A mist-covered mountain in Cambodia gives up its treasure

Opmmur

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A mist-covered mountain in Cambodia gives up its treasure, writes Lindsay Murdoch.
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Scratched and exhausted, Damian Evans pushed through dense jungle into a clearing where mountain villagers long ago attempted to grow rice, stepping on to a weed-covered mound.

''Bingo,'' the Australian archaeologist said as he picked up and examined an ancient sandstone block.

It is hard for the Khmers to think about history when they have empty stomachs.
''This is a collapsed temple that was part of a bustling civilisation that existed 1200 years ago … It looks like the looters were unaware it was here.''

Hidden city

Archaeologists in the Siem Reap region using new maps acquired using LIDAR have discovered an entire Angkor city where previously only a few isolated temples were known to be.


Over the next few hours Evans and a small group of archaeologists hacked through more landmine-strewn jungle and waded through swollen rivers and bogs to discover the ruins of five other previously unrecorded temples and evidence of ancient canals, dykes and roads, confirming data from revolutionary airborne laser-scanning technology called lidar.

The discoveries matched years of archaeological ground research to reveal Mahendraparvata, a lost mediaeval city where people existed on a mist-shrouded mountain called Phnom Kulen 350 years before the building of the famous Angkor Wat temple complex in north-western Cambodia.

Subsequent searches have identified another two dozen hidden temple sites.

Click for more photos
Lost civilization in Cambodia

Bhuddas carved into the mossy rock face. Photo: Nick Moir
Dr Evans, director of the University of Sydney's archaeological research centre in Cambodia, said the ''eureka moment'' in the discovery came weeks earlier when the lidar data popped up on a computer screen.

''With this instrument - bang - all of a sudden we saw an immediate picture of an entire city that no one knew existed which is just remarkable,'' he said.

Heng Heap, a one-legged, chain-smoking former Khmer Rouge soldier, guided the expedition, hacking the way through undergrowth and skirting landmines in the area where he knows every significant outcrop, stream and valley.

Injured in three landmine explosions and wearing a prosthetic plastic leg, Heng Heap said he was surprised when the archaeologists, using GPS co-ordinates, pointed him straight to temple sites that were buried or hidden by jungle and that he never knew existed.

''I knew some things were there but not all of them,'' he said between puffs of a village-made cigarette.

Fairfax Media recorded the archaeologists pulling away undergrowth at several sites to find pedestals from collapsed temples that were probably looted centuries ago.

Guided by the GPS, they stumbled across piles of ancient bricks.

They found two temple sites where no carved rocks or ancient bricks could be found scattered nearby, indicating they have never been looted.

They also found a cave with historically significant carvings that was used by holy hermits who were common during the Angkor period.

The lidar, or light detection and ranging data, revealed hundreds of mysterious mounds several metres high across the mostly buried city.

One untested theory was that they were tombs where the dead were buried but there could be many explanations.

''We are still trying to work out what these things were,'' Evans said. ''There may be implications for society today … for example, we see from the imagery that the landscape was completely devoid of vegetation.

''One theory we are looking at is that the severe environmental impact of deforestation and the dependence on water management led to the demise of the civilisation … perhaps it became too successful to the point of becoming unmanageable.''
For centuries Phnom Kulen has remained a holy place where tens of thousands of pilgrims come each year to bath and perform spiritual rites.

Archaeological research of sculptured caves and river beds showed the area remained occupied throughout the Angkor period between the ninth and 16th centuries.
But the lidar technology has confirmed that Mahendraparvata was built on Phnom Kulen before Jayavarman II descended from the mountain to build another capital near where Angkor Wat now stands.

''This is where it all began, giving rise to the Angkor civilisation that everyone associates with Angkor Wat,'' Evans said.

Built over hundreds of square kilometres with a population of hundreds of thousands, possibly a million people, Angkor was the largest low-density pre-industrial civilisation on Earth, dominating south-east Asia for 600 years.

According to Chinese scholar Zhou Daguan, who recorded life in the then lowland capital between 1294 and 1307, Angkor rulers presided over slave-based civilisations where people went naked to the waist, wrapped only in cloth.

They lived in thriving, low-density cities with canals and villages and temples dedicated to a god.

According to ancient scriptures, a Brahmin priest anointed Jayavarman II a ''universal monarch'' in 802. But little is known about the city he presided over.
Phnom Kulen was covered by jungle for centuries until loggers moved into the area in 1990s after years of civil war.

