137-627: The Zambezi basin is an African drainage basin , whose main flow is the Zambezi River , being the fourth largest basin on the continent, in addition to being the most important basin in southern Africa . It covers approximately 1,390,000 km², crossing regions with high population density, sometimes in areas of low density, such as the Kavango–Zambezi Transfrontier Conservation Area . The Zambezi Watercourse Commission (ZAMCOM) has been in existence since 2004 with
274-573: A Gilman reagent . These can undergo substitution with alkyl halides to form coupling products ; as such, they are important in the field of organic synthesis . Copper(I) acetylide is highly shock-sensitive but is an intermediate in reactions such as the Cadiot–Chodkiewicz coupling and the Sonogashira coupling . Conjugate addition to enones and carbocupration of alkynes can also be achieved with organocopper compounds. Copper(I) forms
411-736: A confederation of seafaring peoples contributed to the New Kingdom 's collapse in 1069 BC, commencing the Third Intermediate Period . Egypt's collapse liberated the more Egyptianised Kingdom of Kush in Nubia, who manoeuvred into power in Upper Egypt and conquered Lower Egypt in 754 BC to form the Kushite Empire . The Kushites ruled for a century and oversaw a revival in pyramid building , until they were driven out of Egypt by
548-696: A covalent character and are relatively weak. This observation explains the low hardness and high ductility of single crystals of copper. At the macroscopic scale, introduction of extended defects to the crystal lattice , such as grain boundaries, hinders flow of the material under applied stress, thereby increasing its hardness. For this reason, copper is usually supplied in a fine-grained polycrystalline form, which has greater strength than monocrystalline forms. The softness of copper partly explains its high electrical conductivity ( 59.6 × 10 S /m ) and high thermal conductivity, second highest (second only to silver) among pure metals at room temperature. This
685-636: A nickel ) consists of 75% copper and 25% nickel in homogeneous composition. Prior to the introduction of cupronickel, which was widely adopted by countries in the latter half of the 20th century, alloys of copper and silver were also used, with the United States using an alloy of 90% silver and 10% copper until 1965, when circulating silver was removed from all coins with the exception of the half dollar—these were debased to an alloy of 40% silver and 60% copper between 1965 and 1970. The alloy of 90% copper and 10% nickel, remarkable for its resistance to corrosion,
822-407: A pinkish-orange color . Copper is used as a conductor of heat and electricity, as a building material , and as a constituent of various metal alloys , such as sterling silver used in jewelry , cupronickel used to make marine hardware and coins , and constantan used in strain gauges and thermocouples for temperature measurement. Copper is one of the few metals that can occur in nature in
959-549: A principality into a major power on the trade route between Rome and India through conquering its unfortunately unknown neighbours, gaining a monopoly on Indian Ocean trade in the region. Aksum's rise had them rule over much of the regions from Lake Tana to the valley of the Nile , and they further conquered parts of the ailing Kingdom of Kush , led campaigns against the Noba and Beja peoples, and expanded into South Arabia . This led
1096-425: A spin of 3 ⁄ 2 . The other isotopes are radioactive , with the most stable being Cu with a half-life of 61.83 hours. Seven metastable isomers have been characterized; Cu is the longest-lived with a half-life of 3.8 minutes. Isotopes with a mass number above 64 decay by β , whereas those with a mass number below 64 decay by β . Cu , which has
1233-597: A Berber tribe originally from Yafran (also known as Ifrane ) in northwestern Libya , as well as the city of Ifrane in Morocco . Under Roman rule, Carthage became the capital of the province then named Africa Proconsularis , following its defeat of the Carthaginians in the Third Punic War in 146 BC, which also included the coastal part of modern Libya . The Latin suffix -ica can sometimes be used to denote
1370-399: A blast furnace. A potential source of copper is polymetallic nodules, which have an estimated concentration 1.3%. Like aluminium , copper is recyclable without any loss of quality, both from raw state and from manufactured products. In volume, copper is the third most recycled metal after iron and aluminium. An estimated 80% of all copper ever mined is still in use today. According to
1507-459: A blue crystalline penta hydrate , the most familiar copper compound in the laboratory. It is used in a fungicide called the Bordeaux mixture . Polyols , compounds containing more than one alcohol functional group , generally interact with cupric salts. For example, copper salts are used to test for reducing sugars . Specifically, using Benedict's reagent and Fehling's solution the presence of
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#17328451791141644-709: A directly usable metallic form ( native metals ). This led to very early human use in several regions, from c. 8000 BC . Thousands of years later, it was the first metal to be smelted from sulfide ores, c. 5000 BC ; the first metal to be cast into a shape in a mold, c. 4000 BC ; and the first metal to be purposely alloyed with another metal, tin , to create bronze , c. 3500 BC . Commonly encountered compounds are copper(II) salts, which often impart blue or green colors to such minerals as azurite , malachite , and turquoise , and have been used widely and historically as pigments. Copper used in buildings, usually for roofing, oxidizes to form
1781-700: A former Italian colony, gained independence. In 1956, Tunisia and Morocco won their independence from France. Ghana followed suit the next year (March 1957), becoming the first of the sub-Saharan colonies to be granted independence. Over the next decade, waves of decolonization took place across the continent, culminating in the 1960 Year of Africa and the establishment of the Organisation of African Unity in 1963. Portugal's overseas presence in sub-Saharan Africa (most notably in Angola , Cape Verde, Mozambique , Guinea-Bissau , and São Tomé and Príncipe) lasted from
1918-457: A green patina of compounds called verdigris . Copper is sometimes used in decorative art , both in its elemental metal form and in compounds as pigments. Copper compounds are used as bacteriostatic agents , fungicides , and wood preservatives . Copper is essential to all living organisms as a trace dietary mineral because it is a key constituent of the respiratory enzyme complex cytochrome c oxidase . In molluscs and crustaceans , copper
2055-495: A half-life of 12.7 hours, decays both ways. Cu and Cu have significant applications. Cu is used in Cu Cu-PTSM as a radioactive tracer for positron emission tomography . Copper is produced in massive stars and is present in the Earth's crust in a proportion of about 50 parts per million (ppm). In nature, copper occurs in
2192-456: A handful of African countries succeeded in obtaining rapid economic growth prior to 1990. Exceptions include Libya and Equatorial Guinea, both of which possess large oil reserves. Copper Copper is a chemical element ; it has symbol Cu (from Latin cuprum ) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity . A freshly exposed surface of pure copper has
2329-550: A land (e.g., in Celtica from Celtae , as used by Julius Caesar ). The later Muslim region of Ifriqiya , following its conquest of the Byzantine (Eastern Roman) Empire's Exarchatus Africae , also preserved a form of the name. According to the Romans, Africa lies to the west of Egypt, while "Asia" was used to refer to Anatolia and lands to the east. A definite line was drawn between
