Lidar imagery of SKBR (Karim Sadr)
'Lost city' revealed in South Africa using laser technology
22 March 2018
Archaeologists in South Africa have located the site of a centuries-old 'lost city' using sophisticated laser technology.
Local landowners had known about ruins at Suikerbosrand near Johannesburg for generations, according to Karim Sadr, professor at the School of Geography, Archaeology and Environmental Studies at the University of the Witwatersrand. "Archaeologists from my University dug several of the homesteads there in the 1970s and 1980s," he told Fox News, via email. "But no one ever saw the ruins as anything more than a scatter of homesteads, a few villages dispersed here and there."
Sadr, who has visited the area multiple times in the past three decades, explained that he used LiDAR (Light Detection and Ranging) technology to reveal the city's secrets. The in-depth aerial images tell a fascinating story of the archaeological site, which is known as 'SKBR.'
"It is only when I obtained LiDAR imagery for about 20 square kilometres (7.72 square miles) of the western foothills and had examined it in minute detail that I started to see the aspects of the built environment that are largely invisible from the ground and on air photos because of the vegetation cover," he said. A host of stone structures showed up on the images.
LiDAR uses a laser to measure distances to the Earth's surface and can prove extremely valuable to study what is hidden in areas with thick vegetation. LiDAR is also used extensively in other applications, including autonomous cars where it allows vehicles to have a continuous 360 degrees view.
Sadr commissioned a LiDAR aerial survey of the first 10 square kilometres in late 2014 and the remainder the following year. "It was only in 2016 after poring over all of that detailed imagery that I eventually realized that the homesteads are not a scatter of villages but parts of one entity; a city, rather than a dispersion of homesteads," he told Fox News.
The Conversation reports that the city was occupied by speakers of the Tswana language from the 15th century until about 200 years ago. Other Tswana cities were known to exist in the region, but not in that specific area. The Tswana city-states collapsed as a result of early 19th-century civil war, according to The Conversation.
"It is significant because we did not know that there was a Tswana city this far east of the group that had already been visited by the European travellers at the beginning of the 19th century; so we have extended the range of this archaeological culture and its city-states," said Sadr.
SKBR covered an area of about 6.2 miles from north to south and was about 1.2 miles to 2 miles wide. "I have counted about 800 homesteads in this area and there are probably more, but it is difficult to say how many people occupied the city at any time, since not all the homesteads would have been occupied concurrently and some may have contained many more people than others," Sadr said. "My guess is that the city never had more than 10,000 people at any one time, but that is just an educated guess.”
While more LiDAR coverage of SKBR is planned, archaeologists are also preparing to examine the site up close. "LiDAR cannot show everything and many of the parts of the city need to investigated on the ground from up close," said Sadr, noting that this research can form the basis of students' theses. "Eventually we will want to excavate some parts of the site and since the deposits are not generally deep, not a lot of earth has to be moved."
"Beyond SKBR, there are also questions about the spatial limits of this city-state, its boundaries, outpost, neighbours, external trade connections and such that need to be answered," he added. "And eventually, the big question to answer is why did the Tswana decide to become an urban population around a quarter of a millennium ago?"
A Takarkori rock shelter. University of Huddersfield
Entomologist confirms first Saharan farming 10,000 years ago
17 March 2018
By analyzing a prehistoric site in the Libyan desert, a team of researchers from the universities of Huddersfield, Rome and Modena & Reggio Emilia has been able to establish that people in Saharan Africa were cultivating and storing wild cereals 10,000 years ago. In addition to revelations about early agricultural practices, there could be a lesson for the future, if global warming leads to a necessity for alternative crops.
The importance of the find came together through a well-established official collaboration between the University of Huddersfield and the University of Modena & Reggio Emilia.
The team has been investigating findings from an ancient rock shelter at a site named Takarkori in south-western Libya. It is desert now, but earlier in the Holocene age[our present age], some 10,000 years ago, it was part of the "green Sahara" and wild cereals grew there. More than 200,000 seeds - in small circular concentrations - were discovered at Takarkori, which showed that hunter-gatherers developed an early form of agriculture by harvesting and storing crops.
