Trek to Erg Zhigaga

Beez Neez now Chy Whella
Big Bear and Pepe Millard
Wed 15 Oct 2008 23:50
To ERG ZHIGAGA
 
After lunch of Tagine of chicken, bread and water, we jumped into a Toyota 4x4 with Aziz our driver and Abdul our guide to drive the 60 kms to the famous dunes of Erg Zhigaga.
 
Some Saharan history. The climate of the Sahara has undergone enormous variation between wet and dry over the last few hundred thousand years. During the last ice age, the Sahara was bigger than it is today, extending south beyond its current boundaries. The end of the ice age brought better times to the Sahara, from about 8000 BC to 6000 BC, perhaps due to low pressure areas over the collapsing ice sheets to the north. Once the ice sheets were gone, the northern part of the Sahara dried out. However, not long after the end of the ice sheets, the monsoon, which currently brings rain only as far as the Sahel, came further north and counteracted the drying trend in the southern Sahara. The monsoon in Africa (and elsewhere) is due to heating during the summer. Air over land becomes warmer and rises, pulling in cool wet air from the ocean, which causes rain. Paradoxically, the Sahara was wetter when it received more solar insolation in the summer. Changes in solar insolation are caused by changes in the Earth's orbital parameters (9,000 years ago the Earth's axis had a stronger tilt than it does presently, and perihelion - the sun's closest point to earth - occurred at the end of July).
 
 
   
 
A Tamarisk hump, the tree exudes a sticky substance that sticks the sand into a protective dune. This keeps the trunk protected from the harsh sun and retains every drop of moisture. The M2. Stones.
 
By around 3400 BC, the monsoon retreated south to approximately where it is today, leading to the gradual rather than abrupt desertification of the Sahara. The Sahara is currently as dry as it was about 13,000 years ago. These conditions are responsible for what has been called the Sahara Pump Theory. The Sahara has one of the harshest climates in the world. The prevailing north-easterly wind often causes the sand to form sand storms and dust devils. Precipitation, while rare, is not unknown. Half of the Sahara receives less than 2 cm of rain a year, with the rest receiving up to 10 cm a year. The rainfall happens very rarely, but when it does it is usually torrential when it occurs after long dry periods, which can last for years. Presently, the climate is changing, and the Sahara is supposedly expanding southward by about 30 miles per year as stated in the popular press.
 
 
 
   
 
 
You feel you are standing in a dried out river or lake bed. Our trusty steed. The boys off searching for fossils to go in Rita's garden. They came back with so many, knowing exactly what stone to turn.
 
Many people only picture the Sahara as rolling sand dunes known as ERG, but there are extensive gravel plains known as REG. The other aspects of the Saharan landscape include the HAMMADAS: vast plateaus swept by winds; and massive mountains. Only about 10-30% of the Sahara is actually covered by sand ( depending which report you read ), and parts of the Sahara are in fact covered by soil. More than half of the area comprises soils known as yermosols, with shallow profiles over gravel or pebble beds. These soils have been developing over the past 50 million years.
 
 
    
 
A real oasis that has been used by caravans for hundreds of years. Lush vegetation. A water pool.
 
 
Recent work using remote sensing radar has revealed ancient river beds under the sands of the Sahara. Pollen records indicate that the Sahara was covered by savannah and steppe vegetation as recently as 5,500 years ago.
 
     
 
 
I almost fell over, the silence was broken by the alarmed shouting of a gang of frogs, not what I had expected in the middle of the Sahara. Then a dog appeared. An abandoned nomad hospital, sadly closed two years ago and relocated.
 
 
   
 
 
A real caravan. A dead donkey not that far from water will become carrion after 5 days - The birds of prey like their meat tenderised, the smell was awesome. The very shallow lake helped by the recent rain, I made the Berber's at camp laugh when I said "I'm responsible for your rain, I offered to drive for Sammy". The next morning in true tradition Bear and I touched the water and wished it to remain throughout the winter.
 
 
            
 
Our bivouac. A double and single bed within, I checked round at bed time to see if any unwanted visitors where with us - not a one. The room was warm, not too hot, with a gentle breeze through the upturned doorway. We read by candlelight before settling down to sleep. The boys putting out the blankets ready for supper. A view of camp and the ' food hall ' on the left, you can see our home to the right of the food hall with the thick curtain door open.
 
 
           
 
 
The reason for being at Erg Zhigaga ( pronounced erg shi garger ) is the sheer size of the dunes, the biggest at over 350 feet. Beds resting on the way to the top after a tiring climb. Bear with Beds. Made it. It was at the top Bear looked down and saw a scorpion trail, we stayed long enough to enjoy the sunset and videoed each other rolling down.
 
The sand is primarily derived from weathering of Cretaceous sandstones in North Africa. When these sandstones were deposited in the Cretaceous, the area where they are now was a shallow sea. The original source of the sand was the large mountain ranges that still exist in the central part of the Sahara. These mountains are volcanic and intrusive, and the granite rock weathers out to leave behind quartz sand grains that are carried by rivers to the sea. These sand deposits eventually formed into sandstone, and as they were uplifted began to weather and break down into sand again.

       
 
 
Traditionally made bricks baked in the sun, cut and stacked for repair work and the new Bivvy being built. The builders invited to their home whilst our supper was cooking. Their goat stew supper. A real nomad who has visited camp for over twenty years and just by speaking to the tourists has learned six or seven languages. A full moon lit the night sky, but we still managed to see many stars.
 
 
   
 
Taking a look inside the food hall, Bear fresh off the dunes, cleaned up ready for Tagine of chicken, vegetables, bread and water. Great coffee to follow.
 
 
All in all a very different adventure in the blazing heat.