2466-683: A layer of brown-black copper oxide which, unlike the rust that forms on iron in moist air, protects the underlying metal from further corrosion ( passivation ). A green layer of verdigris (copper carbonate) can often be seen on old copper structures, such as the roofing of many older buildings and the Statue of Liberty . Copper tarnishes when exposed to some sulfur compounds, with which it reacts to form various copper sulfides . There are 29 isotopes of copper. Cu and Cu are stable, with Cu comprising approximately 69% of naturally occurring copper; both have
2603-677: A millennium. Towards the end of the ancient period, northern Ethiopia and Eritrea bore the Kingdom of D'mt beginning in 980 BC. In modern-day Somalia and Djibouti there was the Macrobian Kingdom , with archaeological discoveries indicating the possibility of other unknown sophisticated civilisations at this time. After D'mt's fall in the 5th century BC the Ethiopian Plateau came to be ruled by numerous smaller unknown kingdoms who experienced strong south Arabian influence , until
2740-625: A monopoly on gold heading north and salt heading south, despite not controlling the gold fields themselves, located in the forest regions . It is probable that Wagadu's dominance on trade allowed for the gradual consolidation of many polities into a confederated state , whose composites stood in varying relations to the core, from fully administered to nominal tribute-paying parity. Based on large tumuli scattered across West Africa dating to this period, it has been stipulated that relative to Wagadu, there were further simultaneous and preceding kingdoms that have unfortunately been lost to time. At
2877-570: A native Libyan tribe, an ancestor of modern Berbers ; see Terence for discussion. The name had usually been connected with the Phoenician word ʿafar meaning "dust", but a 1981 hypothesis has asserted that it stems from the Berber word ifri (plural ifran ) meaning "cave", in reference to cave dwellers. The same word may be found in the name of the Banu Ifran from Algeria and Tripolitania ,
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#17328451791143014-532: A natural color other than gray or silver. Pure copper is orange-red and acquires a reddish tarnish when exposed to air. This is due to the low plasma frequency of the metal, which lies in the red part of the visible spectrum, causing it to absorb the higher-frequency green and blue colors. As with other metals, if copper is put in contact with another metal in the presence of an electrolyte , galvanic corrosion will occur. Copper does not react with water, but it does slowly react with atmospheric oxygen to form
3151-407: A red-brown precipitate with copper(II) salts. Compounds that contain a carbon-copper bond are known as organocopper compounds. They are very reactive towards oxygen to form copper(I) oxide and have many uses in chemistry . They are synthesized by treating copper(I) compounds with Grignard reagents , terminal alkynes or organolithium reagents ; in particular, the last reaction described produces
3288-451: A rich variety of compounds, usually with oxidation states +1 and +2, which are often called cuprous and cupric , respectively. Copper compounds promote or catalyse numerous chemical and biological processes. As with other elements, the simplest compounds of copper are binary compounds, i.e. those containing only two elements, the principal examples being oxides, sulfides, and halides . Both cuprous and cupric oxides are known. Among
3425-464: A transition from " informal imperialism " – military influence and economic dominance – to direct rule. Imperial rule by Europeans continued until after the conclusion of World War II , when almost all remaining colonial territories gradually obtained formal independence. Independence movements in Africa gained momentum following World War II, which left the major European powers weakened. In 1951, Libya,
3562-424: A variety of minerals, including native copper , copper sulfides such as chalcopyrite , bornite , digenite , covellite , and chalcocite , copper sulfosalts such as tetrahedite-tennantite , and enargite , copper carbonates such as azurite and malachite , and as copper(I) or copper(II) oxides such as cuprite and tenorite , respectively. The largest mass of elemental copper discovered weighed 420 tonnes and
3699-436: A variety of weak complexes with alkenes and carbon monoxide , especially in the presence of amine ligands. Copper(III) is most often found in oxides. A simple example is potassium cuprate , KCuO 2 , a blue-black solid. The most extensively studied copper(III) compounds are the cuprate superconductors . Yttrium barium copper oxide (YBa 2 Cu 3 O 7 ) consists of both Cu(II) and Cu(III) centres. Like oxide, fluoride
3836-579: Is a constituent of the blood pigment hemocyanin , replaced by the iron-complexed hemoglobin in fish and other vertebrates . In humans, copper is found mainly in the liver, muscle, and bone. The adult body contains between 1.4 and 2.1 mg of copper per kilogram of body weight. In the Roman era , copper was mined principally on Cyprus , the origin of the name of the metal, from aes cyprium (metal of Cyprus), later corrupted to cuprum (Latin). Coper ( Old English ) and copper were derived from this,
3973-405: Is a highly basic anion and is known to stabilize metal ions in high oxidation states. Both copper(III) and even copper(IV) fluorides are known, K 3 CuF 6 and Cs 2 CuF 6 , respectively. Some copper proteins form oxo complexes , which, in extensively studied synthetic analog systems, feature copper(III). With tetrapeptides , purple-colored copper(III) complexes are stabilized by
4110-401: Is because the resistivity to electron transport in metals at room temperature originates primarily from scattering of electrons on thermal vibrations of the lattice, which are relatively weak in a soft metal. The maximum possible current density of copper in open air is approximately 3.1 × 10 A/m , above which it begins to heat excessively. Copper is one of a few metallic elements with
4247-529: Is melted in a furnace and then reduced and cast into billets and ingots ; lower-purity scrap is refined by electroplating in a bath of sulfuric acid . The environmental cost of copper mining was estimated at 3.7 kg CO2eq per kg of copper in 2019. Codelco, a major producer in Chile, reported that in 2020 the company emitted 2.8t CO2eq per ton (2.8 kg CO2eq per kg) of fine copper. Greenhouse gas emissions primarily arise from electricity consumed by
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4384-787: Is not always to be taken literally. Africa is considered by most paleoanthropologists to be the oldest inhabited territory on Earth, with the Human species originating from the continent. During the mid-20th century, anthropologists discovered many fossils and evidence of human occupation perhaps as early as seven million years ago ( Before present , BP). Fossil remains of several species of early apelike humans thought to have evolved into modern humans, such as Australopithecus afarensis radiometrically dated to approximately 3.9–3.0 million years BP, Paranthropus boisei (c. 2.3–1.4 million years BP) and Homo ergaster (c. 1.9 million–600,000 years BP) have been discovered. After
