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Iron Age

Iron Age

:This article is about the archaeological period known as the Iron Age; for the mythological Iron Age see Ages of Man. In archaeology, the Iron Age is the stage in the development of any people where the use of iron implements as tools and weapons is prominent. The adoption of this new material coincided with other changes in past societies often including differing agricultural practices, religious beliefs and artistic styles. The Iron Age is the last principal period in the three-age system for classifying pre-historic societies and its meaning varies depending on the country or geographical region. This variation even occurs within Europe where the Iron Age distinction was first identified; the Nordic Iron Age and Roman Iron Age are examples. The Iron Age was preceded by the Copper Age and later the Bronze Age in Europe and Asia whilst in the rest of the world it was adopted directly after one or other sub-phases of the Stone Age. For each individual region, the period is very hard to state in years, but the Iron Age corresponds to the stage at which iron production was the most sophisticated form of metalworking. Iron's hardness, high melting point and the abundance of iron ore sources made iron more desirable and "cheaper" than bronze and contributed greatly to its adoption as the most commonly used metal. The arrival of iron use in various areas is listed below, broadly in chronological order. In the Americas and Australasia, there is no Iron Age, since iron working was introduced by European colonists and African slaves (in the Spanish colonies).

The Iron Age

The first signs of iron use come from Ancient Egypt and Sumer, where around 4000 BC small items, such as the tips of spears and ornaments, were being fashioned from iron recovered from meteorites (see Iron: History). By 3000 BC to 2000 BC increasing numbers of smelted iron objects (distinguishable from meteoric iron by the lack of nickel in the product) appear in Anatolia, Egypt and Mesopotamia. However, their use appears to be ceremonial, and iron was an expensive metal, more expensive than gold. Some sources suggest that iron was being created then as a by-product of copper refining, as sponge iron, and was not reproducible by the metallurgy of the time. The earliest systematic production and use of iron implements appears from the 14th century BC in the Hittite Empire though recent excavations in Middle Ganga Valley in India done by archaelogist Rakesh Tewari show Iron working in India since 1800 BC. By 1200 BC, iron was widely used in the Middle East but did not supplant the dominant use of bronze for some time.

The Iron Age in Africa and India

Archaeological sites in India like Malhar, Dadupur, Raja Nala Ka Tila and Lahuradewa in state of Uttar Pradesh show iron implements in period 1800 BC - 1200 BC. The earliest known production of steel occurred around 1400 BC in North Africa where steel was being produced in carbon furnaces. The Egyptian ruler Tutankhamun died in 1323 BC and was buried with an iron dagger with a golden hilt. Also an Egyptian sword bearing the name of pharaoh Merneptah and a battle axe with an iron blade and gold-decorated bronze haft were both found in the excavation of Ugarit (see Ugarit: History and Steel: History of iron and steelmaking), dating to circa 1400 BC. The Kushite city of Meroe near modern-day Khartoum was an important site of iron-smelting during the 5th and 6th centuries BC. The Nok civilization became the first iron smelting people in West Africa. Iron and copper working then continued to spread southward through the continent, reaching the Cape around 200AD. The widespread use of iron revolutionised the Bantu farming communities who adopted it, driving out the stone tool using hunter-gatherer societies they encountered as they expanded to farm wider areas of savannah. The technologically superior Bantu spread across southern Africa and became rich and powerful, producing iron for tools and weapons in large, industrial quantities. Perhaps as early as 300 BC, although certainly by AD 200, high quality steel was being produced in southern India by what Europeans would later call the crucible technique. In this system, high-purity wrought iron, charcoal, and glass were mixed in crucibles and heated until the iron melted and absorbed the carbon. The resulting high-carbon steel, called fūlāḏ فولاذ in Arabic and wootz by later Europeans, was exported throughout much of Asia.

The Iron Age in Asia

Near East

The Iron Age in Asia is believed to have begun with the discovery of iron smelting and smithing techniques in Anatolia or the Caucasus in the late 2nd millennium BC (circa 1300 BC). From here it spread rapidly throughout the Near East as iron weapons replaced bronze weapons by the early 1st millennium BC. The use of iron weapons by the Hittites is believed to have been a major factor in the rapid rise of the Hittite Empire. Because the area in which iron technology first developed was near the Aegean, where Asia meets Europe, the technology propagated equally early into both Asia and Europe, aided by Hittite expansion. The Sea Peoples and the related Philistines are often associated with the introduction of iron technology into Asia, as are the Dorians with respect to Greece. It ought also be noted that the Assyrian Empire had trade contacts with the area in which iron technology was first developed at the time that it was developing.

East Asia

Cast-iron artifacts are found in China that date as early as the Zhou dynasty of the 6th century BC. An Iron Age culture of the Tibetan Plateau has tentatively been associated with the Zhang Zhung culture described in early Tibetan writings. In 1972, near the city of Gaocheng (藁城) in Shijiazhuang (now Hebei province), a iron-bladed bronze tomahawk(铁刃青铜钺) dating back to the 14th century BC was excavated. After the scientific examination, the iron was shown to be made from aerosiderite.

The European Iron Age

Iron working was introduced to Europe around 1000 BC, probably from Asia Minor and slowly spread westwards over the succeeding 500 years. In the Netherlands, a starting date from about 800 BC is generally accepted. The Romans introduced writing and therefore ended the prehistoric Dutch Iron Age around 50 AD.

Eastern Europe

The early 1st millennium BC marks the Iron Age in Eastern Europe. In the steppes north of the Black Sea and Azov Sea and the Caucasus, the Iron Age begins with the Koban and the Chernogorovka and Novocerkassk cultures from ca. 900 BC. By 800 BC, it was spreading to Hallstatt C via the alleged "Thraco-Cimmerian" migrations. From the Hallstatt culture, the Iron Age spreads west with the Celtic expansion from the 6th century BC. In Poland, the Iron Age reaches the late Lusatian culture in about the 6th century, followed in some areas by the Pomeranian culture. The ethnic ascriptions of many Iron age cultures has been bitterly contested, as the roots of Germanii and Slavs were sought in this area.

Central Europe

In Central Europe, the Iron Age is generally divided in the early Iron Age Hallstatt culture (HaC and D, 800-450) and the late Iron Age La Tène culture (beginning in 450 BC). The Iron age ends with the Roman Conquest.

Mediterranean Europe

In Italy, the Iron Age was probably introduced by the Villanovan culture but this culture is otherwise considered a Bronze Age culture, while the following Etruscan civilization is regarded as part of Iron Age proper. The Etruscan Iron Age was then ended with the rise and conquest of the Roman Republic, which conquered the last Etruscan city of Velzna in 265 BC.

British Isles

For a fuller discussion see the British Iron Age article. In Britain, the Iron Age lasted from about the 5th century BC until the Roman conquest and until the 5th century AD in non-Romanised parts. Defensive structures dating from this time are often impressive, for example the brochs of northern Scotland and the hill forts that dotted the rest of the islands.

Northern Scandinavia and Finland

Scandinavia (including Finland) and Northern Balticum shows a small-scaled iron producing very early, but a further dating is currently impossible. The time varies from 3000 BC-1000 AD. This knowledge is associated to the non-Germanic part of Scandinavia. Metalworking and Asbestos-Ceramic pottery are somewhat synonymous in Scandinavia due to the latter's capability to resist and preserve heat. The iron ore used is believed to have been iron sand (such as red soil), because its high phosphorus content can be identified in slag. Together with asbestos ware axes belonging to the Ananjino Culture are sometimes found. The Asbestos-Ceramic remains a mystery, because there are other adiabatic vessels with unknown usage.

Northern Germany and Southern Scandinavia

The Iron Age is divided into the Pre-Roman Iron Age and the Roman Iron Age. This is followed by the migration period. Northern Germany and Denmark was dominated by the Jastorf culture, whereas the culture of the southern half of the Scandinavia was dominated by the very similar Nordic Iron Age.

