Mountain Ranges, Deserts and Landforms of Libya

Geography

The Sahara covers large parts of Algeria, Chad, Egypt, Libya, Mali, Mauritania, Niger, Western Sahara and Sudan, and parts of southern Morocco and Tunisia. It covers 9 million square kilometres (3,500,000 sq mi), 31% of the African continent. If all areas with a mean annual precipitation of less than 250 mm (9.8 in) were included, the Sahara would be 11 million square kilometres (4,200,000 sq mi). It is one of three distinct physiographic provinces of the African massive physiographic division. The Sahara is so large and bright that, in theory, it could be detected from other stars as a surface feature of Earth, with near-current technology.

Climate

The Sahara is the world's largest hot desert. It is located in the horse latitudes under the subtropical ridge, a significant belt of semi-permanent subtropical warm-core high pressure where the air from the upper troposphere usually descends, warming and drying the lower troposphere and preventing cloud formation.

The permanent absence of clouds allows unhindered light and thermal radiation. The stability of the atmosphere above the desert prevents any convective overturning, thus making rainfall virtually non-existent. As a consequence, the weather tends to be sunny, dry and stable with a minimal chance of rainfall. Subsiding, diverging, dry air masses associated with subtropical high-pressure systems are extremely unfavorable for the development of convectional showers.

History

Scientists have identified more than 230 humid periods in North Africa over the past eight million years, recurring at intervals of approximately 21,000 years.

A modern laboratory examination of the Uan Muhuggiag child mummy and Tin Hanakaten child have suggested that the Central Saharan peoples from the Epipaleolithic, Mesolithic, and Pastoral periods possessed dark skin complexions. The creators of the Round Head rock art possessed dark skin.

A 2025 study sequenced individuals from Takarkori (7,000 YBP) and discovered that most of their ancestry was from an unknown ancestral North African lineage, related to the African admixture component found in Iberomaurusians.

Hydrology

The climate is hyper arid, with average annual precipitation of 60 mm in the north of the erg. Further south, it decreases, reaching 25 mm at the southern edge. However, there is a lot of water stored underground: the Aquifer Continental Intercalaire, one of the largest closed aquifers in the world, stores around 60,000 cubic kilometers of water and extends over large areas of the Algerian, Tunisian, and Libyan northern Sahara. Most of this water is fossil water that seeped into the ground during the wet periods of the Pleistocene in the Atlas Mountains and Aurès region, the M'zab ridge west of Touggourt, and the Dahar mountain range in southern Tunisia. These elevations are located in the vicinity of the erg.

Geography

Tassili n'Ajjer is a plateau in south-eastern Algeria at the borders of Libya and Niger, covering an area of 72,000 km2. It ranges from 26°20′N 5°00′E east-south-east to 24°00′N 10°00′E. Its highest point is the Adrar Afao that peaks at 2,158 m (7,080 ft), located at 25°10′N 8°11′E. The nearest towns are Djanet on the southeastern edge and Illizi on the northern edge.

The plateau is of great geological and aesthetic interest. Its panorama of geological formations consisting of rock forests, composed of eroded sandstone, resembles a lunar landscape and hosts a range of rock art styles.

Geology

The range is composed largely of sandstone. The sandstone is stained by desert varnish, a thin outer layer of deposited metallic oxides that colour the rock formations variously from near-black to dull red. Erosion in the area has resulted in nearly 300 natural rock arches being formed in the south east, along with deep gorges and permanent water pools in the north.

The Tuareg Shield, an accumulation of terranes that formed during the Neoproterozoic era between 750 and 550 million years ago, encompassed the area of today's Ahaggar Mountains in Algeria, the Aïr Mountains in Niger, and the Adrar des Ifoghas in Mali. To the west lies the West African Craton, to the east the Saharan Metacraton.

Geography and climate

The Uweinat mountain range at the very south of the plateau extends from Egypt into Libya and Sudan.