4521-444: Is one of the most important constituents of silver and karat gold solders used in the jewelry industry, modifying the color, hardness and melting point of the resulting alloys. Some lead-free solders consist of tin alloyed with a small proportion of copper and other metals. The alloy of copper and nickel , called cupronickel , is used in low-denomination coins, often for the outer cladding. The US five-cent coin (currently called
4658-437: Is recovered from mine tailings and heaps. A variety of methods are used including leaching with sulfuric acid, ammonia, ferric chloride. Biological methods are also used. A significant source of copper is from recycling. Recycling is facilitated because copper is usually deployed in its metallic state. In 2001, a typical automobile contained 20–30 kg of copper. Recycling usually begins with some melting process using
4795-793: Is surrounded by the Mediterranean Sea to the north, the Arabian Plate and the Gulf of Aqaba to the northeast, the Indian Ocean to the southeast and the Atlantic Ocean to the west. The continent includes Madagascar and various archipelagos . It contains 54 fully recognised sovereign states , eight cities and islands that are part of non-African states , and two de facto independent states with limited or no recognition . This count does not include Malta and Sicily , which are geologically part of
4932-411: Is used for various objects exposed to seawater, though it is vulnerable to the sulfides sometimes found in polluted harbors and estuaries. Alloys of copper with aluminium (about 7%) have a golden color and are used in decorations. Shakudō is a Japanese decorative alloy of copper containing a low percentage of gold, typically 4–10%, that can be patinated to a dark blue or black color. Copper forms
5069-649: The 11th dynasty , based in Thebes , conquered the others to form the Middle Kingdom of Egypt , with the 12th dynasty expanding into Lower Nubia at the expense of Kerma . In 1700 BC, the Middle Kingdom fractured in two, ushering in the Second Intermediate Period . The Hyksos , a militaristic people from Palestine , invaded and conquered Lower Egypt, while Kerma coordinated invasions deep into Egypt to reach its greatest extent. In 1550 BC,
5206-627: The 18th dynasty expelled the Hyksos , and established the New Kingdom of Egypt . Using the advanced military technology the Hyksos had brought, the New Kingdom conquered the Levant from the Canaanites , Mittani , Amorites , and Hittites , and extinguished Kerma , incorporating Nubia into the empire, and sending the Egyptian empire into its golden age. Internal struggles, drought, famine, and invasions by
5343-659: The Benin Empire . Towards the end of the 3rd century AD, a wet period in the Sahel created areas for human habitation and exploitation that had not been habitable for the best part of a millennium, with the Kingdom of Wagadu , the local name of the Ghana Empire , rising out of the Tichitt culture , growing wealthy following the introduction of the camel to the western Sahel, revolutionising
5480-675: The British Geological Survey , in 2005, Chile was the top producer of copper with at least one-third of the world share followed by the United States, Indonesia and Peru. Copper can also be recovered through the in-situ leach process. Several sites in the state of Arizona are considered prime candidates for this method. The amount of copper in use is increasing and the quantity available is barely sufficient to allow all countries to reach developed world levels of usage. An alternative source of copper for collection currently being researched are polymetallic nodules , which are located at
5617-629: The Cahora Bassa and Kariba lakes, and in the plains of the Mana Pools , Caprivi Strip , Liuwa-Luena-Baroste-Siloana , Shire , Luangwa and Lake Nyassa , the latter three of which are navigable within two its thirteen sub-basins. Two major sub-basins in the Zambezi basin are interconnected with other major African systems, namely: (a) the Lake Nyassa/Shire River sub-basin, which connects with
Zambezi Basin - Misplaced Pages Continue
5754-521: The Cold War , and neocolonialism . Despite this low concentration of wealth, recent economic expansion and a large and young population make Africa an important economic market in the broader global context. Africa has a large quantity of natural resources and food resources, including diamonds , sugar , salt , gold , iron , cobalt , uranium , copper , bauxite , silver , petroleum , natural gas , cocoa beans , and tropical fruit . The continent
5891-854: The Congo Basin , the Empire of Kitara in the African Great Lakes , the Luba Empire in the Upemba Depression , the Kilwa Sultanate in the Swahili coast by crowding out Azania , with Rhapta being its last stronghold by the 1st century AD, and forming various city states constituting the Swahili civilisation . These migrations also prefaced the Kingdom of Mapungubwe in the Zambezi basin . After reaching
6028-726: The Ekoi civilisation rose circa 2nd century AD, and are most notable for constructing the Ikom monoliths and developing the Nsibidi script . Pre-colonial Africa possessed as many as 10,000 different states and polities. These included small family groups of hunter-gatherers such as the San people of southern Africa; larger, more structured groups such as the family clan groupings of the Bantu peoples of central, southern, and eastern Africa; heavily structured clan groups in
6165-595: The Fatimids , Almoravids , Almohads , Ayyubids , Mamluks , Kongo , Mwene Muji , Luba , Lunda , Kitara , Aksum , Ethiopia , Adal , Ajuran , Kilwa , Sakalava , Imerina , Maravi , Mutapa , Rozvi , Mthwakazi , and Zulu . Slave trades created various diasporas , especially in the Americas . From the late 19th century to early 20th century, driven by the Second Industrial Revolution , most of Africa
6302-588: The Great Lakes may have also been mining copper during this time, making it one of the oldest known examples of copper extraction in the world. There is evidence from prehistoric lead pollution from lakes in Michigan that people in the region began mining copper c. 6000 BC . Evidence suggests that utilitarian copper objects fell increasingly out of use in the Old Copper Complex of North America during
6439-839: The Great Rift Valley , and; (b) the perennial river bifurcation in the Selinda Spillway (or Magwegana river), in the Cuando River sub-basin, which connects the Zambezi Basin to the Kalahari Basin . Africa Africa is the world's second-largest and second-most populous continent after Asia . At about 30.3 million km (11.7 million square miles) including adjacent islands, it covers 20% of Earth 's land area and 6% of its total surface area. With nearly 1.4 billion people as of 2021, it accounts for about 18% of
6576-617: The Horn of Africa ; the large Sahelian kingdoms ; and autonomous city-states and kingdoms, such as those of the Akan ; Edo , Yoruba , and Igbo people in West Africa; and the Swahili coastal trading towns of Southeast Africa. By the 9th century AD, a string of dynastic states, including the earliest Hausa states, stretched across the sub-Saharan savannah from the western regions to central Sudan. The most powerful of these states were Ghana , Gao , and
6713-536: The International Resource Panel 's Metal Stocks in Society report , the global per capita stock of copper in use in society is 35–55 kg. Much of this is in more-developed countries (140–300 kg per capita) rather than less-developed countries (30–40 kg per capita). The process of recycling copper is roughly the same as is used to extract copper but requires fewer steps. High-purity scrap copper
6850-718: The Isthmus of Suez in Egypt. Other migrations of modern humans within the African continent have been dated to that time, with evidence of early human settlement found in Southern Africa, Southeast Africa, North Africa, and the Sahara . The size of the Sahara has historically been extremely variable, with its area rapidly fluctuating and at times disappearing depending on global climatic conditions. At
