocket of Caucasus hunter-gatherers who weathered much of the last Ice Age in apparent isolation. This Caucasus pocket is the fourth major strand of ancient European ancestry, one that we were unaware of until now," he said 

Professor Daniel Bradley, leader of the Trinity team, said: "This is a major new piece in the human ancestry jigsaw, the influence of which is now present within almost all populations from the European continent and many beyond." 

Previously, ancient Eurasian genomes had revealed three ancestral populations that contributed to contemporary Europeans in varying degrees, says Manica. 

Following the 'out of Africa' expansion, some hunter-gatherer populations migrated north-west, eventually colonising much of Europe from Spain to Hungary, while other populations settled around the eastern Mediterranean and Levant, where they would develop agriculture around 10,000 years ago. These early farmers then expanded into and colonised Europe. 

Finally, at the start of the Bronze Age around 5,000 years ago, there was a wave of migration from central Eurasia into Western Europe - the Yamnaya. 

However, the sequencing of ancient DNA recovered from two separate burials in Western Georgia - one over 13,000 years old, the other almost 10,000 years old - has enabled scientists to reveal that the Yamnaya owed half their ancestry to previously unknown and genetically distinct hunter-gatherer sources: the fourth strand.

By reading the DNA, the researchers were able to show that the lineage of this fourth Caucasus hunter-gatherer strand diverged from the western hunter-gatherers just after the expansion of anatomically modern humans into Europe from Africa. 

The Caucasus hunter-gatherer genome showed a continued mixture with the ancestors of the early farmers in the Levant area, which Manica says makes sense given the relative proximity. This ends, however, around 25,000 years ago - just before the time of the last glacial maximum, or peak Ice Age. 

At this point, Caucasus hunter-gatherer populations shrink as the genes homogenise, a sign of breeding between those with increasingly similar DNA. This doesn't change for thousands of years as these populations remain in apparent isolation in the shelter of the mountains - possibly cut off from other major ancestral populations for as long as 15,000 years - until migrations began again as the Glacial Maximum recedes, and the Yamnaya culture ultimately emerges. 

"We knew that the Yamnaya had this big genetic component that we couldn't place, and we can now see it was this ancient lineage hiding in the Caucasus during the last Ice Age," said Manica. 

While the Caucasus hunter-gatherer ancestry would eventually be carried west by the Yamnaya, the researchers found it also had a significant influence further east. A similar population must have migrated into South Asia at some point, says Eppie Jones, a PhD student from Trinity College who is the first author of the paper. 

"India is a complete mix of Asian and European genetic components. The Caucasus hunter-gatherer ancestry is the best match we've found for the European genetic component found right across modern Indian populations," Jones said. Researchers say this strand of ancestry may have flowed into the region with the bringers of Indo-Aryan languages. 

The widespread nature of the Caucasus hunter-gatherer ancestry following its long isolation makes sense geographically, says Professor Ron Pinhasi, a lead senior author from University College Dublin. "The Caucasus region sits almost at a crossroads of the Eurasian landmass, with arguably the most sensible migration routes both west and east in the vicinity."

He added: "The sequencing of genomes from this key region will have a major impact on the fields of palaeogeneomics and human evolution in Eurasia, as it bridges a major geographic gap in our knowledge."

David Lordkipanidze, Director of the Georgian National Museum and co-author of the paper, said: "This is the first sequence from Georgia - I am sure soon we will get more palaeogenetic information from our rich collections of fossils."

Rare warrior tomb filled with Bronze Age wealth and weapons discovered

On the floor of the grave lay the skeleton of an adult male, stretched out on his back. Weapons lay to his left, and jewelry to his right.

Near the head and chest was a bronze sword, its ivory hilt covered in gold. A gold-hilted dagger lay beneath it. Still more weapons were found by the man's legs and feet.

Gold cups rested on his chest and stomach, and near his neck was a perfectly preserved gold necklace with two pendants. By his right side and spread around his head were over one thousand beads of carnelian, amethyst, jasper, agate and gold. Nearby were four gold rings, and silver cups as well as bronze bowls, cups, jugs and basins.