But an alternative possibility was that ants, which are capable of moving seeds, had been responsible for the concentrations. Dr Stefano Vanin, the University of Huddersfield's Reader in Forensic Biology and a leading entomologist in the forensic and archaeological fields, analyzed a large number of samples, now stored at the University of Modena & Reggio Emilia. His observations enabled him to demonstrate that insects were not responsible and this supports the hypothesis of human activity in collection and storage of the seeds.
The investigation at Takarkori provides the first-known evidence of storage and cultivation of cereal seeds in Africa. The site has yielded other key discoveries, including the vestiges of a basket, woven from roots, that could have been used to gather the seeds. Also, chemical analysis of pottery from the site demonstrates that cereal soup and cheese were being produced.
A new article that describes the latest findings and the lessons to be learned appears in the journal Nature Plants. Titled Plant behaviour from human imprints and the cultivation of wild cereals in Holocene Sahara, it is co-authored by Anna Maria Mercuri, Rita Fornaciari, Marina Gallinaro, Savino di Lernia and Dr Vanin.
One of the article's conclusions is that although the wild cereals, harvested by the people of the Holocene Sahara, are defined as "weeds" in modern agricultural terms, they could be an important food of the future.
"The same behavior that allowed these plants to survive in a changing environment in a remote past makes them some of the most likely possible candidates as staple resources in a coming future of global warming. They continue to be successfully exploited and cultivated in Africa today and are attracting the interest of scientists searching for new food resources," state the authors.
Research based on the findings at Takarkori continues. Dr Vanin is supervising PhD student Jennifer Pradelli - one of a cohort of doctoral candidates at the University of Huddersfield funded by a €1 million award from the Leverhulme Trust - and she is analyzing insect evidence in order to learn more about the evolution of animal breeding at the site.
Tooling down: By around 320,000 years ago in
East Africa, Homo sapiens
or a close relative had shifted from making large chopping implements (left) to fashioning spearpoints
and other small tools
Ancient climate shifts may have sparked human ingenuity and networking
15 March 2018
Dramatic shifts in the East African climate may have driven toolmaking advances and the development of trading networks among Homo sapiens or their close relatives by the Middle Stone Age, roughly 320,000 years ago. That's the implication of discoveries reported in three papers published online March 15 in Science.
Newly excavated Middle Stone Age tools and red pigment chunks from southern Kenya's Olorgesailie Basin appear to have been part of a long trend of climate-driven behavior changes in members of the Homo genus that amped up in H. sapiens. Locations of food sources can vary unpredictably on changing landscapes. H. sapiens and their precursors responded by foraging over larger areas with increasingly smaller tools, the researchers propose. Obsidian used for the Middle Stone Age tools came from far away, raising the likelihood of long-distance contacts and trading among hominid populations near humankind's root.
At roughly 320,000 years old, the excavated Middle Stone Age tools are the oldest of their kind, paleoanthropologist Rick Potts and colleagues report in one of the new papers. Researchers had previously estimated that such tools - spearpoints and other small implements struck from prepared chunks of stone - date to no earlier than 280,000 to possibly 300,000 years ago. Other more primitive, handheld cutting stones made of local rock date from around 1.2 million to 499,000 years ago at Olorgesailie. Gradual downsizing of those tools, including oval hand axes, occurred from 615,000 to 499,000 years ago, a stretch characterized by frequent shifts between wet and dry conditions, the scientists say.
It's not known whether that tool trend continued or if a sudden transition to Middle Stone Age implements happened between 499,000 and 320,000 years ago. Erosion at Olorgesailie artifact sites has destroyed sediment from that time period, leaving the nature of toolmaking during that time gap a mystery. Age estimates relied on measures of the decay of radioactive forms of argon and uranium in volcanic ash layers framing tool-bearing sediment. It's unclear whether Homo sapiens or a closely related species made Olorgesailie's Middle Stone Age tools, since no hominid fossils have been found there.
Back-and-forth shifts from dry to wet conditions - many happening over only a few years or decades - continued to regularly reshape the Olorgesailie landscape around 320,000 years ago, conclude Potts, of the Smithsonian Institution in Washington, D.C., and colleagues in another of the new papers. That timing coincides roughly with the emergence of H. sapiens (SN: 12/23/17, p. 24). The team's climate reconstruction is based on microscopic and chemical analyses of the region's soil.