6987-667: The Kanem-Bornu Empire . Ghana declined in the eleventh century, but was succeeded by the Mali Empire , which consolidated much of western Sudan in the thirteenth century. Kanem accepted Islam in the eleventh century. In the forested regions of the West African coast, independent kingdoms grew with little influence from the Muslim north. The Kingdom of Nri , which was ruled by the Eze Nri ,
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#17328451791147124-524: The Kingdom of Dahomey , and the Oyo Empire ) adopted different ways of adapting to the shift. Asante and Dahomey concentrated on the development of "legitimate commerce" in the form of palm oil , cocoa , timber and gold, forming the bedrock of West Africa's modern export trade. The Oyo Empire, unable to adapt, collapsed into civil wars. The Scramble for Africa was the conquest and colonisation of most of Africa by seven Western European powers driven by
7261-661: The Mauro-Roman Kingdom and its numerous successor polities in the Maghreb, namely the kingdoms of Ouarsenis , Aurès , and Altava . The Vandals ruled Ifriqiya for a century until Byzantine reconquest in the early 6th century AD. The Byzantines and the Berber kingdoms fought minor inconsequential conflicts, such as in the case of Garmul , however largely coexisted. Further inland to the Byzantine Exarchate of Africa were
7398-437: The Neolithic period and the Bronze Age was formerly termed the Chalcolithic period (copper-stone), when copper tools were used with stone tools. The term has gradually fallen out of favor because in some parts of the world, the Chalcolithic and Neolithic are coterminous at both ends. Brass, an alloy of copper and zinc, is of much more recent origin. It was known to the Greeks, but became a significant supplement to bronze during
7535-512: The Noba caused their disintegration into Makuria , Alodia , and Nobatia in the 5th century AD. The Romans managed to hold on to Egypt for the rest of the ancient period. In the Horn of Africa , there was the Land of Punt , a kingdom on the Red Sea , likely located in modern-day Eritrea or northern Somaliland . The Ancient Egyptians initially traded via middle-men with Punt until in 2350 BC when they established direct relations. They would become close trading partners for over
7672-430: The Nok culture from 1500 BC in modern-day Nigeria , the Daima culture around Lake Chad from 550 BC, Djenné-Djenno from 250 BC in modern-day Mali , and the Serer civilisation in modern-day Senegal , which built the Senegambian stone circles from the 3rd century BC. There is also detailed record of Igodomigodo , a small kingdom founded presumably in 40 BC, which would later go on to form
7809-399: The Ovambo kingdoms , most of which were later conquered. The 1884 Berlin Conference regulated European colonisation and trade in Africa, and is seen as emblematic of the "scramble". In the last quarter of the 19th century, there were considerable political rivalries between the European empires , which provided the impetus for the colonisation. The later years of the 19th century saw
7946-404: The Punic Wars against the expansionary Roman Republic , however momentum in these wars was not linear, with Carthage initially experiencing considerable success in the Second Punic War following Hannibal 's infamous crossing of the alps into northern Italy . Their defeat and subsequent collapse of their empire would produce two further polities in the Maghreb; Numidia , which had assisted
8083-447: The Romans in 30 BC. The Crisis of the Third Century in the Roman Empire freed the Levantine city state of Palmyra , which conquered Egypt ; their brief rule ended when they were reconquered by the Romans . In the midst of this, Kush regained independence from Egypt, and they would persist as a major regional power until, having been weakened from internal rebellion amid worsening climatic conditions, invasions by Aksum and
8220-494: The Sanhaja in modern-day Algeria , a broad grouping of three groupings of tribal confederations , one of which is the Masmuda grouping in modern-day Morocco , along with the nomadic Zenata ; their composite tribes would later go onto shape much of North African history . In the western Sahel the rise of settled communities occurred largely as a result of the domestication of millet and of sorghum . Archaeology points to sizable urban populations in West Africa beginning in
8357-488: The Sao civilisation flourished for over a millennium beginning in the 6th century BC, in territory that later became part of present-day Cameroon and Chad . Sao artifacts show that they were skilled workers in bronze , copper , and iron , with finds including bronze sculptures, terracotta statues of human and animal figures, coins, funerary urns, household utensils, jewellery, highly decorated pottery, and spears. Nearby, around Lake Ejagham in south-west Cameroon ,
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#17328451791148494-419: The Sassanid Empire and the Himyarite Kingdom in Arabia. The Maghreb and Ifriqiya were mostly cut off from the cradle of civilisation in Egypt by the Libyan desert , exacerbated by Egyptian boats being tailored to the Nile and not coping well in the open Mediterranean Sea . This caused its societies to develop contiguous to those of Southern Europe , until Phoenician settlements came to dominate
8631-417: The Second Industrial Revolution during the era of " New Imperialism " (1833–1914): Belgium , France , Germany , United Kingdom , Italy , Portugal and Spain . In 1870, 10% of the continent was formally under European control. By 1914, this figure had risen to almost 90%; the only states retaining sovereignty were Liberia , Ethiopia , Egba , Aussa , Senusiyya , Mbunda , the Dervish State , and
8768-425: The Vinča culture date to 4500 BC. Sumerian and Egyptian artifacts of copper and bronze alloys date to 3000 BC. Egyptian Blue , or cuprorivaite (calcium copper silicate) is a synthetic pigment that contains copper and started being used in ancient Egypt around 3250 BC. The manufacturing process of Egyptian blue was known to the Romans, but by the fourth century AD the pigment fell out of use and
8905-404: The Zambezi , the Bantu continued southward, with eastern groups continuing to modern-day Mozambique and reaching Maputo in the 2nd century AD. Further to the south, settlements of Bantu peoples who were iron-using agriculturists and herdsmen were well established south of the Limpopo River by the 4th century AD, displacing and absorbing the Khoisan . By the Chari River south of Lake Chad
9042-419: The presidential system of rule. However, few of them have been able to sustain democratic governments on a permanent basis—per the criteria laid out by Lührmann et al. (2018), only Botswana and Mauritius have been consistently democratic for the entirety of their post-colonial history. Most African countries have experienced several coups or periods of military dictatorship . Between 1990 and 2018, though,
9179-780: The trans-Saharan trade that linked their capital and Aoudaghost with Tahert and Sijilmasa in North Africa. Soninke traditions likely contain content from prehistory, mentioning four previous foundings of Wagadu , and holds that the final founding of Wagadu occurred after their first king did a deal with Bida , a serpent deity who was guarding a well, to sacrifice one maiden a year in exchange for assurance regarding plenty of rainfall and gold supply. Wagadu's core traversed modern-day southern Mauritania and western Mali , and Soninke tradition portrays early Ghana as warlike, with horse-mounted warriors key to increasing its territory and population, although details of their expansion are extremely scarce. Wagadu made its profits from maintaining