The above describes what a University of Cincinnati-led international research team found this summer when excavating what was initially thought to be a Bronze Age house.

Instead, the team made a rich and rare discovery of an intact, Bronze Age warrior's tomb dating back to about 1500 B.C., and that discovery is featured in The New York Times, in an article titled: A Warrior's Grave at Pylos, Greece, Could Be a Gateway to Civilizations.

The find is so extraordinay that UC's Shari Stocker, senior research associate in the Department of Classics, McMicken College of Arts and Sciences, states: "This previously unopened shaft grave of a wealthy Mycenaean warrior, dating back 3,500 years, is one of the most magnificent displays of prehistoric wealth discovered in mainland Greece in the past 65 years."

Stocker co-leads the team that unearthed the undisturbed shaft tomb, along with Jack Davis, UC's Carl W. Blegen Chair in Greek Archaeology. Other team members include UC faculty, staff specialists and students, some of whom have worked in the area around the present-day city of Pylos on the southwest coast of Greece for the last quarter century as part of the Pylos Regional Archaeological Project. That UC-based effort is dedicated to uncovering the pre-history and history of the Bronze Age center known as the Palace of Nestor, an extensive complex and a site linked to Homeric legend. Though the palace was destroyed by fire sometime around 1200 B.C., it is nevertheless the best-preserved Bronze Age palace on the Greek mainland.

It was UC archaeologist Carl Blegen, along with Konstantinos Kourouniotis, director of the National Archaeological Museum, who initially uncovered the remains of the famed Palace of Nestor in an olive grove in 1939. Located near the present-day city of Pylos, the palace was a destination in Homer's "Odyssey," where sacrifices were said to be offered on its beaches. The king who ruled at the Palace of Nestor controlled a vast territory that was divided into more than 20 districts with capital towns and numerous small settlements.

Explains Stocker, "This latest find is not the grave of the legendary King Nestor, who headed a contingent of Greek forces at Troy in Homer's 'Iliad.' Nor is it the grave of his father, Neleus. This find may be even more important because the warrior pre-dates the time of Nestor and Neleus by, perhaps, 200 or 300 years. That means he was likely an important figure at a time when this part of Greece was being indelibly shaped by close contact with Crete, Europe's first advanced civilization."

Thus, the tomb may have held a powerful warrior or king -- or even a trader or a raider -- who died at about 30 to 35 years of age but who helped to lay the foundations of the Mycenaean culture that later flourished in the region.

Davis speculates, "Whoever he was, he seems to have been celebrated for his trading or fighting in nearby island of Crete and for his appreciation of the more-sophisticated and delicate are of the Minoan civilization (found on Crete), with which he was buried."

Potential Wealth of Information

The team found the tomb while working in the area of the Palace of Nestor, seeking clues as to how the palace and its rulers came to control an area encompassing all of modern Messenia in western Greece and supporting more than 50,000 inhabitants during the Bronze Age.

Davis says that researchers were there to try and figure out how the Palace of Nestor became a center of power and when this rise in power began, questions they now think the tomb may help answer.
Given the magnitude of this find, it may be necessary to rethink when Plyos and the wider area around it began to flourish. It may have been earlier than previously thought since, somehow, whether via trade or force (e.g., raiding), its inhabitants had acquired the valuable objects found within the tomb.

Many of the tomb's objects were made in nearby Crete and show a strong Minoan style and technique unknown in mainland Greece in the 15th century BC.

The same would likely have been true of the warrior's dwelling during this lifetime. He would have lived on the hilltop citadel of nearby Englianos at a time when great mansions were first being built with walls of cut-stone blocks (vs. uncut rock and stones) in the style then associated with nearby Mediterranean Island of Crete and its Minoan culture, their walls decorated with paintings influenced by earlier Minoan wall paintings.

The weapons of bronze found within the tomb included a meter-long slashing sword with an ivory handle covered with gold.

Wealth of Jewels and Weaponry

A remarkable store of riches was deposited in the tomb with the warrior at the time of his death. The mere fact that the vessels in the tomb are of metal (vs. ceramic pottery) is a strong indication of his great wealth.

