Chronology

The various scholars who have tried to classify and date the Saharan rock art have had to face an extremely complicated task, for very many populations have nomadised over most of the Sahara during the last millennia. Moreover, archaeological excavations are rare in the Sahara, and the relationship between these excavations and the rock art has still to be proved. In addition, direct dating of the paintings and engravings has not yet been carried out with much success in this zone, even if the modern C14 techniques (AMS) for the paintings, and the mineralogic analysis, with an electronic microscope, of the composition of the patinas of the engravings have greatly advanced these last few years. These difficulties are reflected in the various chronologies that the scholars of the different 'schools' have proposed. Some of the classical chronologies are summarized in this table. It should be noted that the classifications proposed by the different scholars are difficult to summarise up in a chronological table as they come from very complex analysis of a large number of rock art works and archaeological, climatological, paleo-botanical and paleo-zoological data. We want however to underline that Lhote defined the "Round Head" group for the Tassili, but that the "Bubaline" group concerns the central Sahara and the Algerian Atlas. Whereas the "Round Head" group, defined in a delimited area, could be associated with a single ethnic group, the "Bubaline" one could hardly be associated with a single ethnic group nomadising in such a large region.

Cultural relations between the hunter-gatherer, or herder, groups of the Tassili and the ones of the Atlas have therefore to be proved by means of more convincing arguments than the engraving technique and style and the fauna depicted.
Mori, Muzzolini, Tauveron-Aumassip and other scholars used the same names to define the rock art styles in different regions of the Sahara. Whereas stylistic criteria seem convincing to characterize ethnic groups of contiguous areas, such as Tassili and Tadrart Acacus, they appear much less convincing for far off regions.

These schematized classifications seem therefore questionable for prehistorians and anthropologists, who attempt to associate rock art styles with the nomadic populations which inhabited the Sahara in the past millennia, but they are useful to illustrate the extraordinary cultural field that has been covered, in different regions and ages (?), by all the ancient populations of the Saharan.

Some writers place the "schematic" engravings among the oldest rock art representations. However, we do not mention them in the present table, as it is quite impossible to distinguish them from the same kind of more recent engravings: only the rock surface alteration, strongly affected by different exposures to weathering agents, and superpositions of known engravings are useful to distinguish between them. Moreover the more "schematic" a picture is, the more widely distributed it is, a fact which weakens comparisons and chronologies.

Karnasahi, enneri Korossom, East Tibesti
 

The "short" chronology proposed by Alfred Muzzolini and Jean-Loïc Le Quellec is based mainly on the presence of domesticated cattle in the 'bubaline' engravings, and on the reliable C14 dates for the remains of domesticated animals. They think that these dates, obtained in the course of archaeological excavation, don't go back beyond 4500-4000 BC. In addition, important stylistic analogies exist between certain "bubaline" engravings depicting large wild animals and those showing domestic animals. However, the argument based on the presence of domesticated cattle isn't entirely convincing.

On the basis of DNA data it is likely that the wild "bos taurus" species split about 22000 bp into a European-Near East version and an African version. Therefore, there may have been an independent domestication of cattle in Northern Africa. The process of domestication may have taken a period of time during which the physical features of the animals were modified by selective breeding. This would mean that the remains of wild and of early domesticated cattle cannot be clearly distinguished. It should, however, be noted that some researchers have found several petroglyphs at a few sites, which are superimposed by bubaline engravings and show a degree of groove erosion much greater than the bubaline ones.

On the other hand, the presence of sheep among the "bubaline" engravings definitely shows that these are domestic animals introduced by man, since wild sheep have never existed in Africa. The date of this introduction is now well known : it does not go back beyond the 5th millennium BC. As far as the "Round Heads" are concerned, Muzzolini remarked that some bovids are represented, but not in hunting scenes. He therefore concluded that they were domestic. But here again, in the absence of sheep, the argument is not very convincing.

The difference between the chronologies is essential, because in the "long" chronology, the oldest representations ("bubaline" and "Round Head" styles) would be the work of groups of hunter-gatherers, whereas in the "short" chronology, all the rock art would have been produced by groups who, in the Neolithic period, had learnt how to produce their means of subsistence, thus gaining a certain independence with regard to the surrounding environment.

For the classification of Saharan rock art, scholars have often used the animals depicted as "fossil indicators": the camel and the horse for the periods (schools and/or styles) bearing their names; the giant buffalo (previously called a "bubalus") for the bubaline, and domestic bovids for the bovidian. Scholars first grouped the works studied by following stylistic criteria, by analysing the subjects depicted, by the superpositions and by the patinas.

They then arranged them in a chronology essentially based on the presence of animals considered as "fossil indicators" (as outlined above). But it is clear that the use of this criterion alone is insufficient to classify works where these animals are not represented.

A sheep superimposed to an "ovoid" sign. W. In-Tullult - Messak Settafet - Libya