A substantial number of Olorgesailie's Middle Stone Age tools are made from obsidian that came from at least 25 to 50 kilometers away from the excavation sites. At one Olorgesailie site in particular, 42 percent of more than 3,400 stone artifacts were obsidian. Some of those finds display signs of having been attached to handles, likely as spearpoints, a group led by archaeologist Alison Brooks of George Washington University in Washington, D.C., reports in the third paper. Brooks is also a coauthor on the other studies.
Formation of trading networks among dispersed groups of H. sapiens, or possibly among closely related populations, best explains how large amounts of obsidian turned up at Olorgesailie by 320,000 years ago, contends Potts, who coauthored the third paper. "Social networking during a long period of climate variability was a key to success for early Homo sapiens," he says. "Greater mobility encouraged inventive thinking about how to acquire resources." Potts has long argued that H. sapiens and close evolutionary relatives evolved to deal with constantly changing environments (SN: 8/20/05, p. 116).
Still, factors other than climate fluctuations, such as hominid population declines or surges, may also have spurred ancient tool innovations to acquire more or different types of food, cautions archaeologist Yonatan Sahle of the University of Tübingen in Germany.
In addition to the obsidian tools, a total of 88 pigment lumps, including two pieces with grinding marks, came from an undetermined distance outside the Olorgesailie vicinity, Brooks' group says. Pigment applied to one's body or belongings may have signaled group identity or social status, the researchers suggest.
The new reports fit with genetic evidence that H. sapiens originated in Africa between 350,000 and 260,000 years ago (SN: 10/28/17, p. 16), says Stone Age archaeologist Marlize Lombard of the University of Johannesburg. Smaller, more specialized Middle Stone Age tools appearing along with pigment "provide strong indicators that by around 300,000 years ago we were well on our way to becoming modern humans in Africa," she holds.
Ancient toolmaking approaches varied greatly from one part of Africa to another, with hominids employing diverse mixes of old-school chopping tools and newer, sharp points, says archaeologist John Shea of Stony Brook University in New York. At Olorgesailie and elsewhere, he says, "early Homo sapiens and their immediate African ancestors were at least as smart as the scientists investigating them."
The research team has
been excavating caves at Pinnacle Point, South
Africa, for nearly 20 years. Glass shards from Mount Toba were discovered at
the PP5-6 location. Erich Fisher
Humans thrived in South Africa through the Toba super-volcanic eruption ~ 74,000 years ago
11 March 2018
Imagine a year in Africa when summer never arrives. The sky takes on a gray hue during the day and glows red at night. Flowers do not bloom. Trees die in the winter. Large mammals like antelope become thin, starve and provide little fat to the predators (carnivores and human hunters) that depend on them. Then, this same disheartening cycle repeats itself, year after year. This is a picture of life on earth after the eruption of the super-volcano, Mount Toba in Indonesia, about 74,000 years ago. In a paper* published this week in Nature, scientists show that early modern humans on the coast of South Africa thrived through this event.
An eruption a hundred times smaller than Mount Toba - that of Mount Tambora, also in Indonesia, in 1815 - is thought to have been responsible for a year without summer in 1816. The impact on the human population was dire - crop failures in Eurasia and North America, famine and mass migrations. The effect of Mount Toba, a super-volcano that dwarfs even the massive Yellowstone eruptions of the deeper past, would have had a much larger, and longer-felt, impact on people around the globe.
The scale of the ash-fall alone attests to the magnitude of the environmental disaster. Huge quantities of aerosols injected high into the atmosphere would have severely diminished sunlight - with estimates ranging from a 25 to 90 percent reduction in light. Under these conditions, plant die-off is predictable, and there is evidence of significant drying, wildfires and plant community change in East Africa just after the Toba eruption.
If Mount Tambora created such devastation over a full year - and Tambora was a hiccup compared to Toba - we can imagine a worldwide catastrophe with the Toba eruption, an event lasting several years and pushing life to the brink of extinctions.