"It is truly amazing that no ceramic vessels were included among the grave gifts. All the cups, pitchers and basins we found were of metal: bronze, silver and gold. He clearly could afford to hold regular pots of ceramic in disdain," according to Stocker.

This member of the elite was accompanied in the afterlife by about 50 seal-stones carved with intricate Minoan designs of goddesses as well as depictions of bulls and human bull jumpers soaring over their horns. Four gold rings in the tomb contain fine Minoan carvings. A plaque of carved ivory with a representation of a griffon with huge wings lay between the man's legs. Nearby was a bronze mirror with an ivory handle. Archaeological conservator Alexandros Zokos was essential partner in the removal, cleaning and preservation of the finds from the grave.

The weapons of bronze within the tomb include a meter-long slashing sword with an ivory handle, several daggers, a spearhead, along with the already-mentioned sword and dagger with gold pommels.

Other grave gifts originally rested above the dead warrior atop a coffin of wood which later collapsed, spilling a crushing load of objects down on the skeleton -- and making the job of excavation difficult and slow.

The gifts atop the coffin included bronze jugs; a large, bronze basin; thin bands of bronze, probably from the warrior's suit of body armor; many wild boar's teeth from the warrior's helmet.
In combination with this weaponry, the discovery of so much jewelry with a male burial challenges the commonly held belief that these apparently "feminine" adornments and offerings accompanied only wealthy women to the hereafter.

Previously Unexplored Field

What would eventually become the successful excavation of the tomb began on the team's very first day of its field work in May 2015, conducted in a previously unexplored field near the Palace of Nestor. They immediately found one of the four walls of the warrior's grave.

"We put a trench in this one spot because three stones were visible on the surface," says Davis, adding, "At first, we expected to find the remains of a house. We expected that this was the corner of a room of a house, but quickly realized that it was the tops of the walls of a stone-lined grave shaft."
In the end, the shaft measured about 5 feet deep, 4 feet wide and 8 feet long. It took the team about two weeks to clear the shaft before "we hit bronze," says Stocker. At that point, they realized they might have an exceptional prize: an undisturbed grave shaft, never stripped by looters. She explains, "The fact that we had not encountered any objects for almost a meter indicated that whatever was at the bottom had been sealed for a long time."

Stocker and Alison Fields, a UC graduate student of classics, did most of the actual excavation because their smaller size allowed them to work more easily and carefully around the tomb and its many precious objects.

What Comes Next

Both Stocker and Davis say it was good luck to discover this intact grave. Given the rarity of the find, it's unlikely to be repeated. "It's almost as if the occupant wants his story to be told," Davis says.
And that story will continue to unfold. The UC team and others are studying the artifacts in detail, with all artifacts remaining in Greece and their final disposition determined by the Greek Archaeological Service. Former UC anthropologist Lynne Schepartz, now of the University of Witwatersrand in Johannesburg, South Africa, will study the skeletal remains.

Catalogue of Objects Found Within the Warrior Tomb

Gold

• Four complete solid-gold seal rings to be worn on a human finger. This number is more than found with any single burial elsewhere in Greece.
• Two squashed gold cups and a silver cup with a gold rim
• One unique necklace of square box-shaped golden wires, more than 30 inches long with two gold pendants decorated with ivy leaves.
• Numerous gold beads, all in perfect condition.

Silver

• Six silver cups.

Bronze

• One three-foot long sword, with an ivory hilt overlaid with gold in a rare technique imitating embroidery (found at warrior's left chest).
• Under this sword was a smaller dagger with a gold hilt employing the same technique.
• Other bronze weapons by his legs and feet.
• Bronze cups, bowls, amphora, jugs and a basin, some with gold, some with silver trim.

Seal Stones

• More than 50 seal stones, with intricate carvings in Minoan style showing goddesses, altars, reeds, lions and bulls, some with bull-jumpers soaring over the bull's horns -- all in Minoan style and probably made in Crete.

