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117-598: In archaeology , a broch / b r ɒ x / is an Iron Age drystone hollow-walled structure found in Scotland . Brochs belong to the classification "complex Atlantic roundhouse " devised by Scottish archaeologists in the 1980s. Brochs are roundhouse buildings found throughout Atlantic Scotland. The word broch is derived from the Lowland Scots 'brough', meaning fort. In the mid-19th century, Scottish antiquaries called brochs 'burgs', after Old Norse borg, with

234-487: A N(n,p) C reaction, direct uranium decay (though reported measured ratios of C/U in uranium-bearing ores would imply roughly 1 uranium atom for every two carbon atoms in order to cause the C/ C ratio, measured to be on the order of 10 ), or other unknown secondary sources of C production. The presence of C in the isotopic signature of a sample of carbonaceous material possibly indicates its contamination by biogenic sources or

351-630: A source of water (some have wells or natural springs rising within their central space). Sometimes, on the other hand, they were sited in wilderness areas (e.g. Levenwick and Culswick in Shetland, Castle Cole in Sutherland). Brochs are often built beside the sea ( Carn Liath , Sutherland); sometimes they are on islands in lochs (e.g. Clickimin in Shetland). About 20 Orcadian broch sites include small settlements of stone buildings surrounding

468-464: A basic level of analysis, artifacts found are cleaned, catalogued and compared to published collections. This comparison process often involves classifying them typologically and identifying other sites with similar artifact assemblages. However, a much more comprehensive range of analytical techniques are available through archaeological science , meaning that artifacts can be dated and their compositions examined. Bones, plants, and pollen collected from

585-563: A big impact throughout Europe. However, prior to the development of modern techniques, excavations tended to be haphazard; the importance of concepts such as stratification and context were overlooked. In the mid-18th century, the German Johann Joachim Winckelmann lived in Rome and devoted himself to the study of Roman antiquities, gradually acquiring an unrivalled knowledge of ancient art. Then, he visited

702-542: A branch of the humanities . It is usually considered an independent academic discipline , but may also be classified as part of anthropology (in North America – the four-field approach ), history or geography . Archaeologists study human prehistory and history, from the development of the first stone tools at Lomekwi in East Africa 3.3 million years ago up until recent decades. Archaeology

819-446: A cell breaking off from the passage beside the door; this is known as the guard cell. It has been found in some Shetland brochs that guard cells in entrance passageways are close to large door-check stones. Although there was much argument in the past, it is now generally accepted among some archaeologists that brochs were roofed, perhaps with a conical timber framed roof covered with a locally sourced thatch. The evidence for this assertion

936-401: A clear objective as to what the archaeologists are looking to achieve must be agreed upon. This done, a site is surveyed to find out as much as possible about it and the surrounding area. Second, an excavation may take place to uncover any archaeological features buried under the ground. And, third, the information collected during the excavation is studied and evaluated in an attempt to achieve

1053-553: A clifftop and cut off from the mainland by huge ditches. Often they are at key strategic points. In Shetland they sometimes cluster on each side of narrow stretches of water: the Broch of Mousa , for instance, is directly opposite another at Burraland in Sandwick . In Orkney there are more than a dozen on the facing shores of Eynhallow Sound , and many at the exits and entrances of the great harbour of Scapa Flow . In Sutherland quite

1170-525: A direct comparison of carbon-14 levels in a sample, with tree ring or cave-deposit C levels of a known age, then gives the wood or animal sample age-since-formation. Radiocarbon is also used to detect disturbance in natural ecosystems; for example, in peatland landscapes, radiocarbon can indicate that carbon which was previously stored in organic soils is being released due to land clearance or climate change. Cosmogenic nuclides are also used as proxy data to characterize cosmic particle and solar activity of

1287-399: A few are placed along the sides and at the mouths of deep valleys. Writing in 1956 John Stewart suggested that brochs in Shetland were forts put up by a military society to scan and protect the countryside and seas. Finally, some archaeologists consider broch sites individually, doubting that there ever was a single common purpose for which every broch was constructed. There are differences in

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1404-451: A field 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 practised in the early days of archaeology. Cultural historians and prior researchers were usually content with discovering

1521-484: A lack of public interest, and opposition to the excavation of human remains. In Ancient Mesopotamia , a foundation deposit of the Akkadian Empire ruler Naram-Sin (ruled c.  2200 BC ) was discovered and analysed by king Nabonidus , c.  550 BC , who is thus known as the first archaeologist. Not only did he lead the first excavations which were to find the foundation deposits of

1638-528: A large region or site can be expensive, so archaeologists often employ sampling methods.) As with other forms of non-destructive archaeology, survey 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 artifact distribution. The simplest survey technique

