Grand Erg Oriental

 

Now this looks like a desert, the Grand Erg Oriental

February 1979

The Grand Erg Oriental (English: 'Great Eastern Sand Sea') is a large erg or "field of sand dunes", or dune field, in the Sahara Desert. Situated for the most part in Saharan lowlands of northeast Algeria, the Grand Erg Oriental covers an area some 600 km wide by 200 km north to south. The erg's northeastern edge spills over into neighbouring Tunisia. (According to Wikipedia). We travel through two ecoregions; mainly the Sahara Desert ecoregion and the West Saharan Montane Xeric Woodland ecoregion as we drive across the Tassili n'Ajjer Plateau, and the Ahaggar Mountains.

It is apparently the second largest Erg of the Sahara. See the map below, 'The major topographic features of the Saharan region', showing the Grand Erg Oriental in yellow at top center.

Saharan topographic elements map

As the name states, it is a sea of sand, with some very big waves.

This was the first real feel of the Sahara as it was envisaged. Lots, and lots of sand, as far as the eye can sea. A road stretching into the distance, albiet not quite straight.

Sand and road

 Unfortunatly I have not been able to locate this on the map. A small escarpment, wide valley crossed by a blacktop road which bends to the right before climing up again on the far side. This is perhaps the begining of the sand desert as there is still a little scrub near the road. Even though the road is surfaced the truck will still pick up some of the standing dust and sand and kindly add it to the EMs experiance inside the back of the truck. Throughout this section of desert the sand slowly gets everywhere. To add to the experiance, there is nowhere to shower to get the sand out of those crevices that it inevitable gets into. Later, in the really sandy areas, looking into the back of the truck would lead you to think that it was a truck load of bandits or bank robbers, with faces covered with scarfes or hankerchives. Not the best look, but it was not always hot, and the dust would get everywhere.

Leaving Tunisia at Bouchebka aka Bou Chebka and crossing the border into Algeria without undue problems or incident, we followed a route westwards to Tebessa before turning southwards to El-Oued. No doubt now, well and trully into the Grand Erg Oriental. Sand, sand and more sand. What fun.

Why did we go on to Tebessa instead of turning left just after the border and cut off the corner via Oum Ali. Could it be for more supplies before we entered the desert? Shopping was another role of the EMs. We would drive into a town, and could generally get close to the souk or market, to park the truck up in a convenient location. Depending on the situation and the time available, it could be a short visit only to pick up fresh food, or somewhat longer allowing a bit of a wander around and explore as well as the shopping. The EMs would have to decide how to share the work, with some shopping and others looking around. The EMs would also decide on what to buy. There was only so much fresh stuff available dependant on which market you were in. Some places it seemed that we had more supplies on the truck than was available at the market. Others, there was an amazing plenitude and a wonderful variety, including meat. The shoppers decided what to buy and what to cook, within an overall budget. Naturally some EMs were more adventurous than others, both in shopping and cooking. That is not a surprise, as that just reflects a wider society. If there was no shopping, there was no fresh food to eat, and that meant that the trucks stocks of dehydrated and tined foods would come into play. Those foods were acceptable but generally not as nice as fresh cooked. Going shopping in strange places also resulted in seeing strange produce. Goat and camel meat. Ladies fingers and cous cous. Now again it is time to remember that times were different then. Today you can go into a supermarket, or online, and be tempted with all sorts of exotic fruit and veg, at almost any time of the year. Back then it was mainly seasonal local produce plus a few imported delicacies such as oranges and bananas. I had never heard of, let alone tasted cous cous before I visited Africa, nor ladies fingers or Okra until a Baba cooked for us on an Asia trip.

Shopping and cooking in foreign places expands knowledge and understanding for EMs and L/D alike, and it all adds to the immersive experience of an overland trip. It is not right to call it a once in a lifetime experience because it appears 40 or so years later, that a lot of people caught the travel bug, and did more than one trip, or even became a L/D for EO or other overland company. Some even set up their own travel company.