In Indonesia, the source of the destruction would have been evident to terrified witnesses - just before they died. However, as a family of hunter-gatherers in Africa 74,000 years ago, you would have had no clue as to the reason for the sudden and devastating change in the weather. Famine sets in and the very young and old die. Your social groups are devastated, and your society is on the brink of collapse.
The effect of the Toba eruption would have certainly impacted some ecosystems more than others, possibly creating areas - called refugia - in which some human groups did better than others throughout the event. Whether or not your group lived in such a refuge would have largely depended on the type of resources available. Coastal resources, like shellfish, are highly nutritious and less susceptible to the eruption than the plants and animals of inland areas.
When the column of fire, smoke and debris blasted out the top of Mount Toba, it spewed rock, gas and tiny microscopic pieces (cryptotephra) of glass that, under a microscope, have a characteristic hook shape produced when the glass fractures across a bubble. Pumped into the atmosphere, these invisible fragments spread across the world.
Panagiotis (Takis) Karkanas, director of the Malcolm H. Wiener Laboratory for Archaeological Science, American School of Classical Studies, Greece, saw a single shard of this explosion under a microscope in a slice of archaeological sediment encased in resin.
"It was one shard particle out of millions of other mineral particles that I was investigating. But it was there, and it couldn't be anything else," says Karkanas.
The shard came from an archaeological site in a rockshelter called Pinnacle Point 5-6, on the south coast of South Africa near the town of Mossel Bay. The sediments dated to about 74,000 years ago.
"Takis and I had discussed the potential of finding the Toba shards in the sediments of our archaeological site, and with his eagle eye, he found one," explains Curtis W. Marean, project director of the Pinnacle Point excavations. Marean is the associate director of the Institute of Human Origins at Arizona State University and honorary professor at the Centre for Coastal Palaeoscience at Nelson Mandela University, South Africa.
Marean showed the shard image to Eugene Smith, a volcanologist with the University of Nevada at Las Vegas, and Smith confirmed it was a volcanic shard.
"The Pinnacle Point study brought me back to the study of glass shards from my master's thesis 40 years earlier," says Smith.
Early in the study, the team brought in expert cryptotephra scientist Christine Lane who trained graduate student Amber Ciravolo in the needed techniques. Racheal Johnsen later joined Ciravalo as lab manager and developed new techniques.
From scratch, with National Science Foundation support, they developed the Cryptotephra Laboratory for Archaeological and Geological Research, which is now involved in projects not only in Africa, but in Italy, Nevada and Utah.
Encased in that shard of volcanic glass is a distinct chemical signature, a fingerprint that scientists can use to trace to the killer eruption. In their paper in Nature, the team describes finding these shards in two archaeological sites in coastal South Africa, tracing those shards to Toba through chemical fingerprinting and documenting a continuous human occupation across the volcanic event.
"Many previous studies have tried to test the hypothesis that Toba devastated human populations," Marean notes. "But they have failed because they have been unable to present definitive evidence linking a human occupation to the exact moment of the event."
Most studies have looked at whether or not Toba caused environmental change. It did, but such studies lack the archaeological data needed to show how Toba affected humans.
The Pinnacle Point team has been at the forefront of development and application of highly advanced archaeological techniques. They measure everything on site to millimetric accuracy with a "total station," a laser-measurement device integrated to handheld computers for precise and error-free recording.
Naomi Cleghorn with the University of Texas at Arlington, recorded the Pinnacle Point samples as they were removed.
Cleghorn explains, "We collected a long column of samples - digging out a small amount of sediment from the wall of our previous excavation. Each time we collected a sample, we shot its position with the total station."
The sample locations from the total station and thousands of other points representing stone artifacts, bone, and other cultural remains of the ancient inhabitants were used to build digital models of the site.
"These models tell us a lot about how people lived at the site and how their activities changed through time," say Erich Fisher, associate research scientist with the Institute of Human Origins, who built the detailed photorealistic 3D models from the data. "What we found was that during and after the time of the Toba eruption people lived at the site continuously, and there was no evidence that it impacted their daily lives."
