Scientists discover 280-million-year-old fossil forest in Antarctica
Antarctica wasn’t quite a region of ice for most of the year. It is widely believed that millions of years ago, when the planet earth was already a massive landmass called Gondwana, trees flourished near the South Pole.
Now, newfound, intricate fossils of some of these trees are revealing how the plants thrived — and what forests might look like as they march northward in today’s warming world.
“Antarctica preserves and ecologic history of polar biomes that ranges for about 400 million years, which is basically the entirety of plant evolution,” said Erik Gulbranson, a paleoecologist at the University of Wisconsin-Milwaukee.
A reconstruction of what the ancient forest look liked 385 million years ago, drawn by Dr. Chris Berry, co-author of the study describing the fossil trees.
TREES IN ANTARCTICA?
It’s hard to look at Antarctica’s frigid landscape today and imagine lush forests. To find their fossil specimens, Gulbranson and his colleagues have to disembark from planes landed on snowfields, then traverse glaciers and brave bone-chilling winds. But from about 400 million to 14 million years ago, the southern continent was a very different, and much greener place.
The climate was warmer, though the plants that survived at the low southern latitudes had to cope with winters of 24-hour-per-day darkness and summers during which the sun never set, just like today.
Partial tree trunk with the base preserved, at the site in Svalbard (left) and a reconstruction of what the ancient forest look liked 380 million years ago (right)
During this event, as many of 95 per cent of Earth’s species died out. The extinction was probably driven by massive greenhouse gas emissions from volcanoes, which raised the planet’s temperatures to extreme levels and caused the oceans to acidify, scientists have found.
There are obvious parallels to contemporary climate change, Gulbranson said, which is less extreme but similarly driven by greenhouse gases.
Prior to the end-Permian mass extinction, the southern polar forests were dominated by one type of tree, those in the Glossopteris genus, Gulbranson told Live Science. These were behemoths that grew from 65 to 131 feet (20 to 40 meters) tall, with broad, flat leaves longer than a person’s forearm, Gulbranson said.
Erik Gulbranson on site in Antarctica.
A photograph taken by Captain Scott on his final expedition of Dr Edward Wilson sketching on Beardmore Glacier.
Before the Permian extinction, Glossopteris dominated the landscape below the 35th parallel south to the South Pole. (The 35th parallel south is a circle of latitude that crosses through two landmasses: the southern tip of South American and the southern tip of Australia.)
BEFORE AND AFTER
Last year, while fossil-hunting in Antarctica, Gulbranson and his team found the oldest polar forest on record from the southern polar region.
They haven’t dated that forest precisely yet, but it probably flourished about 280 million years ago before being rapidly buried in volcanic ash, which preserved it down to the cellular level, the researchers said.
On Thanksgiving Day, Gulbranson will return to Antarctica for more excavations at two sites. Those sites contain fossils from a period spanning from before to after the Permian extinction.
Scientists have since uncovered further evidence of plant life on the continent, including this fossilized fern from the British Antarctic Survey (BAS) fossil collection.
This partial trunk fossil was cracked near its base, but two distinct patterns are still visible in the rock: oval leaf bases at the bottom and diamond-shaped leaf bases moving up the trunk toward the top.
After the extinction, Gulbranson said, the forests didn’t disappear, but they changed. Glossopteris was out, but a new mix of evergreen and deciduous trees, including relatives of today’s gingkoes, moved in.
“What we’re trying to research is what exactly caused those transitions to occur, and that’s what we don’t know very well,” Gulbranson said.
The plants are so well-preserved in the rock that some of the amino acid building blocks that made up the trees’ proteins can still be extracted, said Gulbranson, who specializes in geochemistry techniques. Studying these chemical building blocks may help clarify how the trees handled the southern latitudes’ weird sunlight conditions, as well as the factors that allowed those plants to thrive but drove Glossopteris to its death, he said.
This season, the field team will have access to helicopters, which can land closer to the rugged outcrops in the Transantarctic Mountains where the fossil forests are found.
Subsequent expeditions to the Antarctic Peninsula have unearthed hundreds of amphibian and reptile fossils. This lobster fossil (Hoploparia stokesi) from the BAS fossil collection was found in the Upper Cretaceous (100.5 – 66 million years ago) when the dinosaurs disappeared from the Earth.
The team (members hail from the United States, Germany, Argentina, Italy and France) will camp out for months at a time, hitching helicopter rides to the outcrops as the fickle Antarctic weather allows. The 24-hour sun allows for long days, even middle-of-the-night expeditions that combine mountaineering with fieldwork, Gulbranson said.
