Misplaced Pages

#703296

99-507: The Tibesti Mountains are a mountain range in the central Sahara , primarily located in the extreme north of Chad , with a small portion located in southern Libya . The highest peak in the range, Emi Koussi , lies to the south at a height of 3,415 meters (11,204 ft) and is the highest point in both Chad and the Sahara. Bikku Bitti , the highest peak in Libya, is located in the north of

198-500: A mantle plume in the craton of the African Plate lithosphere , which is about 130 to 140 km (81 to 87 mi) thick. This tectonic uplift may have been accompanied by the opening, and subsequent closure via subduction , of a rift zone . A system of regional faults , although partially obscured by the volcanic product, has two distinct orientations: a NNE-SSW alignment that could be an extension of Cameroon line , and

297-706: A NW-SE alignment that could extend to the Great Rift Valley ; however, the relationship between these fault systems has not been conclusively demonstrated. The basement of the Tibesti is composed of granite , diorite and schist , one of six exposures of Precambrian crystalline rock in North Africa . These are overlaid by sandstone of the Paleozoic era, while the peaks consist of volcanic rock . The continental hotspot activity began as early as

396-524: A broader military campaign by Garamantes against the populace of Agisymba. In the 12th century, the geographer Muhammad al-Idrisi spoke of a "country of Zaghawa negroes", or camel herders, that had converted to Islam . The historian Ibn Khaldun described the Toubou in the 14th century. In the 15th and 16th centuries, Al-Maqrizi and Leo Africanus referred to the "country of the Berdoa", meaning Bardaï,

495-504: A conflict between the Toubou and the civilization of Garamantes based in present-day Libya. Between AD 83 and 92, a Roman traveler, likely a trader, named Julius Maternus , explored the territory of the Tibesti Mountains with, or under the charge of, the king of Garamantes. The Tibesti are suspected by modern historians to have been part of an unidentified country named Agisymba , and Maternus's expedition may have been part of

594-476: A gentle rise, while the northern slope of the range is a cliff overlooking the vast Libyan desert pavement known as the Serir Tibesti . Five rivers in the northern half of the Tibesti Mountains flow to Libya, while the southern half belongs to the endorheic basin of Lake Chad. However, none of the rivers travel long distances, as the water evaporates in the desert heat or seeps into the ground, although

693-689: A rift between the French and Chadian governments. Another rift formed between Goukouni and Habré, which by 1976 had spread to the Second Liberation Army, leaving one side commanded by Habré and the other commanded by Goukouni and supported by Libya. In June 1977, Goukouni's forces attacked the Chadian government stronghold in Bardaï. The rebels also attacked Zouar. These battles resulted in the death of 300 government troops. Bardaï surrendered to

792-418: A small plateau at just 490 km (190 sq mi), and the even smaller Tarso Tamertiou at 98 km (38 sq mi). The plateaus are strewn with volcanic spires and are separated by canyons that have been formed by the irregular flow of wadis . After often-violent rains, they see the formation of ephemeral streams and flora. The southern, southwestern and eastern slopes of the mountain range have

891-527: Is a 3,100-metre (10,200 ft) high stratovolcano in the north of the Republic of Chad . It is located in the western center of the Tibesti Mountains . The summit of the mountain is dominated by the 14-by-18-kilometre (8.7 mi × 11.2 mi) relatively flat caldera . Extensive basaltic flows lie on the northeastern side in a 180-degree arc and are a result of the high activity in

990-411: Is accessible from Bardaï via Aderké, or from the town of Aouzou via Irbi. These rough tracks extend southward towards Yebbi Souma and Yebbi Bou, and then follow the course of Enneri Misky. The eastern half of the Tibesti is cut off from the western half, and the eastern village of Aozi is accessible from Libya via Ouri. Zouar has an airport , as does Bardaï at Zougra . Bardaï also has a hospital, although

1089-538: Is at work while the mountains are being uplifted until the mountains are reduced to low hills and plains. The early Cenozoic uplift of the Rocky Mountains of Colorado provides an example. As the uplift was occurring some 10,000 feet (3,000 m) of mostly Mesozoic sedimentary strata were removed by erosion over the core of the mountain range and spread as sand and clays across the Great Plains to

SECTION 10

#1732765561704

1188-521: Is located on the southern flank of Emi Koussi at about 850 m (2,800 ft) elevation. Water emerges from the springs at 37 °C (99 °F). A dozen hot springs are also located at the Soborom geothermal field on the northwest side of Tarso Voon, where water emerges at temperatures ranging between 22 and 88 °C (72 and 190 °F). The Tibesti Mountains are a large area of tectonic uplift that, according to contemporary theory, resulted from

1287-514: Is low. The volcano's crater, Trou au Natron , is 8 km (5.0 mi) in diameter and 768 m (2,520 ft) deep. On the northwest side of Tarso Voon is the Soborom geothermal field , which contains mud pools and fumaroles that vent sulfuric acid . The sulfur has stained the surrounding soil bright colors. Fumaroles are also present at the Yi Yerra hot springs on Emi Koussi. Tarso Tôh