See also


- List of archaeological periods
- List of archaeological sites
- Iron#History Category:Periods and stages in archaeology
- Category:Prehistory ko:철기 시대 ja:鉄器時代 simple:Iron Age

Ages of Man

:This article is about mythology. For the Grammy winning album by Sir John Gielgud, see Ages of Man (album) The Ages of Man are the stages of human existence on the Earth according to Classical mythology. In his Works and Days, the Boeotian poet Hesiod described Five Ages of Man: # The Golden Age - This took place during the reign of Cronus. Peace and harmony prevailed during this age. Humans did not grow old, but died peacefully. Spring was eternal and people were fed on acorns from a great oak as well as wild fruits and honey that dripped from the trees. This race eventually died out. # The Silver Age - These people lived for one hundred years as children without growing up, then they suddenly aged and died. Zeus destroyed these people because of their impiety. # The Bronze Age - These humans were fierce and warlike and their tools and implements were made of bronze. They destroyed one another in wars. # The Heroic Age - In this period lived noble demigods and heroes. This race of humans died and went to Elysium. # The Iron Age - This is the current age where humans bicker and fight, and have to struggle to eke out their existence. Zeus will someday destroy this race of humans. In Metamorphoses, Ovid followed a similar tradition, translated into Roman terms. Ovid described Four Ages of Man: Golden, Silver, Brazen, and Iron. In the Book of Daniel, Nebuchadnezzar has a dream of a statue made of the four metals which is interpreted by Daniel. Whether this story derives from a common literary tradition with that of the classical accounts is uncertain. These mythological ages are sometimes associated with historical timelines. In particular, the Bronze Age and Iron Age are well known eras in archaeology, which may have some relation to the mythology. Category:Greek mythology Category:Roman mythology

Archaeology

Archaeology or archeology (from the Greek words αρχαίος = ancient and λόγος = word/speech/discourse) is the study of human cultures through the recovery, documentation and analysis of material remains and environmental data, including architecture, artifacts, biofacts, human remains, and landscapes. The goals of archaeology are to document and explain the origins and development of human culture, understand culture history, chronicle cultural evolution, and study human behaviour and ecology, for both prehistoric and historic societies.

Ontology and definition

In the Old World, archaeology has tended to focus on the study of physical remains, the methods used in recovering them and the theoretical and philosophical underpinnings in achieving the subject's goals. The discipline's roots in antiquarianism and the study of Latin and Ancient Greek provided it with a natural affinity with the field of history. In the New World, archaeology is more commonly devoted to the study of human societies and is treated as one of the four subfields of Anthropology. The other subfields of anthropology supplement the findings of archaeology in a holistic manner. These subfields are cultural anthropology, which studies behavioural, symbolic, and material dimensions of culture; linguistics, which studies language, including the origins of language and language groups; and physical anthropology, which includes the study of human evolution and physical and genetic characteristics. Other disciplines also supplement archaeology, such as paleontology, paleozoology, paleoethnobotany, paleobotany, geography, geology, art history, and classics. Archaeology has been described as a craft that enlists the sciences to illuminate the humanities. Writing in 1948, the American archaeologist Walter Taylor asserted that "Archaeology is neither history nor anthropology. As an autonomous discipline, it consists of a method and a set of specialised techniques for the gathering, or 'production' of cultural information". Archaeology is an approach to understanding human culture through its material remains regardless of chronology. In England, archaeologists have uncovered the long-lost layouts of medieval villages abandoned after the crises of the 14th century and the equally lost layouts of 17th century parterre gardens swept away by a change in fashion. In downtown New York City archaeologists have exhumed the 18th century remains of the Black burial ground. Traditional Archaeology is viewed as the study of pre-historical human cultures; that is cultures that existed before the development of writing for that culture. Historical archaeology is the study of post-writing cultures. In the study of relatively recent cultures, which have been observed and studied by Western scholars, archaeology is closely allied with ethnography. This is the case in large parts of North America, Oceania, Siberia, and other places where the study of archaeology mingles with the living traditions of the cultures being studied. Kennewick_Man is an example of archaeology interacting with modern culture. In the study of cultures that were literate or had literate neighbours, history and archaeology supplement one another for broader understanding of the complete cultural context, as at Hadrian's Wall. Hadrian's Wall

Importance and applicability

Most of human history is not described by any written records. Writing did not exist anywhere in the world until about 5000 years ago, and only spread among a relatively small number of technologically advanced civilisations. In contrast Homo sapiens have existed for at least 200,000 years, and other species of Homo for millions of years (see Human evolution). These civilisations are, not coincidentally, the best-known; they have been open to the inquiry of historians for centuries, while the study of pre-historic cultures has arisen only recently. Even within a civilisation that is literate at some levels, many important human practices are not officially recorded. Any knowledge of the formative early years of human civilisation - the development of agriculture, cult practices of folk religion, the rise of the first cities - must come from archaeology. Even where written records do exist, they are invariably incomplete or biased to some extent. In many societies, literacy was restricted to the elite classes, such as the clergy or the bureaucracy of court or temple. The literacy even of an aristocracy has sometimes been restricted to deeds and contracts. The interests and world-view of elites are often quite different from the lives and interests of the rest of the populace. Writings that were produced by people more representative of the general population were unlikely to find their way into libraries and be preserved there for posterity. Thus, written records tend to reflect the biases of the literate classes, and cannot be trusted as a sole source. The material record is nearer to a fair representation of society, though it is subject to its own inaccuracies, such as sampling bias and differential preservation. In addition to their scientific importance, archaeological remains sometimes have political significance to descendants of the people who produced them, monetary value to collectors, or simply strong aesthetic appeal. Many people identify archaeology with the recovery of such aesthetic, religious, political, or economic treasures rather than with the reconstruction of past societies. This view is often espoused in works of popular fiction, such as Raiders of the Lost Ark, The Mummy, and King Solomon's Mines. When such unrealistic subjects are treated more seriously, accusations of pseudoscience are invariably levelled at their proponents (see Pseudoarchaeology, below). However, these endeavours, real and fictional, are not representative of the modern state of archaeology.

Goals

There is still a tremendous emphasis in the practice of archaeology on field techniques and methodologies. These include the tasks of surveying areas in order to find new sites, digging sites in order to unearth the cultural remains therein, and classification and preservation techniques in order to analyse and keep these remains. Every phase of this process can be a source of information. The goals of archaeology are not always the same. There are at least three broad, distinct theories of exactly what archaeological research should do. (These are beyond the scope of the present discussion, and are discussed at length below.) Nevertheless, there is much common ground.

Academic sub-disciplines

Main article: Archaeological sub-disciplines As with most academic disciplines, there are a very large number of archaeological sub-disciplines characterised by a specific method or type of material (e.g. lithic analysis, music, archaeobotany), geographical or chronological focus (e.g. Near Eastern archaeology, Medieval archaeology), other thematic concern (e.g. landscape archaeology), or a specific archaeological culture or civilisation (e.g. Egyptology).

Cultural resources management

Cultural resources management (CRM) (also called heritage management in Britain) is a branch of archaeology that accounts for most research done in the United States and much of that in western Europe as well. In the United States, CRM archaeology has been a growing concern since the passage of the National Historic Preservation Act of 1966 and most of the archaeology done in that country today proceeds from either direct or related requirements of that measure. In the United States, the vast majority of taxpayers, scholars, and politicians believe that CRM has helped to preserve much of that nation's history and prehistory that would have otherwise been lost in the expansion of cities, dams, and highways. Along with other statutes, this mandates that no construction project on public land or involving public funds may damage an unstudied archaeological site. The application of CRM in the United Kingdom is not limited to government-funded projects. Since 1990 PPG 16 has required planners to consider archaeology as a material consideration in determining applications for new development. As a result, numerous archaeological organisations undertake mitigation work in advance of (or during) construction work in archaeologically sensitive areas, at the developer's expense. Among the goals of CRM are the identification, preservation, and maintenance of cultural sites on public and private lands, and the removal of culturally valuable materials from areas where they would otherwise be destroyed by human activity, such as proposed construction. This study involves at least a cursory examination to determine whether or not any significant archaeological sites are present in the area affected by the proposed construction. If these do exist, time and money must be allotted for their excavation. If initial survey and/or test excavation indicates the presence of an extraordinarily valuable site, the construction may be prohibited entirely. CRM is a thriving entity, especially in the United States and Europe where archaeologists from private companies and all levels of government engage in the practice of their discipline. Cultural resources management has, however, been criticized. CRM is conducted by private companies that bid for projects by submitting proposals outlining the work to be done and an expected budget. It is not unheard-of for the agency responsible for the construction to simply choose the proposal that asks for the least funding. CRM archaeologists face considerable time pressure, often being forced to complete their work in a fraction of the time that might be allotted for a purely scholarly endeavour.

