Sunday, 10 August 2014

An Adventure in the Western Desert of Egypt (1)

(1) The 2002 expedition and the pharaoh's jewel

The March 2002 expedition

'The Desert is the skeleton of the Earth' I kept hearing this sentence of Theodore Monod, a  naturalist and explorer of the Sahara, when our convoy of three 4x4 Toyotas left suddenly the military tar road, 700 km from Cairo, and made a wide arc into into flat yellow nothingness.  It was March 2002, and two years before I had written a feature for New Scientist  about the most mysterious mineral of all, Libyan Desert Silica Glass. The purest glass on Earth, that I had found resulting from a mighty meteoritic explosion. (see article below)
Chianti Camp, Almasy's breakfast place. Tins and bottle are still there, in the crack of a rock. (all photos, unless otherwise stated, by me)

In the scorching heat,  in the three bumping Landcruisers, there was a mixed European crowd, with different aims, from birding to archaeological exploration. Andras Zboray, our expedition leader, had as a task to find and catalogue  new rock paintings in the Uweinat Mountain, and in the Gilf Plateau.  I had to check the strewn fields of Libyan Desert Glass, a cosmic material that had been found at the center of a King Tutankhamen necklace.

A sample of Libyan Desert Glass (yellow dominant)

According to achaeologists between 7000 and 5.000 yrs b.C., before the last general dessiccation, those barren lands  had seen the first men and the beginnings of a civilization, at the end of the hunter-gatherer phase, as documented by one the largest collections of Prehistoric Art in Africa found in shelters and caves. Mind you, if you look at the Michelin map, the most detailed yet in Africa, you'll draw an absolute blank, there are no roads, and not even paths. Just sand and geological formations. The lines drawn retrace just earlier explorations.

Andras and I also shared an Arab legend about the place: where was the legendary kingdom of birds,  the Lost City of Zertura which had for so long mesmerized the explorers of the 1930s?
People like Arabist Wilkinson and Count Almasy, the explorer, had been drawn to this forgotten, superarid corner of the World, just for this reason.

Almasy's car trying to cross a Dune of the Great Sand Sea, circa 1930.

The city of the Black Queen and King, who owned the greatest treasures of the Ancient World. A Lost City, the rarest mineral in the World, and a long forgotten civilization, were motivations enough for us to travel for two weeks, making a periple of 2000 km, all off road.

Note that we were bringing everything with us,  water in jerrycans, never to waste,  other jerrycans of gasoline, but also food. As for spares we were ready to cannibalize one of the Landcruisers, which had been bought second hand in Cairo.
The Toyotas seem to totter at times, so oberburdened were their roofs. The duration of the stay was calculated,  on the basis of the weight the three Toyotas could carry, never to exceed 15 days, based on each of us' personal water consumption, some 1,5 liters per day each. Not enough to wash oneself with!

Nobody could reach us easily 700 km from the Nile, although we had a satellite phone, which batteries must be spared. In case of an accident, our only hope of rescue was an Egyptian military helicopter, that we had paid for in advance.

Temperatures went between 40 C and -5 C, ideal for the Sahara. If you have been there you know that it can be done, due to the lack of humidity. In March however the deadly desert wind, the Khamsin, blowing from the South, can rear its ugly head.
Accordingly, the first two days as we began exploring the reliefs in the outer reaches of the Gilf Plateau, we were caught in a Khamsin. A running yellow, stinging fog of particles so strong that it obliterates everything, from one meter onwards. All you can do is bury yourself fully dressed in your miserable tent, which shakes as a living beast. 

Cameras of course need special care.  Knowing my customer, I had brought a tank built Praktica BC1,  with  a 35-70, and an additional 28 mm, that I kept always wrapped in a plastic bag. Sandstorms can also make your batteries suddenly flat. The BC1 however has also a mechanical shutter at 1/60, and is sturdy enough to stand the incessant bumps of the Toyota. The digitals of our group instead went flat, but there was also a spray of mechanical Leicas. Those, like my Praktica, kept working flawlessly. 

