Landscapes – a journey across Saudi Arabia
Flying across Saudi Arabia, particularly from north to south, you might be forgiven for thinking it is totally sand, interspersed
with bright rings of green vegetation dotted at random accross the landscape.
just over one third of the country (700,000 square kilometrs) is
covered by desert. The Rub’ Al Khali, also known as ‘The
Empty Quarter’ is the largest sand desert in the world. In
the north of the country the Great Nefud desert covers 60,000 square
kilometers. Between these lies the Dahna, a vast arc of dunes that
runs over 1,000 kilometres and joins the two great sand seas. The
bright green rings are circles of wheat. Using huge watering pipes
that irrigate circles for growing crops, Saudi is now a major producer
While the view from the air gives an impression of featureless land, on the ground the reality is very different.
The sands themselves are of many different types. Where did they come from? Essentially, they are formed from
the granite and coarse-grained igneous rocks of the Arabian Shield. As the granite was eroded, its component
parts crumbled into quartz and feldspar and individual crystals broke free as coarse sand. As time passed, the
softer feldspar broke down even further into dust while the quartz grains, being much harder, took much longer
to have their angular shape softened by further erosion.
Dunes come in many shapes and sizes but there are four basic configurations:
These occur when the wind blows predominantly from the same direction. The ridges run perpendicular
to the wind’s
direction. They are long, gently rounded ridges often with a steep face on the lee side. Crescent dunes also form in these conditions with
to windward. Crescent dunes are mobile and will spread the desert into surrounding areas.
These are long, rolling dunes. They tend to be quite stable and often have grass and bushes growing on them particularly in the hollows. They are the typical
dunes of the Nefud.
As their name implies, these are huge mounds of sand rising to over 300 metres. Some of the biggest are in the south east corner of
the Rub al Khali.
In Arabic Uruq means veins or roots and this describes their shape, long and thin with well defined edges and a sharp ridge on top.
The sands are being constantly blown by the wind, forming dunes of differing shapes and
sizes. Whilst generally the desert is barren, the occasional shower of rain produces a transformation. Plants and flowers appear with amazing
rapidity. They have to grow quickly as the rain
is unlikely to reoccur for some considerable time. They therefore have to sprout, flower and drop their seeds back onto the sand in double
quick time. The seeds will then lie dormant until the next rains. In the Dahna arc of dunes, rain regularly falls in spring and the dunes
are covered with grasses. These are prized for the grazing they provide for herds of goat, sheep and camels.
In the Great Nefud desert rain
falls very seldom and the landscape is bleak. Even more so is the Rub al-Khali where, between huge dunes, there are great areas of gleaming
white sabkha; the result of rivers and lakes that dried up many centuries ago.
An amazing journey
Saudi Arabia contains many differing landscapes. If you were to undertake a journey across the country from
east to west, a journey of 1,400 kilometres, what would you see?
Sabkhaf and salt marshes
Assuming you don’t want to use the excellent highways, you will need a four-wheel drive vehicle – remembering
that less than 100 years ago all journeys would have had to be made by camel! Leaving the low-lying shoreline of the Arabian Gulf, you
would encounter sabkhas,
salt marshes where the underlying water is being constantly lost through evaporation, thus leaving the salt behind. The water comes from
rain, underground aquifers and near the coast, seawater. With evaporation, the surface is a hard salt crust, which is comparatively smooth,
but just below the surface there is a salty mush. Drive carefully across the sabkha, as any vehicle or animal breaking the surface crust
finds itself in deep trouble and many have been lost in this way.
sabkha continues inland for up to 100 kilometres from the coast and even by then the land has risen to no more than 50 metres above sea level.
Although inhospitable, a surprising number of plants live there. You would almost
certainly see the desert hyacinth – not as pretty as the hyacinth in your own garden, but very similar in shape.
Eventually, you will reach a low, east-facing cliff with isolated steep jebels (hills) surrounding the al Ahsa
oasis. You are now onto the Summan plateau. The action of the waves on the shore back in the Pliocene era deeply
undercut the soft rock leaving, in the Jebel Qara oasis, caves cut into the heart of the jebel. This is a favourite
spot for tourists.
land now stretches as a featureless plain for 300 kilometres to
the northwest with little to see on the surface. However, just below,
in the soft, crumbling soil, marine fossils, molluscs and sharks’
teeth are plentiful. Further along, the surface changes to duricrust,
a thin skin of hard, cemented limestone covering soft, porous stone.
The ground here is riddled with tunnels and caves, the only visible
sign of which are the small holes known as dahls, which give access
to the subterranean landscape. The Summan Plain’s bleak aspect
is relieved at this point by occasional rawdat (the plural of ‘riyadh’,
meaning ‘garden’ or ‘meadow’).
Reaching the city of As Salamiyah, you turn slightly south westerly and head towards Jeddah. Leaving the Rub
al Khali to your left, you encounter much hillier country with increasingly dramatic rocky outcrops, divided
by deep wadis .Wadis are old riverbeds where pools of water may remain, the result of the infrequent rainfall.
Sometimes, the pools may be fed from underground aquifers. Here, as elsewhere in the desert, wherever water,
the essential element of survival is present, you can be sure to find humans and animals.
Westwards to the coast
you continue your journey westwards, you will encounter spectacular
mountains, 2-3000 metres high, where the rock takes on fantastic
shapes, carved by the wind and rain. The land rises slowly, through
Rumah to Riyadh and on to Makkah, with the highest most spectacular
escarpment to be found at Jebel Tuwaiq. One hundred kilometres west
of the Tuwaiq escarpment you will have reached the start of the
Arabian Shield – dark, forbidding hills followed by desolate
countryside, a black basalt plain stretching into the distance..
Strange shapes have been formed by the molten rock, which has the
appearance of frozen black treacle, interspersed with wadis and
tunnels. This was a land of volcanoes – an immense volcanic
explosion scattering rocks for miles around formed the crater at
Wahbah. Extinct volcanoes dot the landscape, and if you can struggle
up one of these, you will be rewarded with spectacular views and
see the skin of white salt that sits at the crater bottom.
Approaching the coast, you come to some of the most picturesque country in Saudi Arabia;
fine mountain views with the Tihama Plain in the distance. As the road plunges down through Wadi ad Dila and crosses the Tihama River, at last we see the Red Sea with its coral reefs and
reach the end of our journey.
For more information:
Origins of Arabia
Andrew Thompson, ISBN 1-900-988-046
Photographs courtesy of Peter Sanders and John Smith.