Field methods

Survey

A modern archaeological project often begins with a survey. Regional survey is the attempt to systematically locate previously unknown sites in a region. Site survey is the attempt to systematically locate features of interest, such as houses and middens, within a site. Each of these two goals may be accomplished with largely the same methods. Survey was not widely practiced in the early days of archaeology. Cultural historians and prior researchers were usually content with discovering the locations of monumental sites from the local populace, and excavating only the plainly visible features there. Gordon Willey pioneered the technique of regional settlement pattern survey in 1949 in the Viru Valley of coastal Peru, and survey of all levels became prominent with the rise of processual archaeology some years later. Survey work has many benefits if performed as a preliminary exercise to, or even in place of, excavation. It requires relatively little time and expense, because it does not require processing large volumes of soil to search out artefacts. (Nevertheless, surveying a large region or site can be expensive, so archaeologists often employ sampling methods.) It avoids ethical issues (of particular concern to descendant peoples) associated with destroying a site through excavation. It is the only way to gather some forms of information, such as settlement patterns and settlement structure. Survey data are commonly assembled into maps, which may show surface features and/or artefact distribution. The simplest survey technique is surface survey. It involves combing an area, usually on foot but sometimes with the use of mechanised transport, to search for features or artefacts visible on the surface. Surface survey cannot detect sites or features that are completely buried under earth, or overgrown with vegetation. Surface survey may also include mini-excavation techniques such as augers, corers, and shovel test pits. Aerial survey is conducted using cameras attached to aircraft, balloons, or even kites. A bird's-eye view is useful for quick mapping of large or complex sites. Aerial imaging can also detect many things not visible from the surface. Plants growing above a stone structure, such as a wall, will develop more slowly, while those above other types of features (such as middens) may develop more rapidly. Photographs of ripening grain, which changes colour rapidly at maturation, have revealed buried structures with great precision. Aerial survey also employs infrared, ground-penetrating radar wavelengths, and thermography. Geophysical survey is the most effective way to see beneath the ground. Magnetometers detect minute deviations in the Earth's magnetic field caused by iron artefacts, kilns, some types of stone structures, and even ditches and middens. Devices that measure the electrical resistivity of the soil are also widely used. Most soils are moist below the surface, which gives them a relatively low resistivity. Features such as hard-packed floors or concentrations of stone have a higher resistivity. Although some archaeologists consider the use of metal detectors to be tantamount to treasure hunting, others deem them an effective tool in archaeological surveying. Examples of formal archaeological use of metal detectors include musketball distribution analysis on English Civil War battlefields, metal distribution analysis prior to excavation of a nineteenth century ship wreck, and service cable location during evaluation. Metal detectorists have also contributed to the archaeological record where they have made detailed records of their results and refrained from raising artifacts from their archaeological context. In the UK, metal detectorists have been solicited for involvement in the Portable Antiquities Scheme. Regional survey in maritime archaeology uses side-scan sonar.

Excavation

Archaeological excavation existed when the field was still the domain of amateurs, and it remains the source of the majority of data recovered in most field projects. It can reveal several types of information usually not accessible to survey, such as stratigraphy, three-dimensional structure, and verifiably primary context. Modern excavation techniques require that the precise locations of objects and features, known as their provenance or provenience, be recorded. This always involves determining their horizontal locations, and sometimes vertical position as well. Similarly, their association, or relationship with nearby objects and features, needs to be recorded for later analysis. This allows the archaeologist to deduce what artefacts and features were likely used together and which may be from different phases of activity. For example, excavation of a site reveals its stratigraphy; if a site was occupied by a succession of distinct cultures, artefacts from more recent cultures will lie above those from more ancient cultures. Excavation is the most expensive phase of archaeological research. Also, as a destructive process, it carries ethical concerns. As a result, very few sites are excavated in their entirety. Sampling is even more important in excavation than in survey. It is common for large mechanical equipment, such as backhoes (JCBs), to be used in excavation, especially to remove the topsoil (overburden), though this method is increasingly used with great caution. Following this it is usual to hand-clean the exposed area with trowels or hoes to ensure that all features are apparent. The next task is to produce a site plan and then use it to help decide the method of excavation. Features dug into the natural subsoil are normally excavated in portions in order to produce a visible archaeological section for recording. Scaled plans and sections of individual features are all drawn on site, black and white and colour photographs of them are taken, and recording sheets are filled in describing the context of each. All this information serves as a permanent record of the now-destroyed archaeology and is used in describing and interpreting the site.

Post-excavation analysis

Once artefacts and structures have been excavated, or collected from surface surveys, it is necessary to properly study them, to gain as much data as possible. This process is known as post-excavation analysis, and is normally the most time-consuming part of the archaeological investigation. It is not uncommon for the final excavation reports on major sites to take years to be published. At its most basic, the artefacts found are cleaned, catalogued and compared to published collections, in order to classify them typologically and to identify other sites with similar artefact assemblages. However, a much more comprehensive range of analytical techniques are available through archaeological science, meaning that artefacts can be dated and their compositions examined. The bones, plants and pollen collected from a site can all be analysed (using the techniques of zooarchaeology, paleoethnobotany, and palynology), while any texts can usually be deciphered. These techniques frequently provide information that would not otherwise be known and therefore contribute greatly to the understanding of a site.

History of archaeology

Main article: History of archaeology The history of archaeology has been one of increasing professionalisation, and the use of an increasing range of techniques, to obtain as much data on the site being examined as possible. Excavations of ancient monuments and the collection of antiquities have been taking place for thousands of years, but these were mostly for the extraction of valuable or aesthetically pleasing artefacts. It was only in the 19th century that the systematic study of the past through its physical remains began to be carried out. Archaeological methods were developed by both interested amateurs and professionals, including Augustus Pitt Rivers and William Flinders Petrie. This process was continued in the 20th century by such people as Mortimer Wheeler, whose highly disciplined approach to excavation greatly improved the quality of evidence that could be obtained. During the 20th century, the development of urban archaeology and then rescue archaeology have been important factors, as has the development of archaeological science, which has greatly increased the amount of data that it is possible to obtain.

Archaeological theory

Main article: Archaeological theory There is no single theory of archaeology, and even definitions are disputed. Until the mid-20th century and the introduction of technology, there was a general consensus that archaeology was closely related to both history and anthropology. The first major phase in the history of archaeological theory is commonly referred to as cultural, or culture, history, which was developed during the late 19th and early 20th centuries. In the 1960s, a number of young, primarily American archaeologists, such as Lewis Binford, rebelled against the paradigms of cultural history. They proposed a "New Archaeology", which would be more "scientific" and "anthropological", with hypothesis testing and the scientific method very important parts of what became known as processual archaeology. In the 1980s, a new movement arose led by the British archaeologists Michael Shanks, Christopher Tilley, Daniel Miller, and Ian Hodder. It questioned processualism's appeals to science and impartiality and emphasised the importance of relativism, becoming known as post-processual archaeology. However, this approach has been criticised by processualists as lacking scientific rigour. The validity of both processualism and post-procuessualism is still under debate. Archaeological theory now borrows from a wide range of influences, including neo-Darwinian evolutionary thought, phenomenology, postmodernism, agency theory, cognitive science, Functionalism, gender-based and Feminist archaeology, and Systems theory.