If I think in retrospect, I should have brought at least a lens shade, and a 300 mm or even a 600 mm lens. Innocently I believed that a Wide Angle would have been all I needed, but the desert is so vast, and in places so featureless, that a WA is completely redundant. Teles are welcome, the longest the best. Distances are so vast  that they flatten the features, and details vanish in the horizon flare. Lenses don't need to be fast anyway: there is so much light that you'll always be shooting in the vicinity of f/16, with a 100 ISO film!

Seen from some relief the Toyotas' convoy must have looked to progress slow as  snails, across the imposing landscape of rocky flats and dunes.. But in fact our beduin drivers, Salama, and Mahamud, pushed the Landcruisers as frenzied camels, taking long curves to avoid the most cutting rocks that would have made our tyres explode. They did so with ease, to the sound of Arabic party dances, yelling as if they were running some beast.

In a bag separate from the camera, below the seats for freshness, I kept a ten pack of Ecktachromes 100 and some 400 ASA. I later duplicated the BC1 slides with a Digital body and a macro tube. After colour correction in PhotoShop, they are not too shoddy all considered, even ten years later. Some still have an orange dominant though. At any rate the expedition was far more than what they show, you will find an objective account by Andras here:

We really did some intensive exploration, never spending a night in the same place. Our dozen tents had to be raised each evening and broken again each morning. Then, with the setting sun  came the ritual of a sundowner, and then eating  some tastless rice boiled on the fire, with a tin of nameless Hungarian things. You are not there for the cooking anyway,there went the saying :)

Karkhur Talh

But how could I ever describe my arrival at the end of the day to the foot of the mighty Uweinat Mountain, all covered with feather like Zilla Spinosa, light green Acacia leaves, inhabited by the Zerzura bird, that was rumoured to guard the Lost City?
 I have seen the swallow-like black and white birds jumping from branch to branch, but they are so tiny and fleeting that I could never make anything of them with a 35-70. Again the need for a 300mm.

Note that the place had only been discovered by the Egyptian Crown Prince Kemal el Din in the 1910s, with his mixed retinue of camels and Citroen half tracks. Before him, nobody even knew that there was this 1000 m. mountain! And at a rate of exploration of a couple of explorations a year, lasting two weeks each, no wonder that there is still so much left to explore.

However  you can also enjoy just being there, in one of the last places untainted by Man. Sometimes contemplation and utter inner happiness floods  everything, so one forgets even to shoot!
In that mountain made of cyclopean granite boulders we were to discover an old artesian well that might well have watered the last camels of the Warriors of Zerzura, or one the last Tebu tribes that were seen there by an old camel guide at the beginning of last century. 

The expedition from Shaw's Cave
We advanced through the rocky flanks in a row, so not to miss anything, and accordingly we discovered the mountain was as covered by rock drawings, like  a cathedral covered  by frescoes!
The Uweinat must have been a high place for the covens of Prehistoric Saharans, being one of the rare places to still have water a century ago, as related by the witings of the early explorers.

Claire Spottiswoode at rock paintings

Picture Hannah McKeand
Andras was taking pictures and GPS readings simultaneously, documenting the first messages at the dawn of humanity. Some might have been as old of the Palaleolithic when the Neanderthals still roamed uncivilized Europe. They showed horned gods of goddesses, in shamanistic dealings, and even human sacrifices.

Shaman making a charm to an addax

Two prehistoric grinding stones
In a shelter, called the Cave of Swimmers, and discovered in 1930 by Count Almasy, we found the celebrated swimmers, in somehow foetal positions! 
 Water must have literally flowed there at the end of the last Glaciation, some 7000 yrs. ago. Represented in other caves there were pregnant cows and gazelles, and scenes of hunting with spears. But there were also hand prints, made by blowing ocre over the hands. Those have been interpreted as trance devices to make contact with the Other World, across the stone wall!
Count Lazlo Almasy at the Cave of Swimmers, 1930

The Cave of Swimmers

Hand Prints by blown hematite dust
It was then that in dawned on me that we were discovering  the first pictographic language of humanity, born in the Desert from the need of marking the water sources (see Part Two) by a society of hunters-gatherers, whose resources were dwindling. 
Rock paintings indeed convey information as much as photography. They are simply associated with the relevant features, like marks.
Climatologist and archaologists alike tell us that this Saharan culture was born while the waters where retreating from the then verdant Sahara.  With the dwindling waters those herds and populations reatreated towards the Nile, more or less at the rise of the first Egyptian kingdoms. Was that a coincidence that their pictographic language was later to be found superimposed to the hieroglypic language of the Pharaohs? Did the animal gods come from the Sahara?