9316-410: The tropic of Cancer , in the northern temperate zone . In the other extreme of the continent, southern Namibia , southern Botswana , great parts of South Africa , the entire territories of Lesotho and Eswatini and the southern tips of Mozambique and Madagascar are located below the tropic of Capricorn , in the southern temperate zone . Africa is highly biodiverse ; it is the continent with
9453-424: The written word . During the colonial period , oral sources were deprecated by European historians, which gave them the impression Africa had no recorded history. African historiography became organized at the academic level in the mid-20th century, and saw a movement towards utilising oral sources in a multidisciplinary approach, culminating in the General History of Africa , edited by specialists from across
9590-459: The 16th and 19th centuries. In West Africa, the decline of the Atlantic slave trade in the 1820s caused dramatic economic shifts in local polities. The gradual decline of slave-trading, prompted by a lack of demand for slaves in the New World , increasing anti-slavery legislation in Europe and America, and the British Royal Navy's increasing presence off the West African coast, obliged African states to adopt new economies. Between 1808 and 1860,
9727-420: The 16th century to 1975, after the Estado Novo regime was overthrown in a military coup in Lisbon . Rhodesia unilaterally declared independence from the United Kingdom in 1965, under the white minority government of Ian Smith , but was not internationally recognized as an independent state (as Zimbabwe ) until 1980, when black nationalists gained power after a bitter guerrilla war . Although South Africa
9864-590: The 1st and 4th cataracts of the Nile . The 4th dynasty oversaw the height of the Old Kingdom , and constructed many great pyramids . Under the 6th dynasty power gradually decentralised to the nomarchs, culminating in the disintegration of the kingdom, exacerbated by drought and famine, thus commencing the First Intermediate Period in 2200 BC. This shattered state would last until 2055 BC when
10001-567: The 2nd century BC Mauretania fought alongside Numidia's Jugurtha in the Jugurthine War against the Romans after he had usurped the Numidian throne from a Roman ally. Together they inflicted heavy casualties that quaked the Roman Senate , with the war only ending inconclusively when Mauretania's Bocchus I sold out Jugurtha to the Romans. At the turn of the millennium, they both would face
10138-663: The 4th millennium BC the Congo Basin was inhabited by the Bambenga , Bayaka , Bakoya , and Babongo in the west, the Bambuti in the east , and the Batwa who were widely scattered and also present in the Great Lakes region ; together they are grouped as Pygmies . On the later-named Swahili coast there were Cushitic -speaking peoples, and the Khoisan (a neologism for the Khoekhoe and San ) in
10275-416: The 4th millennium BC, which had crucially developed iron metallurgy by 1200 BC, in both smelting and forging for tools and weapons. Extensive east-west belts of deserts , grasslands , and forests from north to south were crucial for the moulding of their respective societies and meant that prior to the accession of trans-Saharan trade routes , symbiotic trade relations developed in response to
10412-539: The 9th or 10th century AD. Carbon dating has established mining at Alderley Edge in Cheshire , UK, at 2280 to 1890 BC. Ötzi the Iceman , a male dated from 3300 to 3200 BC, was found with an axe with a copper head 99.7% pure; high levels of arsenic in his hair suggest an involvement in copper smelting. Experience with copper has assisted the development of other metals; in particular, copper smelting likely led to
10549-513: The African continent. Algeria is Africa's largest country by area, and Nigeria is its largest by population. African nations cooperate through the establishment of the African Union , which is headquartered in Addis Ababa . Africa straddles the equator and the prime meridian . It is the only continent to stretch from the northern temperate to the southern temperate zones. The majority of
10686-678: The Assyrians in 663 BC in reprisal for their expansion towards the Assyrian Empire . The Assyrians installed a puppet dynasty that later gained independence and once more unified Egypt , until they were conquered by the Achaemenid Empire in 525 BC. Egypt regained independence under the 28th dynasty in 404 BC but they were reconquered by the Achaemenids in 343 BC. The conquest of Achaemenid Egypt by Alexander
10823-553: The British West Africa Squadron seized approximately 1,600 slave ships and freed 150,000 Africans who were aboard. Action was also taken against African leaders who refused to agree to British treaties to outlaw the trade, for example against "the usurping King of Lagos ", deposed in 1851. Anti-slavery treaties were signed with over 50 African rulers. The largest powers of West Africa (the Asante Confederacy ,
10960-565: The Bronze Age and a shift towards an increased production of ornamental copper objects occurred. Natural bronze, a type of copper made from ores rich in silicon, arsenic, and (rarely) tin, came into general use in the Balkans around 5500 BC. Alloying copper with tin to make bronze was first practiced about 4000 years after the discovery of copper smelting, and about 2000 years after "natural bronze" had come into general use. Bronze artifacts from
11097-635: The Great in 332 BC marked the beginning of Hellenistic rule and the installation of the Macedonian Ptolemaic dynasty in Egypt. The Ptolemaics lost their holdings outside of Africa to the Seleucids in the Syrian Wars , expanded into Cyrenaica and subjugated Kush in the 3rd century BC. In the 1st century BC, Ptolemaic Egypt became entangled in a Roman civil war , leading to its conquest by
11234-564: The Iberian peninsula during the eleventh century. The Banu Hilal and Banu Ma'qil were a collection of Arab Bedouin tribes from the Arabian Peninsula who migrated westwards via Egypt between the eleventh and thirteenth centuries. Their migration resulted in the fusion of the Arabs and Berbers, where the locals were Arabized , and Arab culture absorbed elements of the local culture, under
11371-535: The Middle East; a copper pendant was found in northern Iraq that dates to 8700 BC. Evidence suggests that gold and meteoric iron (but not smelted iron) were the only metals used by humans before copper. The history of copper metallurgy is thought to follow this sequence: first, cold working of native copper, then annealing , smelting , and, finally, lost-wax casting . In southeastern Anatolia , all four of these techniques appear more or less simultaneously at
11508-550: The Persian prophet Mani to consider Aksum as one of the four great powers of the 3rd century AD alongside Persia , Rome , and China . In the 4th century AD Aksum's king converted to Christianity and Aksum's population, who had followed syncretic mixes of local beliefs , slowly followed. The end of the 5th century saw Aksum allied with the Byzantine Empire , who viewed themselves as defenders of Christendom , balanced against
11645-558: The Romans in the Second Punic War, Mauretania , a Mauri tribal kingdom and home of the legendary King Atlas , and various tribes such as Garamantes , Musulamii , and Bavares . The Third Punic War would result in Carthage's total defeat in 146 BC and the Romans established the province of Africa , with Numidia assuming control of many of Carthage's African ports. Towards the end of