Public archaeology

Early archaeology was largely an attempt to uncover spectacular artifacts and features, or to explore vast and mysterious abandoned cities. Such pursuits continue to fascinate the public, portrayed in books (such as King Solomon's Mines) and films (such as The Mummy and Raiders of the Lost Ark). Much thorough and productive research has indeed been conducted in dramatic locales such as Copán and the Valley of the Kings, but the stuff of modern archaeology is not so reliably sensational. In addition, archaeological adventure stories tend to ignore the painstaking work involved in modern survey, excavation, and data processing techniques. Some archaeologists refer to such portrayals as "pseudoarchaeology". Nevertheless, archaeology has profited from its portrayal in the mainstream media. Many practitioners point to the childhood excitement of Indiana Jones films and Tomb Raider games as the inspiration for them to enter the field. Archaeologists are also very much reliant on public support, the question of exactly who they are doing their work for is often discussed. Without a strong public interest in the subject, often sparked by significant finds and celebrity archaeologists, it would be a great deal harder for archaeologists to gain the political and financial support they require. In the UK, popular archaeology programmes such as Time Team and Meet the Ancestors have resulted in a huge upsurge in public interest. Where possible, archaeologists now make more provision for public involvement and outreach in larger projects than they once did. However, the move towards being more professional has meant that volunteer places are now relegated to unskilled labour, and even this is less freely available than before. Developer-funded excavation necessitates a well-trained staff that can work quickly and accurately, observing the necessary health and safety and indemnity insurance issues involved in working on a modern building site with tight deadlines. Certain charities and local government bodies sometimes offer places on research projects either as part of academic work or as a defined community project. There is also a flourishing industry selling places on commercial training excavations and archaeological holiday tours. Archaeologists prize local knowledge and often liaise with local historical and archaeological societies. Anyone looking to get involved in the field without having to pay to do so should contact a local group.

Pseudoarchaeology

Main article: Pseudoarchaeology. Pseudoarchaeology is an umbrella term for all activities that claim to be archaeological but in fact violate commonly accepted archaeological practices. It includes much fictional archaeological work (discussed above), as well as some actual activity. Many non-fiction authors have ignored the scientific methods of processual archaeology, or the specific critiques of it contained in Post-processualism. An example of this type is the writing of Erich von Däniken. His Chariots of the Gods (1968), together with many subsequent lesser-known works, expounds a theory of ancient contacts between human civilisation on Earth and more technologically advanced extraterrestrial civilisations. This theory, known as palaeocontact theory, is not exclusively Däniken's nor did the idea originate with him. Works of this nature are usually marked by the renunciation of well-established theories on the basis of limited evidence, and the interpretation of evidence with a preconceived theory in mind.

Looting

Looting of archaeological sites by people in search of hoards of buried treasure is an ancient problem. For instance, many of the tombs of the Egyptian pharaohs were looted in antiquity. The advent of archaeology has made ancient sites objects of great scientific and public interest, but it has also attracted unwelcome attention to the works of past peoples. A brisk commercial demand for artefacts encourages looting and the illicit antiquities trade, which smuggles items abroad to private collectors. Looters damage the integrity of a historic site, deny archaeologists valuable information that would be learnt from excavation, and are often deemed to be robbing local people of their heritage. The popular consciousness often associates looting with poor Third World countries. Many are former homes to many well-known ancient civilisations but lack the financial resources or political will to protect even the most significant sites. Certainly, the high prices that intact objects can command relative to a poor farmer's income make looting a tempting financial proposition for some local people. However, looting has taken its toll in places as rich and populous as the United States and Western Europe as well. Abandoned towns of the ancient Sinagua people of Arizona, clearly visible in the desert landscape, have been destroyed in large numbers by treasure hunters. Sites in more densely populated areas farther east have also been looted. Where looting is proscribed by law it takes place under cover of night, with the metal detector a common instrument used to identify profitable places to dig.

Public outreach

Motivated by a desire to halt looting, curb pseudoarchaeology, and to secure greater public funding and appreciation for their work, archaeologists are mounting public-outreach campaigns. They seek to stop looting by informing prospective artefact collectors of the provenance of these goods, and by alerting people who live near archaeological sites of the threat of looting and the danger that it poses to science and their own heritage. Common methods of public outreach include press releases and the encouragement of school field trips to sites under excavation. The final audience for archaeologists' work is the public and it is increasingly realised that their work is ultimately being done to benefit and inform them. The putative social benefits of local heritage awareness are also being promoted with initiatives to increase civic and individual pride through projects such as community excavation projects and better interpretation and presentation of existing sites.

Descendant peoples

In the United States, examples such as the case of Kennewick Man have illustrated the tensions between Native Americans and archaeologists which can be summarised as a conflict between a need to remain respectful towards burials sacred sites and the academic benefit from studying them. For years, American archaeologists dug on Indian burial grounds and other places considered sacred, removing artefacts and human remains to storage facilities for further study. In some cases human remains were not even thoroughly studied but instead archived rather than reburied. Furthermore, Western archaeologists' views of the past often differ from those of tribal peoples. The West views time as linear; for many natives, it is cyclic. From a Western perspective, the past is long-gone; from a native perspective, disturbing the past can have dire consequences in the present. To an archaeologist, the past is long-gone and must be reconstructed through its material remains; to indigenous peoples, it is often still alive. As a consequence of this, American Indians attempted to prevent archaeological excavation of sites inhabited by their ancestors, while American archaeologists believed that the advancement of scientific knowledge was a valid reason to continue their studies. This contradictory situation was addressed by the Native American Graves Protection and Repatriation Act (NAGPRA, 1990), which sought to reach a compromise by limiting the right of research institutions to possess human remains. Due in part to the spirit of postprocessualism, some archaeologists have begun to actively enlist the assistance of indigenous peoples likely to be descended from those under study. Archaeologists have also been obliged to re-examine what constitutes an archaeological site in view of what native peoples believe to constitute sacred space. To many native peoples, natural features such as lakes, mountains or even individual trees have cultural significance. Australian archaeologists especially have explored this issue and attempted to survey these sites in order to give them some protection from being developed. Such work requires close links and trust between archaeologists and the people they are trying to help and at the same time study. While this cooperation presents a new set of challenges and hurdles to fieldwork, it has benefits for all parties involved. Tribal elders cooperating with archaeologists can prevent the excavation of areas of sites that they consider sacred, while the archaeologists gain the elders' aid in interpreting their finds. There have also been active efforts to recruit aboriginal peoples directly into the archaeological profession.

Repatriation

A new trend in the heated controversy between First Nations groups and scientists is the repatriation of native artifacts to the original descendents. An example of this occurred June 21, 2005, when a community members and elders from a number of the 10 Algonquian nations in the Ottawa area convened on the Kitigan Zibi reservation in Kanawagi, Quebec, to inter ancestral human remains and burial goods — some dating back 6,000 years. The ceremony marked the end of a journey spanning thousands of years and many miles. The remains and artifacts, including beads, tools and weapons, were originally excavated from various sites in the Ottawa Valley, including Morrison and the Allumette Islands. They had been part of the Canadian Museum of Civilization’s research collection for decades, some since the late 1800s. Elders from various Algonquin communities conferred on an appropriate reburial, eventually deciding on traditional cedar and birchbark boxes lined with cedar chips, muskrat and beaver pelts. Now, an inconspicuous rock mound marks the reburial site where close to 90 boxes of various sizes are buried. Although negotiations were at times tense between the Kitigan Zibi community and museum, they were able to reach agreement. (Source: [http://www.canadiangeographic.ca/magazine/SO05/indepth/archaeology.asp Canadian Geographic Online].)