In addition to understanding how Toba affected humans in this region, the study has other important implications for archaeological dating techniques. Archaeological dates at these age ranges are imprecise - 10 percent (or 1000s of years) error is typical. Toba ash-fall, however, was a very quick event that has been precisely dated. The time of shard deposition was likely about two weeks in duration - instantaneous in geological terms.
"We found the shards at two sites," explains Marean. "The Pinnacle Point rockshelter (where people lived, ate, worked and slept) and an open air site about 10 kilometers away called Vleesbaai. This latter site is where a group of people, possibly members of the same group as those at Pinnacle Point, sat in a small circle and made stone tools. Finding the shards at both sites allows us to link these two records at almost the same moment in time."
Not only that, but the shard location allows the scientists to provide an independent test of the age of the site estimated by other techniques. People lived at the Pinnacle Point 5-6 site from 90,000 to 50,000 years ago. Zenobia Jacobs with the University of Wollongong, Australia, used optically stimulated luminescence (OSL) to date 90 samples and develop a model of the age of all the layers. OSL dates the last time individual sand grains were exposed to light.
"There has been some debate over the accuracy of OSL dating, but Jacobs' age model dated the layers where we found the Toba shards to about 74,000 years ago - right on the money," says Marean. This lends very strong support to Jacobs' cutting-edge approach to OSL dating, which she has applied to sites across southern Africa and the world.
"OSL dating is the workhorse method for construction of timelines for a large part of our own history. Testing whether the clock ticks at the correct rate is important. So getting this degree of confirmation is pleasing," says Jacobs.
In the 1990s, scientists began arguing that this eruption of Mount Toba, the most powerful in the last two million years, caused a long-lived volcanic winter that may have devastated the ecosystems of the world and caused widespread population crashes, perhaps even a near-extinction event in our own lineage, a so-called bottleneck.
This study shows that along the food-rich coastline of southern Africa, people thrived through this mega-eruption, perhaps because of the uniquely rich food regime on this coastline. Now other research teams can take the new and advanced methods developed in this study and apply them to their sites elsewhere in Africa so researchers can see if this was the only population that made it through these devastating times.
Aerial photo of the dig in December 2017. Credit: Vincent Francigny /
Sedeinga archaeological mission
Archaeologists unearth tombs in ancient Nubia
5 March 2018
The archaeological site of Sedeinga is located in Sudan, a hundred kilometers to the north of the third cataract of the Nile, on the river's western shore. Known especially for being home to the ruins of the Egyptian temple of Queen Tiye, the royal wife of Amenhotep III, the site also includes a large necropolis containing sepulchers dating from the kingdoms of Napata and Meroe (seventh century BCE-fourth century CE), a civilization (1) mixing local traditions and Egyptian influences. Tombs, steles, and lintels have just been unearthed by an international team led by researchers from the CNRS and Sorbonne Université as part of the French Section of Sudan's Directorate of Antiquities, co-funded by the CNRS and the Ministry for Europe and Foreign Affairs (2). They represent one of the largest collections of Meroitic inscriptions, the oldest language of black Africa currently known.
The necropolis of Sedeinga stretches across more than twenty-five hectares and is home to the vestiges of at least eighty brick pyramids and over a hundred tombs, dating from the kingdoms of Napata and Meroe (seventh century BCE-fourth century CE). The research programs carried out since 2009 (3) have focused on the chronology of the construction of this necropolis, which is difficult as there is very little remaining historical information on this civilization. The researchers have shown that most of the pyramids and tombs are buildings dating from the era of the Napata kingdom that were later adjusted by the Meroitics. These adjustments were thus made five centuries after the initial building on the site, which the Meroitics supplemented with new chapels built out of brick and sandstone blocks on the western side of the pyramids, and which were intended for the worship of the deceased. This practice was particular to the Napatans and Meroitics, who veritably revered the monuments of the past, unlike their Egyptian neighbors.