Meanwhile we were going to look in one of the valleys of the Gilf Plateau, so huge that it can be observed from space, where Count Almasy situates the first City of Zerzura, mentioned by Arabist Sir Gardiner Wilkinson in one of his ancient manuscripts.

The flanks of the Gilf Plateau

Salama checking our engines in the morning
It was not so easy to climb with the Toyotas the craggy and steep flanks of the 300m tall plateau, as huge and steep as Switzerland. Once on the flat top we could push at 60 km/h for hours, and Salama flirted with the ravines.
However  it was harder to descend between the narrow passes to the mysterious valley, described by Almasy  They are precipitous descents among rock flanks, with a sandy bottom. The Toyota must be cranked at full speed and enter the rock walls of the pass at full blast to avoid getting stuck in the sand, by  keeping exactly in the middle - or get shattered - to safely reach the floor of the valley, if luck is with you. 

I got a seat next to Salama, feeling I couldn't leave him alone at the moment of danger.
I thought I would die in a tremendous blast, but with a swift turn of the wheel, and a graceful curve,  we were at last on the sandy bottom of the hidden valley, with Salama laughing like a madman. 

The Wadi el Melik pass - Photo Marc Bovym
Allow me an anticlimax. No we didn't find the Mysterious Kingdom, only a horned skull and bones, attesting that the last inhabitants had pushed there from Libya at the beginning of last century, before the valley dried up completely. The Zilla Spinosa and the Zerzur birds were nagging us again, exactly like Almasy, and the legend,  had described.

 In this valley Almasy was even told a tale by an old camel herder, el Melik, who had said before the Caliphe christened it with his name, among the tribes of old it was known as the Zertura valley.
So if there had been a kingdom it must have vanished long beforeAlmasy's time. 

The Last Addax - Picture Lajos Nemeth
More to the point, as the second leg of the expedition, we still had a mission to find the site of the strewn fields of Silica Glass,  a material so power yelding that it had been incorporated at the heart of a necklace belonging to King Tutankhamun! 

The Pectoral of King Tut with LDG at the heart. Cairo Museum.

How could it have reached his court from a site so remote that had completely dried up before his time, some 7000 yrs. ago? 

That was an even deeper mistery than the origin of the glass that  I had clarified with  top geologists and astrophysicists, as having a cosmic origin.

More would come about how the glass had reached King Tut, by  the camel expeditions of explorer Carlo Bergmann. Thanks to him we would have insights, not only about the travels of the glass, but  also about the dawn of Egyptian Civilisation, and the origin of hieroglyphic writing in the desert.

I was extremely happy of having hit one of the main leading pieces of evidence in the cosmic glass.

 But first things, first: what created the Desert Silica Glass? See below.


( I have inserted some images, not originally in the text, to ease the reading.)

The Riddle of the Sands

10 July 1999 by Giles Wright
Magazine issue 2194. 

BUFFETED by the might of the hot Khamsin wind that sweeps across the Egyptian Sahara, the mountainous dunes of the Great Sand Sea are the stuff of legends. Here, ancient armies lie buried and the fabulous wealth of lost cities awaits discovery. But in the 1930s, these myths came under threat. Explorers arrived with camels, cars and flimsy biplanes and criss-crossed the blistering sands, searching for a legendary oasis called Zerzura. Though they never found Zerzura, Patrick Clayton, a surveyor with the Egyptian Geological Survey stumbled upon something almost as fantastic.