Gilf Kebir Plateau lies in the heart of the eastern part of the vast Sahara Desert, and thus experiences an extremely hyper-arid climate. The area receives very little rainfall, with annual average precipitation hardly reaching 0.1 mm, and has a geological aridity index/dryness ratio of over 200, meaning that solar energy received at the ground evaporates more than 200 times the amount of precipitation received.

History

Magharet el Kantara in the southern Gilf Kebir contains only one known rock art site, a cave discovered by Shaw & party in 1936.

Wadi Sura in the southwestern Gilf Kebir: the "Cave of Swimmers", discovered by the Hungarian Count László Almásy (The English Patient), plus many other paintings nearby.

In January 2003, Zerzura Expeditions and Jacopo Foggini independently discovered a major new rock art site in the Western Gilf Kebir (Foggini-Mestekawi Cave).

The North-western half of the Gilf Kebir aside from Wadi Sura has only a few scattered engravings, of an apparently very ancient age.

Karkur Talh and Karkur Murr: major eastern valleys of the Uweinat contain one of the richest concentrations of rock art in the whole Sahara.

Geography

The Libyan Desert covers an area of approximately 1,300,000 km2 (500,000 square miles), and extends approximately 1,100 km (680 miles) from east to west, and 1,000 km from north to south, in about the shape of a rectangle slanting to the south-east. Like most of the Sahara, this desert is primarily sand and hamada or stony plain.

Sand plains, dunes, ridges, and some depressions (basins) typify the endorheic region, with no rivers draining into or out of the desert. The Gilf Kebir plateau reaches an altitude of just over 1,000 m (3,300 feet), and along with the nearby massif of Jebel Uweinat is an exception to the uninterrupted territory of basement rocks covered by layers of horizontally bedded sediments, forming a massive sand plain, low plateaus, and dunes.

Climate

The Libyan Desert is said to be one of the least hospitable regions on Earth. Its climate is surprisingly variable, being hot in summer, with average daytime temperatures of 50 °C (122 °F) and above, though this drops rapidly at night. In winter, days are cool, with temperatures averaging 27 °C (81 °F), but at night this can drop below freezing, with temperatures of −9 °C (16 °F) recorded. At these times the formation of hoar frost is not uncommon, and they are known as "White Nights".

In the north, along the Mediterranean shore, cool onshore winds blow inland, while further south, hot, dry winds, known as Ghibli, blow from the interior, creating blinding sand-storms. Periodic droughts are common in the desert, often lasting several years.

History

Historically, "Libya" referred to an ill-defined area to the west of Ancient Egypt, whose boundary traditionally was the lake of Mareotis, outside Alexandria. The ancient Greeks, such as Herodotus, regarded the whole of the North African littoral, to Cape Spartel in Morocco, as "Libya". Later, the Romans organized the region the provinces of Libya Inferior and Libya Superior, which covered western Egypt and Cyrenaica. Thus the "Libyan Desert" was the desert to the south of Ancient Libya. With the organization of the Italian colony of Libya in the 20th century the term "Libyan Desert" for this region became a misnomer, and the area of desert within Egypt became known as the "Western Desert" (i.e. west of the Nile, in contradistinction to the Eastern Desert, east of the Nile).

Geography

In its southern part is the fertile upland area of Jebel Akhdar. North of this is a dry, sub-desert area between the uplands and the Mediterranean on its northern edge. Libya has mostly a flat undulating plain and occasional plateau, with an average elevation of around 423 m (1,388 ft). Around 91 per cent of the land is covered by desert, with only 8.8 per cent agricultural land (with only 1% arable lands) and 0.1 per cent of forests. The major resources are petroleum, gypsum and natural gas. Along the coastal regions, the climate is Mediterranean in coastal areas, while it is desert climate in all other parts. Dust storms lasting four to eight days is pretty common during spring. Triplotania is the northwest region, while it is Cyrenacia in the east and Fezzen in the southwest.