11782-756: The Sahara region was becoming increasingly dry and hostile. Around 3500 BC, due to a tilt in the Earth's orbit , the Sahara experienced a period of rapid desertification. The population trekked out of the Sahara region towards the Nile Valley below the Second Cataract where they made permanent or semi-permanent settlements. A major climatic recession occurred, lessening the heavy and persistent rains in Central and Eastern Africa . Since this time, dry conditions have prevailed in Eastern Africa and, increasingly during
11919-517: The Saharan climate started to become drier at an exceedingly fast pace. This climate change caused lakes and rivers to shrink significantly and caused increasing desertification . This, in turn, decreased the amount of land conducive to settlements and encouraged migrations of farming communities to the more tropical climate of West Africa. During the first millennium BC, a reduction in wild grain populations related to changing climate conditions facilitated
12056-521: The affected areas is highly acidic, with a pH range of 2.1–4.9, and shows elevated electrical conductivity levels between 280 and 1561 mS/cm. These changes in water chemistry make the environment inhospitable for fish, essentially rendering the water uninhabitable for aquatic life. Numerous copper alloys have been formulated, many with important uses. Brass is an alloy of copper and zinc . Bronze usually refers to copper- tin alloys, but can refer to any alloy of copper such as aluminium bronze . Copper
12193-423: The aim of strengthening cooperation in sharing its resources concerned. Another supranational initiative for watershed management is Zambezi River System Action Plan (ZACPLAN). The drainage area of the basin covers Angola , Botswana , Tanzania , Namibia , Zambia , Zimbabwe , Malawi and Mozambique , being the main supplier of fresh water, electricity and fish to the populations of these regions, mainly from
12330-531: The atmosphere; 150 mg/kg in soil; 30 mg/kg in vegetation; 2 μg/L in freshwater and 0.5 μg/L in seawater. Most copper is mined or extracted as copper sulfides from large open pit mines in porphyry copper deposits that contain 0.4 to 1.0% copper. Sites include Chuquicamata , in Chile, Bingham Canyon Mine , in Utah, United States, and El Chino Mine , in New Mexico, United States. According to
12467-731: The beginning of the Neolithic c. 7500 BC . Copper smelting was independently invented in different places. The earliest evidence of lost-wax casting copper comes from an amulet found in Mehrgarh , Pakistan, and is dated to 4000 BC. Investment casting was invented in 4500–4000 BC in Southeast Asia Smelting was probably discovered in China before 2800 BC, in Central America around 600 AD, and in West Africa about
12604-527: The company, especially when sourced from fossil fuels, and from engines required for copper extraction and refinement. Companies that mine land often mismanage waste, rendering the area sterile for life. Additionally, nearby rivers and forests are also negatively impacted. The Philippines is an example of a region where land is overexploited by mining companies. Copper mining waste in Valea Şesei, Romania, has significantly altered nearby water properties. The water in
12741-532: The continent and its countries are in the Northern Hemisphere , with a substantial portion and a number of countries in the Southern Hemisphere . Most of the continent lies in the tropics, except for a large part of Western Sahara , Algeria , Libya and Egypt , the northern tip of Mauritania , and the entire territories of Morocco , Ceuta , Melilla , and Tunisia , which in turn are located above
12878-463: The continent as a whole has trended towards more democratic governance. Upon independence an overwhelming majority of Africans lived in extreme poverty . The continent suffered from the lack of infrastructural or industrial development under colonial rule, along with political instability. With limited financial resources or access to global markets, relatively stable countries such as Kenya still experienced only very slow economic development. Only
13015-424: The continent most vulnerable to climate change . The history of Africa is long, complex, and varied, and has often been under-appreciated by the global historical community . In African societies the oral word is revered, and they have generally recorded their history via oral tradition , which has led anthropologists to term them oral civilisations, contrasted with literate civilisations which pride
13152-457: The continent's south. The Bantu expansion constituted a major series of migrations of Bantu peoples from central Africa to eastern and southern Africa and was substantial in the settling of the continent. Commencing in the 2nd millennium BC, the Bantu began to migrate from Cameroon to central, eastern, and southern Africa, laying the foundations for future states such as the Kingdom of Kongo in
13289-473: The continent. Africa, particularly Eastern Africa , is widely accepted to be the place of origin of humans and the Hominidae clade , also known as the great apes . The earliest hominids and their ancestors have been dated to around 7 million years ago, and Homo sapiens (modern human) are believed to have originated in Africa 350,000 to 260,000 years ago. Africa is also considered by anthropologists to be
13426-522: The deprotonated amide ligands. Complexes of copper(III) are also found as intermediates in reactions of organocopper compounds, for example in the Kharasch–Sosnovsky reaction . A timeline of copper illustrates how this metal has advanced human civilization for the past 11,000 years. Copper occurs naturally as native metallic copper and was known to some of the oldest civilizations on record. The history of copper use dates to 9000 BC in
13563-454: The depths of the Pacific Ocean approximately 3000–6500 meters below sea level. These nodules contain other valuable metals such as cobalt and nickel . Copper has been in use for at least 10,000 years, but more than 95% of all copper ever mined and smelted has been extracted since 1900. As with many natural resources, the total amount of copper on Earth is vast, with around 10 tons in
13700-550: The discovery of iron smelting . Production in the Old Copper Complex in Michigan and Wisconsin is dated between 6500 and 3000 BC. A copper spearpoint found in Wisconsin has been dated to 6500 BC. Copper usage by the indigenous peoples of the Old Copper Complex from the Great Lakes region of North America has been radiometrically dated to as far back as 7500 BC. Indigenous peoples of North America around
13837-428: The earliest instances of agriculture in human history. Its cultivation would gradually spread across Africa, before spreading to India around 2000 BC. People around modern-day Mauritania started making pottery and built stone settlements (e.g., Tichitt , Oualata ). Fishing, using bone-tipped harpoons , became a major activity in the numerous streams and lakes formed from the increased rains. In West Africa,
13974-535: The end of the Ice ages , estimated to have been around 10,500 BC, the Sahara had again become a green fertile valley, and its African populations returned from the interior and coastal highlands in sub-Saharan Africa , with rock art paintings depicting a fertile Sahara and large populations discovered in Tassili n'Ajjer dating back perhaps 10 millennia. However, the warming and drying climate meant that by 5,000 BC,
