Between the Mediterranean and the Sahara: Geoarchaeological Reconnaissance in the Jebel Gharbi, Libya

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Introduction

Recent archaeological research in North Africa has brought into focus the final phase of the Pleistocene which increasingly appears to have been a period of critical environmental and human changes. Starting from the Middle Palaeolithic in the Nile Valley, it has been possible to reconstruct the entire sequence related to the Nile floodings and to recognise different cultural phases linked with the gradual emergence of anatomically modern humans (Vermeersch 2000). However, with a few exceptions (i.e. Roche 1963; Lubell 2000; Barton et al. 2005; Wengler et al. in press), the cultural sequence in the western Maghreb region is still largely incomplete. This is due to the lack of modern investigation in this coastal area of North Africa, but also to the limited accessible record of human occupation which, during the most arid phase of the last glaciation (20-18 000 BP), moved to zones later submerged by sea transgression.

The chronology of Pleistocene human settlements in North Africa has often been assessed by using artefacts to date the geological sediments, and not vice-versa. Technologically, the Early Middle Stone Age (MSA) exhibits a generalised stone industry occasionally (although incorrectly) called Mousterian or Middle Palaeolithic for its apparent similarities with Eurasian lithic industries (for a discussion on the use of African vs. European terminologies, see Garcea 2004). The Late MSA corresponds to the typically North African industrial complex, named Aterian.

The Aterian was thought to have existed during a humid period and therefore it was supposedly dated between 40 000 and 20 000 years BP (e.g. Debenath 1992). Its beginning was attributed to the transition from the lower to the upper Soltanian, which corresponds to the Wurm in Europe, dating from around 40 000 years BP (see, among others, Wengler 1985, 1990a). Finite radiocarbon dating has confirmed this chronology. Some samples associated with Aterian artefacts also provided infinite values, long regarded as more unreliable than finite ones. Furthermore, as they suggested an earlier chronology, >30 000 or even >40000 years BP, they seemed to be doubtful (cf. Dares Soltan: Roche 1956; Wadi Saoura: Chavaillon 1964; Grotte des Contrebandiers: Delibrias et al. 1982; Taforalt: Debenath 1992).

Later Stone Age is the definition employed for the lithic complexes, and, more generally, for the cultural milieux that appear in Africa towards the end of the Pleistocene, showing notable innovations (Garcea in press). Formally established in 1955, in the framework of the Livingstone PanAfrican Congress, the LSA generally referred to sub-Saharan complexes. By contrast, for North Africa and the Sahara, the term 'Epipalaeolithic' used for Mediterranean contexts is more common, in spite of criticisms (Sinclair et al. 1993). The sequences associated with Aterian assemblages suggested ages earlier than 30 000 years and later than oxygen isotope stage (OIS) 4, possibly in association with OIS 3, dated from 59 000 BP. There seemed to be a gap of about 10 000 years between the latest Aterian evidence and the early Later Stone Age (LSA). Iberomaurusian and Capsian are the two main cultural spheres of the Maghrebi Epipalaeolithic. The Iberomaurusian, named by Pallary (1909), is spread along the coast, and in the subcoastal moist region, from eastern Morocco to the gulf of Tunis, with a chronological range from >20 000 to 10 000 BP. The Capsian (Vaufrey 1933) is described by Camps (1974) as a culture initially located in the region around Tebessa and, from there, spread in the pre-desert territories in a generally later period (> 12 000 BP). The Iberomaurusian is an industry with a backed bladelet index generally above 40 per cent, including the typical La Mouillah points and the Ouchtata retouch (Roche 1963; Tixier 1963), whereas the Capsian features a considerable number of geometrics (triangles and trapezes) and a decreasing frequency of backed bladelets in favour of more 'opportunistic' tools, such as sidescrapers and denticulates. …