In December 1932, he was bumping across the dunes towards the high, wind-swept red rocks of the Saad plateau when he felt the tyres of his car crunch across chunks of glass. It was an incredibly clear, green-yellow glass that glittered like gems in the bright sun. Over the next few years he returned on expeditions to collect samples  with LJ Spencer, curator at the British Museum.

When in winter 1934 Spencer and Clayton combed the dunes and the interdune corridors    they found  that the glass was strewn for  an area  of some two hundred square miles, later figures being  3500 km2 ,  and that a mass above ground is 1400 tons.  Another proof   of how large the phenomena must have been is how varied the glass was: color went from yellow to light, sometimes dark green.  Some chunks were so clear they could be used as lenses, some had streams of bubbles, whitish  inclusions, pointing  to a tumultuous origin. Others yet had dark layers  or black swirls, looking like ink dropped in water. Many were layered and could be easily splintered. Indeed Spencer noticed  clusters of LDG chips that looked as debris of  prehistoric workshops.   An archaeological mistery was added to the geological one. 

By  analysing the samples Spencer discovered that it was the purest natural glass ever seen, with 98-99% silica, a composition which had never been observed in  impact glasses formed by meteorites, nor in glass spewed by volcanoes, which is 75% silica at most.  He also discovered that he could heat the material to 1700°C before it began to melt, more than 500°C higher than other natural glasses. It could be dropped into cold water even when it when red hot and it didn't disintegrate.   What was the mighty event that had created such a tough substance?  Sadly,  five years after his trip in the GSS, in 1939, L.J. Spencer wrote "publication of the... notes has been delayed now for five years in the forlorn hope that some clue might turn up to help solve the mystery of Silica Glass of the Libyan Desert"  
Searches for LDG did not resume  until  1971, when  US geologists Barnes and Underwood,  prospecting for oil reached the Saad plateau from the Kufra oasis, finding on their way a fallen aircraft with the corpses of the unfortunate passengers.They collected 26 samples of LDG, but stayed only a few days, not enough to find conclusive geological evidence about the origin of the glass.  
A decade later, in 1981, French naturalist and Sahara doyen Theodore Monod, journeying towards the Gilf Kebir, reported numerous LDG artefacts in the glass dispersion area, and gave his samples to some of the best French labs and universities.

A piece of LDG on location. See the signature of meteoritic dust inside
In 1983, having noticed some extinct lakes (playas) in the neighbourhood of the glass dispersion area,  University of Koln's Ulrich Jux, a geologist who was there with a German arcaeological mission, proposed a hydrothermal origin for the glass. Silica glass may have formed at the bottom of a warm, volcanic lake. Over millions of years, water trickling through hot underground channels close to a volcano could have dissolved silica from the surrounding rocks. When this warm, silica-rich water collected into lakes and cooled, pure silica glass would begin to precipitate out. It would become a gel, that would solidify with time, becoming glass. According to Jux this formation process is demonstrated by the presence of organic remains such as diatoms trapped during the precipitation phase. Such remains supposedly produced macroscopic dark streaks in SG, which were attributed by the american geologists Murali, Underwood, and alii (1989) to inclusions of ET matter. A controversy ensued.
Dating the glass was important to solve the issue. Previously to 1987 no  technology to date events older than 10,000 years had been available: it was a matter of putting the glass samples into an expensive nuclear reactor and bombarding it with neutrons.  In that year German geochemists  dated the glass at 28,5 million years old, by a process called fission track, that measures the rate of decay of radioactive elements trapped in the glass. This was a time, the Oligocene,  when the elephant and the hippo still roamed in Europe, and where Homo Sapiens was still a dream in some monkey's mind. Clearly  it could have nothing to do with the catastrophe that had destroyed Zerzura.  Nor had it to do with  the dried-up remains of the ancient lakes that Jux had spotted near the site. They  turned out to be far too young, just 9000 years old. 