1386-497: Is replenished several times a year during flooding, and salinity levels are low. The Mare de Zoui is a small permanent body of water 600 m (2,000 ft) above sea level, located in the northern part of the mountains in the wadi of the Enneri Bardagué, 10 km (6.2 mi) east of Bardaï . Supplied by sources upstream of the wadi, in heavy rains it overflows and spills into small wetlands . The Yi Yerra hot springs

1485-410: Is the endemic grass Eragrostis kohorica , named after the volcano's crater. The vegetation above 2,600 meters (8,500 feet) consists of dwarf shrubs, which are generally limited to 20 to 60 cm (8 to 24 in) in height and do not exceed one meter (3 ft). The shrubbery consists of the species Pentzia monodiana , Artemisia tilhoana and Ephedra tilhoana . At the highest elevations of

1584-414: Is the most common grass in the area. Other plants have more Mediterranean characteristics, such as Globularia alypum and lavender or the more tropical sweet Indian mallow and least snout-bean . The liverwort Plagiochasma rupestre is found around the wadis at these elevations, as are mosses of the genera Fissidens , Gymnostomum and Timmiella . Saharomontane grasslands are found on

1683-528: Is unregulated in the region, and vegetation has suffered from overgrazing in the past. The flora in the Tibesti is Saharomontane, mixing Mediterranean , Sahara , Sahel and Afromontane vegetation. Biodiversity and endemism levels are higher in the Tibesti than in the Aïr Mountains or the Ennedi Plateau, although the vegetation's coverage is highly dependent on rainfall. Oases lie along

1782-475: The African sharptooth catfish , East African red-finned barb , Tibesti labeo ( Labeo tibestii , an endemic species) and the redbelly tilapia . The town of Bardaï, located on the northern flank of the mountains at an elevation of 1,020 m (3,350 ft), is the capital of the Tibesti region. It is connected to the town of Zouar, to the southwest, by a track that crosses Tarso Toussidé. The village of Omchi

1881-865: The Alpide belt . The Pacific Ring of Fire includes the Andes of South America, extends through the North American Cordillera , the Aleutian Range , on through Kamchatka Peninsula , Japan , Taiwan , the Philippines , Papua New Guinea , to New Zealand . The Andes is 7,000 kilometres (4,350 mi) long and is often considered the world's longest mountain system. The Alpide belt stretches 15,000 km across southern Eurasia , from Java in Maritime Southeast Asia to

1980-551: The Annamite Range . If the definition of a mountain range is stretched to include underwater mountains, then the Ocean Ridge forms the longest continuous mountain system on Earth, with a length of 65,000 kilometres (40,400 mi). The position of mountain ranges influences climate, such as rain or snow. When air masses move up and over mountains, the air cools, producing orographic precipitation (rain or snow). As

2079-854: The Bodélé Depression , as does Enneri Miski a little further to the east, along with other wadis such as the Enneri Korom and Enneri Aouei. Several rivers flow radially on the southern slopes of the Emi Koussi before seeping into the sands of Borkou and then reemerging at escarpments up to 400 km (250 mi) south of the summit, near the Ennedi Plateau . At the bottom of many canyons are gueltas , wetlands that accumulate water mainly during storms. Above 2,000 m (6,600 ft), enneri beds sometimes contain sequential pools of water that remain largely unexplored. The water

SECTION 20

#1732765561704

2178-624: The Hawaiian–Emperor and Cook - Austral seamount chains. This phenomenon is also seen in Martian volcanoes , particularly Elysium Mons . Early volcanic activity created trap basalt formations that extend tens of kilometers and stack up to 300 m (1,000 ft) thick. Basanite and andesite are also found in the volcanic layer. More recently in geologic time , volcanic activity has deposited dacite , rhyolite and ignimbrite , as well as trachyte and trachyandesite . This trend towards

2277-522: The Holocene , creating fumaroles , hot springs , mud pools and deposits of natron and sulfur . Erosion has shaped volcanic spires and carved an extensive network of canyons through which run rivers subject to highly irregular flows that are rapidly lost to the desert sands. Tibesti, which means "place where the mountain people live", is the domain of the Toubou people . The Toubou live mainly along

2376-804: The Iberian Peninsula in Western Europe , including the ranges of the Himalayas , Karakoram , Hindu Kush , Alborz , Caucasus , and the Alps . The Himalayas contain the highest mountains in the world, including Mount Everest , which is 8,848 metres (29,029 ft) high. Mountain ranges outside these two systems include the Arctic Cordillera , Appalachians , Great Dividing Range , East Siberians , Altais , Scandinavians , Qinling , Western Ghats , Vindhyas , Byrrangas , and

2475-703: The Italians occupied the Fezzan , a French column entered the Tibesti in early 1914 from Kaouar. The region was at the heart of a dispute between the colonial powers, with the Italian Empire to the north and French West Africa to the south. During World War I , a Senussi revolt forced the Italians to temporarily withdraw from the Fezzan and the northeastern part of the Tibesti. Likewise, fierce resistance from

