Fewet: an oasis at the margin of wadi Tanezzuft (central Sahara)

The palaeoenvironmental and geoarchaeological setting of the oasis of Fewet (SW Libya, Central Sahara) is discussed in the frame of the regional and local climate changes that occurred since the late Holocene. The oasis of Fewet originated after the dramatic reduction in size of the palaeo-oasis of Wadi Tanezzuft following the drop of monsoonal precipitation in the Sahara since the 4th millennium BP. A compared analysis of several palaeohydrological archives indicates that the wide green valley of Wadi Tanezzuft changed into an assemblage of small-sized oases, which represented econiches where Garamantian exploitation of natural resources was guaranteed by residual water availability feeding shallow wells. The Garamantian settlement within the oasis of Fewet was established in the late 3rd millennium BP, when its area was larger than today, whereas it was abandoned around 2000 years BP. The dendroclimatic record of the Tassili cypress reveals that these events correspond to a phase of relatively high precipitations (origin and development of the settlement), followed by a progressive reduction in water availability, which announced the dry climatic event that contributed to the collapse of the Garamantian kingdom. Finally, the most recent evolution of the oases of Fewet, Ghat and Barkat is discussed on the basis of fi eld and remote sensing evidence and documentary records.