Mourdi depression and Demi oasis in the Sahara
February 19th, 2018
The Mourdi depression lies in northern Chad and features vast expanses of sand dunes interspersed by dry river beds, oases and barren mountains, in a landscape typical of Sahara Desert when we imagine a deserted environment. We visit Demi Oasis and its mine of sodium carbonate.
Today we leave behind the sandstone formations of Ennedi massif, that have accompanied us in the last days, to move north to Mourdi depression where lot of beautiful landscapes await us. We say goodbye to the last oddly shaped rocks and to Ennedi region.
Before leaving, we come across some petroglyph
which, accordingly to the sharp edges of the figures, should be relatively recent.
Once out from Ennedi mountains, the landscape changes radically within just a few kilometers. In fact, we can observe the first sand dunes
of the Mourdi depression
, actually called "depression" not because it is below sea level (as the real meaning of the word would say), but just because it is at a lower altitude compared to the vast surrounding Saharan regions.
Initially, low sand dunes alternate with vast stretches of pebbles, while a well
dug in an ancient river bed
, offers an opportunity to fill up our bottles.
The sand dunes
becomes progressively more and more orange, while the midday sun cancels all the shadows, creating a landscape without contrasts, almost intangible.
The sand is so orange, that all the landscape, as well as the sky, show a cast of that color.
In the vicinity of a group of rocky hills, with strongly eroded sides, we find a purely mineral landscape
, with very strong colors due to the particular composition of the soil. Such minerals were probably collected and used in the past by primitive communities, to make the dye used for rock art.
In particular, the yellowish cast is probably due to ocher
, excellent to make a strong dye of that color.
The beautiful soil of orange sand
mixed with dark pebbles.
The desert does not forgive...
Other photos of the wonderful landscape that flows from the window, while driving further north into the Mourdi depression
And suddenly, in the middle of nowhere... an oasis! Demi
is an oasis
where the superficial aquifer allows the palms to grow vigorously, letting a small human settlement to develop as well. This small village is inhabited more or less permanently year-round, because it works also as a logistic base for the various dromedary caravans that cross the Sahara desert. Last but not least, as we will see later, the Demi oasis
is known for its mine of sodium carbonate
, which is collected and delivered to other regions.
As said, the soil of Demi oasis
is rich in sodium carbonate
, a salt used mainly to integrate the diet of farm animals, as it is very healthy for them, especially in a dry environment. Sodium carbonate is extracted by creating grooves in the soil with a normal hoe, until the miner will not find a profitable vein of the mineral, which consists of crystals of a particularly elongated shape. The crystals are then collected by hand, piled up and stored under mats, waiting for the dromedaries to arrive and transport them to the south, where they will be sold or exchanged with millet and sorghum.
After crossing a last barren mountain range, we suddenly find ourselves surrounded by a dramatic landscape dominated by an endless expanse of sand dunes
. This is probably the most typical landscape that we imagine when thinking to a "desert".
A really fantastic place where to put up the camp for the coming night.