Ivory

• Several pieces of carved ivory, one with a griffon with large wings and another depicting a lion attacking a griffon.
• Six decorated ivory combs.

Precious Stone Beads

• An astonishing hoard of over 1000 beads, most with drill holes for stringing together. The beads are of carnelian, amethyst, jasper and agate. Some beads appear to be decorations from a burial shroud of woven fabric, suggested by several square inches of cross woven threads which survived in the grave for 3,500 years.

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Ancient babies boost Bering land bridge layover: DNA links many Native Americans to infants in Alaskan grave

This map shows the location of the Upward Sun River site in Alaska where the remains of two infants, Upward Sun River individuals 1 and 2, were found in an 11,500-year-old burial. A new University of Utah analysis shows the infants belong to two genetic groups or lineages known as B2 and C1. The maps shows other Native American groups throughout the Americas that are part of the same lineages.

CREDIT
Ben Potter, University of Alaska Fairbanks

University of Utah scientists deciphered maternal genetic material from two babies buried together at an Alaskan campsite 11,500 years ago. They found the infants had different mothers and were the northernmost known kin to two lineages of Native Americans found farther south throughout North and South America.

By showing that both genetic lineages lived so far north so long ago, the study supports the "Beringian standstill model." It says that Native Americans descended from people who migrated from Asia to Beringia - the vast Bering land bridge that once linked Siberia and Alaska - and then spent up to 10,000 years in Beringia before moving rapidly into the Americas beginning at least 15,000 years ago.

"These infants are the earliest human remains in northern North America, and they carry distinctly Native American lineages," says University of Utah anthropology professor Dennis O'Rourke, senior author of the paper set for online publication the week of Oct. 26 in the journal Proceedings of the National Academy of Sciences.

"We see diversity that is not present in modern Native American populations of the north and we see it at a fairly early date. This is evidence there was substantial genetic variation in the Beringian population before any of them moved south."

Another theory was that the two Native Americans lineages evolved as the people moved south and dispersed, not while they still were in Beringia, says Justin Tackney, the new study's first author and a University of Utah anthropology doctoral student. But finding those lineages in the infants only a few thousand years after the migration south began indicates those lineages already were present before the migration started.

"It supports the Beringian standstill theory in that if they [the infants] represent a population that descended from the earlier Beringian population, it helps confirm the extent of genetic diversity in that source population," O'Rourke says. "You don't see any of these lineages that are distinctly Native American in Asia, even Siberia, so there had to be a period of isolation for these distinctive Native American lineages to have evolved away from their Asian ancestors. We believe that was in Beringia."

The burial of ancient infants is rare. One was a 6- to 12-week-old baby; the other a stillborn or preterm 30-week fetus. The discovery of the infant burials first was reported in the same journal this past November. They are among human remains at only eight sites in North America older than 8,000 years and from which researchers obtained mitochondrial DNA - genetic information inherited only from mothers. The infants are the northernmost of all those remains and of the two lineages they represent.

In the eight sites, "we find all five of the major lineages of Native Americans," Tackney says. "That indicates that all were present in the early population in Beringia that gave rise to all modern Native Americans."

Sequencing DNA from the burials of Upward Sun River

The Upward Sun River ancient campsite was discovered in 2006 in the Tanana River valley about 50 miles southeast of Fairbanks. The area once was part of Beringia. The land bridge between Asia and Alaska existed when sea levels were low during the last Ice Age from 28,000 years ago to at least 18,000 years ago.

In 2010, a team led by University of Alaska Fairbanks anthropologist Ben Potter discovered the remains of a cremated 3-year-old child buried near the hearth of a residential structure. The child's DNA couldn't be recovered from the charred remains.

In 2013, Potter's team found the remains of two more buried infants beneath the first. They had't been cremated. Potter says it's hard to tell how the infants died. Potter, who co-authored the new study, asked O'Rourke to analyze their mitochondrial DNA.

O'Rourke and Tackney worked with University of Utah geneticists to sequence the mitochondrial DNA of the two infants - known as USR1 and USR2 for Upward Sun River. Mitochondrial DNA is located in mitochondria, or the power plants of cells.