14111-625: The evolution of Homo sapiens approximately 350,000 to 260,000 years BP in Africa, the continent was mainly populated by groups of hunter-gatherers . These first modern humans left Africa and populated the rest of the globe during the Out of Africa II migration dated to approximately 50,000 years BP, exiting the continent either across Bab-el-Mandeb over the Red Sea , the Strait of Gibraltar in Morocco, or
14248-647: The expansion of farming communities and the rapid adoption of rice cultivation around the Niger River. By the first millennium BC, ironworking had been introduced in Northern Africa. Around that time it also became established in parts of sub-Saharan Africa, either through independent invention there or diffusion from the north and vanished under unknown circumstances around 500 AD, having lasted approximately 2,000 years, and by 500 BC, metalworking began to become commonplace in West Africa. Ironworking
14385-545: The fastest water exchange rate (speed of water ligands attaching and detaching) for any transition metal aquo complex . Adding aqueous sodium hydroxide causes the precipitation of light blue solid copper(II) hydroxide . A simplified equation is: Aqueous ammonia results in the same precipitate. Upon adding excess ammonia, the precipitate dissolves, forming tetraamminecopper(II) : Many other oxyanions form complexes; these include copper(II) acetate , copper(II) nitrate , and copper(II) carbonate . Copper(II) sulfate forms
14522-502: The growth and expansion of Aksum in the 1st century BC. Along the Horn's coast there were many ancient Somali city-states that thrived off of the wider Red Sea trade and transported their cargo via beden , exporting myrrh , frankincense , spices , gum , incense , and ivory , with freedom from Roman interference causing Indians to give the cities a lucrative monopoly on cinnamon from ancient India . The Kingdom of Aksum grew from
14659-443: The historical process is largely a communal one, with eyewitness accounts, hearsay , reminiscences, and occasionally visions , dreams, and hallucinations, crafted into oral traditions . Time is sometimes mythical and social, and truth generally viewed as relativist . Oral tradition can be exoteric or esoteric . It speaks to people according to their understanding, unveiling itself in accordance with their aptitudes, and
14796-509: The kingdoms of Lower Egypt and Upper Egypt in northeast Africa . Around 3100 BC Upper Egypt conquered Lower Egypt to unify Egypt under the 1st dynasty , with the process of consolidation and assimilation completed by the time of the 3rd dynasty who formed the Old Kingdom of Egypt in 2686 BC. The Kingdom of Kerma emerged around this time to become the dominant force in Nubia , controlling territory as large as Egypt between
14933-507: The largest number of megafauna species, as it was least affected by the extinction of the Pleistocene megafauna . However, Africa also is heavily affected by a wide range of environmental issues , including desertification, deforestation, water scarcity , and pollution . These entrenched environmental concerns are expected to worsen as climate change impacts Africa . The UN Intergovernmental Panel on Climate Change has identified Africa as
15070-599: The last 200 years, in Ethiopia . The domestication of cattle in Africa preceded agriculture and seems to have existed alongside hunter-gatherer cultures. It is speculated that by 6,000 BC, cattle were domesticated in North Africa. In the Sahara-Nile complex, people domesticated many animals, including the donkey and a small screw-horned goat that was common from Algeria to Nubia . Between 10,000 and 9,000 BC, pottery
15207-560: The last five nations. The basin is home to immense wet plains, being responsible for the climatic regulation of a rich ecosystem of savannas and humid forests that surround it. Its main navigable course is through the Zambezi River, being the stretch of the mouth in the Indian Ocean (more precisely in the Mozambique Channel ) until it surrounds the city of Tete , in the northwest of Mozambique. There are also navigable courses in
15344-511: The later spelling first used around 1530. Copper, silver , and gold are in group 11 of the periodic table; these three metals have one s-orbital electron on top of a filled d- electron shell and are characterized by high ductility , and electrical and thermal conductivity. The filled d-shells in these elements contribute little to interatomic interactions, which are dominated by the s-electrons through metallic bonds . Unlike metals with incomplete d-shells, metallic bonds in copper are lacking
15481-419: The level of <1% Cu. Concentration of the ore is required, which begins with comminution followed by froth flotation . The remaining concentrate is the smelted, which can be described with two simplified equations: Cuprous oxide reacts with cuprous sulfide to convert to blister copper upon heating This roasting gives matte copper, roughly 50% Cu by weight, which is purified by electrolysis. Depending on
15618-472: The modern world. The price of copper is volatile . After a peak in 2022 the price unexpectedly fell. The global market for copper is one of the most commodified and financialized of the commodity markets , and has been so for decades. The great majority of copper ores are sulfides. Common ores are the sulfides chalcopyrite (CuFeS 2 ), bornite (Cu 5 FeS 4 ) and, to a lesser extent, covellite (CuS) and chalcocite (Cu 2 S). These ores occur at
15755-643: The most genetically diverse continent as a result of being the longest inhabited. In the 4th and 3rd millennia BC Ancient Egypt , Kerma , Punt , and the Tichitt Tradition emerged in North , East and West Africa , while from 4000 BC until 1000 AD the Bantu expansion was substantial in laying the foundations for societies and states in Central , East , and Southern Africa . Some African empires include Wagadu , Mali , Songhai , Sokoto , Ife , Benin , Asante ,
15892-399: The most lucrative trading locations in the Gulf of Tunis . Phoenician settlements subsequently grew into Ancient Carthage after gaining independence from Phoenicia in the 6th century BC, and they would build an extensive empire and a strict mercantile network, all secured by one of the largest and most powerful navies in the ancient Mediterranean . Carthage would meet its demise in
16029-516: The numerous copper sulfides , important examples include copper(I) sulfide ( Cu 2 S ) and copper monosulfide ( CuS ). Cuprous halides with fluorine , chlorine , bromine , and iodine are known, as are cupric halides with fluorine , chlorine , and bromine . Attempts to prepare copper(II) iodide yield only copper(I) iodide and iodine. Copper forms coordination complexes with ligands . In aqueous solution, copper(II) exists as [Cu(H 2 O) 6 ] . This complex exhibits
16166-439: The official religion, built mosques, and brought to Gao Muslim scholars, including al-Maghili (d.1504), the founder of an important tradition of Sudanic African Muslim scholarship. By the eleventh century, some Hausa states – such as Kano , Jigawa , Katsina , and Gobir – had developed into walled towns engaging in trade, servicing caravans , and the manufacture of goods. Until the fifteenth century, these small states were on
16303-460: The opportunities afforded by north–south diversity in ecosystems. Various civilisations prospered in this period. From 4000 BC, the Tichitt culture in modern-day Mauritania and Mali was the oldest known complexly organised society in West Africa, with a four tiered hierarchical social structure. Other civilisations include the Kintampo culture from 2500 BC in modern-day Ghana ,