Treasures dating back some 9,500 years is uncovered in Alpine glaciers as climate change causes ice to melt
The group climbed the steep mountainside, clambering across an Alpine glacier, before finding what they were seeking: A crystal vein filled with the precious rocks needed to sculpt their tools. That is what archaeologists have deduced after the discovery of traces of an ancient hunt for crystals by hunters and gatherers in the Mesolithic era, some 9,500 years ago.
It is one of many valuable archaeological sites to emerge in recent decades from rapidly melting glacier ice, sparking a brand-new field of research: glacier archaeology. Amid surging temperatures, glaciologists predict that 95 per cent of some 4,000 glaciers dotted throughout the Alps could disappear by the end of this century.
While archaeologists lament the devastating toll of climate change, many acknowledge it has created “an opportunity” to dramatically expand understanding of mountain life millennia ago.
“We are making very fascinating finds that open up a window into a part of archaeology that we don’t normally get,” said Marcel Cornelissen, who headed an excavation trip last month to the remote crystal site near the Brunifirm glacier in the eastern Swiss canton of Uri, at an altitude of 2,800 metres (9,100 feet).
‘Truly exceptional’
Up until the early 1990s, it was widely believed that people in prehistoric times steered clear of towering and intimidating mountains. But a number of startling finds have since emerged from melting ice indicating that mountain ranges like the Alps have been bustling with human activity for thousands of years.
Early humans are now believed to have hiked up into the mountains to travel to nearby valleys, hunt or put animals out to pastures, and to search for raw materials. Christian Auf der Maur, an archaeologist with Uri canton who participated in the crystal site expedition, said the find there was “truly exceptional.”
Laced shoe found with the remains of a prehistoric man dating to around 2,800 BCE.
“We know now that people were hiking up to the mountains to up to 3,000 metres altitude, looking for crystals and other primary materials.”
The first major ancient Alpine find to emerge from the melting ice was the discovery in 1991 of “Oetzi,” a 5,300-year-old warrior whose body had been preserved inside an Alpine glacier in the Italian Tyrol region. Theories that he may have been a rare example of a prehistoric human venturing into the Alps have been belied by findings since of numerous ancient traces of people crossing high altitude mountain passes.
One of the most famous discovers in the Alpine was ‘Otiz’ (pictured) in 1991, which was the preserved body of a 5,300-year-old warrior found in the Italian Tyrol region
Rare organic materials
The Schnidejoch pass, a lofty trail in the Bernese Alps 2,756 metres (9,000 feet) above sea level, has for instance been a boon to scientists since 2003, with the find of a birch bark quiver – a case for arrows – dating as far back as 3,000 BCE. Later, leather trousers and shoes, likely from the same ill-fated person, were also discovered, along with hundreds of other objects dating as far back as about 4,500 BCE.
“It is exciting because we find stuff that we don’t normally find in excavations,” archaeologist Regula Gubler told AFP. She pointed to organic materials like leather, wood, birch bark, and textiles, which are usually lost to erosion but here have been preserved intact in the ice.
This blackened braided basket from the Neolithic Age is from the Bernese Alps.
Just last month, she led a team to excavate a fresh finding in Schnidejoch: a knotted string of bast – or plant – fibres believed to be over 6,000 years old. It resembles the fragile remains of a blackened bast-fibre, braided basket from the same period, brought back last year.
While climate change has made possible such extraordinary finds, it is also a threat: if not found quickly, organic materials freed from the ice rapidly disintegrate and disappear.
‘Very short window’
“It is a very short window in time. In 20 years, these finds will be gone and these ice patches will be gone,” Gubler said. “It is a bit stressful.”
Cornelissen agreed, saying the understanding of glacier sites’ archaeological potential had likely come “too late”.
“The retreat of the glaciers and melting of the ice fields has already progressed so far,” he said. “I don’t think we’ll find another Oetzi.”
The problem is that archaeologists cannot hang out at each melting ice sheet waiting for treasure to emerge. Instead, they rely on hikers and others to alert them to finds. That can sometimes happen in a roundabout way.
When two Italian hikers in 1999 stumbled across a wood carving on the Arolla glacier in southern Wallis canton, some 3,100 metres above sea level, they picked it up, polished it off, and hung it on their living room wall. It was only through a string of lucky circumstances that it 19 years later came to the attention of Pierre Yves Nicod, an archaeologist with the Wallis historical museum in Sion, where he was preparing an exhibition about glacier archaeology.