Related topics


- List of famous archaeological discoveries
- List of archaeological sites sorted by country
- List of archaeologists
- Biblical archaeology
- List of archaeological periods

External links


- [http://www.archaeologynews.org Archaeology News] Current News and Information pertaining to all areas of archaeology, plus free news feeds for webmasters.
- [http://nefer-seba.net/Archaeological-Fieldwork.php Excavation Sites] Archaeological work and volunteer pages.
- [http://wasteflake.com/tiki-index.php?page=PopularArchaeology Archaeology in Popular Culture]
- [http://www.anthropologie.net/ Anthropology Resources on the Internet] - Anthropology Resources on the Internet : a web directory with over 3000 links grouped in specialised topics.
- [http://www.archaeology.org/ Archaeology magazine] published by the Archaeological Institute of America
- [http://www.archaeologydirectory.com/ Archaeology Directory] - Directory of archaeological topics on the web.
- [http://cctr.umkc.edu/user/fdeblauwe/iraq.html The 2003- Iraq War & Archaeology] Information about looting in Iraq.

Further reading


- Ashmore, W. and Sharer, R. J., Discovering Our Past: A Brief Introduction to Archaeology Mountain View: Mayfield Publishing Company. ISBN 076741196X. This has also been used as a source.
- Neumann, Thomas W. and Robert M. Sanford, Practicing Archaeology: A Training Manual for Cultural Resources Archaeology [http://www.rowmanlittlefield.com/ Rowman and Littlefield Pub Inc], August, 2001, hardcover, 450 pages, ISBN 0759100942
- Renfrew, Colin & Bahn, Paul G., Archaeology: Theories, Methods and Practice, Thames and Hudson, 4th edition, 2004. ISBN 0500284415
- Sanford, Robert M. and Thomas W. Neumann, Cultural Resources Archaeology: An Introduction, [http://www.rowmanlittlefield.com/ Rowman and Littlefield Pub Inc], December, 2001, trade paperback, 256 pages, ISBN 0759100950
- Trigger, Bruce. 1990. "A History of Archaeological Thought". Cambridge: Cambridge University Press. ISBN 0521338182 Category:Anthropology Category:Humanities occupations als:Archäologie ko:고고학 ms:Arkeologi ja:考古学 simple:Archaeology th:โบราณคดี

Iron

Iron is a chemical element with the symbol Fe (L.: Ferrum) and atomic number 26. Iron is a group 8 and period 4 metal. Iron is notable for being the final element produced by stellar nucleosynthesis, and thus the heaviest element which does not require a supernova or similarly cataclysmic event for its formation. It is therefore the most abundant heavy metal in the universe.

Notable characteristics

Iron is the most abundant metal on Earth, and is believed to be the tenth most abundant element in the universe. Iron is also the most abundant (by mass, 34.6%) element making up the Earth; the concentration of iron in the various layers of the Earth ranges from high at the inner core to about 5% in the outer crust; it is possible the Earth's inner core consists of a single iron crystal although it is more likely to be a mixture of iron and nickel; the large amount of iron in the Earth is thought to contribute to its magnetic field. Iron is a metal extracted from iron ore, and is hardly ever found in the free (elemental) state. In order to obtain elemental iron, the impurities must be removed by chemical reduction. Iron is used in the production of steel, which is not an element but an alloy, a solution of different metals (and some non-metals, particularly carbon). Nuclei of iron have some of the highest binding energies per nucleon, superseded only by the nickel isotope 62Ni. The universally most abundant of the highly stable nucleides is, however, 56Fe. This is formed by nuclear fusion in the stars. Although a further tiny energy gain could be extracted by synthesizing 62Ni, conditions in stars are not right for this process to be favoured. When a very large star contracts at the end of its life, internal pressure and temperature rise, allowing the star to produce progressively heavier elements, despite these being less stable than the elements around mass number 60 (the "iron group"). This leads to a supernova. Some cosmological models with an open universe predict that there will be a phase where as a result of slow fusion and fission reactions, everything will become iron.

Applications

Iron is the most used of all the metals, comprising 95 percent of all the metal tonnage produced worldwide. Its combination of low cost and high strength make it indispensable, especially in applications like automobiles, the hulls of large ships, and structural components for buildings. Steel is the best known alloy of iron, and some of the forms that iron takes include:
- Pig iron has 4% – 5% carbon and contains varying amounts of contaminants such as sulfur, silicon and phosphorus. Its only significance is that of an intermediate step on the way from iron ore to cast iron and steel.
- Cast iron contains 2% – 4.0% carbon , 1% – 6% silicon , and small amounts of manganese. Contaminants present in pig iron that negatively affect the material properties, such as sulfur and phosphorus, have been reduced to an acceptable level. It has a melting point in the range of 1420–1470 K, which is lower than either of its two main components, and makes it the first product to be melted when carbon and iron are heated together. Its mechanical properties vary greatly, dependant upon the form carbon takes in the alloy. 'White' cast irons contain their carbon in the form of cementite, or iron carbide. This hard, brittle compound dominates the mechanical properties of white cast irons, rendering them hard, but unresistant to shock. The broken surface of a white cast iron is full of fine facets of the broken carbide, a very pale, silvery, shiny material, hence the appellation. In 'grey' cast iron, the carbon exists free as fine flakes of graphite , and also, renders the material brittle due to the stress-raising nature of the sharp edged flakes of graphite. A newer variant of grey iron, referred to as 'ductile iron' is specially treated with trace amounts of magnesium to alter the shape of graphite to sheroids, or nodules, vastly increasing the toughness and strength of the material.
- Carbon steel contains between 0.5% and 1.5% carbon, with small amounts of manganese, sulfur, phosphorus, and silicon.
- Wrought iron contains less than 0.2% carbon. It is a tough, malleable product, not as fusible as pig iron. It has a very small amount of carbon, a few tenths of a percent. If honed to an edge, it loses it quickly. Wrought iron is characterised, especially in old samples, by the presence of fine 'stringers' or filaments of slag entrapped in the metal.
- Alloy steels contain varying amounts of carbon as well as other metals, such as chromium, vanadium, molybdenum, nickel, tungsten, etc. They are used for structural purposes, as their alloy content raises their cost and necessitates justification of their use. Recent developments in ferrous metallurgy have produced a growing range of microalloyed steels, also termed 'HSLA' or high-strength, low alloy steels, containing tiny additions to produce high strengths and often spectacular toughness at minimal cost.
- Iron(III) oxides are used in the production of magnetic storage in computers. They are often mixed with other compounds, and retain their magnetic properties in solution.