1755-440: A nuclear reactor) are summarized in the table. Another source of carbon-14 is cluster decay branches from traces of naturally occurring isotopes of radium , though this decay mode has a branching ratio on the order of 10 relative to alpha decay , so radiogenic carbon-14 is extremely rare. The above-ground nuclear tests that occurred in several countries in 1955-1980 (see List of nuclear tests ) dramatically increased

1872-460: A site can all be analyzed using the methods of zooarchaeology , paleoethnobotany , palynology and stable isotopes while any texts can usually be deciphered . Radiocarbon There are three naturally occurring isotopes of carbon on Earth: carbon-12 ( C), which makes up 99% of all carbon on Earth; carbon-13 ( C), which makes up 1%; and carbon-14 ( C), which occurs in trace amounts, making up about 1-1.5 atoms per 10 atoms of carbon in

1989-504: A site excavated depends greatly on the country and "method statement" issued. Sampling is even more important in excavation than in survey. Sometimes large mechanical equipment, such as backhoes ( JCBs ), is used in excavation, especially to remove the topsoil ( overburden ), though this method is increasingly used with great caution. Following this rather dramatic step, the exposed area is usually hand-cleaned with trowels or hoes to ensure that all features are apparent. The next task

2106-414: A site reveals its stratigraphy; if a site was occupied by a succession of distinct cultures, artifacts from more recent cultures will lie above those from more ancient cultures. Excavation is the most expensive phase of archaeological research, in relative terms. Also, as a destructive process, it carries ethical concerns. As a result, very few sites are excavated in their entirety. Again the percentage of

2223-403: A slower rate to form CO 2 , radioactive carbon dioxide . The gas mixes rapidly and becomes evenly distributed throughout the atmosphere (the mixing timescale on the order of weeks). Carbon dioxide also dissolves in water and thus permeates the oceans , but at a slower rate. The atmospheric half-life for removal of CO 2 has been estimated at roughly 12 to 16 years in

2340-408: A sole source. The material record may be closer to a fair representation of society, though it is subject to its own biases, such as sampling bias and differential preservation. Often, archaeology provides the only means to learn of the existence and behaviors of people of the past. Across the millennia many thousands of cultures and societies and billions of people have come and gone of which there

2457-527: A stone 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 photographs taken at different times of day will help show the outlines of structures by changes in shadows. Aerial survey also employs ultraviolet , infrared , ground-penetrating radar wavelengths, Lidar and thermography . Geophysical survey can be

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2574-449: A subject population. However, the castle theory fell from favour among Scottish archaeologists in the 1980s, due to a lack of supporting archaeological evidence. These archaeologists suggested defensibility was never a major concern in the siting of a broch, and argued that they may have been the "stately homes" of their time, objects of prestige and very visible demonstrations of superiority for important families. Once again, however, there

2691-487: A systematic guide to the ruins and topography of ancient Rome in the early 15th century, for which he has been called an early founder of archaeology. Antiquarians of the 16th century, including John Leland and William Camden , conducted surveys of the English countryside, drawing, describing and interpreting the monuments that they encountered. The OED first cites "archaeologist" from 1824; this soon took over as

2808-495: A wide range of influences, including systems theory , neo-evolutionary thought , [35] phenomenology , postmodernism , agency theory , cognitive science , structural functionalism , Marxism , gender-based and feminist archaeology , queer theory , postcolonial thoughts , materiality , and posthumanism . An archaeological investigation usually involves several distinct phases, each of which employs its own variety of methods. Before any practical work can begin, however,

2925-649: Is cosmic ray action on nitrogen in the atmosphere, and it is therefore a cosmogenic nuclide . However, open-air nuclear testing between 1955 and 1980 contributed to this pool. The different isotopes of carbon do not differ appreciably in their chemical properties. This resemblance is used in chemical and biological research, in a technique called carbon labeling : carbon-14 atoms can be used to replace nonradioactive carbon, in order to trace chemical and biochemical reactions involving carbon atoms from any given organic compound. Carbon-14 undergoes beta decay : By emitting an electron and an electron antineutrino , one of

3042-490: Is 0.05 mm. Radiocarbon dating is a radiometric dating method that uses C to determine the age of carbonaceous materials up to about 60,000 years old. The technique was developed by Willard Libby and his colleagues in 1949 during his tenure as a professor at the University of Chicago . Libby estimated that the radioactivity of exchangeable C would be about 14 decays per minute (dpm) per gram of carbon, and this

3159-450: Is a lack of archaeological proof for this reconstruction, and the sheer number of brochs makes it problematic. The article concludes by stating that the purpose of brochs may have been a combination of defensive, offensive, and symbolic functions. The word broch is derived from Lowland Scots 'brough', meaning (among other things) fort. In the mid-19th century Scottish antiquaries called brochs 'burgs', after Old Norse borg , with