2574-563: The Mithrim Montes and Doom Mons on Titan, and Tenzing Montes and Hillary Montes on Pluto. Some terrestrial planets other than Earth also exhibit rocky mountain ranges, such as Maxwell Montes on Venus taller than any on Earth and Tartarus Montes on Mars . Jupiter's moon Io has mountain ranges formed from tectonic processes including the Boösaule , Dorian, Hi'iaka and Euboea Montes . Tarso Voon The Tarso Voon

2673-791: The Oligocene , although most of the volcanic rock dates from the Lower Miocene to the Pleistocene and, in places, to the Holocene. Due to the comparatively slow movement of the African Plate—roughly between 0 and 20 mm (0 and 0.8 in) per year since the Lower Miocene—there is no relationship between the age of the volcanoes and their dimensions, geographic distribution or alignment, in contrast to hotspots such as

2772-600: The Paleolake Chad until the 5th millennium BC . The Tibesti climate is substantially less dry than that of the surrounding Sahara Desert , but rainfall events are highly variable from year to year. In the south of the range, this variation is largely due to oscillations of the Intertropical Convergence Zone (ITCZ), which steadily moves northward toward northern Chad from November until August, accompanied by humid monsoonal air. Normally,

2871-517: The Quaternary . In the neighborhood in northwestern direction is the Ehi Mousgau, a stratovolcano with the same elevation, 3,100 metres (10,200 ft) above sea level. Deposits from pyroclastic clouds are found 15 to 35 kilometres (9.3 to 21.7 mi) around the caldera. The mountain was constructed over a basement of Precambrian schists . The well known Soborom Solfataric field is

2970-515: The Stone Age , when denser paleovegetation facilitated human habitation. The Toubou were settled in the region by the 5th century BC and eventually established trade relations with the Carthaginian civilization. Around this time, Herodotus mentioned the Toubou, whom he labeled " Aethiopians ", and described them as having a language akin to the "cry of bats". Herodotus further remarked on

3069-673: The Toubou and voided the traditional power of the then Derdé, Oueddei Kichidemi . Kichidemi went into exile in Libya the following year and became a national symbol in Chad for opposition to the government. These events sparked the First Chadian Civil War , which lasted from 1965 to 1979. In 1968, the French Army , at the request of Tombalbaye, intervened in an attempt to put an end to the rebellion. However, French General Edouard Cortadellas admitted their attempts to quell

Tibesti Mountains - Misplaced Pages Continue

3168-513: The cheetah , as well as several canine species, including the golden jackal , fennec fox and Rüppell's fox . The striped hyena may also occupy the range. African wild dogs formerly roamed the range, although these populations are now extirpated . Olive baboons , found as recently as 1960, are now likely extirpated as well. Bats are heavily represented in the Tibesti, including the Egyptian mouse-tailed bat , Egyptian slit-faced bat and

3267-496: The trident bat . The Cape hare and the rock hyrax also populate the area. Reptiles and amphibians , on the other hand, are sparse. Snake species include the braid snake and the long-nosed worm snake . Among the lizards are Bibron's agama , the ringed wall gecko and the Sudan mastigure . Mid-20th-century herpetological studies noted the presence of brown frogs and true toads . Many resident birds can be found in

3366-431: The wadis , on rare oases where palm trees and limited grains grow. They harness the water that collects in gueltas , the supply of which is highly variable from year-to-year and decade-to-decade. The plateaus are used to graze livestock in the winter and harvest grain in the summer. Temperatures are high, although the altitude ensures that the range is cooler than the surrounding desert. The Toubou, who were settled in

3465-567: The "place where the mountain people live". Most of the mountain names are derived from Arabic as well as the Tedaga and Dazaga languages. The term ehi precedes the names of peaks and rocky hills, emi precedes those of larger mountains, and tarso precedes high plateaus and gently-sloping mountainsides. For example, the Ehi Mousgou is a 2,849-meter (9,347 ft) stratovolcano near Tarso Voon . The name Toussidé means "that which killed

3564-428: The 2,845-meter (9,334 ft) Tarso Voon, the 2,820-meter (9,250 ft) Ehi Sunni, and the 2,774-meter (9,101 ft) Ehi Yéy near the center of the range. The 3,376-meter (11,076 ft) Mouskorbé is a peak notable for its height in the northeastern part of the mountain range. The 2,266-meter (7,434 ft) Bikku Bitti , the highest point in Libya, is nearby, on the other side of the border. The average elevation of

3663-661: The Borkou region, south of the Tibesti, settled in the range in the 16th and 17th centuries. These include the Keressa and Odobaya in the west, Foctoa in the northwest and northeast, and Emmeouia in the north. Several other clans—the Mogode in the west, Terintere in the north, Tozoba in the center, and Tegua and Mada in the south—are originally clans of the Bideyat people who immigrated from the Ennedi Plateau, southeast of Tibesti, around