In 1999, Italian hikers found a wood carving on the Arolla glacier in southern Wallis canton and instead of alerting experts, they hung it on their living room wall
He tracked down the 52-centimetre-long human-shaped statuette, with a flat, frowning face, and had it dated. It turned out to be over 2,000 years old – “a Celtic artefact from the Iron Age,” Nicod told AFP, lifting up the statuette with gloved hands. Its function remains a mystery, he said.
Another unknown, Nicod said, is “how many such objects have been picked up throughout the Alps in the past 30 years and are currently hanging on living room walls.
“We need to urgently sensibilise populations likely to come across such artifacts.” “It is an archaeological emergency.”
Large Hidden Lakes Found Draining Below Antarctic Glacier
Thwaites Glacier on the edge of West Antarctica is one of the planet’s fastest-moving glaciers. Research shows that it is sliding unstoppably into the ocean, mainly due to warmer seawater lapping at its underside.
Thwaites Glacier reaches speeds of more than 33 feet (11 m) per day. The black box shows the location of four subglacial lakes that drained in 2013, increasing the glacier’s speed by about 10 percent.
But the details of its collapse remain uncertain. The details are necessary to provide a timeline for when to expect 2 feet of global sea-level rise, and when this glacier’s loss will help destabilize the much larger West Antarctic Ice Sheet.
Recent efforts have used satellites to map the underlying terrain, which affects how quickly the ice mass will move, and measure the glacier’s thickness and speed to understand the physics of its changes.
Researchers at the University of Washington and the University of Edinburgh used data from the European Space Agency’s CryoSat-2 to identify sudden drainage of large pools below Thwaites Glacier, one of two fast-moving glaciers at the edge of the ice sheet.
The study published Feb. 8 in The Cryosphere finds four interconnected lakes drained in the eight months from June 2013 and January 2014. The glacier sped up by about 10 percent during that time, showing that the glacier’s long-term movement is fairly oblivious to trickles at its underside.
The ice surface above the lakes sank by as much as 20 meters (66 feet) in less than a year due to the drainage. Subglacial lakes are commonly seen with fast-flowing glaciers.
“This was a big event, and it confirms that the long-term speed-up that we’re observing for this glacier is probably driven by other factors, most likely in the ocean,” said corresponding author Ben Smith, a glaciologist with the UW’s Applied Physics Laboratory. “The water flow at the bed is probably not controlling the speed.”
Other glaciers, like some in Alaska and Greenland, can be very susceptible to changes in meltwater flow. The water there can pond beneath the glacier until it lifts off parts of its bed and suddenly surges forward. This can increase a glacier’s speed by several times and account for most of its motion.
Researchers were not certain whether such an effect might be at play with Thwaites Glacier.
Part of the Thwaites Glacier on the edge of West Antarctica.
“It’s been difficult to see details about water flow under the ice,” Smith said.
A new technique revealed how meltwater from lakes beneath Thwaites Glacier drained into the sea. It is the largest outflow from sub-glacial lakes reported for this region of West Antarctica.
For the new study, the authors use a new technique to discover drops at the glacier’s surface of up to 70 feet (20 meters) over a 20 kilometer by 40-kilometer area. Calculations show it was likely due to the emptying of four interconnected lakes, the largest about the size of Lake Washington, far below.
The peak drainage rate was about 8,500 cubic feet (240 cubic meters) per second, about half the flow of the Hudson River — the largest meltwater outflow yet reported for subglacial lakes in this region.
“This lake drainage is the biggest water movement that you would expect to see in this area, and it didn’t change the glacier’s speed by that much,” Smith said. The reason is likely that Thwaites Glacier is moving quickly enough, he said, that friction is heating up its underside to ice’s melting point. The glacier’s base is already wet and adding more water doesn’t make it much more slippery.
The new study supports previous UW research from 2014 showing that Thwaites Glacier will likely collapse within 200 to 900 years to cause seas to rise by 2 feet. Those calculations were made without detailed maps of how water flows at the glacier’s underbelly. The new results suggest that doesn’t really matter.
“If Thwaites Glacier had really jumped in response to this lake drainage, then that would have suggested that we need a more detailed model of where water is flowing at the bed,” Smith said. “Radar data from NASA’s Operation Ice Bridge program has told us a lot about the shape of Thwaites Glacier, but it’s very difficult to see how water is moving. Based on this result, that may not be a big problem”
Melting at the ice sheet base would refill the lakes in 20 to 80 years, Smith said. Over time meltwater gradually collects in depressions in the bedrock. When the water reaches a certain level it breaches a weak point, then flows through channels in the ice. As Thwaites Glacier thins near the coast, its surface will become steeper, Smith said, and the difference in ice pressure between inland regions and the coast may push water coastward and cause more lakes to drain.