Thermal Lake by Saad Plateau.
In the universities round the world the LDG question was coming to a head:  more than a hundred and forty  papers had been published without conlusive results, when  in  1985  Sahara explorer and archaeologist Giancarlo Negro, heading for the rock paintings of Gilf Kebir,  found Clayton's  bottle among the chunks of Silica Glass.  "I found Clayton's camp in 1985, with petrol and water  tins still constellating the sand.  I was amazed to see that whisky bottle full of sand with a message sticking out, carrying the message 'March 1934. Spencer, Little, Clayton' I was shocked at the sight of a bottle dating some 50 years before, also because that meant that nobody had been there, in Camp 10,  in the interval." He was so intrigued that he decided to carry their torch; after making four expeditions researching Silica Glass from 1991 to 1996, he organised the first international meeting on LDG at the University of Bologna: 'Silica 96'. It was high time to assess the post-war expeditions made  by German, French, American and Italian research teams. More than 170 papers had accumulated.

Could the material have been spewed by volcanoes? Robert Rocchia  from the environmental sciences lab at the French national agency for scientific research (CNRS) in Gif Sur Yvette, who inherited the collection of  Monod's LDG samples.There are at least two ancient volcanic craters in the area (Abu Ballas, El Baz crater),  says Rocchia but they are hundreds of kilometres away from the site of the glass, probably too far away to have been involved.  Moreover, these volcanos have a typical basaltic composition (rather poor in Silica). And Horn and Christian Koeberl, a geochemist at the University of Vienna identified whitish inclusions in the glass as minerals such as cristobalite,and baddeleyite which form at temperatures far higher than those found in volcanic lava.  
The best clue to the origin of the glass lies  in the swirling black marks resembling drops of ink found in  some fragments. Rocchia   bombarded these samples with neutrons in a nuclear reactor to trigger gamma-ray emissions from elements trapped inside. The energy of these emissions can help identify elusive trace elements locked up in the glass. They made an intriguing discovery: the dark samples are very rich in iridium. Now, high iridium levels are typical of extraterrestrial bodies such as meteorites and comets. The proportions of other elements such as ruthenium, cobalt and iron told the same story. The only explanation, says Rocchia, is that the glass formed when a meteorite crashed into the desert . 

A piece of the LDG on location at Saad Plateau (center of the frame)
This suggestion seems to make good sense. The local Nubian sandstone is rich in silica and should you want to melt thousands of tonnes of the stuff, there is no better way to do it than with a large meteorite travelling at several kilometres per second. Smash it into the ground and the explosive impact would vaporise a huge area of the desert, melting rocks   and sand at temperatures easily high enough to form minerals like baddeleyite and cristobalite. And as the molten rock cools, it turns to clear, green-yellow coloured glass.
A neat explanation, but peppered with holes: photographs taken by the Landsat and Discovery satellites showed no sign of an impact crater at the glass site. NASA's X-SAR radar imaging camera and The European Space Agency's ERS radar satellites both swept the area, this time probing beneath the surface of the sand with microwaves. They drew a blank, says geologist Farouk El Baz, head of the center for remote sensing at Boston University. 
"We have plenty of impact craters on the Earth," says Koeberl, "but this is the only known occurrence on the whole Earth of such glass. Why did it form here and nowhere else?"
Vincenzo De Michele, keeper of minerals at the Museum of Natural History of Milan  and Romano Serra, an astrophysicist at the University of Bologna believe they know the answer. During their expedition in 1996, Serra and de Michele made a thorough search of the site and discovered that the glass is concentrated in two areas: one oval shaped, and the other a ring 21 kilometres across and about 6 kilometres wide. The area at the centre of the ring is empty, says de Michele. Since a geological upheaval couldn't create a feature that small, de Michele and Serra have another theory. 
Imagine that a chondritic meteorite--a brittle lump of stone and organic matter about the size of a house--is crashing into the atmosphere with the energy of ten thousand express trains. The friction and massive shock wave this creates compresses and heats the atmosphere, shattering the brittle meteorite in mid-air. The heat from this explosion would toast the rock and sand beneath. Scientists call this huge blast a "soft" impact and most believe something similar happened above Tunguska in Siberia in 1908, flattening thousands of kilometres of forest .
A soft impact might just explain why the centre of the ring in the desert is free of glass: "The ground could have responded in an elastic way to the blast wave and rebounded, leaving a ring and a central peak which was later eroded" says de Michele. From the size of this ring, Serra calculates that the meteorite must have been 10 to 12 kilometres above the desert when it exploded.De Michele is particularly impressed by the size of the glass chunks: "This points to a thick mantle of glass and to an enormous amount of heat," he says. "Molten silica is highly viscous, yet the streaks in some samples show that it was flowing like a river."