3276-447: Is also generated inside nuclear fuels (some due to transmutation of oxygen in the uranium oxide , but most significantly from transmutation of nitrogen-14 impurities), and if the spent fuel is sent to nuclear reprocessing then the C is released, for example as CO 2 during PUREX . After production in the upper atmosphere, the carbon-14 reacts rapidly to form mostly (about 93%) CO ( carbon monoxide ), which subsequently oxidizes at

3393-606: Is distinct from palaeontology , which is the study of fossil remains. Archaeology is particularly important for learning about prehistoric societies, for which, by definition, there are no written records. Prehistory includes over 99% of the human past, from the Paleolithic until the advent of literacy in societies around the world. Archaeology has various goals, which range from understanding culture history to reconstructing past lifeways to documenting and explaining changes in human societies through time. Derived from Greek,

3510-910: Is evidence for an unusually high production rate in AD 774–775 , caused by an extreme solar energetic particle event, the strongest such event to have occurred within the last ten millennia. Another "extraordinarily large" C increase (2%) has been associated with a 5480 BC event, which is unlikely to be a solar energetic particle event. Carbon-14 may also be produced by lightning but in amounts negligible, globally, compared to cosmic ray production. Local effects of cloud-ground discharge through sample residues are unclear, but possibly significant. Carbon-14 can also be produced by other neutron reactions, including in particular C (n,γ) C and O (n,α) C with thermal neutrons , and N (n,d) C and O (n, He) C with fast neutrons . The most notable routes for C production by thermal neutron irradiation of targets (e.g., in

3627-406: Is in the oceans. The following inventory of carbon-14 has been given: Many human-made chemicals are derived from fossil fuels (such as petroleum or coal ) in which C is greatly depleted because the age of fossils far exceeds the half-life of C. The relative absence of CO 2 is therefore used to determine the relative contribution (or mixing ratio ) of fossil fuel oxidation to

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3744-451: Is little or no written record or existing records are misrepresentative or incomplete. Writing as it is known today did not exist in human civilization until the 4th millennium BC, in a relatively small number of technologically advanced civilizations. In contrast, Homo sapiens has existed for at least 200,000 years, and other species of Homo for millions of years (see Human evolution ). These civilizations are, not coincidentally,

3861-426: Is no one approach to archaeological theory that has been adhered to by all archaeologists. When archaeology developed in the late 19th century, the first approach to archaeological theory to be practised was that of cultural-historical archaeology , which held the goal of explaining why cultures changed and adapted rather than just highlighting the fact that they did, therefore emphasizing historical particularism . In

3978-547: Is now little doubt that the hollow-walled broch tower was an invention in what is now Scotland. The first brochs may have been built circa 300 BCE, and there is evidence to suggest that they were used primarily for defensive or offensive purposes. The distribution of brochs is centred on northern Scotland, with the densest concentrations found in Caithness , Sutherland , and the Northern Isles . A few examples occur in

4095-443: Is reflected or emitted from the observed scene. Passive instruments sense only radiation emitted by the object being viewed or reflected by the object from a source other than the instrument. Active instruments emit energy and record what is reflected. Satellite imagery is an example of passive remote sensing. Here are two active remote sensing instruments: The archaeological project then continues (or alternatively, begins) with

4212-430: Is small compared to the doses from K (0.39 mSv/year) and radon (variable). C can be used as a radioactive tracer in medicine. In the initial variant of the urea breath test , a diagnostic test for Helicobacter pylori , urea labeled with about 37  kBq (1.0  μCi ) C is fed to a patient (i.e. 37,000 decays per second). In the event of a H. pylori infection, the bacterial urease enzyme breaks down

4329-524: Is still used as the activity of the modern radiocarbon standard . In 1960, Libby was awarded the Nobel Prize in chemistry for this work. One of the frequent uses of the technique is to date organic remains from archaeological sites. Plants fix atmospheric carbon during photosynthesis; so the level of C in plants and animals when they die, roughly equals the level of C in the atmosphere at that time. However, it thereafter decreases exponentially; so

4446-405: Is still very scanty, although excavations at Dun Bharabhat, Lewis, may support it. The main difficulty with the interpretation continues to be identifying potential sources of structural timber, though bog and driftwood may have been sources. Very few of the brochs on the islands of Orkney and Shetland have cells on the ground floor . Most brochs have scarcements (ledges) which may have allowed

4563-428: Is surface survey. It involves combing an area, usually on foot but sometimes with the use of mechanized transport, to search for features or artifacts 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. If no materials are found,

4680-436: Is the preferred method although more recently, accelerator mass spectrometry has become the method of choice; it counts all the carbon-14 atoms in the sample and not just the few that happen to decay during the measurements; it can therefore be used with much smaller samples (as small as individual plant seeds), and gives results much more quickly. The G-M counting efficiency is estimated to be 3%. The half-distance layer in water