The area was a former stronghold of the Khmer Rouge, a Maoist-influenced organisation that failed spectacularly in the 1970s to replicate the agricultural achievements of the Angkor period, causing the deaths of more than a million people from overwork or starvation, while hundreds of thousands more were executed.
Heng Heap's village, called Anlong Thom, is in the middle of the discovered city but none of the 1200 brooding villagers knew it.

David Sandilands, an Australian working in the village for the London-based Archaeological and Development Foundation, said more than half the villagers were malnourished.

''It is hard for the Khmers to think about history when they have empty stomachs,'' he said.

Sandilands is showing the villagers how to grow mushrooms that are nutritious and can be sold in markets.

He said the village was a ''fractured society'' but he hoped the villagers would benefit from intensified archaeological research on the mountain in that it would provide work and additional income. More than 25 villagers are already employed to clear vegetation and protect the mountain's historical sites.

When sites are being excavated in the 37,500-hectare Kulen National Park, the Archaeology and Development Foundation employs more than 100 people, mostly villagers.

But the work has been restricted by landmines that were laid indiscriminately across the mountain during the civil war.

Areas around the mountain's known historical sites are thought to have been cleared of the mines but they still pose a risk to archaeologists and villagers.

Now the lidar technology is set to replace the need for explorers and scientists to rely on the machete to clear the dense vegetation that covers the remains of mediaeval civilisations.

The technology was used in 2009 to reveal extensive terraced farming and a road network in the ancient Maya city of Caracol in the Central American country of Belize.
It has also been used recently at Stonehenge and other European archaeological sites.
The instrument fires rapid laser pulses at the landscape and a sensor mounted on it measures the amount of time for each pulse to bounce back.

By repeating the process, the instrument builds up a complex picture of the terrain it is measuring.

When Evans learnt of the technology he helped set up the Khmer Archaeology Lidar Consortium, made up of eight organisations including the foundation, Cambodia's APSARA National Authority and the University of Sydney's Robert Christie research centre.

The project was a gamble: the technology had never been used for archaeology research in tropical Asia. It would require the broadest co-operation ever among diverse groups of archaeologists from seven nations who were working in Cambodia and would cost more than a quarter of a million dollars.

High-level approval had to be sought from the government in Phnom Penh.
The consortium commissioned Indonesian company PT McElhanney to transport a Leica airborne laser scanner to Cambodia.

Over seven days in intense tropical heat, a helicopter flying at 800 metres methodically criss-crossed 370 square kilometres of remote, forested areas of north-west Cambodia.

The instrument collected billions of data points and about 5000 digital aerial photographs that would keep archaeologists busy for years.

Members of the Indiana Jones-like expedition who matched the lidar findings traversed deep, rutted goat tracks and knee-deep bogs after travelling high into the mountain on motorbikes.

Everyone involved was sworn to secrecy until the lidar findings were scientifically peer-reviewed.

Evans said it was still not known how large Mahendraparvata was because the lidar search covered only a limited area.

''The network doesn't stop at the edge of the survey area,'' he said, adding that money was being raised for further research.

''Maybe what we see was not the central part of the city so there is a lot of work to be done to discover the extent of this civilisation.''
 

Opmmur

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Laser scans flesh out the saga of Cambodia's 1,200-year-old lost city

A Cambodian tourism documentary provides scenes from the Mahendraparvata archaeological site.

By Alan Boyle, Science Editor, NBC News

The Video Link: Laser scans flesh out the saga of Cambodia's 1,200-year-old lost city - Cosmic Log

Laser-scanning technology reveals that the Cambodian lost city of Mahendraparvata, dating back to a time before Angkor Wat, was much more extensive than previously thought. The latest word about the high-tech hunt for hidden ruins came over the weekend in an on-the-scene report from Australia's Fairfax Media.

Archaeologists have known about the Hindu-Buddhist-influenced city, situated about 25 miles (40 kilometers) north of the better-known Angkor Wat temple complex, for decades. Some of the ruins rank among the tourist attractions on the holy Khmer mountain known as Phnom Kulen ("Mountain of the Lychees"). However, experts weren't sure how extensive the site was ... until now.

"We're talking about a city that is more than 1,000 years old and is all underground. If you didn't know, you might think it's natural," Stephane De Greefe, the archaeological project's lead cartographer, told Cambodia Daily.