History

The first signs of use of iron come from the Sumerians and the Egyptians, where around 4000 BC, a few items, such as the tips of spears, daggers and ornaments, were being fashioned from iron recovered from meteorites. Because meteorites fall from the sky some linguists have conjectured that the English word iron (OE īsern), which has cognates in many northern and western European languages, derives from the Etruscan aisar which means "the gods". By 3000 BC to 2000 BC, increasing numbers of smelted iron objects (distinguishable from meteoric iron by the lack of nickel in the product) appear in Mesopotamia, Anatolia, and Egypt. However, their use appears to be ceremonial, and iron was an expensive metal, more expensive than gold. In the Iliad, weaponry is mostly bronze, but iron ingots are used for trade. Some resources (see the reference What Caused the Iron Age? below) suggest that iron was being created then as a by-product of copper refining, as sponge iron, and was not reproducible by the metallurgy of the time. By 1600 BC to 1200 BC, iron was used increasingly in the Middle East, but did not supplant the dominant use of bronze. bronze In the period from the 12th to 10th century BC, there was a rapid transition in the Middle East from bronze to iron tools and weapons. The critical factor in this transition does not appear to be the sudden onset of a superior ironworking technology, but instead the disruption of the supply of tin. This period of transition, which occurred at different times in different parts of the world, is the ushering in of an age of civilization called the Iron Age. Concurrent with the transition from bronze to iron was the discovery of carburization, which was the process of adding carbon to the irons of the time. Iron was recovered as sponge iron, a mix of iron and slag with some carbon and/or carbide, which was then repeatedly hammered and folded over to free the mass of slag and oxidise out carbon content, so creating the product wrought iron. Wrought iron was very low in carbon content and was not easily hardened by quenching. The people of the Middle East found that a much harder product could be created by the long term heating of a wrought iron object in a bed of charcoal, which was then quenched in water or oil. The resulting product, which had a surface of steel, was harder and less brittle than the bronze it began to replace. In China the first irons used were also meteoric iron, with archeological evidence for items made of wrought iron appearing in the northwest, near Xinjiang, in the 8th century BC. These items were made of wrought iron, created by the same processes used in the Middle East and Europe, and were thought to be imported by non-Chinese people. In the later years of the Zhou Dynasty (ca 550 BC), a new iron manufacturing capability began because of a highly developed kiln technology. Producing blast furnaces capable of temperatures exceeding 1300 K, the Chinese developed the manufacture of cast, or pig iron. Iron was used in India as early as 250 BCE. The famous iron pillar in the Qutb complex in Delhi is made of very pure iron (98%) and has not rusted or eroded till this day. Delhi of wood annually from 1827 to 1891.]] If iron ores are heated with carbon to 1420–1470 K, a molten liquid is formed, an alloy of about 96.5% iron and 3.5% carbon. This product is strong, can be cast into intricate shapes, but is too brittle to be worked, unless the product is decarburized to remove most of the carbon. The vast majority of Chinese iron manufacture, from the Zhou dynasty onward, was of cast iron. Iron, however, remained a pedestrian product, used by farmers for hundreds of years, and did not really affect the nobility of China until the Qin dynasty (ca 221 BC). Cast iron development lagged in Europe, as the smelters could only achieve temperatures of about 1000 K. Through a good portion of the Middle Ages, in Western Europe, iron was still being made by the working of sponge iron into wrought iron. Some of the earliest casting of iron in Europe occurred in Sweden, in two sites, Lapphyttan and Vinarhyttan, between 1150 and 1350 AD. There are suggestions by scholars that the practice may have followed the Mongols across Russia to these sites, but there is no clear proof of this hypothesis. In any event, by the late fourteenth century, a market for cast iron goods began to form, as a demand developed for cast iron cannonballs. Early iron smelting (as the process is called) used charcoal as both the heat source and the reducing agent. In 18th century England, wood supplies ran down and coke, a fossil fuel, was used as an alternative. This innovation by Abraham Darby supplied the energy for the Industrial Revolution.

Occurrence

Industrial Revolution Iron is one of the more common elements on Earth, making up about 5% of the Earth's crust. Most of this iron is found in various iron oxides, such as the minerals hematite, magnetite, and taconite. The earth's core is believed to consist largely of a metallic iron-nickel alloy. About 5% of the meteorites similarly consist of iron-nickel alloy. Although rare, these are the major form of natural metallic iron on the earth's surface. Iron is also one of the least reactive metals, and therefore, it is sometimes found pure in nature.

Extraction from ore

Industrially, iron is extracted from its ores, principally hematite (nominally Fe2O3) and magnetite (Fe3O4) by a carbothermic reaction (reduction with carbon) in a blast furnace at temperatures of about 2000°C. In a blast furnace, iron ore, carbon in the form of coke, and a flux such as limestone are fed into the top of the furnace, while a blast of heated air is forced into the furnace at the bottom. In the furnace, the coke reacts with oxygen in the air blast to produce carbon monoxide: :6 C + 3 O2 → 6 CO The carbon monoxide reduces the iron ore (in the chemical equation below, hematite) to molten iron, becoming carbon dioxide in the process: :6 CO + 2 Fe2O3 → 4 Fe + 6 CO2 The flux is present to melt impurities in the ore, principally silicon dioxide sand and other silicates. Common fluxes include limestone (principally calcium carbonate) and dolomite (magnesium carbonate). Other fluxes may be used depending on the impurities that need to be removed from the ore. In the heat of the furnace the limestone flux decomposes to calcium oxide (quicklime): :CaCO3 → CaO + CO2 Then calcium oxide combines then with silicon dioxide to form a slag. :CaO + SiO2 → CaSiO3 The slag melts in the heat of the furnace, which silicon dioxide would not have. In the bottom of the furnace, the molten slag floats on top of the more dense liquid iron, and spouts in the side of the furnace may be opened to drain off either the iron or the slag. The iron, once cooled, is called pig iron, while the slag can be used as a material in road construction or to improve mineral-poor soils for agriculture. Approximately 1100Mt (million tons) of iron ore was produced in the world in 2000, with a gross market value of approximately 25 billion US dollars. While ore production occurs in 48 countries, the five largest producers were China, Brazil, Australia, Russia and India, accounting for 70% of world iron ore production. The 1100Mt of iron ore was used to produce approximately 572Mt of pig iron.

Compounds

2000 production.]] Common oxidation states of iron include:
- the Iron(-II) state, Fe2- (e.g. Fe(CO)42-,Fe(CO)2(NO)2.
- the Iron(0) state, Fe(CO)5, Fe(PF3)5.
- the Iron(I) state, [Fe(H2O)5NO]2+.
- the Iron(II) state, Fe2+, previously ferrous is very common.
- the Iron(III) state, Fe3+, previously ferric, is also very common, for example in rust.
- the Iron(IV) state, Fe4+, previously ferryl, stabilized in some enzymes (e.g. peroxidases).
- the Iron(VI) state, Fe6+ is also known, if rare, in potassium ferrate. Iron carbide Fe3C is known as cementite.

Biological role

Iron is essential to all organisms, except for a few bacteria. It is mostly stably incorporated in the inside of metalloproteins, because in exposed or in free form it causes production of free radicals that are generally toxic to cells. To say that iron is free doesn't mean that it is free floating in the bodily fluids. Iron binds avidly to virtually all biomolecules so it will adhere nonspecifically to cell membranes, nucleic acids, proteins etc. Many animals incorporate iron into the heme complex, an essential component of cytochromes, which are proteins involved in redox reactions (including but not limited to cellular respiration), and of oxygen carrying proteins hemoglobin and myoglobin. Inorganic iron involved in redox reactions is also found in the iron-sulfur clusters of many enzymes, such as nitrogenase (involved in the synthesis of ammonia from nitrogen and hydrogen) and hydrogenase. A class of non-heme iron proteins is responsible for a wide range of functions within several life forms, such as enzymes methane monooxygenase (oxidizes methane to methanol), ribonucleotide reductase (reduces ribose to deoxyribose; DNA biosynthesis), hemerythrins (oxygen transport and fixation in marine invertebrates) and purple acid phosphatase (hydrolysis of phosphate esters). When the body is fighting a bacterial infection, the body sequesters iron inside of cells (mostly stored in the storage molecule ferritin so that it cannot be used by bacteria. Iron distribution is heavily regulated in mammals, both as a defense against bacterial infection as well as the potential biological toxicity of iron. The iron absorbed from the duodenum binds to transferrin, and is carried by blood to different cells. There it gets by an as yet unknown mechanism incorporated into target proteins. [http://www.plosbiology.org/plosonline/?request=get-document&doi=10.1371%2Fjournal.pbio.0000079]. A lengthier article on the system of human iron regulation can be found in the article on human iron metabolism. Good sources of dietary iron include meat, fish, poultry, lentils, beans, leaf vegetables, tofu, chickpeas, black-eyed pea, strawberries and farina. Iron provided by dietary supplements is often found as Iron (II) fumarate. The RDA for iron varies considerably based on the age, gender, and source of dietary iron (heme-based iron has higher bioavailability)[http://www.iom.edu/Object.File/Master/7/294/0.pdf]. Also note the section below on precautions.

