The Sahara, the world’s largest hot desert, reveals a diversity of fascinating landscapes, often unknown to the general public. Among these iconic landscapes, two main types of geological formations stand out: the ERG and the REG.
The ERG: the Sahara’s sand dunes
Contrary to popular belief, ergs, these vast expanses of sand dunes, cover only about 20% of the Sahara’s total surface area. This type of desert is composed of dunes formed by the accumulation of sand transported primarily by the wind, but also by wadis, the temporary watercourses that cross the desert.
The wadis, mostly dry, can transform into natural water reservoirs during heavy rains, creating veritable oases or temporary grazing areas, ideal for livestock. These sandy regions offer a spectacular and ever-changing landscape, constantly reshaped by the winds.
The Reg: A Mineral Desert with a Lunar Landscape
Unlike ergs, regs are the most widespread desert landscapes in the Sahara. They are characterized by vast rocky expanses covered with gravel, pebbles, and stones polished by erosion over millennia. This type of desert, also called a stone desert, offers a lunar, almost supernatural appearance that fascinates travelers and photographers.
Vegetation in regs is extremely sparse due to the extreme climatic conditions. However, one can sometimes spot resilient plants such as acacias and tamarisk trees, scattered here and there in this arid environment.
A Desert with Many Faces
The distinction between erg and reg helps to better understand the geological and ecological diversity of the Sahara. These two types of desert contribute to the natural richness and striking beauty of this unique environment. Whether it is the golden dunes of the erg or the mineral expanses of the reg, each landscape of the Sahara tells a thousand-year-old story shaped by wind, water and time.
