Economic and cultural prehistory of the Niger Delta

African Arts, Spring, 2002 by A.A. Derefaka, F.N. Anozie

Lacking the written records on which the historian relies, the prehistorian seeks to reconstruct the past through means of archaeological evidence.

   [O]bjects recovered from archaeological excavations ... bear the evidence
   of man's exploitation of his natural resources and utilization of those
   materials that serve to fulfill his aspirations. These may be objects of
   warfare, tools for hunting, procuring and preparing his food, for
   collecting and storing drinking water, ornaments for beautifying his body,
   objects to satisfy psychological and philosophical needs, ritual objects,
   and currency. These objects and their placement within a geographical
   context assume added importance if they are associated with materials such
   as charcoal and shell for radiometric dating; or objects of trade such as
   beads, copper manillas and cowrie shells for cross-cultural dating. Each
   object has its potential for supplying information on the disposition,
   habits, attitudes and technological progress of the people who lived on the
   site or in the area under study. (Anozie 1988:141)

The archaeologist must carefully select sites for investigation, rigorously record the locations of finds, and painstakingly analyze their relationships. It is through this careful attention to what may have been the household refuse of another era that the culture of a people can begin to be reconstructed, as well as their place of origin and patterns of migration. Often, however, physical artifacts cannot tell the "story" in its full complexity. Oral tradition, ethnographic studies, and environmental data can then complement or help to explicate the archaeologist's finds.

This essay will follow in a general way the course of the archaeologist's inquiry. First, we will briefly discuss the geology and environment of the Niger Delta--factors that are essential to site selection and the dating of artifacts. We will then examine the history of archaeology in the Delta, summarize the finds that have been discovered to date, and offer the results of radiometric testing of selected objects. Using these data in combination with the other forms of evidence noted above, we can then begin to consider conclusions that might be suggested regarding the region's economic and cultural prehistory.

Geology and Environment

The Niger Delta is the largest delta in Africa, covering approximately 75,000 square kilometers. Its formation as we know it today has been traced to the early Tertiary period, about 65 million years ago. During times of increased rainfall, the sea exceeded its natural boundaries and encroached on land. It retreated in subsequent periods of prolonged dryness, leaving deposits of sediments. It was through this alternating process that the Delta originated.

I. P. Okonny has indicated that "the near-radial disposition of the main delta rivers and their non-interrupted discharge into the sea classifies the Niger Delta as ... highly-constructive.... a delta that has been gradually building up and gaining more ground than it loses to erosion" (1988:23). As M. A. Sowunmi (1981) has noted, based on the work of J.R.C. Allen, "sediments entering the Niger Delta come from three independent sources; the Niger Benue drainage basins of rivers east of the delta, and drainage basins of rivers to the west probably including the Volta in Ghana." The maximum thickness of the detrital sediments of the Delta to date is approximately 8,000 meters (Hospers 1965). This subsurface has been divided into three layers: the Akata Formation, a shaley layer that extends from the sedimentary base; the Agbada Formation, which consists of alternating sandstone and shale and is the main oil reservoir sediment layer; and the Benin Formation, which is the sandy uppermost layer. The three layers extend across the entire Delta, and they all date from the Tertiary period (Okonny 1988:26). These detrital sediments have, however, been investigated archaeologically only to a depth of less than five meters in any part of the Niger Delta.

From an environmental standpoint, the Delta can be divided into three main zones: first, the freshwater swamps and forest on both sides of the Niger River; second, the saltwater mangrove swamps, which lie south of the freshwater swamps and are composed of mud and silt, covering approximately 10,360 square kilometers; and, last, the sandy beach ridges at the edge of the outer Delta (Udo 1978:227; Nzewunwa 1979:4; Derefaka 1991:16).

The History of Archaeological Investigation in the Niger Delta

The first organized archaeological fieldwork in the Delta was undertaken in December 1972 by a research team from the University of Ibadan composed of Professor E. J. Alagoa, Professor Thurstan Shaw, and Dr. E N. Anozie (Nzewunwa & Derefaka 1989:111-12). The team's initial reconnaissance tour included the sites of Onyoma, Nembe, Oruokolo, Kaiko, Ke, Brass, and Ogbolomabiri (Fig. 1).

As articulated by Alagoa, the investigations were aimed at determining "the earliest dates and locations of human settlement in the Niger Delta and its immediate hinterland [and] the relationships through migration, and diffusion of goods and ideas, between peoples and regions within the Delta and other parts of Nigeria" (Alagoa 1988a:18). The sites were selected from those named in oral tradition.