| Chalcolithic Eneolithic, Aeneolithic, or Copper Age |
|---|
| ↑ Stone Age ↑ Neolithic |
| ↓ Bronze Age ↓ Iron Age |
Copper metallurgy in Africa encompasses the study of copper production across the continent and an understanding of how it influenced aspects of African archaeology.
Scholars previously believed that sub-Saharan Africans either did not have a period of using copper until the nineteenth century (going from the Stone Age directly into the Iron Age), or that they started smelting iron and copper at the same time. [1] Copper smelting is thought to have been practiced in Nubia, during the early Old Kingdom c. 2686–2181 BC. [2]
The principal evidence for this claim is an Egyptian outpost established in Buhen (near today's Sudanese-Egyptian border) around 2600 BC to smelt copper ores from Nubia. Alongside this, a crucible furnace dating to 2300–1900 BC for bronze casting has been found at the temple precinct at Kerma (in present-day northern Sudan), however the source of the tin remains unknown. Over the next millennium Nubians developed great skill in working copper and other known metals. [2]
Discoveries in the Agadez Region of Niger evidence signs of copper metallurgy as early as 2000 BC. This date pre-dates the use of iron by a thousand years. [1] Copper metallurgy seems to have been an indigenous invention in this area, because there is no clear evidence of influences from Northern Africa, and the Saharan wet phase was coming to an end, hindering human interactions across the Saharan region. It appeared to not be fully developed copper metallurgy, which suggests it was not from external origins. The people used native copper at first, and experimented with different furnace styles in order to smelt the ore between 2500 and 1500 BC. [3]
Copper metallurgy has been recorded at Akjoujt in western Mauritania. The Akjoujt site is later than Agadez, dating back to around 850 BC. There is evidence of mining between 850 and 300 BC. Radiocarbon dates from the Grotte aux Chauves-souris mine shows that the extraction and smelting of malachite goes back to the early fifth century BC. A number of copper artifacts—including arrow points, spearheads, chisels, awls and plano-convex axes as well as bracelets, bead and earrings—were found at Neolithic sites in the region. [4]
Collecting dates from Tropical Africa has been extremely difficult. No dates are available for the copper mine in pre-colonial Nigeria, and the earliest dates available south of the equator are around 345 AD at Naviundu springs near Lubumbashi in the Democratic Republic of Congo (DRC). Kansanshi mine in Zambia and Kipushi mine in the DRC date to between the fifth and twelfth centuries. Sites further south have produced later dates, for example the Thakadu mines in Botswana date to between 1480 and 1680; other major mines in Botswana, Namibia, and South Africa remain undated. [4]
The mineralization of copper is restricted to a few areas in western, central and southern Africa, and some have the richest deposits of copper in the world. In the west, copper has only been found in the arid regions of the Sahel and southern Sahara. The main sources of copper are:
There are not any known mines in tropical West Africa, however copper and lead workings have been in the Benue Trough in southeastern Nigeria. With the exception of a few areas near Kilembe in Uganda and Rwanda, there are no sources of copper in East Africa. The largest concentration of copper found in Africa is the Lufilian Arc. It is an eight hundred kilometer crescent shaped belt, which extends from the Copperbelt in Zambia to the southern Shaba Province in Congo. [4]
Early African miners used copper oxides and carbonates rather than sulfides, because they were able to reduce oxides and carbonates to copper metal, but not sulfides. Sulfides were more complex to reduce to metal and required multiple stages. Complex deep-mining methods and special tools were not needed, because oxides were structurally weakened by decomposition processes and contained the most desirable ores, and although the techniques used seemed to be simple, Africans were very successful in extracting large quantities of high-grade ore. [4]
The copper mines themselves were most frequently open stopes or open stopes with shafts. Shafts were rare in African copper mining. There are several ethnographic accounts of African copper mining techniques, and they all seem to be on the same technological level. Any variation depended upon different geological circumstances and capabilities of the miners. [4]
There are more variations of copper smelting than there are of mining, and most of the observations and photos that were taken are in major copper producing areas. There is a lack of evidence of smelting in West Africa; however casting continued to be present and is well documented. The most common ore in Africa is malachite and it was used mainly with hardwood charcoal the smelting process. [4]
In sub-Saharan West Africa, there were only two known source of copper that were commercially viable: Dkra near Nioro, Mali and Takedda in Azelik, Niger. Akjoujt was a significant source of copper, but due to the lack of timber it lost its significance in early historic times. The sources for West Africa's copper came from southern Morocco, northwestern Mauritania, the Byzantine Empire and Central Europe. [5]