From fragments of skull bone, the researchers read 58.7 million DNA sequences from USR1 and 55.8 million from USR2. From those, the Utah scientists obtained 20,004 high-quality mitochondrial DNA sequences for USR1 and 32,979 for USR2.

"We were able to obtain the entire mitochondrial genome [genetic blueprint] sequence for each of them, as opposed to just a partial sequence," O'Rourke says.

Infants related to two native lineages throughout the Americas

Potter says the new findings help in "understanding the genetic diversity among very early Beringian populations that connects them in many ways to Native Americans in both North and South America."

The researchers identified infant USR1 as belonging to Native American lineage C1b, while infant USR2 is part of a more common native lineage known as B2. (Native American lineages begin with the letters A, B, C, D or X.)

"It's not common to find infants buried together that are not related maternally," O'Rourke says. "It raises questions about the social structure and mortuary practices of these early people," including whether the babies had a common father.

Lineage C1 (most remains aren't identified to the subgroup C1b level) is found most often among the Pima and Hualapai Indians of Arizona, the Delta Yuman of California, and six other tribes, including the Ignaciano in Bolivia, the extinct Tainos in Puerto Rico and a group represented by 700-year-old bones at Norris Farms in Illinois.

Lineage B2 is found most often in 37 tribes throughout the Americas, including the Yakama, Wishram, Northern Paiute-Shoshoni, Navajo, Hualapai (which also carries C1 genes), Zuni and Jemez in North America and the Quecha and Aymara in Peru. The B2 lineage also was common among the U.S. Southwest's ancient Fremont and Anasazi.

The genetic data indicate that the most recent common ancestor of the C1b lineage existed at least 12,854 years ago, and the most recent common ancestor of the B2 lineage existed at least 12,024 years ago. O'Rourke suspects the real times were even earlier, but that nonetheless both 11,500-year-old infants were at or near the root of their respective genealogical trees.

"It may well be that the population represented by Upward Sun River is indicative of many such isolated populations distributed across Beringia, each of which may have contributed migrants to that early American Indian dispersal, and each may have been slightly genetically different from the others," O'Rourke says.

Native lineages spread unevenly in the Americas

Modern tribal populations in northern North America show little mitochondrial DNA diversity, O'Rourke says. Why did lineages that once occupied the subarctic vanish there but show elsewhere in the Americas? And why aren't the five major lineages spread evenly across the Americas?

"The reason is changes in population size and rates of population migration," O'Rourke says. "In small populations, some lineages just get lost and don't get passed on, and in others they become established and more common."

"Studying the DNA of ancient individuals is important in researching how the Western Hemisphere was populated," Tackney says. "Studying the genetics of these infants who died 11,500 years ago in what is now central Alaska helps answer questions of who these people were and how they are related to modern native populations."

Rise and fall of ancient agrarian states in Mexico and Peru influenced by climate volatility

Climate variability is one of the major forces in the rise and fall of agrarian states in Mexico and Peru, according to a team of researchers looking at both climate and archaeological records.

"We are arguing that the climate information in both areas is good enough to establish that climate is playing some role in the rise and fall of these city states," said Douglas Kennett, professor of environmental archaeology. "Now we need to further refine the archaeological data."

Kennett, working with Norbert Marwan, climatologist and statistician, Potsdam Institute for Climate Impact Research, Germany, looked at climate records for central Mexico gleaned from a stalagmite collected from Juxtlahuaca Cave in the state of Guerrero. They also looked at the climate record preserved in the Quelccaya ice cape in the Cordillera Vilcanota portion of the Peruvian Andes.

In both cases the climate records are based on oxygen isotope measurements on datable layers of ice or stalagmite cave deposition. These records show annual changes in rainfall and temperature for 2,000 years in Mexico and 1,800 years in Peru.

"There is a long tradition of archaeology in both central Mexico and the Peruvian highlands," said Kennett. "There are also new high resolution climate records available that have not yet been capitalized on by archaeologists."