Isotopes

Naturally occurring iron consists of four isotopes: 5.845% of radioactive 54Fe (half-life: >3.1E22 years), 91.754% of stable 56Fe, 2.119% of stable 57Fe and 0.282% of stable 58Fe. 60Fe is an extinct radionuclide of long half-life (1.5 million years). Much of the past work on measuring the isotopic composition of Fe has centered on determining 60Fe variations due to processes accompanying nucleosynthesis (i.e., meteorite studies) and ore formation. The isotope 56Fe is of particular interest to nuclear scientists. A common misconception is that this isotope represents the most stable nucleus possible, and that it thus would be impossible to perform fission or fusion on 56Fe and still liberate energy. This is not true, as both 62Ni and 58Fe are more stable. In phases of the meteorites Semarkona and Chervony Kut a correlation between the concentration of 60Ni, the daughter product of 60Fe, and the abundance of the stable iron isotopes could be found which is evidence for the existence of 60Fe at time formation of solar system. Possibly the energy released by the decay of 60Fe contributed, together with the energy released by decay of the radionuclide 26Al, to the remelting and differentiation of asteroids after their formation 4.6 billion years ago. The abundance of 60Ni present in extraterrestrial material may also provide further insight into the origin of the solar system and its early history. Of the stable isotopes, only 57Fe has a nuclear spin (−1/2). For this reason, 57Fe has application as a spin isotope in chemistry and biochemistry.

Precautions

Excessive dietary iron is toxic, because excess ferrous iron reacts with peroxides in the body, producing free radicals. When iron is in normal quantity, the body's own antioxidant mechanisms can control this process. In excess, uncontrollable quantities of free radicals are produced. The lethal dose of iron in a two-year-old is about three grams of iron. One gram can induce severe poisoning. There are reported cases of children being poisoned by consuming between 10 and 50 tablets of ferrous sulfate over a period of several hours. Over-consumption of iron is the single highest cause of death in children by unintentional ingestion of pharmaceuticals. The DRI lists the Tolerable Upper Intake Level (UL) for adults as 45 mg/day. For children under fourteen years old the UL is 40 mg/day. If iron intake is excessive a number of iron overload disorders can result, such as hemochromatosis. For this reason, people should not take iron supplements unless they suffer from iron deficiency and have consulted a doctor. Blood donors are at special risk of low iron levels and are often recommended to supplement their iron intake. A specific chelating agent called Desferrioxime is used to expell excess iron from the body in case of iron toxicity.

References


- [http://periodic.lanl.gov/elements/26.html Los Alamos National Laboratory — Iron]

External links


- [http://www.webelements.com/webelements/elements/text/Fe/index.html WebElements.com – Iron]
- [http://education.jlab.org/itselemental/ele026.html It's Elemental – Iron]
- [http://hyperphysics.phy-astr.gsu.edu/hbase/nucene/nucbin2.html The Most Tightly Bound Nuclei] Category:Chemical elements Category:Transition metals ko:철 ms:Besi ja:鉄 simple:Iron th:เหล็ก

Three-age system

The three-age system is a system of classifying human prehistory into three consecutive time periods, named for their respective predominant tool-making technologies:
- The Stone Age
- The Bronze Age
- The Iron Age

Origin

Its formal introduction is attributed to the Dane Christian Jürgensen Thomsen in the 1820s in order to classify artefacts in the collection which later became the National Museum of Denmark. Thomsen was not the first to use tool-making materials as a basis for classifying prehistoric societies; the Frenchman Nicholas Mahudel had proposed a similar system in the early eighteenth century and the idea gathered supporters in the intervening hundred years. Thomsen and his predecessors argued that nobody would have used stone tools if bronze ones had been available and that similarly, no one would have wanted to use bronze tools if there had been iron ones around instead. Reasoning that the advances must therefore have come in chronological sequence, he suggested this as a workable basis for dating artefacts and sites. Such a system was revolutionary and a vast improvement on the disorganised nature of previous prehistoric archaeology.

Divisions

Later, the Stone Age was divided into the Palaeolithic and the Neolithic and further subdivisions were introduced to divide all the ages into early, mid or late (or lower, middle and upper in the case of the Palaeolithic) sections. There are also the Mesolithic and Epipaleolithic periods between the Palaeolithic and Neolithic. In some cultures, archaeological evidence has made it necessary to add a Copper Age period between the Neolithic and the Bronze Age. The term Megalithic does not refer to a period of time and merely describes the use of large stones by ancient peoples from any period. The discovery of thousands of carved jades in the Liangzhu region of Ancient China lends support for a "Jade Age" previous to the Bronze Age [http://www.nga.gov/exhibitions/chbro_preh.shtm]).

Dating

Advances made in the fields of seriation, typology, stratification and the associative dating of artefacts and features permitted even greater refinement of the system. However, because no precise numerical date could be given to finds using the three age system, they could only be placed in a relative sequence. Elaborate efforts were often made to align European and Near Eastern sequences with the datable chronology of Ancient Egypt; but more direct and convincing scientific dating methods such as carbon dating were not invented until the mid twentieth century.

Difficulties

The three age system has been difficult to apply fully outside Europe. Some societies skipped some of the stages or never developed them when their societies didn't need them. Amazonian tribes in South America remain in the Neolithic for example, while there was no Bronze Age south of the Sahara; techonological innovation progressed from stone to iron working. It also soon became apparent that the switches from one age to another did not happen quickly or decisively. Flint tools remained in use in a limited fashion into the Iron Age in Europe and early metal items often appear in what should technically be the Neolithic. Although the three age system has been rendered less and less accurate by modern archaeological discoveries, it still remains the bedrock of prehistoric archaeology as the terms have become ingrained in people's minds, including those of archaeologists. Their clarity and explicability mean that the field and the long periods of time involved in prehistoric archaeology can also be more easily conveyed to the public.

See also


- list of archaeological periods Category:Methods and principles in archaeology Category:Prehistory Category:Civilization Time Scale

Europe

:This article is about the continent. For other meanings, see Europe (disambiguation). Europe is geologically and geographically a peninsula or subcontinent, forming the westernmost part of Eurasia. It is conventionally considered a continent, which, in this case, is more of a cultural distinction than a geographic one. It is bounded to the north by the Arctic Ocean, to the west by the Atlantic Ocean and to the south by the Mediterranean and Black Seas and the Caucasus. Europe's boundary to the east is vague, but has traditionally been given as the Ural Mountains and Caspian Sea to the southeast: the Urals are considered by most to be a geographical and tectonic landmark separating Asia from Europe. :See also Continent, Bicontinental country, and Table of European territories and regions. Table of European territories and regions Table of European territories and regions Europe is the world's second-smallest continent in terms of area, covering around 10,790,000 km² (4,170,000 sq mi) or 2.1% of the Earth's surface, and is only larger than Australia. In terms of population, it is the third-largest continent (Asia and Africa are larger) with a population of more than 700,000,000, or about 11% of the world's population.

Etymology

Africa.]] In Greek mythology, Europa was a Phoenician princess who was abducted by Zeus in bull form and taken to the island of Crete, where she gave birth to Minos. For Homer, Europé (Greek: Ευρωπη; see also List of traditional Greek place names) was a mythological queen of Crete, not a geographical designation. Later Europa stood for mainland Greece, and by 500 BC its meaning had been extended to lands to the north. The Greek term Europe has been derived from Greek words meaning broad (eurys) and face (ops) -- broad having been an epitheton of Earth herself in the reconstructed Proto-Indo-European religion; see Prithvi (Plataia). A minority, however, suggest this Greek popular etymology is really based on a Semitic word such as the Akkadian erebu meaning "sunset" (see also Erebus). From the Middle Eastern vantagepoint, the sun does set over Europe, the lands to the west. Likewise, Asia is sometimes thought to have derived from the Akkadian word asu, meaning "sunrise", and is the land to the east from a Mesopotamian perspective.