The discovery of copper metallurgy in the Akjoujt region in Mauritania [6] [7] and the Eghazzer basin [8] [9] dated to the second and early first millennium BCE shook the foundation of that consensus. In all the other areas reviewed in this article, however, iron metallurgy was adopted directly by Late Stone Age mixed-farming and horticulturalist communities. A general outline of the origins of African copper metallurgy is presented by Michael S. Bisson [10] . Native copper was exploited for one to two millennia. “The mining and smelting of copper ore appears to have arisen independently in Asia Minor, Eastern Europe, and Egypt between 5000 and 4000 BC” [11] . He outlines a number of elements suggesting a link between the Akjoujt copper metallurgy, Western Europe Early Bronze Age, and Phoenician North Africa. First, the large proportion of utilitarian objects tends to suggest that copper technology was introduced in the area as a package, in contrast to all cases of early metallurgy development in which status objects are dominant. Second, there are striking stylistic similarities between Mauritanian, North African, and Iberic Peninsula copper artifacts. He concludes that the presence of more prosaic copper artifacts at the beginning of the Mauritanian sequence suggests that the technology may have its roots elsewhere.” [12] The cases from the Eghazzer basin that point to the late third–early second millennium BCE age of copper smelting are still strongly debated [13] [14] [15] [16] [17] [18] [19] . Egypt was suggested as the most likely initial source of the Eghazzer copper metallurgy: It is not inconceivable that communications, however indirect and periodic, between the Nile Valley and interior Sahara regions occurred over a long period and that the knowledge of working with metals (particularly copper) was along the numerous routes to the west, southwest and south. Iron technology may have been introduced along similar networks by the turn of the first millennium BC, although additional stimulus was provided by the new links to the northern coast.
In West Africa, there is a great deal of documentation about copper in trade, but the travelers who wrote these documents only visited the major centers of West African polities and there is no information on the people who lived out the polities or from the savanna and forest zones to the south, in terms of their use of copper. Arab and European trader documented that the principal goods that were in demand in West African markets were salt and copper. There has been a lack of research done in the savannah and forest regions of West Africa so the evidence of the diffusion copper there is spotty at best. Despite West Africa's rich gold resources, high status people were most often buried with copper grave goods. The only sites prior to 1500 AD to have gold were Djenné, Tedaoust, and several tumuli in Senegal. [1]
In West Africa, copper was used as medium of exchange, symbols of status and kingship, jewelry, and ritual purposes; this was a part of Bantu tradition prior to their expansion into Central Africa. The use of copper in the Iron Age of Central Africa was produced because of indigenous or internal demand rather than those from outside, and it is thought to be a sensitive sign of political and social change. [20]
Copper appeared to be a prestigious metal in Central and Southern Africa. In Central Africa copper has been found in places where copper is not produced, implying some sort of commerce. Also the majority of artifacts found suggest that the primary use for copper in the area was for decorative purposes. The available evidence shows that prior to fifteenth century Zimbabwean Iron Age site also placed higher value in copper than gold, though the date may have to be pushed with recent carbon dates. [1]
It is thought that through trade with India and later Portugal Zimbabwe started to value gold as prestige metal, however it did not replace copper. Archaeological and documentary sources may skew the record in favor of nonperishable elements of culture and not give enough credit to pastoral and mixed farming activities that were needed to sustain these Iron Age populations. They do make it clear that copper was an important part of the exchange economies of Central and Southern Africa. [1] The site of Bosutswe is evidence that copper and other precious metals were vital to trade in the area. [21]
Tswana towns of the pre-colonial period in South Africa, such as the Tlokwa capital at Marothodi near the Pilanesberg National Park, demonstrate a continuation of native copper production into the early nineteenth century. In this period, archaeological research suggests that copper production had intensified significantly to meet growing regional demands. [22]
Copper is almost non-existent for most of the interior of East Africa, with a few exceptions particularly Kilwa and medieval sites in Nubia and Fostat, and there is not enough information yet to reconstruct copper on the Swahili Coast. [1]
Bisson (2000) thought that because of copper's redness, luminosity and sound, it was valued by Africans. For many African cultures, the redness could be with life giving powers. Bisson (2000) also noted that the redness is a symbol of transition and it association with transition could explain why the wide use of copper in rituals in various African states. Also, its ability to reflect sunlight is suggested represent aggression and liminal boundaries between states, thus emphasizing its transformative properties. Finally, because of copper's use in bells and drums, it is thought to aid in the summoning spirits, when the instruments are played. [4]
The Bronze Age was a historical period characterised principally by the use of bronze tools and the development of complex urban societies, as well as the adoption of writing in some areas. The Bronze Age is the middle principal period of the three-age system, following the Stone Age and preceding the Iron Age. Conceived as a global era, the Bronze Age follows the Neolithic, with a transition period between the two known as the Chalcolithic. The final decades of the Bronze Age in the Mediterranean basin are often characterised as a period of widespread societal collapse known as the Late Bronze Age collapse, although its severity and scope is debated among scholars.
