History of Iron Smelting Technology in Sub-Saharan Africa

History of Iron Smelting Technology in Sub-Saharan Africa Introduction: The arrival of iron smelting technology in sub-Saharan Africa played a significant role in shaping the historical record of the area by bringing profound changes to the lives and societies of its inhabitants (Haaland Shinnie 7). In the parts of Africa south of the Sahara and south of the Ethiopian highlands, there has been no archaeological evidence supporting a Bronze Age (Van Der Merwe 463; Alpern ; Holl 6) and the evidence archaeologists do have point to iron being the first metal used to replace stone tools (Fagan 1). One area of intense debate regarding the African Iron Age is the process in which the technology of iron smelting arrived in sub-Saharan Africa. Over the past half-century, the interpretations and reconstructions of the origins of iron smelting in sub-Saharan Africa have changed considerably. The initial theory was based on an unquestioned belief of the superiority of Ancient Egypt over sub-Saharan Africa (Kense 12). Based on this framework, the site of Meroe was pr oposed by Arkell as an important link and the general belief was that the collapse of the Kingdom of Kush precipitated the spread of technology and Meroitic culture into the southwest (Kense 13). However excavations conducted in the 1960s determined that the iron smelting furnaces found at Meroe mostly dated to the first few centuries B.C.E (Shinnie 30) and its pivotal role in the spread of iron smelting technology was shown to be increasingly hard to defend (Kense 13). Three theories regarding the origins of iron smelting in sub-Saharan Africa have emerged and are currently disputed amongst scholars (Holl 7). Two of the theories are diffusionist meaning these theories claim the technology originated elsewhere and was transported into the region. These theories are based on the premise that iron smelting originated somewhere in Anatolia and from there the technology was adopted by other populations and spread throughout the Mediterranean and into Africa. The main diffusionist theory was first proposed by Raymond Muany in 1952. He argues that since the Phoenicians had iron by about 1100 B.C. and that they started colonizing Northern Africa at around the same time; it was possible that the knowledge of iron smelting was transmitted into sub-Saharan Africa with the Berber tribes living in the Saharan Desert as a medium (Alpern 46). The other diffusionist hypothesis arose as a counter to early iron smelting furnaces found west of Lake Victoria in Tanzania. This hypothesis proposes that the technology came from Arabia via the Horn of Africa (Alpern 80). The theory that has gained the most acceptance recently is the one arguing for the independent invention of iron smelting in sub-Saharan Africa (Alpern 41). A slew of archaeological discoveries in the past twenty years have strengthened the case for independent invention. Some people have even gone as far as arguing that, based on controversial discoveries made in 2008, inhabitants of sub-Saharan Africa were the first to smelt iron, preceding Anatolia by about 700 years (Pringle ). The strongest case against independent invention is the complexity of iron smelting. Iron requires specialized knowledge in order to transform iron ore into usable iron (Kense 19) and it has long been held that people without prior knowledge of smelting techniques would not be able to smelt iron successfully (Sassoon 5). Two areas of sub-Saharan Africa have emerged as candidates for areas where iron smelting could have developed, the Western Africa region around the Niger-Nigeria border or north-western Ta nzania. This essay will argue for the independent discovery of iron smelting technology in sub-Saharan Africa based on discoveries made in Western Africa. Background: To understand why there has been such a strong opposition to the idea of sub-Saharan Africa independently inventing iron smelting technology, it is necessary to consider the difficulty and skill required to smelt iron. It is hypothesized that iron was first used as a flux, a substance that is smelted together with the desired ore in order to make the slag, or waste rock, more liquid, in the smelting of copper (Wheeler Madden 114). The iron mixed with slag would have been spongy at the temperatures inside a copper smelting furnace. It could only then be shaped into something usable through repeated hammering and heating (Wheeler Madden 114). The difficulty in creating iron objects is testament in the value iron objects had during the early and mid Bronze Age. In Egypt, for example, Tutankhamen was wrapped in with a golden dagger and a matching iron dagger with a gold hilt (van der Merwe 466). So although ancient smiths, masters of smelting bronze and copper, knew about iron, the diffi culties in smelting the metal took a long time to overcome. The smelting of iron occurs when iron ore is heated together with a charcoal fuel. This causes the iron in the ore to fuse chemically with the carbon from the charcoal. The more carbon dissolved in the iron, the lower its melting point. The amount of ore to fuel, and the supply of combustion air determine whether cast iron, steel, wrought iron, or a useless lump of metal will form (Alpern 82). Copper on the other hand melts readily at 1084ÂÂ °, temperatures that can be reached in a charcoal fire or during ceramic firing (Holl 6). In sum, the reduction of iron ore requires much more sophisticated expertise than does the smelting of other metal ores. Without pre-existing furnace technology, the likelihood of stumbling upon the process required is slim (Sassoon 5). Due to these foundations and a lack of archaeological evidence supporting very early iron smelting in sub-Saharan Africa at the time, Mauny proposed the most plausible scenario for the diffusion of iron metallurgy (Alpern 45). He speculated that when the Phoenicians settled in North Africa, the Berbers living in the region, being from a nomadic warrior culture, would