The researchers note that some refinement in archaeological dating in some areas is still needed, but that the rise and fall of major polities is reasonably well known.

Comparing the climate record with organized agrarian state level societies in Mexico, Kennett and Marwan looked at the rise and falls of three states -- Teotihuacán from 100 BCE to 650 CE, Toltec from 900 to 1150 CE and the Aztec Empire from 1400 to 1519.

"The fluorescence and expansion of Teotihuacán as a regional power between 100 and 400 CE occurred during an interval of persistent and stable rainfall," the researchers report today (Oct. 18) in Philosophical Transactions of the Royal Society A. Teotihuacán, during its heyday, influenced large portions of central Mexico.

The decline of Teotihuacán from 600 to 700 occurred during "some of the most volatile climate conditions evident in the Juxtlahuaca Cave climate record." This was followed by extended drought after 700 recognized by previous studies.

The decline of major states was typically followed by dispersal or decentralization of populations and power. Smaller, usually weaker cities arose in these regions, but were highly unstable and controlled little territory.

In the early 10th Century, Tula emerged as a major force in the central highlands. This corresponded to a wetter and more stable climate period than the 7th century. The researchers note that while there is some discussion as to the dating of the Tula civilization, "it appears that Tula was established during a relatively stable climatic interval and went into decline as climatic conditions became more volatile."

"While there is some support for the hypothesis that stable climatic conditions favored political centralization and that unstable climatic conditions contributed to sociopolitical instability and decentralization," said Kennett. "Additional chronological work is needed."

By the early 15th century, Tenochtitlan, now Mexico City, was one of the large cities vying for control of the Basin of Mexico. It eventually grew to a city of 200,000 people. The growth of the Aztec empire coincided with an extremely wet and stable climatic period. The empire fell under the conquistadors who arrived in 1519, so the potential societal effects of highly volatile climatic conditions during the 16th century are difficult to evaluate.

During each of these time periods urban populations developed agricultural methods that relied on the persistent availability of rainfall - irrigation. During the climate's unstable periods, evidence of population dispersal, destruction and warfare are evident in the archaeological record.

About 3,000 miles to the south, the situation in Peru looks very similar to Mexico. Three civilizations -- Wari and Tiwanaku from 300 BCE to 1000 CE and Inka from 1438 to 1525 CE -- emerged in the Andes. The Wari and Tiwanaku states developed side by side in the highlands covering the area from what is now northern Peru to northern Chile. These civilizations developed sophisticated methods of intensive agriculture suitable for these high elevations. However, these methods were sensitive to changes in temperature and precipitation. States developed when the climate was warm, wet and stable. The climate became highly volatile and dry in 1000 CE when these states both went into decline.

Again from 1000 to 1300 CE the climate was highly volatile, populations dispersed, and smaller competing polities are evident throughout the highlands. As conditions stabilized the Inka Empire emerged and dominated the Andes from Ecuador to southern Chile by the end of the 15th century. A complex combination of irrigation, cropping and other agricultural approaches along with an intricate network of regional capitals, rituals and military campaigns created this large empire. This time was also a stable climate period. Just as the Aztec empire fell, the Inka Empire fell to the Spanish conquistadors in 1533.

Both of these regions show the formation, decline and eventual reestablishment of states in a pattern that mirrors the stability and instability of climate conditions in each region. It appears that political fragmentation, sociopolitical instability and warfare occurred during the unstable climate periods, while the growth of strong, stable, successful states were favored during stable climatic intervals.

Ashkenazi Jews all come from a founding population of about 350 people.

Ashkenazi Jews (AJ), identified as Jewish individuals of Central- and Eastern European ancestry, form the largest genetic isolate in the United States. AJ demonstrate distinctive genetic characteristics including high prevalence of autosomal recessive diseases and relatively high frequency of alleles that confer a strong risk of common diseases, such as Parkinson’s disease and breast and ovarian cancer. 

Several recent studies have employed common polymorphisms to characterize AJ as a genetically distinct population, close to other Jewish populations as well as to present-day Middle Eastern and European populations. Previous analyses of recent AJ history highlighted a narrow population bottleneck of only hundreds of individuals in late medieval times, followed by rapid expansion.