He hopes to apply the same techniques to study lake drainage below other glaciers, to understand how water flow at the base affects overall glacier movement. When NASA’s ICESat-2 satellite launches in 2018 the calculations will be easy to do with high precision.
“In 2018 this changes from a hard project to an easy project, and I’m excited about that,” Smith said.
Other co-authors are Alexander Huth and Ian Joughin at the UW and Noel Gourmelen at the University of Edinburgh. The research was funded by NASA and the European Space Agency.
The archaeologist J.A. Clason finds extensive accounts of Viking voyages in earlier Icelandic sagas. They describe a mysterious “sunstone”, which Scandinavian seafarers used to locate the Sun in the sky and navigate on cloudy days.
So, What is Iceland spar?
Iceland spar is a crystal of calcite (calcium carbonate). Calcite is a fairly common mineral and comes in a spectacular range of colors caused by the impurities it contains.
Iceland spar is rather unique among the calcites. It contains no impurities, so it’s nearly colorless and transparent to both visible and ultraviolet light.
For centuries, the only source of this pure calcite was located near Reydarfjördur fjord in eastern Iceland, hence most of the world called it Iceland spar (spar means a crystal with smooth surfaces). The Icelanders just called it silfurberg, meaning silver rock.
A crystal of Iceland spar has two very interesting properties. First, it is a natural polarizing filter. Second, because of its natural polarization, Iceland spar is birefringent, meaning light rays entering the crystal become polarized, split, and take two paths to exit the crystal – creating a double image of an object seen through the crystal.
There is good evidence that the Vikings used the polarizing effect of Iceland spar to navigate the North Atlantic. The constant fog and mist in the North Atlantic often make navigation by stars or sun impossible.
The Vikings called Iceland spar a ‘sunstone’ because the polarizing effect can be used to find the direction of the sun even in dense fog and overcast conditions. It can even find the direction of the sun when the sun is actually below the horizon, as happens when you’re sailing above the Arctic circle.
The polarizing effect of Iceland spar can accurately locate the sun even through heavy clouds or mist. If you’re a Viking. I’ve tried it and had no success at all.
The second interesting feature of Iceland spar is birefringence, meaning it refracts light into two separate images, which is more noticeable.
The double image may just seem mildly interesting to you and me. But it turned the scientific world (at least the optical part of it) upside down back in the 1600s.
A piece of Iceland spar on my worktable, doubly refracting the gridlines.
How did that help the Vikings?
Researchers studied a piece of Iceland spar discovered aboard an Elizabethan ship that sunk in 1592.
They found that moving the stone in and out of a person’s field of vision causes them to see a distinctive double dot pattern that lines up with the direction of the hidden Sun.
Screenshot from the TV show Viking
The polarization of sunlight in the Arctic can be detected, and the direction of the sun identified within a few degrees in both cloudy and twilight conditions using the sunstone and the naked eye.
The process involves moving the stone across the visual field to reveal a yellow entoptic pattern on the fovea of the eye, probably Haidinger’s brush.
When light passes through calcite crystals, it is split into two rays. The asymmetry in the crystal’s structure causes the paths of these two beams to be bent by different amounts, resulting in a double image.
Giant Headless Buddha Statue found Beneath Chinese Apartments
In the old neighborhood of Chongqing, southwest China, people had passed by two residential buildings constructed upon a steep hill, indifferent to what lay underneath. It turns out that these two apartment buildings that sit upon the cliff face had been carved by Lord buddha.
The massive statue — about 30-feet tall and with its head missing — was hidden by a dense coating of foliage, and only exposed during recent repairs to the residential building, according to the local Nan’an district government.
Photos of the enigmatic headless sculpture have gone viral on Chinese social media since the accidental discovery, where many have referred to it as “the Buddha,” attracting headlines and stirring instant curiosity in its history and origins.
The seated Buddha sculpture uncovered in Chongqing is missing its head.
Now only partially covered in moss, the statue is depicted seated with its forearms resting on its lap and its hands holding what appears to be a round stone. The folds and some details of the figure’s clothes are also visible.
The statue is believed to have been built during China’s Republican era (1912-1949), according to a national survey of cultural relics.
While that study was conducted just over a decade ago, the sculpture had been neglected and appears to have been completely forgotten until recently.
Its head was likely destroyed during the 1950s, and the apartment buildings around it were built in the 1980s, said the district government on China’s Twitter-like platform, Weibo.