have been keen to acquire improved weapons made from iron metal. These Berbers living near the coast would then pass on this technology to their fellow Berbers living in the Sahara (Kense 24). He then suggested that the technology could have been taken south into the sub-Saharan savannah by fleeing slaves, or deliberately transmitted to the lands of black farmers where both iron ore and the wood to fuel smelting furnaces were relatively abundant. The farmers would in turn supply the Berbers with raw metal for ironworking in exchange (Alpern 46). Mauny offered some linguistic evidence for his model. Derivatives of the Phoenician word for iron, barzel, are found in Berber vocabularies throughout the Sahara and also in the Teda (Tubu) language of Tibesti and the Fezzan.20 Mauny also saw affiliations with the terms for iron among several savanna-dwelling black peoples, including the Bariba, Jukun, and Kanuri.21 He might have added that Carthaginian influence on the Berbers may be attested to this day by the Tifinagh alphabet of the Tuareg, which is thought by some scholars to derive ultimately from a Punic script. There is a strong case that Africa independently invented ceramics, however there does seem to be evidence for Berber transfer of metallurgy across the Sahara, but it comes not from Niger but from Mauritania in the far west. Ancient copper artifacts began to be noticed in that region in the early twentieth century. By 1951 enough had been found for Mauny to wonder, in print, whether Mauritania had experienced a Copper Age.70 An answer came in 1968, when French archeologist Nicole Lambert began excavating what was known as the Grotte aux Chauves-souris (Bat Cave) on a hill called the Guelb Moghrein near Akjoujt in western Mauritania. It was not a cave at all, but an ancient mining gallery dug by humans following a rich vein of malachite ore. The ore was not only extracted, but locally smelted, as furnace remains and slag attest. Four other ancient exploitation sites were found later on the Guelb Moghrein. Ra-diocarbon datings, eventually calibrated, are nearly all in the range 800 to 200 cal BCE. Subsequently at least three other metallurgical centers from the same period were discovered in the Akjoujt region. The number of ancient copper objects found in the western Sahara and attributed to the Akjoujt industry exceeded 160 at last count. The great majority are weapons: arrowheads, lance points, and daggers. Tools include hatchets, pins, awls, burins, and hooks. There are the inevitable personal ornaments-rings, earrings, pendants-and some ingots. All the items are very small and very light; when the number reached about 140, the total weight barely topped two kilograms. They were produced in a Neolithic context in which stone tools vastly outnumbered the metal ones, so one can hardly speak of a Copper Age on the basis of present evidence. How did copper mining and working get started at Akjoujt? It is possible the industry was indigenous, but no one yet seems to have made a real case for that. Lambert saw a resemblance between the Akjoujt products and those of the El Argar culture in southeastern Spain, where copper was being manufactured by at least 1700 BCE and bronze some 200 years later. She thought the few ancient brass and bronze artifacts also found in Mauritania might have been imported from the western Maghreb. She noted that chariot engravings had been found on rocks in three places near Akjoujt and thought they might be road signs indicating an early traffic between Morocco and Mauritania.71 Mauny discerned Phoenician or Carthaginian initiatives behind the Akjoujt industry, with Berbers actually importing the technology, but Lamberts idea of an Iberian connection might have some merit.72 In the late 1960s and early 1970s, British archeologist Colin Renfrew, in a sweeping challenge to the then-reigning diffusionist orthodoxy, suggested that copper metallurgy was independently invented on the Iberian Peninsula long before Phoenicians or Greeks reached the western Mediterranean. 73 Since then much evidence has accumulated that he was right, and that Iberian copper metallurgy dates back at least to 3000 BCE.74 It also seems that the technology crossed from Spain to Morocco before the Phoenicians set foot on the Moroccan coast. Until the mid-twentieth century, it was thought the western Maghreb had not experienced a Copper or Bronze Age. Finds of metal objects, ancient mines, and, especially, rock engravings have undercut that notion: copper in Morocco may date all the way back to the third millennium BCE, according to some leading researchers.75 Rock art in the High Atlas shows weapons typical of the El Argar culture, especially daggers, halberds, and axes.76 Conceivably, cuprous objects reached Morocco in exchange for two North African products, ivory and ostrich eggshells, that have been found in third- and second- millennium-BCE graves in southeast Spain.77 But no certain proof of early copper smelting has yet turned up in the Maghreb. Did the Akjoujt copper industry, whatever its origins, lead to an independent invention of iron metallurgy? The malachite of Bat Cave occurred in a matrix of hematite and magnetite that was discarded in the smelting process. There is no evidence that the coppersmiths ever produced iron, although the raw material was at hand. However, proof of ironworking from the same period has recently been found some 250 miles south of Akjoujt in the middle Senegal river valley. At a site called Walalde, iron artifacts dating to somewhere between 800 and 550 cal BCE have been found, and in a second phase of occupation, from ca. 550 to 200 cal BCE, clear evidence of iron smelting has been excavated. The latter phase also yielded three copper artifacts with a telltale chemical signature of the Akjoujt ores-more than 1% of arsenic and a smaller amount of nickel. Further excavation and study are required to evaluate the find, but it is clearly an important contribution to the history of metallurgy in sub-Saharan Africa.