A new study improves imputation accuracy for AJ SNP arrays by 28%, and covers at least one haplotype in ≈67% of any AJ genome with long, identical-by-descent segments. Reconstruction of recent AJ history from such segments confirms a recent bottleneck of merely ≈350 individuals.

Modelling of ancient histories for AJ and European populations using their joint allele frequency spectrum determines AJ to be an even admixture of European and likely Middle Eastern origins. We date the split between the two ancestral populations to ≈12–25 Kyr, suggesting a predominantly Near Eastern source for the repopulation of Europe after the Last Glacial Maximum.

The study, in other words, found that 

“the central and eastern European Jewish population, known as Ashkenazi Jews, from whom most American Jews are descended, started from a founding population of about 350 people between 600 and 800 years ago.”

According to Columbia University researcher Itsik Pe’er, who was involved with the study, their research also showed that the group of 350 was made up of Jews of Middle Eastern and European—thereby disproving the much-debated theory that Jews descended from Khazars, a Turkic people who lived in the Caucasus region between the 7th and 10th centuries.

A Rare 1,500 Year Old Mosaic was Discovered that Depicts Ancient Streets and Buildings in Egypt

Photographic credit: Nikki Davidov

A 1,500 year old mosaic, depicting a map with streets and buildings, was exposed about two years ago in archaeological excavations the Israel Antiquities Authority conducted together with school children and employees from the Qiryat Gat Industrial Park. The excavation of the mosaic was generously underwritten by the Y.S. Gat Company–Qiryat Gat Industrial Park Management Company. This extraordinary mosaic served as the floor of a church dating to the Byzantine period. It was removed from the site for the purpose of conservation and was recently returned to its permanent location in the industrial park. The mosaic will be revealed to the public for the first time at the “Factories from Within” festival to be held October 1, during the Sukkot holiday.

According to archaeologists Sa‘ar Ganor and Dr. Rina Avner of the Israel Antiquities Authority, “The appearance of buildings on mosaic floors is a rare phenomenon in Israel. The buildings are arranged along a main colonnaded street of a city, in a sort of ancient map. A Greek inscription preserved alongside one of the buildings exposed in the mosaic indicates that the place which is depicted is the settlement חורטסו, in Egypt. According to Christian tradition, the prophet Habakkuk was buried in חורטסו. The appearance of this Egyptian city on the floor of the public building in Qiryat Gat might allude to the origin of the church’s congregation”.

The mosaic pavement was part of the floor of a church that did not survive. Two sections of the mosaic were preserved; animals such as a rooster, deer and birds and a special goblet with red fruits are portrayed on one part of the pavement. According to Ganor, “The artist utilized tesserae of seventeen different colors in preparing the mosaic. The investment in the raw materials and their quality are the best ever discovered in Israel”. A Nile River landscape in Egypt consisting of a boat with a rolled-up sail, streets and buildings is depicted on the second carpet. The buildings are portrayed in detail and in three dimensions, and they have two–three stories, balconies and galleries, roofs, roof tiles and windows.

The “Factories from Within” festival will be held this year for the first time in the Qiryat Gat Industrial Park during the Sukkot holiday, in what will become an annual tradition. On October 1 the Qiryat Gat Industrial Park will be turned into an event-filled arena of one-time performances in unconventional locations, with rare visits inside some of the best known factories in Israel. The children will enjoy performances of Adon Shoko with songs by Arik Einstein, “Shukhnat Hop” and a variety of creative activities. A unique offering of events awaits adults with appearances by Shalom Hanoch and Moshe Levi in a performance of “Exit” that will be held in a printer factory, the singer Dikla will appear in the park, and Hemi Rudner will hold a fascinating master’s class in the Negev Beer brewery.

The project will give the general public a rare opportunity to peek into the hidden world of the factories in one of the country’s most modern industrial areas. The “Factories from Within” festival is the inaugural event slated to launch the 60th anniversary of Qiryat Gat, and the public is invited to enjoy the unique musical and visual experience.