The Khmer Archaeology Lidar Consortium set up an aerial survey of the Mahendraparvata site and its surroundings, using a technique known as lidar (short for "light detection and ranging"). The process involves flying an instrument-equipped helicopter over the area, bouncing pulses of laser light off the ground below, and then analyzing the scattered light readings to produce a 3-D map of the terrain beneath the jungle's vegetation.

Billions of data points and about 5,000 digital photographs were collected during a week's worth of aerial surveys, taking in an area amounting to 143 square miles (370 square kilometers).

'Eureka moment'

University of Sydney archaeologist Damian Evans told Fairfax Media that seeing the map displayed on a computer screen marked the "eureka moment" in a years-long search. The readings revealed dozens of temple sites, hundreds of mysterious mounds that may represent burial sites, and traces of canals and roads criss-crossing the area.

An on-the-ground expedition followed, during which the team came across two temple sites that may still be intact, and a cave with centuries-old carvings that may have been a refuge for hermits during the Angkor period.

A video from Fairfax Media focuses on the Mahendraparvata expedition.

Phnom Kulen served as a center of the Angkor civilization between the ninth and the 16th centuries. Tradition has it that Mahendraparvata was where the founder of the Khmer Empire, Jayavarman II, celebrated his people's freedom from Javanese control in the year 802. Angkor Wat was built nearby more than 300 years later.

How a city got lost

Why did Mahendraparvata fade away? "We see from the imagery that the landscape was completely devoid of vegetation" at some point during the site's history, Evans told Fairfax Media's Lindsay Murdoch. "One theory we are looking at is that the severe environmental impact of deforestation and the dependence on water management led to the demise of the civilization. ... Perhaps it became too successful to the point of becoming unmanageable."

Some reports have made it sound as if Mahendraparvata was only now being discovered, but Evans told Cambodia Daily that the real point behind the research has to do with how lidar resolved the debate over the lost city's extent. Lidar surveys are becoming a routine part of "lost city" quests — including the discovery of centuries-old ruins in Honduras that may be linked to the legendary city of Ciudad Blanca, and an extensive survey of Caracol, a Maya center in Belize.

Details about the Cambodian project are to be published in the Proceedings of the National Academy of Sciences.

Update for 6:30 p.m. ET June 17: The Proceedings of the National Academy of Sciences just sent journalists a pre-publication draft of the paper submitted by Evans and his colleagues — suggesting that Mahendraparvata as well as Angkor Wat were part of a vast urban network.

"We identify an entire, previously undocumented, formally planned urban landscape into which the major temples such as Angkor Wat were integrated," the researchers write. "Beyond these newly identified urban landscapes, the lidar data reveal anthropogenic changes to the landscape on a vast scale, and lend further weight to an emerging consensus that infrastructural complexity, unsustainable modes of subsistence and climate variation were crucial factors in the decline of the classical Khmer civilization."

The researchers say their mapping reveals a pattern of regular "city blocks," within which mounds and ponds were built to create temple precincts. Such cityscapes existed in ancient Angkor as well as the Phnom Kulen region and another area farther northeast, known as Koh Ker.

"These 'urban temples' are not isolated; rather, they are nodes in an increasingly concentrated medieval cityscape," they said.


imagesizer

Evans et al. / PNAS

A map of northwest Cambodia provides an overview of the areas where lidar imagery was acquired, indicated with yellow shading. The background data is from NASA's Shuttle Radar Topography Mission.

imagesizer

Evans et al. / PNAS

Lidar imagery shows the central area of Angkor, with the "walled city" of Angkor Thom above Angkor Wat. Red lines indicate post-medieval features, including roads and canals. The other features are from the Angkor era.

The paper echoes Evans' comments about the potential environmental roots of the Khmer Empire's decline: "The archaeological record shows that episodes of failure were commonplace within the hydraulic infrastructure within the medieval period. ... For several centuries at Angkor, episodic renovation of the water management system offered a series of provisional solutions that were adequate for mitigating the risk of low rainfall on an annual scale. Eventually, however, the civilization was confronted with decadal-scale megadroughts in the 14th and 15th centuries."

The researchers speculate that those megadroughts triggered the doom of Cambodia's megacities. In that, they see a parallel to the classic Maya civilization, which is thought to have gone into decline due to a similar pattern of deforestation and drought. And they include a chilling observation about our own era, attributed to University of Sydney archaeologist Roland Fletcher: "If the infrastructure of low-density cities is inherently liable to be or to become a constraint on the viability of a city’s daily life, then this is an issue of some serious consequence for our engagement with a future of giant, low-density cities."
 


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