16440-428: The ore, sometimes other metals are obtained during the electrolysis including platinum and gold. Aside from sulfides, another family of ores are oxides. Approximately 15% of the world's copper supply derives from these oxides. The beneficiation process for oxides involves extraction with sulfuric acid solutions followed by electrolysis. In parallel with the above method for "concentrated" sulfide and oxide ores, copper
16577-524: The periphery of the major Sudanic empires of the era, paying tribute to Songhai to the west and Kanem-Borno to the east. Slavery had long been practiced in Africa. Between the 15th and the 19th centuries, the Atlantic slave trade took an estimated 7–12 million slaves to the New World. In addition, more than 1 million Europeans were captured by Barbary pirates and sold as slaves in North Africa between
16714-585: The predecessor to the African Union. The nascent countries decided to keep their colonial borders, with traditional power structures used in governance to varying degrees. Afri was a Latin name used to refer to the inhabitants of what was then known as northern Africa , located west of the Nile river, and in its widest sense referring to all lands south of the Mediterranean , also known as Ancient Libya . This name seems to have originally referred to
16851-475: The same fate as Carthage and be conquered by the Romans who established Mauretania and Numidia as provinces of their empire, while Musulamii , led by Tacfarinas , and Garamantes were eventually defeated in war in the 1st century AD however weren't conquered. In the 5th century AD the Vandals conquered north Africa precipitating the fall of Rome . Swathes of indigenous peoples would regain self-governance in
16988-715: The secret to its manufacturing process became lost. The Romans said the blue pigment was made from copper, silica, lime and natron and was known to them as caeruleum . The Bronze Age began in Southeastern Europe around 3700–3300 BC, in Northwestern Europe about 2500 BC. It ended with the beginning of the Iron Age, 2000–1000 BC in the Near East, and 600 BC in Northern Europe. The transition between
17125-438: The sugar is signaled by a color change from blue Cu(II) to reddish copper(I) oxide. Schweizer's reagent and related complexes with ethylenediamine and other amines dissolve cellulose . Amino acids such as cystine form very stable chelate complexes with copper(II) including in the form of metal-organic biohybrids (MOBs). Many wet-chemical tests for copper ions exist, one involving potassium ferricyanide , which gives
17262-399: The top kilometer of Earth's crust, which is about 5 million years' worth at the current rate of extraction. However, only a tiny fraction of these reserves is economically viable with present-day prices and technologies. Estimates of copper reserves available for mining vary from 25 to 60 years, depending on core assumptions such as the growth rate. Recycling is a major source of copper in
17399-481: The two continents by the geographer Ptolemy (85–165 CE), indicating Alexandria along the Prime Meridian and making the isthmus of Suez and the Red Sea the boundary between Asia and Africa. As Europeans came to understand the real extent of the continent, the idea of "Africa" expanded with their knowledge. Other etymological hypotheses have been postulated for the ancient name "Africa": In African societies,
17536-489: The unifying framework of Islam. Following the breakup of Mali, a local leader named Sonni Ali (1464–1492) founded the Songhai Empire in the region of middle Niger and the western Sudan and took control of the trans-Saharan trade. Sonni Ali seized Timbuktu in 1468 and Jenne in 1473, building his regime on trade revenues and the cooperation of Muslim merchants. His successor Askia Mohammad I (1493–1528) made Islam
17673-516: The wet phase ushered in an expanding rainforest and wooded savanna from Senegal to Cameroon . Between 9,000 and 5,000 BC, Niger–Congo speakers domesticated the oil palm and raffia palm . Black-eyed peas and voandzeia (African groundnuts), were domesticated, followed by okra and kola nuts . Since most of the plants grew in the forest, the Niger–Congo speakers invented polished stone axes for clearing forest. Around 4,000 BC,
17810-497: The world's human population . Africa's population is the youngest among all the continents; the median age in 2012 was 19.7, when the worldwide median age was 30.4. Based on 2024 projections, Africa's population will reach 3.8 billion people by 2099. Africa is the least wealthy inhabited continent per capita and second-least wealthy by total wealth, ahead of Oceania . Scholars have attributed this to different factors including geography , climate , corruption , colonialism ,
17947-418: Was rapidly conquered and colonised by European nations , save for Ethiopia and Liberia . European rule had significant impacts on Africa's societies , and colonies were maintained for the purpose of economic exploitation and extraction of natural resources. Most present states emerged from a process of decolonisation following World War II , and established the Organisation of African Unity in 1963,
18084-495: Was established around the ninth century, making it one of the oldest kingdoms in present-day Nigeri. The Nri kingdom is famous for its elaborate bronzes , found at the town of Igbo-Ukwu . The Kingdom of Ife , historically the first of these Yoruba city-states or kingdoms, established government under a priestly oba ('king' or 'ruler' in the Yoruba language ), called the Ooni of Ife . Ife
18221-515: Was found in 1857 on the Keweenaw Peninsula in Michigan, US. Native copper is a polycrystal , with the largest single crystal ever described measuring 4.4 × 3.2 × 3.2 cm . Copper is the 26th most abundant element in Earth's crust , representing 50 ppm compared with 75 ppm for zinc , and 14 ppm for lead . Typical background concentrations of copper do not exceed 1 ng/m in
18358-450: Was fully established by roughly 500 BC in many areas of East and West Africa, although other regions did not begin ironworking until the early centuries AD. Copper objects from Egypt , North Africa, Nubia, and Ethiopia dating from around 500 BC have been excavated in West Africa, suggesting that Trans-Saharan trade networks had been established by this date. From 3500 BC, nomes (ruled by nomarchs ) coalesced to form
18495-593: Was independently invented in the region of Mali in the savannah of West Africa. In the steppes and savannahs of the Sahara and Sahel in Northern West Africa, people possibly ancestral to modern Nilo-Saharan and Mandé cultures started to collect wild millet , around 8,000 to 6,000 BC. Later, gourds , watermelons , castor beans , and cotton were also collected. Sorghum was first domesticated in Eastern Sudan around 4,000 BC, in one of
18632-547: Was noted as a major religious and cultural centre in West Africa and for its unique naturalistic tradition of bronze sculpture. The Ife model of government was adapted by the Oyo Empire , whose obas, called the Alaafins of Oyo , controlled many other Yoruba and non-Yoruba city-states and kingdoms including the Fon Kingdom of Dahomey . The Almoravids were a Berber dynasty from the Sahara that spread over northwestern Africa and
18769-514: Was one of the first African countries to gain independence, the state remained under the control of the country's white minority, initially through qualified voting rights and from 1956 by a system of racial segregation known as apartheid , until 1994. Today, Africa contains 54 sovereign countries. Since independence, African states have frequently been hampered by instability, corruption, violence, and authoritarianism. The vast majority of African states are republics that operate under some form of
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