The memory of art.
The Sahara once contained large inland tropical lakes, but these began to dry up about two and a half million years ago, due to 1) the northward movement of the African tectonic plate into the arid tropical zone, 2) the formation of the easterly jet stream, and 3) the accumulation of ice in the Antarctic and Europe. Cycles of alternating dry and wet conditions began, and they lasted for about 100,000 years, the last arid cycle ending about 12,000 years ago. Between 12,000-6,000 years ago, the Sahara was a land of lakes and rivers; around this time, people started to paint the rocks of Tassili. They used shades of yellow, red, and brown made by mixing ochre with a liquid, then applied the colors using feathers or animal hair brushes.
The earliest pictorial style, the so-called round head style, lasted about 2,000 years. The stylized heads are round and featureless. The animals painted include the African elephant (Loxodonta africana), giraffe (Giraffa camelopardalis), and the now-extinct giant buffalo, Homoioceras antiquus (also known as Bubalus).
This phase was followed by the pastoralist style, which began about 7,000 years ago. These paintings are naturalist representations of everyday life, including wildlife and large herds of piebald cattle with elegant curved horns, some with collars around their necks. The artists also portrayed people standing upright among their cattle, sitting beside huts, hunting with bows in their hands, and dancing with masks on their faces. These pictures are detailed and well composed, providing much information about the breeds of cattle, ecological conditions, and human society. The wild animals represented include the hippopotamus (Hippopotamus amphibius), whose bones have also been found nearby, showing the area had abundant surface water. Giraffes are also portrayed. There are now no hippopotamuses or giraffes within many hundreds of kilometers of Tassili.
Roughly 5,000 years ago there was a major change in many of the rock art pictures and the tools used to make them--the result of the migration of small populations from the north. It seems that the morphology of these new arrivals was similar to the Fulani (or Fulbe), who now live farther south in Niger, Senegal, and Chad. As a result of racial mixing, they had dark skin and long straight hair. These peoples were in turn displaced by migrations from the Mediterranean coastline and the Near East, but some settled on the remaining islands of vegetation and worked for the first nomadic Berbers, the ancestors of today's Tuareg populations.
The following style, characterized by representations of horses (Equus caballus), began about 3,200 years ago. These pictures represent horse-drawn chariots, and the last paintings (from 2,600 years ago onward) show riders using neither halters nor reins. The horses are often shown doing a flying gallop, vividly conveying the impression of motion, but totally incorrect and quite impossible. The horse-drawn chariots reflect contact with the cultures of the eastern Mediterranean.
The last style includes representations of camels or dromedaries (Camelus dromedarius), showing that climatic conditions had deteriorated. The dromedary was introduced from Asia because of the increasing aridity and eventually replaced the horse. Camel period paintings started about 2,100 years ago and are crude in comparison with the pastoralist period. The area was by then becoming too dry to support significant populations of humans and animals, but there are still a few trees dating from the period, namely the Tassili cypresses (Cupressus sempervirens var. dupreziana, see pp. 269-272). These trees are thought to be 2,000-3,000 years old and are the last living traces of the period of fertility, silent testimony of the activities of the last rock painters of Tassili.
Until the 1960s, rock art was rejected as a tool in reconstructing past environments. Recent study of this art has become more specialized, and experts conclude that much can be deduced from the paintings, including the types of fauna and vegetation present, and thus the climate. Their style, content, and composition indicate the society's level of development, and the superimposition of several layers of painting may help their dating. Identifying all these pictorial characteristics is laborious, especially in a region like Tassili where the paintings are so abundant and so widely scattered. Even using modern techniques such as 14C (carbon-14) dating and stylistic analysis, many of the mysteries surrounding the Tassili paintings remain, as there are no corroborative archeological remains. If only these paintings could tell us what they have seen.
|Printer friendly Cite/link Email Feedback|
|Publication:||Encyclopedia of the Biosphere|
|Date:||Apr 1, 2000|
|Previous Article:||2 The road to desertification.|
|Next Article:||2 Life in the cold deserts and subdeserts.|