Fuelled up again and well provisioned it was time to set off into the desert. Let’s keep to the roads in the first instance, there will be plenty of time to practice with the sand mats later in the trip. Sand is sand, a simple silica compound. Well that is not quite a true statement, but more importantly different sand behaves defiantly. Soft round mobile sand is the worst for driving in. The last word most significant. With hard sands you drive over and on, and they are relatively stable. Soft sands, it is more a case of sinking in and using momentum to keep forward progress. It is very easy, in soft sand, not to achieve this. So roads it is to start with.

Now we really are in the desert we may have imagined. A real sand dune, and it is sand coloured. It may not be the bigest in the world. On a more recent trip to Namibia, I saw one called Big Daddy, which is the tallest dune in Sossusvlei standing some 1,066 feet (325 meters) in height, and is composed of five-million-year-old sand, and it was a red colour, No, at over 300m high and over 35 degrees C in the shade, I did not climb it. Oh, there was no shade there either. The big dunes of Isaouane-n-Tifernine, bigger than Big Daddy are futher south and west. However, this one was big enough for us, bigger than the ones I remember at Sandbanks.

A proper sand dune

Fortunatly the winds blow the sand dunes into a line, forming a dunefield, leaving a flat interdune area to travel along, between the next parallel dune line. The interdune floor is relaivly easy going and firm, that is until you come across a transverse dune.

The very next slide has cloud cover instead of the clear blue sky of the previous one. Yes, cloud cover in the sahara, how strange is that?

Sand dune with cloud cover

It may on first glance look like the same sand dune, but where has the clear blue sky gone. No, the one with the bright blue sky is not just painted on. Hands up, it did not look quite like that whilst there either, without the polaroid shades on, it looked a bit washed out and over exposed. So I just dehaze and apply a polaroid filter and that is what it really looked like, with the polariod shades on of course. 

 Another sand dune wisps of clouds

Sand dune with cloud cover again

 

 Linear sand dunes

The road changes as does the sand. Tyre tracks left in the desert. Not ours, where were they going? How old were they? Linear sand dunes, as were the previous photos, but not smaller, farther away. Linear dunes generally form sets of parallel ridges separated by miles of sand, gravel, or rocky interdune corridors. The long axes of these dunes extend in the resultant direction of sand movement. See the satellite images link below to see it more clearly.

Tyre tracks in the sand 

 What another sand dune

Each sand dune looks unique with ridges waves and shadows.

 Sunset and silhouette

The shadows lengthen and the sun starts to go down. Another brilliant sunset. We are begining to get used to these.

Time to put the front prop on. What is that I hear you ask? On a two wheel drive Bedford rotary power comes from the engine through the clutch, gear box, then to the prop, propeller shaft or driveshaft all the way back to the diff or differential, where the power is turned at right angles into the wheels. On a four wheel drive Bedford M Type there is a transfer box about half way along the prop so there are two shorter props to get power to the back axle. The transfer box has three functions, one to split the power with cogs and gears and turn it back towards the front, under the engine where it was created to the diff on the front axle. The transfer box is also used to change from high ratio, or normal, down to low ratio which is used for difficult conditions and to change from two to four wheel drive. The props obviously have to take a lot of torque to transfer the power without becoming spiral, fusilli pasta comes to mind, before shearing, also known as breaking. Hence, they are quite heavy. All that weight being spun around without actually doing anything is a waste. The bearings and splines working without result. There is some discussion as to whether the transfer box should be left in two or four wheel drive when the prop is not attached. It is not too difficult or time consuming job to unstrap the front prop shaft from the side of the truck, clamber under the truck and attach the flanges at each end of the prop shaft to the front axle and the transfer box. Eight bolts in total has it done. All properly cleaned and greased up. I seem the recall that the U Joints had a grease nipple, if so that would have been filled until all the sand was clear.

Now we are prepared to fall of the end of the blacktop. 