3762-457: The Bounaï lava dome and Tarso Voon. To the east, the lava flows formed the large plateaus of Tarso Emi Chi, Tarso Ahon and Tarso Mohi. Emi Koussi increased in height. The fourth phase saw the formation of Tarso Toussidé and the lava flows of Tarso Tôh in the west, the collapse of the caldera on the summit of Tarso Voon and associated ejecta deposits in the center, and the decline in lava production in

3861-572: The Cerdegua, Zouia, Kossseda (nicknamed yobat or "hunters of well water"), and possibly the Ederguia, although the Ederguia's origin may be Zaghawa and only go back to the 17th century. These clans controlled the palm groves, and made a peace pact with the Tomagra, a nearby clan of camel herders who practiced Ghazw . It was upon the agreement to this pact at the end of the 16th century that power

3960-519: The Chadian government led by François Tombalbaye imposed its administrative and judicial authority in the Tibesti. Mere days after the withdrawal of French troops from the region, rebellion erupted in Bardaï, followed by numerous small battles over subsequent months and a more significant battle in Bardaï in September. In response, the Tombalbaye government imposed travel and trade restrictions on

4059-687: The Daza clans and lived in isolation until winning the favor of a Dirsina woman. The Mahadena occupy the northeast quarter of the range and are likely from the Jalo oasis of Cyrenaica and thus related to the Mogharba Arab tribes, although an alternative hypothesis is that they are of Bideyat origin. Following years of conflict, a branch of the Mahadena clan, the Fortena, withdrew to the western margin of

Tibesti Mountains - Misplaced Pages Continue

4158-606: The ITCZ repels the Harmattan , a dry trade wind that blows west or southwest from the Sahara Desert, and brings rainfall to southern Tibesti. However, sometimes the front retires early, before reaching the Tibesti, leaving its southern portion dry. In the arid northern Tibesti, where the monsoon has little influence, storms are caused by episodic Sahara-Sudanese weather systems . For example, between 1957 and 1968, Bardaï, on

4257-660: The Libyan districts of Murzuq and Kufra , around 1,000 kilometers (620 mi) north of N'djamena and 1,500 kilometers (930 mi) south-southeast of Tripoli . The range is adjacent to Niger and located approximately halfway between the Gulf of Sidra and Lake Chad , just south of the Tropic of Cancer . The East African Rift is 1,900 km (1,200 mi) to the east and the Cameroon line lies 1,800 km (1,100 mi) to

4356-713: The Mediterranean Sea down to Lake Chad. In response, the Toubou allied with the Senussi Arabs of Libya and agreed that the southern half of the Tibesti could serve as a fallback base for the Senussi in their struggle against the French Colonial Army . As the Sennussis' influence moved southward, so did their headquarters, which in 1899 was moved to the town of Gouro on the southeast flank of

4455-421: The Sahara 650 km (400 mi) to the east. Most of the ecoregion remains unexplored due to its remoteness and persistent political instability, yet it is known to contain a number of endemic and endangered species. Indeed, the isolation of the region is a benefit to its flora and fauna , serving as a sort of refuge, allowing plants to grow untrammeled and animals to roam unmolested. Nevertheless, hunting

4554-402: The Second Liberation Army. In April 1974, the Second Liberation Army captured Bardaï from the Chadian government and took hostage the French archeologist Françoise Claustre , German doctor Christophe Staewen and Marc Combe, an assistant to Claustre's husband, and held them in the mountains. Staewen's wife and two soldiers of the Chadian army were killed. The West German government quickly paid

4653-409: The Teda, and Dazaga, spoken by the Daza. Despite their differences, the two Toubou groups generally identify as a single ethnic group. The Toubou elect a chief, the Derdé , from the Tomagra clan, although never from the same family consecutively. Historically, individual clans rarely had more than a thousand members and were quite dispersed throughout the Tibesti. In 2009, the population of the Tibesti

4752-409: The Tibesti Mountains is about 2,000 m (6,600 ft); sixty percent of its area exceeds 1,500 m (4,900 ft) in elevation. The range includes five shield volcanoes with broad bases whose diameter can reach 80 km (50 mi): Emi Koussi; Tarso Toon, which rises 2,575 m (8,448 ft) above sea level; Tarso Voon; Tarso Yega; and Tarso Toussidé , which culminates in the peak of

4851-475: The Tibesti, tree heath grows from moist crevices formed by early lava flows, while 24 different species of moss provide substrate for the tree heath. Various genera of mosses also grow around fumaroles, including Fissidens , Campylopus , Gymnostomum and Trichostomum . Lichens , though rare in the dry climate of the Tibesti, also grow at these elevations, with green rock shield , scrambled-egg lichen , sunken disk lichen and Squamarina crassa found on

4950-399: The Tibesti. The Fortena Mado ("Red Fortena") settled there, while the Fortena Yasko ("Black Fortena") pushed further west to Kaouar. The Tuareg people intermixed with the Toubou clans, especially with the early Goga clan, which produced the Gouboda, and with the later Arna clan, which produced the Mormorea. In both instances, the new clans were placed under the authority of suzerain clans of