The Chalcolithic was an archaeological period characterized by the increasing use of smelted copper. It followed the Neolithic and preceded the Bronze Age. It occurred at different periods in different areas, but was absent in some parts of the world, such as Russia, where there was no well-defined Copper Age between the Stone and Bronze Ages. Stone tools were still predominantly used during this period.
The Iron Age is the final epoch of the three historical Metal Ages, after the Chalcolithic and Bronze Age. It has also been considered as the final age of the three-age division starting with prehistory and progressing to protohistory. In this usage, it is preceded by the Stone Age and Bronze Age. These concepts originated for describing Iron Age Europe and the Ancient Near East. The indigenous cultures of the New World did not develop an iron economy before 1500.
Metallurgy is a domain of materials science and engineering that studies the physical and chemical behavior of metallic elements, their inter-metallic compounds, and their mixtures, which are known as alloys.
Smelting is a process of applying heat and a chemical reducing agent to an ore to extract a desired base metal product. It is a form of extractive metallurgy that is used to obtain many metals such as iron, copper, silver, tin, lead and zinc. Smelting uses heat and a chemical reducing agent to decompose the ore, driving off other elements as gases or slag and leaving the metal behind. The reducing agent is commonly a fossil-fuel source of carbon, such as carbon monoxide from incomplete combustion of coke—or, in earlier times, of charcoal. The oxygen in the ore binds to carbon at high temperatures, as the chemical potential energy of the bonds in carbon dioxide is lower than that of the bonds in the ore.
Copper extraction refers to the methods used to obtain copper from its ores. The conversion of copper ores consists of a series of physical, chemical, and electrochemical processes. Methods have evolved and vary with country depending on the ore source, local environmental regulations, and other factors.
A bloomery is a type of metallurgical furnace once used widely for smelting iron from its oxides. The bloomery was the earliest form of smelter capable of smelting iron. Bloomeries produce a porous mass of iron and slag called a bloom. The mix of slag and iron in the bloom, termed sponge iron, is usually consolidated and further forged into wrought iron. Blast furnaces, which produce pig iron, have largely superseded bloomeries.
The history of metallurgy in the Indian subcontinent began prior to the 3rd millennium BCE. Metals and related concepts were mentioned in various early Vedic age texts. The Rigveda already uses the Sanskrit term ayas. The Indian cultural and commercial contacts with the Near East and the Greco-Roman world enabled an exchange of metallurgic sciences. The advent of the Mughals further improved the established tradition of metallurgy and metal working in India. During the period of British rule in India, the metalworking industry in India stagnated due to various colonial policies, though efforts by industrialists led to the industry's revival during the 19th century.
Ferrous metallurgy is the metallurgy of iron and its alloys. The earliest surviving prehistoric iron artifacts, from the 4th millennium BC in Egypt, were made from meteoritic iron-nickel. It is not known when or where the smelting of iron from ores began, but by the end of the 2nd millennium BC iron was being produced from iron ores in the region from Greece to India, The use of wrought iron was known by the 1st millennium BC, and its spread defined the Iron Age. During the medieval period, smiths in Europe found a way of producing wrought iron from cast iron, in this context known as pig iron, using finery forges. All these processes required charcoal as fuel.
The metals of antiquity are the seven metals which humans had identified and found use for in prehistoric times in Africa, Europe and throughout Asia: gold, silver, copper, tin, lead, iron, and mercury.
Metallurgy in pre-Columbian America is the extraction, purification and alloying of metals and metal crafting by Indigenous peoples of the Americas prior to European contact in the late 15th century. Indigenous Americans had been using native metals from ancient times, with recent finds of gold artifacts in the Andean region dated to 2155–1936 BC, and North American copper finds being dated to approximately 5000 BC. The metal would have been found in nature without the need for smelting, and shaped into the desired form using hot and cold hammering without chemical alteration or alloying. As of 1999, "no one has found evidence that points to the use of melting, smelting and casting in prehistoric eastern North America."