 Picture of Kebira crater, a candidate for meteor impact, next to the Gilf, and South of Saad plateau.

According to Mark Boslough of Sandia National Labs at Albuquerque in New Mexico, a meteorite 30 metres across could create an explosion equivalent to a 3-megatonne nuclear bomb --easily hot enough to melt thousands of tonnes of glass. And when this meteorite hits the atmosphere, a plume of air would rocket outwards into space like the splashes thrown up by a rock as it drops into water. 
As the plume came down, its kinetic energy would heat the atmosphere to more than 2000°C, says Boslough. At this temperature, the hot air would have sprayed infrared radiation onto the desert, melting the sand like sugar beneath a blowtorch.
Serra believes that this  thermal blanket  might have kept the glass sizzling at thousands of degrees for over a week. During this time, bits of meteorite  would have mixed with the silica and after the glass had cooled and solidified, it would have begun to break down into chunks.
Not everyone agrees with this view: "Airblast melting alone would not work," objects Koeberl. "To melt thousands of kilometres of desert, you need a big body. But big bodies don't make airblasts, unless you make unrealistic assumptions about their density and composition. They make impacts on the ground." And because the glass is contaminated, he says, it suggests the meteorite made contact with the glass.
Koeberl believes that a large meteorite raced through the Earth's atmosphere at a very shallow angle and skimmed across the surface of the Sahara like a stone skipping across a pond. In the moments the meteorite spent in contact with the desert, friction would have created enough heat to melt the sand and rock. This process could create far more melted silica than a meteorite smashing straight into the ground. And it wouldn't leave a very deep crater: "In 28 million years a lot of sedimentation and infill can happen," says Koeberl. "The crater might still be there, covered by hundred of metres of sand." 
But there may be a simple way to overcome Koeberl's objections to a soft impact yet still account for the huge amount of melted glass at the site. According to calculations made by Boslough, massive amounts of heat could have come from an impact involving multiple simultaneous soft impacts--when more than one piece of meteorite dropped into the atmosphere and exploded. Much the same thing occurred when pieces of Comet Shoemaker-Levy smashed into Jupiter in 1996. "Close-packed arrays of soft impacts lead to dense plumes, generating higher temperatures," he says. 

                                 a meteorite crashes on jupiter.

Even without a crater, Rocchia prefers to stick with the hard impact theory. Researchers  have found shocked quartz grains inside silica glass, he says: "They are unlikely to result from an atmospheric explosion." But the arguments look set to continue: Koeberl plans to return to the Great Sand Sea to hunt for signs of his crater. Meanwhile, Serra is devoting much of his efforts to studying Tunguska in the hope of strengthening the air blast theory. 
Even if we never learn exactly what created the beautiful desert glass, it is helping us to appreciate how vulnerable our planet is to meteorite impact. "Events like this  or Tunguska are much more frequent than previously thought," says Serra. In fact, estimates suggest that impacts caused by objects 30 to 40 metres across happen once every one or two centuries. Smaller events, caused by 10 to 20 metre objects, may even occur once a month, says Serra. "But soft impacts leave no trace in the geological record and may easily pass unnoticed" says Boslough. This may change as increasing numbers of sensors, orbiting the Earth on satellites, keep watch for their fiery signatures.


our three drivers watching the Gilf

I'll give you in the next instalment the second leg of the expedition, and an insight on the prehistoric origin of the hieroglyphic language, derived from ordinary rock drawings - a notion I will develop with a multiple  interview with explorer Carlo Bergmann.

He discovered what he called Zertura 2, one of the fabled lost cities, along the lost desert paths that Silica Glass might have taken to reach the court of King Tut.

Our camp at Abu Ballas, the Hill of Jars - Picture Hannah McKeand

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