The ‘Buddha’ statue (location identified with the red square) used to be covered by dense foliage. ( Weibo)
However, experts invited by the district’s cultural relics management office to study the statue said it was not of Buddhist origin and is likely related to folk religion.
A temple dedicated to the Daoist god of thunder was once built next to the statue, though it was dismantled in 1987, the district government told state-run media outlet The Paper.
The religious statue was already designated as a district-level cultural relic before 1997, it added.
That the statue could be so quickly hidden is perhaps, a reflection of the rapid urban expansion that has unfolded in Chongqing.
In recent decades, countless structures have been built to accommodate a bustling population of over 30 million people, sometimes at the expense of historical and cultural relics. Because of the city’s mountainous terrain, many homes are built on hillsides.
Archaeologists find the source of Stonehenge sarsen stones
A team of researchers from the UK and South Africa has discovered that most of the hulking sandstone boulders — called sarsens — that make up the famous Stonehenge monument appear to share a common origin 25 km (15.5 miles) away in West Woods on the edge of the Marlborough Downs, Wiltshire.
The origins of the stones used to build Stonehenge around 2500 BCE and their transportation methods and routes have been the subject of debate among archaeologists and geologists for over 400 years.
Two main types of stones are present at the monument: the sarsen stones that form the primary architecture of Stonehenge and the bluestones near the centre of the monument.
Feasts at nearby Durrington Walls drew attendees from all over Britain.
The smaller bluestones have been traced to Wales, but the origins of the sarsens have remained unknown, until now.
“Archaeologists and geologists have been debating where the sarsen stones used to build Stonehenge came from for more than four centuries,” said Professor David Nash, a scientist in the School of Environment and Technology at the University of Brighton and the School of Geography, Archaeology and Environmental Studies at the University of the Witwatersrand.
“These significant new data will help explain more of how the monument was constructed and, perhaps, offer insights into the routes by which the 20- to 30-ton stones were transported.”
Stonehenge in context: (A) distribution of silcrete boulders across southern Britain, including sarsens and conglomeratic variants known as puddingstone; (B) sampling sites and topography in the Stonehenge-Avebury area, along with proposed transportation routes for the sarsen stones; (C) plan of Stonehenge showing the area of the monument enclosed by earthworks plus numbered peripheral sarsen stones; (D) detail of the main Stonehenge monument showing the remaining bluestones and numbered sarsen stones.
To learn where the huge boulders came from, Professor Nash and colleagues used portable x-ray fluorescence spectrometry (PXRF) to initially characterize their chemical composition, then analyzed the data statistically to determine their degree of chemical variability.
Next, they performed inductively coupled plasma mass spectrometry (ICP-MS) and ICP-atomic emission spectrometry (ICP-AES) of samples from a core previously drilled through one sarsen stone — Stone 58 — and a range of sarsen boulders from across southern Britain.
After comparing these signatures, they were able to point to West Woods as the sarsens’ earliest home.
The reason the monument’s builders selected this site remains a mystery, although the scientists suggest the size and quality of West Woods’ stones, and the ease with which the builders could access them may have factored into the decision.
“We still don’t know where two of the 52 remaining sarsens at the monument came from,” Professor Nash said.
“These are upright Stone 26 at the northernmost point of the outer sarsen circle and lintel Stone 160 from the inner trilithon horseshoe.”
“It is possible that these stones were once more local to Stonehenge, but at this stage, we do not know.”
“We also don’t know the exact areas of West Woods where the sarsens were extracted.”
“Further geochemical testing of sarsens and archaeological investigations to discover extraction pits are needed to answer these questions.”
Revealed: Cambodia’s vast medieval cities hidden beneath the jungle
Archaeologists in Cambodia have found multiple, previously undocumented medieval cities not far from the ancient temple city of Angkor Wat, the Guardian can reveal, in groundbreaking discoveries that promise to upend key assumptions about south-east Asia’s history.
The Australian archaeologist Dr Damian Evans, whose findings will be published in the Journal of Archaeological Science, will announce that cutting-edge airborne laser scanning technology has revealed multiple cities between 900 and 1,400 years old beneath the tropical forest floor, some of which rival the size of Cambodia’s capital, Phnom Penh.