Pieces of decorated sandstone, such as steles as well as lintels and door surrounds, have been discovered at the surface, providing magnificent examples of Meroitic funerary art. For example, pigments - mainly blue in color- have been preserved on a stele found lying on its side. This is rare for objects of this kind, which typically are subjected to the vagaries of time. Another exceptional find: a chapel lintel representing Maat, the Egyptian goddess of order, equity, and peace. This is the first extant representation of this goddess depicting her with African characteristics. During the last excavation campaign in late 2017, the researchers discovered a stele in the name of a Lady Maliwarase. The stele sets out her kinship with the notables of Nubia (in the north of the kingdom of Meroe): she was the sister of two grand priests of Amon, and one of her sons held the position of governor of Faras, a large city bordering the second cataract of the Nile. The archeologists have also unearthed a lintel inscribed with four lines of text describing the owner of the sepulcher, another great lady, Adatalabe. She hailed from an illustrious lineage that included a royal prince, a member of the reigning family of Meroe. These two steles written for high-ranking women are not isolated examples in Sedeinga. In Meroitic society, it was indeed women who embodied the prestige of a family and passed on its heritage.
1 The kingdoms of Napata and Meroe formed one and the same civilization, known as the "Kush kingdom" by their ancient Egyptian neighbors.
2 The director of the mission, Claude Rilly, is a CNRS researcher at the Langage, Langues et Cultures d'Afrique Noire laboratory (CNRS/Inalco). He is co-leading this mission with Vincent Francigny, director of the SFDAS (MEAE). This research has been funded by the excavation commission of the French Ministry for Europe and Foreign Affairs (MEAE) and the Orient et Mèditerranée - Textes-Archéologie-Histoire laboratory (CNRS/Sorbonne Université/Université Panthéon-Sorbonne/EPHE/Collège de France). The campaign carried out between November, 14 and December 19, 2017, the last to date, was awarded the Fondation Jean et Marie-Thérèse Leclant prize.
3 Excavation work on the site began in 1963 and recommenced in 2009. It will continue until 2020 and is divided into three four-year plans, the last of which began in November 2017.
Microscopic plant remains,
called phytoliths, from
grasses, sedges, palms,
forbs, and trees that lived
near Lake Malawi in East
Africa about 74,000 years ago. Chad L. Yost,
University of Arizona Department of
No volcanic winter in East Africa from ancient Toba eruption
6 February 2018
The massive Toba volcanic eruption on the island of Sumatra about 74,000 years ago did not cause a six-year-long "volcanic winter" in East Africa and thereby cause the human population in the region to plummet, according to new University of Arizona-led research.
The new findings disagree with the Toba catastrophe hypothesis, which says the eruption and its aftermath caused drastic, multi-year cooling and severe ecological disruption in East Africa.
"This is the first research that provides direct evidence for the effects of the Toba eruption on vegetation just before and just after the eruption," said lead author Chad L. Yost, a doctoral candidate in the UA Department of Geosciences. "The Toba eruption had no significant negative impact on vegetation growing in East Africa."
Researchers can use ancient plant parts that wash into and accumulate on the bottoms of lakes to reconstruct a region's past ecosystem. Yost and his colleagues studied microscopic bits of plants preserved in two sediment cores from Lake Malawi, which is approximately 570 kilometers (354 miles) long and is the southernmost of the East African Rift lakes.
Previous investigators found material from the Toba eruption in the Lake Malawi cores. That material pinpoints the time of the eruption and allowed Yost and colleagues to peer back in time 100 years before to 200 years after the Toba eruption. The team analyzed samples that represented, on average, every 8.5 years within that 300-year interval.
"It is surprising," Yost said. "You would have expected severe cooling based on the size of the Toba eruption--yet that's not what we see."
Yost and his colleagues did not find marked changes in lower-elevation vegetation post-eruption. The team did find some die-off of mountain plants just after the eruption. Cooling from the eruption might have injured frost-intolerant plants, he said.
Had the region experienced the drastic, multi-year cooling post-Toba, the cores would have evidence of a massive die-off of the region's vegetation at all elevations, Yost said.
Part of the Toba catastrophe hypothesis suggests the eruption caused human populations to shrink.
"We know anatomically modern humans were living within 50 kilometers of Lake Malawi," Yost said. "People would have been able to travel to habitats and lower elevations that had little to no cooling effect from the Toba eruption."
Most of the region's known archaeological sites are from low elevations, not the mountains, he said.