5049-518: The Tibesti. These include the crowned sandgrouse , bar-tailed lark , blackstart , desert lark , desert sparrow , fulvous babbler , greater hoopoe-lark , Lichtenstein's sandgrouse , pale crag martin , trumpeter finch and the white-crowned wheatear . The Tibesti massif has been designated an Important Bird Area (IBA) by BirdLife International . The gueltas are flushed periodically each year by stormwater, maintaining low salinity and supporting several species of freshwater fish . These include

SECTION 50

#1732765561704

5148-403: The Tou," as in the Toubou, reflecting the danger of the still active volcano. The name of Bardaï , the principal town in the range, means "cold" in Chadian Arabic . In the Tedaga language, the town is known as Goumodi , which means "red pass," signifying the color of the mountains at dusk. The mountains lie on the border between Chad and Libya , straddling the Chadian region of Tibesti and

5247-440: The Toubou forced the French troops to retreat southward from the Tibesti in 1916. After a period of internal disorder, the Tibesti was reconquered by the French colonial empire in 1929, and the region was placed under the administration of French Equatorial Africa . Libya gained its independence from Italy in 1947, and was released from British and French oversight in 1951. Chad gained independence from France in 1960, and in 1965

5346-411: The Toubou were essentially hopeless, remarking, "I believe we should draw a line below [the Tibesti region] and leave them to their stones. We can never subdue them." The French therefore focused their intervention on the center and east of the country, leaving the Tibesti region largely alone. In 1969, Goukouni Oueddei , a Teda leader, and Hissène Habré , a Daza leader, emerged from the Tibesti to form

5445-575: The air descends on the leeward side, it warms again (following the adiabatic lapse rate ) and is drier, having been stripped of much of its moisture. Often, a rain shadow will affect the leeward side of a range. As a consequence, large mountain ranges, such as the Andes, compartmentalize continents into distinct climate regions . Mountain ranges are constantly subjected to erosional forces which work to tear them down. The basins adjacent to an eroding mountain range are then filled with sediments that are buried and turned into sedimentary rock . Erosion

5544-415: The arrival of the Toubou. The isolation of the Tibesti has sparked the cultural imagination in both art and literature. The Tibesti Mountains are named for the Toubou people , also written Tibu or Tubu , that inhabit the area. In the Kanuri language , tu means "rocks" or "mountain" and bu means "a person" or "dweller," and thus Toubou roughly translates to "people of the mountains" and Tibesti to

5643-449: The central part of the mountain range: Tarso Tieroko; Ehi Yéy; Ehi Mousgou; and Tarso Abeki, which rises to 2,691 m (8,829 ft) above sea level. These volcanic complexes are now considered inactive, but according to the Smithsonian Institution were active during the Holocene . Tarso Toussidé is an active volcano that has spewed lava over the past two millennia. Gases escaping from fumaroles on Toussidé are visible when evaporation

5742-557: The courses of the enneris , such as Enneri Yebige, which is virtually unexplored. These oases, which are more numerous to the north and west of the range, are scattered with acacia , figs , palms and tamarisks . Most gueltas are lined with macrophytes —including smooth flatsedge and branched horsetail —and bryophytes —including Oxyrrhynchium speciosum and species of Bryum . Egyptian acacia grows near these water basins. Saharan myrtle and oleander grow between elevations of 1,500 and 2,300 m (4,900 and 7,500 ft) in

5841-402: The dominant fluvial or wind patterns in the valleys of Tibesti during the Quaternary Period . The phases of erosion and sendimentation are indicative of the climate alternating between dry and wet conditions, the latter of which fostered vegetation in the Tibesti that was likely significantly denser than that which exists today. Furthermore, the discovery of calcified charophyta (particularly of

5940-437: The east, with the exception of Emi Koussi, which continued to rise. In the fifth phase, volcanic activity became much more localized and lava production continued to wane. Calderas formed on top of Tarso Toussidé and Emi Koussi, and the lava domes Ehi Sosso and Ehi Mousgou appeared. Finally, in the sixth phase, Pic Toussidé formed on the western rim of several pre-Trou au Natron calderas, along with new lava flows, including Timi on

6039-485: The east. This mass of rock was removed as the range was actively undergoing uplift. The removal of such a mass from the core of the range most likely caused further uplift as the region adjusted isostatically in response to the removed weight. Rivers are traditionally believed to be the principal cause of mountain range erosion, by cutting into bedrock and transporting sediment. Computer simulation has shown that as mountain belts change from tectonically active to inactive,

SECTION 60

#1732765561704

6138-416: The east: the 7,700 km (3,000 sq mi) Tarso Emi Chi , the 6,500 km (2,500 sq mi) Tarso Aozi, the 3,000 km (1,200 sq mi) Tarso Ahon to the north of Emi Koussi, and the 1,200 km (460 sq mi) Tarso Mohi. In the center is Tarso Ourari at about 700 km (270 sq mi). To the west, in the vicinity of Tarso Toussidé, is the aforementioned Tarso Tôh,