Invisible city
For centuries, the Angkor region’s wealth of artefacts drew looters, archaeologists. They focused their attention, both good and ill, on Angkor Wat and a few other nearby moated temple complexes. Based on those ruins, the first European explorers to encounter Angkor in the 19th century assumed Khmer urbanites lived in what were basically moated cities of a few thousand people. These European explorers thought Angkor Wat was something like a medieval walled city in Europe, which typically held fewer than 10,000 people. They explained all the moated complexes in the Angkor area by suggesting that maybe the royal family and their people were moving from one moated city to the next overtime. But as archaeologists learned more in the intervening century, something about those population numbers seemed off. Beyond the moated cities were vast canal systems and reservoirs hinting at something bigger.
The ruins of Preah Khan of Kompong Svay covered with forest. An urban network was revealed by the lidar imagery around this temple.
Unfortunately, most of Angkor had become a tangle of jungles and small farms by the 20th century. There was little evidence of medieval settlements beyond the moats’ precise edges. Even if explorers were willing to hack through the dense growth, there was little to find. In a Khmer city, only the temples were made from stone. Everything else was built from perishable materials like wood. All that remained of Angkor’s homes and other non-religious structures were the elevated clay mounds of their foundations, which had been designed to prevent flooding during Cambodia’s intense wet season. Most of the city’s dramatic waterworks for flood runoff and water storage had been reduced to pits and troughs in the Earth. It was practically impossible to identify a medieval Angkorian house deep within the jungle.
All that changed when airborne LiDAR (for “Light Imaging, Detection, And Ranging”) came into common use for mapping in the early 2000s. Archaeologists working in Cambodia immediately seized on it. By scattering light off the surface of the planet, LiDAR systems can produce maps with accuracy down to the centimetre even if the ground is covered in heavy vegetation. The system is ideal for a place like Angkor, where the city’s remains are cloaked in vegetation and characterized almost entirely by elevated or depressed plots of ground.
The LiDAR rig was a Leica ALS70 HP instrument, mounted in a pod attached to the right skid of a Eurocopter AS350 B2 helicopter along with a 60 megapixel Leica RCD30 camera.
With funding from the National Geographic Society and European Research council, archaeologist Damian Evans and his colleagues conducted broad LiDAR surveys of Angkor in 2012 and 2015. The team’s mapping rig consisted of a Leica ALS70 HP LiDAR instrument mounted in a pod attached to the right skid of a Eurocopter AS350 B2 helicopter alongside a 60 megapixel Leica RCD30 camera. It was as if an invisible city suddenly appeared where only overgrowth and farmland existed before. For the first time in centuries, people could discern Angkor’s original urban grid. And what they saw changed our understanding of global history.
Archaeological researcher Piphal Heng, who studies Cambodian settlement history, told Ars that the LiDAR maps peeled back the forest canopy to reveal meticulous grids of highways and low-density neighbourhoods of thousands of houses and pools of water. There was “a complex urban grid system that extended outside the walls of Angkor Thom and other large temple complexes such as Angkor Wat,Preah Khan, and Ta Prohm,” he said. With the new data, scientists had solid evidence that the city of Angkor sprawled over an area of at least 40 to 50 square km. It was home to almost a million people. The scattered, moated complexes like Angkor Wat and Angkor Thom were merely the most enduring features of what we now know was the biggest city on Earth during the 12th and 13th centuries.
This aerial photo shows what Angkor Wat looks like today, surrounded by vegetation and a few areas of modern farms and homes. None of the vast city grid from 800 years ago is visible.
In the LiDAR map, you can clearly see the central urban grid of Angkor extending from Angkor Thom (top left) and Angkor Wat (bottom left).
Here you can see the areas covered by the LiDAR surveys in 2012 and 2015.
A map of the greater Angkor area, showing the extent of the urban sprawl revealed by LiDAR.
From legend to reality
The city of Angkor has its origins in the ninth century during the reign of Jayavarman II. He unified large parts of Southeast Asia by establishing the Khmer Empire across regions we know today as Cambodia, Thailand, Vietnam, and Laos. Inscriptions on temple walls at Sadok Kok Thom in Thailand describe how he established a city called Hariharalaya, located near Siem Reap in the Angkor area. But the inscriptions also say that Jayavarman II declared himself a supreme ruler or “god-king” in a lavish Hindu ceremony held at his residence on Kulen Mountain in a city called Mahendraparvata. Accounts of the Kulen Mountain phase in Jayavarman’s life are so sparse and fantastical that debates have raged among scholars about whether he actually lived in Mahendraparvata at all.