Iron metallurgy in Africa concerns the origin and development of ferrous metallurgy on the African continent. Whereas the development of iron metallurgy in North Africa and the Horn closely mirrors that of the Ancient Near East and Mediterranean region, the three-age system is ill-suited to Sub-Saharan Africa, where copper metallurgy generally does not precede iron working. Whether iron metallurgy in Sub-Saharan Africa originated as an independent innovation or a product of technological diffusion remains a point of contention between scholars. Following the beginning of iron metallurgy in Western and Central Africa by 800 BC - 400 BC, and possibly earlier, agriculturalists of the Chifumbaze Complex would ultimately introduce the technology to Eastern and Southern Africa by the end of the first millennium AD.
The Copper Age, also called the Eneolithic or the Chalcolithic Age, has been traditionally understood as a transitional period between the Neolithic and the Bronze Age, in which a gradual introduction of the metal took place, while stone was still the main resource utilized. Recent archaeology has found that the metal was not introduced so gradually and that this entailed significant social changes, such as developments in the type of habitation, long-distance trade, and copper metallurgy.
Mining archaeology is a specific field well-developed in the British Isles during recent decades. A reason of ongoing interest in this field is the particular bond between regional history and the exploitation of metals. References to mines in the area exist in Strabo's works. However the first accomplished study on the topic was attempted by Oliver Davies in 1935. Other momentous researches were that of geologist John S. Jackson about mines in Ireland and Lewis, Jones in Dolaucothi goldmine in Wales, and the pioneering work of Ronald F. Tylecote. Moreover, in the 1980s and 1990s a new generation of amateurs and scientists began investigations in different locations in the British Isles, including Duncan James on the Great Orme's Head, Simon Timberlake with the Early Mines Research Group at sites in Wales and William O'Brien in Ireland.
Metals and metal working had been known to the people of modern Italy since the Bronze Age. By 53 BC, Rome had expanded to control an immense expanse of the Mediterranean. This included Italy and its islands, Spain, Macedonia, Africa, Asia Minor, Syria and Greece; by the end of the Emperor Trajan's reign, the Roman Empire had grown further to encompass parts of Britain, Egypt, all of modern Germany west of the Rhine, Dacia, Noricum, Judea, Armenia, Illyria, and Thrace. As the empire grew, so did its need for metals.
Tin is an essential metal in the creation of tin-bronzes, and its acquisition was an important part of ancient cultures from the Bronze Age onward. Its use began in the Middle East and the Balkans around 3000 BC. Tin is a relatively rare element in the Earth's crust, with about two parts per million (ppm), compared to iron with 50,000 ppm, copper with 70 ppm, lead with 16 ppm, arsenic with 5 ppm, silver with 0.1 ppm, and gold with 0.005 ppm. Ancient sources of tin were therefore rare, and the metal usually had to be traded over very long distances to meet demand in areas which lacked tin deposits.
Experimental archaeometallurgy is a subset of experimental archaeology that specifically involves past metallurgical processes most commonly involving the replication of copper and iron objects as well as testing the methodology behind the production of ancient metals and metal objects. Metals and elements used primarily as alloying materials, such as tin, lead, and arsenic, are also a part of experimental research.
Taruga is an archeological site in Nigeria famous for the artifacts of the Nok culture that have been discovered there, some dating to 600 BC, and for evidence of very early iron working. The site is 60 km southeast of Abuja, in the Middle Belt.
Non-ferrous extractive metallurgy is one of the two branches of extractive metallurgy which pertains to the processes of reducing valuable, non-iron metals from ores or raw material. Metals like zinc, copper, lead, aluminium as well as rare and noble metals are of particular interest in this field, while the more common metal, iron, is considered a major impurity. Like ferrous extraction, non-ferrous extraction primarily focuses on the economic optimization of extraction processes in separating qualitatively and quantitatively marketable metals from its impurities (gangue).
African metallurgy has a long history, spanning several millennia and encompassing a wide range of techniques and innovations. This article explores the development and significance of metalworking in different regions of Africa, highlighting the social, economic, and cultural impacts of metallurgical practices. From the earliest use of metals in ancient Egypt to the sophisticated ironworking traditions across sub-Saharan Africa, metallurgy has played a crucial role in shaping African civilizations.