6237-427: The family Characeae ) and gastropod fossils in Trou au Natron indicates the presence of a lake at least 300 m (1,000 ft) deep during the Late Pleistocene . These phenomena are associated with various changes in climate, most notably during the last glacial maximum , which increased precipitation and reduced evaporation due to lower temperatures. In fact, the Tibesti supplied a considerable amount of water to

6336-427: The former associating the Toubou with the Berbers and the latter describing them as Numidian relatives of the Tuareg . The Toubou settled in the Tibesti in several waves. Generally, newcomers either killed or absorbed the previous clans after battles that were often both long-lasting and bloody. The Teda clans, considered indigenous to the area, were first established around Enneri Bardagué. Namely, these clans were

6435-400: The highest peaks. Mammals abound in the Tibesti. Bovids include the endangered addax along with the dorcas gazelle , rhim gazelle and a significant population of Barbary sheep . Rodents are the most represented order of mammals, and include the spiny mouse , bushy-tailed jird and the North African gerbil . Also present are cats such as the African wildcat and, more rarely,

6534-412: The highest point in Chad and the Sahara Desert, is the 3,415-meter (11,204 ft) Emi Koussi, located at the southern end of the range. Other prominent peaks include Pic Toussidé at 3,296 m (10,814 ft) and the 3,012-meter (9,882 ft) Timi on its western side, the 2,972-meter (9,751 ft) Tarso Yega, the 2,925-meter (9,596 ft) Tarso Tieroko, the 2,849-meter (9,347 ft) Ehi Mousgou,

6633-409: The highlands, the buildings were built of stone, forming circles 1.5 m (5 ft) in diameter and one meter (3 ft) high, which served as shelters for goats, or as granaries, or as human shelters and defense structures. In other cases, the Toubou lived in tents that could be easily moved between the fields and the palm groves. There is evidence of human occupation of the Tibesti dating back to

6732-418: The lack of infrastructure has hampered the development of tourism. The Saharomontane flora and fauna , which include the rhim gazelle and Barbary sheep , have adapted to the mountains, yet the climate has not always been as harsh. Greater biodiversity existed in the past, as evidenced by scenes portrayed in rock and parietal art found throughout the range, which date back several millennia, even before

6831-449: The latter may flow great distances through subterranean aquifers . The wadis in the Tibesti are called enneris . The water mainly originates from the storms that periodically rage over the mountains. Their flow is highly variable. For example, the largest wadi, named Bardagué (or Enneri Zoumeri on its upstream portion) and located in the northern part of the range, recorded a flow of 425 m/s (15,000 cu ft/s) in 1954, yet over

6930-441: The massif, including hot springs at the Soborom geothermal field and fumaroles on Tarso Voon, Yi Yerra near Emi Koussi and Pic Toussidé. Carbonate deposits in the Trou au Natron and Era Kohor craters are also representative of more recent volcanic activity. The study of fluvial terraces has revealed coarse sand and gravel alternating with terraces of silt , clay and fine sand. This alternation highlights repeated changes in

7029-485: The medical supply is very much dependent upon the prevailing political situation. The vast majority of the population is Teda , one of the two ethnicities of the Toubou people. However, some clans are Daza, the other Toubou ethnicity, who left their traditional homes in the lowlands to the south and moved north to the Tibesti. The Toubou live primarily in northern Chad, but also in southern Libya and eastern Niger. The Toubou language has two main dialects, Tedaga, spoken by

7128-463: The mountain range. Much like an island surrounded by ocean, the ecology of the Tibesti Mountains is distinguishable from that of the surrounding desert. As such, the mountains lie within their own biome , the 82,000-square-kilometer (31,700 sq mi) Tibesti-Jebel Uweinat montane xeric woodlands ecoregion , along with the Jebel Uweinat , a disjunct mountain range that also rises from

7227-482: The next nine years it experienced four years of total drought, four years of flow less than 5 m/s (180 cu ft/s) and one year where three different flow rates were measured: 4, 9 and 32 m/s (140, 320 and 1,130 cu ft/s). Other major rivers cut into the mountains: the Enneri Yebige flows northward until its riverbed disappears on the Serir Tibesti , while Enneri Touaoul joins

7326-458: The north and southwest of Chad, along with significant mixing of the populations, forged a significant degree of cohesion among the Toubou ethnicities. Periods of territorial expansion in the 10th and 13th centuries and periods of recession in the 15th and 16th centuries likely coincided with more or less pronounced wet and dry periods. Several clans with traditions similar to those of the Donzas of

7425-436: The northern flank of the range, saw an average of 12 mm (0.47 in) of precipitation annually, yet some years were completely dry while others saw 60 mm (2.4 in) of rainfall. In general, the range receives less than 20 mm (0.79 in) of rainfall per year. However, precipitation increases with altitude; for example Trou au Natron 2,250 m (7,380 ft) receives 126 mm (5.0 in) annually. When