To find out more, archaeologists targeted Kulen Mountain in their latest LiDAR survey. Evans published some of the first results from this 2015 survey in the Journal of Archaeological Science. Royal Academy of Cambodia archaeologist Kaseka Phon explained to Ars via e-mail that the LiDAR has uncovered an Angkor-like city grid at the abandoned city of Mahendraparvata on Kulen Mountain. Plus, the LiDAR “shows not only features of the construction, but also water features” that are clearly versions of Angkor’s incredible water management facilities. The new survey revealed massive stone quarries, now filled in, that produced the rock used to build some of the temples of Angkor. Kulen Mountain’s role in the birth of the Khmer Empire is no longer a legend—it’s an established historical fact.
This transformation of legend into fact has been a theme of the LiDAR surveys. Angkor’s huge population is described in temple inscriptions and reports written by Chinese travellers who visited the city during the 12th-century reign of King Suryavarman II, who built Angkor Wat. But historical sources are often exaggerated or incomplete. Plus, it was difficult for Western researchers to believe that the Khmer Empire’s great city was home to almost a million people, dwarfing European cities of the same era. Now, such facts are impossible to deny.
Angkor city planning
Angkor reached megacity proportions in the 12th century when Suryavarman II ordered the construction of Angkor Wat (which he dedicated to the Hindu god Vishnu). At that time, the urban sprawl in Angkor was not only enormous, but it was centrally planned with rigorous precision. Heng told Ars that “the shape of roads, walls, moats, mounds, and ponds were probably made based on urban templates commissioned by the Angkorian rulers” while residents of different neighbourhoods probably had different degrees of freedom to modify those plans. Heng continued:
At temples such as Angkor Wat and Ta Prohm, the grid usage was significantly varied. For example, based on our recent excavations, after the urban grid was laid out, there is little evidence of modification—if at all—in a series of habitation mounds inside Angkor Wat. While for Ta Prohm, its inhabitants seem to have more freedom in modifying parts of their gridded mounds.
To learn more about everyday life in Angkor Wat, University of Illinois Urbana-Champaign archaeologist Alison Carter has done excavation work on some of the residential mounds inside the enclosure. In 2015, she got funding from the National Geographic Society to excavate one of the residential mounds identified via LiDAR. Carter discovered what appears to be the remains of a brick stove, complete with ceramic vessels for cooking. Chemical analysis revealed remains of pomelo fruit rind, seeds from a relative of the ginger plant, and grains of rice. This is what archaeologists call “ground-truthing,” and it’s further confirmation that the mounds we see in LiDAR are actually from households rather than other structures.
The picture that’s emerging of Angkor is much like a modern low-density city with mixed-use residential and farm areas. As Evans put it to Ars, “in the densely inhabited downtown core there are no fields, but that nice, formally planned city centre gradually gives way to an extended agro-urban hinterland where neighbourhoods are intermingled with rice-growing areas, and there is no clear distinction between what is ‘urban’ or ‘rural’.” The city was a miracle of geoengineering with every acre transformed by human hands, whether for agriculture or architecture.
Perhaps Angkor’s greatest technological achievement was its sophisticated waterworks, including artificial canals and reservoirs. People strolling through the city 800 years ago would have passed through neighborhoods whose carefully arranged homes were built alongside rainfall ponds for families, as well as enormous canals for the city as a whole. Massive rectangular reservoirs held water all year around for agricultural use.
Each neighbourhood would have looked slightly different, though all relied on the same water infrastructure. The city had to survive the floods of the rainy season and slake the thirst of people and farms in the dry season. For centuries, it accomplished this incredible feat, which modern cities still struggle with. Suryavarman II ruled a city whose mythic proportions were enabled by the most sophisticated engineering techniques of his day.
Comparison of major temple complexes in the 12th to 13th centuries, all at the same scale. Later developments (right column) show more variable grids than earlier ones (left column), with areas within the moat divided neatly into ~100×100 m “city blocks.” 6a: Angkor Wat. 6b: Beng Mealea. 6c: Preah Khan of Kompong Svay. 6d: Preah Khan of Angkor. 6e: Ta Prohm. 6f: Banteay Chhmar.
“Mound fields” across Cambodia. Panels a,b are in the Phnom Kulen area. Panels c,d are immediately to the north of the main temple complex at Sambor Prei Kuk. Panels e,f are Immediately to the west of Banteay Srei temple at Angkor. Panels g,h: Near the exit of the East Baray reservoir at Angkor, new archaeological mapping (3g) based on the 2012 ALS data has added further detail to a ~10×10 grid of mounds (3h) and revealed a second mound field to the south of the exit. Panels 3a,c and e are conventional aerial imagery acquired in the 2015 campaign. Panel 3g is based on archaeological maps by Damian Evans, Christophe Pottier and Pelle Wijker.