Co-author Andrew S. Cohen, UA Distinguished Professor of Geosciences, said, "That a singular event in Earth history 75,000 years ago caused human populations in the cradle of humankind to drop is not a tenable idea."
The team's paper, "Subdecadal phytolith and charcoal records from Lake Malawi, East Africa imply minimal effects on human evolution from the ~74 ka Toba supereruption," is published online this week in the Journal of Human Evolution.
Yost's and Cohen's co-authors are Lily J. Jackson of the University of Texas at Austin, and Jeffery R. Stone of Indiana State University, Terre Haute. The National Science Foundation and the International Continental Scientific Drilling Program funded the research.
The Lake Malawi Drilling Project took the cores from the lake bottom in 2005, said Cohen, one of the principal investigators on the collaborative project. The lake is one of the deepest in the world. The material archived in the cores goes back more than one million years.
Plant and animal material washes into lakes and is deposited on the bottom in annual layers, so a sediment core contains a record of the past environments of a lake and of the surrounding land.
Yost studied two cores taken from the lake: one from the north end of the lake, which is closer to the mountains, and the other from the central part of the lake. Other researchers had pinpointed what layer in those cores had glass and crystals from the Toba eruption, Cohen said.
Yost took samples from the cores that straddled the eruption and analyzed the samples for charcoal and for silica-containing plant parts called phytoliths.
The work required hundreds of hours of peering through a microscope, said Yost, who is an expert in identifying the type of plant a particular phytolith came from.
If the Toba catastrophe hypothesis is true, the massive die-off of vegetation would have resulted in more wildfires and therefore more charcoal washing into the lake. However, he did not find an increase in charcoal outside the range of normal variability in the sediments deposited after the eruption.
"We determined that the Toba eruption had no significant negative impact on vegetation growing in East Africa," Yost said. "We hope this will put the final nail in the coffin of the Toba catastrophe hypothesis."
This is Sub-Saharan Africa glass. Credit: Abidemi Babatunde Babalola
Researchers find first evidence of sub-Saharan Africa glassmaking
18 January 2018
Scholars from Rice University, University College London and the Field Museum have found the first direct evidence that glass was produced in sub-Saharan Africa centuries before the arrival of Europeans, a finding that the researchers said represents a "new chapter in the history of glass technology."
The discovery is discussed in "Chemical Analysis of Glass Beads from Igbo Olokun, Ile-Ife (SW Nigeria): New Light on Raw Materials, Production and Interregional Interactions," which will appear in an upcoming volume of the Journal of Archaeological Science.
Lead author Abidemi Babatunde Babalola, a recent graduate of Rice with a Ph.D. in anthropology and a visiting fellow at Harvard University, came across evidence of early glassmaking during archaeological excavations at Igbo Olokun, located on the northern periphery of Ile-Ife in southwestern Nigeria. He recovered more than 12,000 glass beads and several kilograms of glass-working debris.
"This area has been recognized as a glass-working workshop for more than a century," Babalola said. "The glass-encrusted containers and beads that have been uncovered there were viewed for many years as evidence that imported glass was remelted and reworked."
However, 10 years ago this idea was challenged when analyses of glass beads attributed to Ile-Ife showed that some had a chemical composition very different from that of known glass production areas. Researchers raised the possibility of local production in Ife, although direct evidence for glassmaking and its chronology was lacking.
"The Igbo Olokun excavations have provided that evidence," Babalola said.
The researchers' analysis of 52 glass beads from the excavated assemblage revealed that none matched the chemical composition of any other known glass-production area in the Old World, including Egypt, the eastern Mediterranean, the Middle East and Asia. Rather, the beads have a high-lime, high-alumina (HLHA) composition that reflects local geology and raw materials, the researchers said. The excavations provided evidence that glass production at Igbo Olokun dates to the 11th through 15th centuries A.D., well before the arrival of Europeans along the coast of West Africa.
Babalola said the presence of the HLHA glass at other important early West African sites suggests that it was widely traded. He hopes the research will cast more light on the innovation and development of glass in early sub-Saharan Africa and how the regional dynamics in glass production connect with the global phenomenon of glass invention and exchange. He also hopes his work will help researchers understand its impact on the social, political and economic fabrics of the African societies.