We are at the southern edge of Grand Erg Oriental and it has changed. Sand has been replaced with rock at about Hassi Bel Guebbour, a mere 350km south of Hassi Messaoud, the last settlement. The rock is Tinrhert Plateau which can be seen from space with the Tifernine Dune Field. Another photo from space.

An extract from the Tifernine Dune Field photo from space caption.

The oldest landform is represented by the rocks of the Tinrhert Plateau, where numerous channels incise the bedrock; these channels were eroded during a wet and cool climate period, most probably by glacial meltwater streams. As the dry and hot climate that characterizes the Sahara today became established, water ceased to flow in these channels. Winds eroded and moved large amounts of drying sediment (sand, silt, and clay), which piled up in large, linear dunes that roughly parallel the direction of the prevailing winds of the time.

La Grande Falaise Algerie

Another 20km or so from Hassi Bel Guebbour and we get to some good hot springs.  At the edge of the world at La Grande Falaise, Algeria, we drop of the plateau and down an escarpment, losing over 100m of altitude in one short go. The looking west towards the sun and the heat haze makes the view magical. Now we are leaving the Plateau du Tinrhert, and are on the northern edge of the Issaouane Erg or Erg Issaouane. This erg has some very very big sand dunes. The route takes us skiting around the northern edge eastwards towards In Amenas.

La Grande Falaise Algerie into the sun 

Sand, rock, sand alternate. Then another settlement, In Amenas.

In Amenas is an important Tuareg settlement a mere 30km form the border with Libya, albeit no crossing point nearby, apparently. Road permits are obligatory to go further south, but they are not issued to Tamanrasset, only for D'Janet, then as a second stage, D'Janet -Tamanrasset at D'Janet. (i.e. one must go to D'Janet). D'Janet now appears on Google Maps as Djanet, Algeria. Djanet is 650km away from In Amenas, including going across the middle of Tassili N'Ajjer National Park, which is now a UNESCO World Heritage Site.

The route before the park, close or in the Issaouane Erg generally keeps to the interdune flats, also known as dune streets, and hops from one rock island to the next, amid a sea of sand. A good concept, but not always successful as occasionally the dunes decide to have an impromptu party, and get together. The road becomes soft sand. What road? 

Conflicting information from other police stations and tourists suggests the travel permits are only for one's own safety, and not obligatory, but we were unable to get a definite ruling, so we would prefer to assume they are mandatory.

The sand dunes just south of In Amenas, near the oil production photos, and a 20k stretch about 190 -170 km's north of D'Janet are spectacular, the rest of the route was painful, hard going.

Oil rig in the Erg Issaouane

 A further 20km on from the oil rig, and looking back from the massive dune some of us climbed, we saw oil storage tanks in a secure compound.

 Oil storage on the edge of the dune field

 

About 65km after leaving In Amenas, past the Oil rig and the storage tanks we are on the edge of another dune field, and the dunes are even bigger. It is not clear where the Grand Erg Oriental ends and the Erg Issaouane begins, but I think this is the Erg Issaouane, but included here just in case.

You remember the days when a grassy bank just had to be rolled down. This is the same but more so. A long hard climb to the top before you can start the descent. But first savour the 'King of the Castle'. Then the descent. An exhilarating adventure. The loose sand gets everywhere, with nowhere to shower, and a slight shortage of water, to get rid of it. Part of the experience. Have a look at the NASA photos from the International Space Station and here.

Bigger dunes in Erg Issaouane 

 

Some people lower the tyre pressures for soft sand, which is a really good idea, and can be really beneficial. However, when the road switches back to rock or gravel, they need to be inflated again to avoid being shredded. Garages with and air compressor are not and available solution in this situation. I have seen people put a flammable fluid, lighter fluid I think, into the tyre and light it to inflate the tyre, on a glacier in Iceland, much quicker than with air pump. Whist it would have been quicker than the truck's air compressor, it is not a safe procedure at the best of times. So, on balance, we left the tyres at the normal pressure. It is all part of the experience for the EMs.

 

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To see a map of the approximate route,  click here

 

 

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