Unexplained, rectangular coil patterns associated with major temples across northwest Cambodia, revealed in LiDAR maps.
Mysterious coils and mounds
Plenty of unknowns remain at Angkor, and the LiDAR surveys have revealed two previously unseen structures that nobody has been able to explain so far. The first is a complicated rectangular maze pattern dubbed the “coils,” “spirals,” or “geoglyphs.” These were first spotted outside the moat at Angkor Wat during the 2012 survey, but the 2015 survey revealed similar coils outside the enclosures at Beng Mealea and Preah Khan. At first glance, they appear to be waterworks, but Evans and his colleagues dismissed that idea because they are too shallow and are cut off from the city’s general waterworks.
Currently, the reigning hypothesis is that these rectilinear coils were specialized gardens for growing plants used in temple rituals. The often-flooded channels might have contained lotus, while the raised areas could have supported “aromatics such as sandalwood trees.”
More mysterious are the so-called “mound fields” found near some of Angkor’s largest reservoirs and canals. Unlike the residential mounds excavated by Carter and her colleagues, these mounds aren’t packed with ceramics and food remains. They are just mounds, clearly the foundations for an elevated structure or structures. Their locations suggest that they may have been related to the city’s waterworks, but of course, correlation does not equal causation. Further research is needed to unlock the secrets of the coils and mound fields.
The lost city in the sands: Inside the ancient citadel of the Black Pharaoh’s which has pyramids to rival Egypt.
This is the lost city of Meroë in Sudan, with beautifully maintained pyramids as impressive as their more famous counterparts in Egypt. However, unlike the famed pyramids of Giza, the Sudanese site is largely deserted.
The pyramids at Meroë, some 125 miles north of Sudan’s capital, Khartoum, are rarely visited despite being a Unesco World Heritage site.
Sanctions against the government of longtime President Omar al-Bashir over Sudan’s long-running internal conflicts limit its access to foreign aid and donations, while also hampering tourism.
The pyramids bear decorative elements inspired by Pharaonic Egypt, Greece and Rome, according to UNESCO, making them priceless relics, Unlike their more famous counterparts in Giza, Egypt, the Sudanese site is largely deserted and visited by very few tourists each year.
The site, known as the Island of Meroë because an ancient, long-dried river ran around it, once served as the principal residence of the rulers of the Kush kingdom – one of the earliest civilizations in the Nile region – and known as the Black Pharaohs.
Their pyramids, ranging from 20 feet to 100 feet tall, were built between 720 and 300 B.C. The entrances usually face east to greet the rising sun.
‘Egypt doesn’t have the monopoly on pyramids,’ said Eric Lafforgue, a photographer who travels the world documenting tribes.
‘Sudan has many of them and discovers new ones regularly. The most beautiful and impressive pyramids form the Meroë Necropolis.’
The Unesco World Heritage website describes the site as: ‘The heartland of the Kingdom of Kush, a major power from the 8th century B.C. to the 4th century A.D.’
It explains that the property consists of the royal city of the Kushite kings at Meroe and the nearby religious site of Naqa and Musawwarat es Sufra.
Meroë and others bear the marks of more recent history, with many marked out by their flat tops – the result of being dynamited by Italian explorer Giuseppe Ferlini, who is 1834, came and pillaged the site.
The pyramids bear decorative elements inspired by Pharaonic Egypt, Greece, and Rome, according to Unesco, making them priceless relics.
However, overeager archaeologists in the 19th century tore off the golden tips of some pyramids and reduced some to rubble, according to Abdel-Rahman Omar, the head of the National Museum of Sudan in Khartoum.
Tourists are few and far between in the forgotten pyramid village of Meroë in Sudan, with around 15,000 visiting a year
The ruins of a kiosk discovered in Naga, a religious site near to the ancient Kush city of Meroe, where the rulers were one of the earliest civilisations in the Nile region
Naga, where this sculpture of a ram was one of many discovered dating back to the first century B.C., forms part of the Unesco world heritage site with Meroe and religious site Musawwarat es Sufra
On a recent day, locals reported just a few tourists and white camels roaming the site, watched by a handful of security guards.
Sudan’s tourism industry has been devastated by economic sanctions imposed over the conflicts in Darfur and other regions.
Al-Bashir’s government, which came to power following a bloodless Islamist coup in 1989, has struggled to care for its antiquities.
Qatar has pledged $135 million to renovate and support Sudan’s antiquities in the last few years. But Mr Omar said Sudan still receives just 15,000 tourists per year.