7524-561: The northern slope of Tarso Toussidé. With scarce time for erosion, these lava flows have a dark, youthful appearance. The Trou au Natron and Doon Kidimi craters have formed even more recently, with the former dissecting the earlier Toussidé calderas. Lava flows, minor pyroclastic deposits, and the appearance of small cinder cones , and the formation of the Era Kohor crater are the most recent volcanic activities on Emi Koussi. Presently, there are reports of volcanic activity in various parts of

7623-463: The open water. Although the lake appears rich in phytoplankton , it has not been thoroughly studied. To the south and southwest of the range, between 1,600 and 2,300 m (5,200 and 7,500 ft) elevation, the wadis support woody species characteristic of the Sahel, such as Egyptian balsam , grey-leaved cordia , red-leaved fig , sycamore fig , wonderboom and gay acacia . Chrysopogon plumulosus

7722-547: The production of more felsic , viscous lavas could be a sign of a waning mantle plume. Volcanic activity in the Tibesti took place in several phases. In the first phase, uplift and extension of the Precambrian basement occurred in the central area. The first structure to be formed was probably Tarso Abeki, followed by Tarso Tamertiou, Tarso Tieroko, Tarso Yega, Tarso Toon and Ehi Yéy. The product of this early volcanic activity has been completely obscured by later eruptions. In

7821-1073: The rainfall coincides with low temperatures, it can fall as snow. This occurs, on average, once every seven years. The average monthly maximum temperature is 28 °C (83 °F) in the central Tibesti Mountains, while the average monthly minimum is 12 °C (53 °F). Lows of −10 °C (14 °F) are not uncommon. Bardaï, located 1,020 m (3,350 ft) above sea level, experiences average temperatures ranging between 4.6 and 23.7 °C (40.3 and 74.7 °F) in January, between 14.4 and 34 °C (57.9 and 93.2 °F) in April, and between 19.4 and 36.7 °C (66.9 and 98.1 °F) in August. The combination of high temperatures and low humidity results in potentially high evaporation rates, ranging from 129 mm (5 in) in January to 254 mm (10 in) in May, parching many enneris before they can exit

7920-599: The range by the 5th century BC, adapted to these conditions and turned the range into a large natural fortress. They arrived in several waves, taking refuge in times of conflict and dispersing in times of prosperity, although not without intense internal hostility at times. The Toubou came into contact with the Carthaginians , Berbers , Tuaregs , Ottomans and the Arabs , as well as the French colonists who first entered

8019-429: The range in 1914 and took control of the area in 1929. The independent spirit of the Toubou and the geopolitics of the region has complicated the exploration of the range as well as the ascent of its peaks. Tensions continued after Chad and Libya gained independence in the mid-20th century, with hostage-taking and armed struggles occurring amid disputes over the allocation of natural resources. The geopolitical situation and

8118-745: The range. The Senussi founded a Zawiya in Bardaï, which quickly promoted the total Islamization of the Tibesti. At the outbreak of the Italo-Turkish War , the Senussi allied with the Ottoman Empire and, at the request of the Derdé, the Turks established garrisons in Tibesti beginning in March 1911. These garrisons fell apart a few months later when the Toubou attacked the Turkish troops. While

8217-410: The range. The central third of the Tibesti is of volcanic origin and consists of five volcanoes topped by large depressions: Emi Koussi, Tarso Toon , Tarso Voon , Tarso Yega and Toussidé . Major lava flows have formed vast plateaus that overlie Paleozoic sandstone. The volcanic activity was the result of a continental hotspot that arose during the Oligocene and continued in some places until

8316-468: The ransom and Staewen was released. The French government sent the military officer Pierre Galopin to negotiate with the rebels, but he was captured by the rebels and executed in April 1975. Marc Combe was able to escape in May 1975. The remaining hostages were released in January 1977 in Tripoli after France acceded to the rebel's ransom demand. The hostage incident, known as " L'affaire Claustre ", caused

8415-627: The rate of erosion drops because there are fewer abrasive particles in the water and fewer landslides. Mountains on other planets and natural satellites of the Solar System, including the Moon , are often isolated and formed mainly by processes such as impacts, though there are examples of mountain ranges (or "Montes") somewhat similar to those on Earth. Saturn 's moon Titan and Pluto , in particular, exhibit large mountain ranges in chains composed mainly of ices rather than rock. Examples include

8514-401: The rebels on July 4, while Zouar was evacuated. The Chadian government, led by Félix Malloum since Tombalbaye's overthrow in 1975, signed a peace agreement with Habré in 1978, although fighting with other rebel groups, many aligned with Libya, continued. Mountain range Mountain ranges are usually segmented by highlands or mountain passes and valleys . Individual mountains within

8613-531: The same mountain range do not necessarily have the same geologic structure or petrology . They may be a mix of different orogenic expressions and terranes , for example thrust sheets , uplifted blocks , fold mountains, and volcanic landforms resulting in a variety of rock types . Most geologically young mountain ranges on the Earth's land surface are associated with either the Pacific Ring of Fire or

