Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Titre : Structure sociale d’une communauté oasis en Libye

Auteur : Dalton, William G.

Université de soutenance : Manchester University

Grade : Doctor of Philosophy (PhD) 1971

Résumé partiel
The western Libyan desert is a land of great physical variation, of plains and plateaus, sand and gravel seas, of broad wadis (dry river beds) and depressions, sharply outlined escarpments and uplands which have eroded into desert badlands. The Jebel Nafusa mountains stand at the northern rim of a vast interior plateau. At the northwestern rim, the Jebel Nafusa escarpment drops abruptly for over 2,000 feet to the coastal plain of Tripolitania. Eastward, it decreases in elevation and widens into a belt of sharply dissected hill lands, which ends near Homs and gives way to the undulating landscape of the Sirte region to the east. Typical desert conditions of extreme aridity and high year-round temperatures are characteristic of the region south of the Jebel Nafusa. Even in areas immediately south of the escarpment, rainfall rarely exceeds three inches in any given year, while annual averages are considerably lower. Nowhere in the western Sahara is there a perennial, or even a seasonal stream.The extreme environment of the Sahara desert imposes severe limits on the way of life of its human population, sedentary and nomadic alike. The ecological conditions demand that pastoralists make long forced marches in search of spring grazing, while sedentary life is confined to those few places where water is available for agriculture.Permanent settlements in the area south of the Jebel Nafusa are widely dispersed. Clusters of towns, villages and hamlets are confined to the larger depressions, where subterranean water resources are close to the surface and easily accessible. The great majority of the population of the western Sahara is located in the depressions to the east end of the Ubari sand sea in the Wadi Ash Shati, which flanks the sand sea to the north, and in the Wadi al Ajial to its south. Other large concentrations of population are to be found in the Murzuq depression south of the main Fezzan depression, and in the Al Jufrah depression north of the Jebel-es-Soda. The total population of this vast area is 60,000 people, averaging roughly 9 persons to 1 100 square kilometers. Most of that population is concentrated in the oases settlements. Throughout the area the construction of settlements is similar. Each oasis community usually consists of a nucleated town or village, surrounded by irrigated gardens and date palm plantations. Since in the wadis and depressions , the ground water table is relatively near the surface, the water necessary for irrigation requires a lift of only a few meters.

Présentation

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