History

Europe has a long history of cultural and economic achievement, starting as far back as the Palaeolithic, although this is true for the rest of the Old World as well. The recent discovery at Monte Poggiolo, Italy, of thousands of hand-shaped stones, tentatively carbon-dated to 800,000 years ago, may prove to be of particular importance. The origins of Western democratic and individualistic culture are often attributed to Ancient Greece, though numerous other distinct influences, in particular Christianity, can also be credited with the spread of concepts like egalitarianism and universality of law. The Roman Empire divided the continent along the Rhine and Danube for several centuries. Following the decline of the Roman Empire, Europe entered a long period of changes arising from what is known as the Age of Migrations. That period has been known as the "Dark Ages" to Renaissance thinkers. During this time, isolated monastic communities in Ireland and elsewhere carefully safeguarded and compiled written knowledge accumulated previously. The Renaissance and the New Monarchs marked the start of a period of discovery, exploration, and increase in scientific knowledge. In the 15th century Portugal opened the age of discoveries, soon followed by Spain. They were later joined by France, the Netherlands and the United Kingdom in building large colonial empires with vast holdings in Africa, the Americas, and Asia. After the age of discovery, the ideas of democracy took hold in Europe. Struggles for independence arose, most notably in France during the period known as the French Revolution. This led to vast upheaval in Europe as these revolutionary ideas propagated across the continent. The rise of democracy led to increased tensions within Europe on top of the tensions already existing due to competition within the New World. The most famous of these conflicts was when Napoleon Bonaparte rose to power and set out on a conquest, forming a new French empire that soon collapsed. After these conquests Europe stabilised, but the old foundations were already beginning to crumble. The Industrial Revolution started in the United Kingdom in the late 18th century, leading to a move away from agriculture, much greater general prosperity and a corresponding increase in population. Many of the states in Europe took their present form in the aftermath of World War I. From the end of World War II through the end of the Cold War, Europe was divided into two major political and economic blocks: Communist nations in Eastern Europe and capitalist countries in Western Europe. Around 1990, with the fall of the Berlin Wall, the Eastern bloc disintegrated.

Geography and extent

Eastern bloc Geographically Europe is a part of the larger landmass known as Eurasia. The continent begins at the Ural Mountains in Russia, which define Europe's eastern boundary with Asia. The southeast boundary with Asia isn't universally defined. Most commonly the Ural or, alternatively, the Emba river can serve as possible boundaries. The boundary continues with the Caspian Sea, and then the Araxes river in the Caucasus, and on to the Black Sea; the Bosporus, the Sea of Marmara, and the Dardanelles conclude the Asian boundary. The Mediterranean Sea to the south separates Europe from Africa. The western boundary is the Atlantic Ocean, but Iceland, much farther away than the nearest points of Africa and Asia, is also often included in Europe. There is ongoing debate on where the geographical centre of Europe is. At times "Europe" is defined with greater regard to political, economic, and other cultural considerations. This has led to there being several different Europes that are not always identical in size, including or excluding countries according to the definition of Europe used. Almost all European countries are members of the Council of Europe, the exceptions being Belarus, and the Holy See (Vatican City). The idea of the European continent is not held across all cultures. Some non-European geographical texts refer to the continent of Eurasia, or to the European peninsula, given that Europe is not surrounded by sea. In the past concepts such as Christendom were deemed more important. In another usage, Europe is increasingly being used as a short-form for the European Union (EU) and its members, currently consisting of 25 member states. A number of other European countries are negotiating for membership, and several more are expected to begin negotiations in the future (see Enlargement of the European Union).

Physical features

In terms of shape, Europe is a collection of connected peninsulas. The two largest of these are "mainland" Europe and Scandinavia to the north, divided from each other by the Baltic Sea. Three smaller peninsulas (Iberia, Italy and the Balkans) emerge from the southern margin of the mainland into the Mediterranean Sea, which separates Europe from Africa. Eastward, mainland Europe widens much like the mouth of a funnel, until the boundary with Asia is reached at the Ural Mountains. Land relief in Europe shows great variation within relatively small areas. The southern regions, however, are more mountainous, while moving north the terrain descends from the high Alps, Pyrenees and Carpathians, through hilly uplands, into broad, low northern plains, which are vast in the east. This extended lowland is known as the Great European Plain, and at its heart lies the North German Plain. An arc of uplands also exists along the northwestern seaboard, beginning in the western British Isles and continuing along the mountainous, fjord-cut spine of Norway. This description is simplified. Sub-regions such as Iberia and Italy contain their own complex features, as does mainland Europe itself, where the relief contains many plateaus, river valleys and basins that complicate the general trend. Iceland and the British Isles are special cases. The former is a land unto itself in the northern ocean which is counted as part of Europe, while the latter are upland areas that were once joined to the mainland until rising sea levels cut them off. Due to the few generalisations that can be made about the relief of Europe, it is less than surprising that its many separate regions provided homes for many separate nations throughout history.

Biodiversity

Having lived side-by-side with agricultural peoples for millennia, Europe's animals and plants have been profoundly affected by the presence and activities of man. With the exception of Scandinavia and northern Russia, few areas of untouched wilderness are today to be found in Europe, except for different natural parks. The main natural vegetation cover in Europe is forest. The conditions for growth are very favourable. In the north, the Gulf Stream and North Atlantic Drift warm the continent. Southern Europe could be described as having a warm, but mild climate. There are frequent summer droughts in this region. Mountain ridges also affect the conditions. Some of these (Alps, Pyrenees) are oriented east-west and allow the wind to carry large masses of water from the ocean in the interior. Others are oriented south-north (Scandinavian Mountains, Dinarides, Carpathians, Apennines) and because the rain falls primarily on the side of mountains that is oriented towards sea, forests grow well on this side, while on the other side, the conditions are much less favourable. Few corners of mainland Europe have not been grazed by livestock at some point in time, and the cutting down of the pre-agricultural forest habitat caused disruption to the original plant and animal ecosystems. Eighty to ninety per cent of Europe was once covered by forest. It stretched from the Mediterranean Sea to the Arctic Ocean. Though over half of Europe's original forests disappeared through the centuries of colonisation, Europe still has over one quarter of the world's forests - spruce forests of Scandinavia, vast pine forests in Russia, chestnut rainforests of the Caucasus and the cork oak forests in the Mediterranean. During recent times, deforestation has been stopped and many trees were planted. However, in many cases conifers have been preferred over original deciduous trees, because these grow quicker. The plantations and monocultures now cover vast areas of land and this offers very poor habitats for European forest dwelling species. The amount of original forests in Western Europe is just two to three per cent (in the European part of Russia five to ten per cent). The country with the smallest forest-covered area is Ireland (eight per cent), while the most forested country is Finland (72 per cent). In "mainland" Europe, deciduous forest prevails. The most important species are beech, birch and oak. In the north, where taiga grows, a very common tree species is the birch tree. In the Mediterranean, many olive trees have been planted, which are very well adapted to its arid climate. Another common species in Southern Europe is the cypress. Coniferous forests prevail at higher altitudes up to the forest boundary and as one moves north within Russia and Scandinavia, giving way to tundra as the Arctic is approached. The semi-arid Mediterranean region hosts much scrub forest. A narrow east-west tongue of Eurasian grassland—the steppe—extends eastwards from Ukraine and southern Russia and ends in Hungary and traverses into taiga to the north. Glaciation during the most recent ice age and the presence of man affected the distribution of European fauna. As for the animals, in many parts of Europe most large animals and top predator species have been hunted to extinction. The woolly mammoth and aurochs were extinct before the end of the Neolithic period. Today wolves (carnivores) and bears (omnivores) are endangered. Once they were found in most parts of Europe. However, deforestation caused these animals to withdraw further and further. By the Middle Ages the bears' habitats were limited to more or less inaccessible mountains with sufficient forest cover. Today, the brown bear lives primarily in the Balkan peninsula, in the North and in Russia; a small number also persist in other countries across Europe (Austria, Pyrenees etc.), but in these areas brown bear populations are fragmented and marginalised because of the destruction of their habitat. In the far North of Europe, polar bears can also be found. The wolf, the second largest predator in Europe after the brown bear, can be found primarily in Eastern Europe and in the Balkans. Other important European carnivores are Eurasian lynx, European wild cat, foxes (especially the red fox), jackal an