8712-520: The same name. Several of these peaks are topped with large calderas. Tarso Yega has the largest caldera, with a diameter of 19 to 20 km (12 to 12 mi) and a depth of approximately 300 m (980 ft), while Tarso Voon has the deepest caldera, with a depth of approximately 1,000 m (3,300 ft) and a diameter of 12 to 13 km (7.5 to 8.1 mi). They are complemented by four large lava dome complexes, 1,300 to 2,000 m (4,300 to 6,600 ft) high and several km wide, all located in

8811-449: The same time. The Mada, however, have since largely emigrated to Borkou, Kaouar and Kanem . The early 17th century also saw the arrival of three clans from the region of Kufra to the northeast. The Taïzera settled in the plateau in the center and west of the mass, probably fleeing the Arab push into present-day Libya. According to oral tradition , their leader was initially rejected by

8910-415: The second phase, the volcanic activity moved north and east, forming Tarso Ourari and the ignimbrite bases of the vast tarsos , as well as Emi Koussi to the southeast. Thereafter, during the third phase, the outpouring of lava and ejecta deposits increased from Tarso Yega , Tarso Toon , Tarso Tieroko and Ehi Yéy; the collapse of these structures formed the first calderas. This phase also saw the formation of

9009-413: The slopes, plateaus and the upper portions of the wadis at elevations between 1,800 and 2,700 m (5,900 and 8,900 ft). They are dominated by Stipagrostis obtusa and Aristida caerulescens , as well some Eragrostis papposa locally. In addition, shrubs represented by jointed anabis , Fagonia flamandii and Zilla spinosa dot this environment. On the sheltered upper slopes of Emi Koussi

9108-401: The south-flowing Enneri Ke to form Enneri Miski, which then disappears in the plains of Borkou . Their basins are separated by an 1,800-meter (5,900 ft) high watershed that runs from Tarso Tieroko in the west to Tarso Mohi in the east. The Enneri Tijitinga is the longest wadi in the range, flowing some 400 km (250 mi) southward. It forms in the west of the range and peters out in

9207-407: The southwest. The range is 480 km (300 mi) in length, 350 km (220 mi) in width, and spans 100,000 km (39,000 sq mi). It draws a large triangle with sides of 400 km (250 mi) and vertices facing south, northwest and northeast in the heart of the Sahara, making it the largest mountain range of the desert. The highest peak in the Tibesti Mountains, as well as

9306-569: The southwest. These later Daza arrivals include the Arna Souinga in the south, Gouboda in the center-west, Tchioda and Dirsina in the west, Torama in the northwest and center-east, and the Derdekichia (literally, "descendants of the chief," the products of a union between an Arna Souinga and an Emmeouia) in the north. The Tibesti then played the role of an impregnable mountain stronghold for the newcomers. Meanwhile, constant migration between

9405-506: The traditionally feudal Tuareg, although they were eventually assimilated into the Toubou majority. In the mid-19th century the Ottoman Empire began a campaign of territorial conquest across northern Africa from its regional headquarters in Libya, yet was unable to subdue the Tibesti. In 1890, to the chagrin of the Turks, France and Great Britain signed a declaration recognizing a French zone of influence in northern Africa from

9504-566: The western part of the range, while Nile tamarisk grows at similar elevations in its northern part. Downstream, where the current of the enneris is slower and the riverbed is deeper, there are dense thickets of Athel tamarisk and arak . Around the edge of the Tibesti, where the canyons exit the range, are doum palms . The banks of Mare de Zoui are home to dense stands of reeds ( Phragmites australis and Typha capensis ), along with sedges ( Scirpoides holoschoenus ), sea rush , toad rush and branched horsetail, while pondweed grows in

9603-530: Was an active volcano in the early Holocene. The volcanic area of the Tibesti Mountains is located entirely in Chad; it covers about a third of the total area of the Tibesti Mountains and is responsible for between 5,000 and 6,000 km (1,200 and 1,400 cu mi) of rock. The rest of the Tibesti Mountains consists of volcanic plateaus ( tarsos ), located between 1,000 and 2,800 m (3,300 and 9,200 ft) elevation, as well as lava fields and ejecta deposits. The plateaus are larger and more numerous in

9702-525: Was consolidated under the Derdé, the principal regulator of the clans, whose appointment is always made from the Tomagra clan. There is evidence of early Daza settlements in the Tibesti; however, these early clans—the Goga, Kida, Terbouna and Obokina—were assimilated into later Daza clans, who arrived in the Tibesti between the 15th and 18th centuries, possibly having fled the Kanem-Bornu Empire in

9801-600: Was officially estimated at 21,000 inhabitants. As of 2017, that number has risen to 54,000 inhabitants. Yet the Toubou, in general, are semi-nomadic, moving between the mountains and other regions, and thus the Tibesti may have no more than 10,000 to 15,000 permanent residents. Traditional Toubou life is punctuated by the seasons, divided between animal husbandry and agriculture . Twentieth-century anthropological studies show Toubou, particularly around palm groves, living in primitive round huts built with stone walls bound by mortar or clay, or built from clay or salt blocks. In

#703296