4797-596: Is through archaeology. Because archaeology is the study of past human activity, it stretches back to about 2.5 million years ago when the first stone tools are found – The Oldowan Industry . Many important developments in human history occurred during prehistory, such as the evolution of humanity during the Paleolithic period, when the hominins developed from the australopithecines in Africa and eventually into modern Homo sapiens . Archaeology also sheds light on many of humanity's technological advances, for instance

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4914-431: Is to form 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 to produce a visible archaeological section for recording. A feature, for example a pit or a ditch, consists of two parts: the cut and the fill . The cut describes the edge of the feature, where the feature meets the natural soil. It is the feature's boundary. The fill

5031-420: Is what the feature is filled with, and will often appear quite distinct from the natural soil. The cut and fill are given consecutive numbers for recording purposes. 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

5148-525: The Royal Commission on the Ancient and Historical Monuments of Scotland (RCAHMS) identifies a total of 571 candidate broch sites throughout the country. Researcher Euan MacKie, using a restricted definition, has proposed a much smaller total for Scotland of 104. The origin of brochs is a subject of continuing research. Eighty years ago most archaeologists believed that brochs, usually regarded as

5265-469: The Scottish Borders and on the west coast of Dumfries and Galloway , and near Stirling . The original interpretation of brochs was that they were defensive structures, places of refuge for the community and their livestock. They were sometimes regarded as the work of Danes or Picts , and from the 1930s to the 1960s, archaeologists regarded them as castles where local landowners held sway over

5382-580: The trench method , on several Native American burial mounds in Virginia . His excavations were prompted by the "Moundbuilders" question ; however, his careful methods led him to admit he saw no reason why ancestors of the Native Americans of his time could not have raised those mounds. One of the major achievements of 19th-century archaeology was the development of stratigraphy . The idea of overlapping strata tracing back to successive periods

5499-462: The 'castles' of Iron Age chieftains, were built by immigrants who had been pushed northward after being displaced first by the intrusions of Belgic tribes into what is now southeast England at the end of the 2nd century BC and later by the Roman invasion of southern Britain beginning in AD 43. Yet there is now little doubt that the hollow-walled broch tower was an invention in what is now Scotland; even

5616-559: The 1870s. These scholars individuated nine different cities that had overlapped with one another, from prehistory to the Hellenistic period . Meanwhile, the work of Sir Arthur Evans at Knossos in Crete revealed the ancient existence of an equally advanced Minoan civilization . The next major figure in the development of archaeology was Sir Mortimer Wheeler , whose highly disciplined approach to excavation and systematic coverage in

5733-642: The 1920s and 1930s brought the science on swiftly. Wheeler developed the grid system of excavation , which was further improved by his student Kathleen Kenyon . Archaeology became a professional activity in the first half of the 20th century, and it became possible to study archaeology as a subject in universities and even schools. By the end of the 20th century nearly all professional archaeologists, at least in developed countries, were graduates. Further adaptation and innovation in archaeology continued in this period, when maritime archaeology and urban archaeology became more prevalent and rescue archaeology

5850-426: The 1980s, due to a lack of supporting archaeological evidence. These archaeologists suggested defensibility was never a major concern in the siting of a broch, and argued that they may have been the " stately homes " of their time, objects of prestige and very visible demonstrations of superiority for important families (Armit 2003). Once again, however, there is a lack of archaeological proof for this reconstruction, and

5967-534: The 1st century BC is Crosskirk in Caithness, but a recent review of the evidence suggests that it cannot plausibly be assigned a date earlier than the 1st centuries BC/AD. The distribution of brochs is centred on northern Scotland. Caithness , Sutherland and the Northern Isles have the densest concentrations, but there are many examples in the west of Scotland and the Hebrides . Although mainly concentrated in

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6084-508: The 1st century BC, basing them on earlier, simpler, promontory forts. This view contrasted, for example, with that of Sir W. Lindsay Scott , who argued, following V. Gordon Childe (1935), for a wholesale migration into Atlantic Scotland of people from southwest England. MacKie's theory has fallen from favour too, mainly because starting in the 1970s there was a general move in archaeology away from 'diffusionist' explanations towards those pointing to exclusively indigenous development. Meanwhile,

6201-564: The Northern Hemisphere. The transfer between the ocean shallow layer and the large reservoir of bicarbonates in the ocean depths occurs at a limited rate. In 2009 the activity of C was 238 Bq per kg carbon of fresh terrestrial biomatter, close to the values before atmospheric nuclear testing (226 Bq/kg C; 1950). The inventory of carbon-14 in Earth's biosphere is about 300 megacuries (11  E Bq ), of which most

6318-505: The Song period, were revived in the 17th century during the Qing dynasty , but were always considered a branch of Chinese historiography rather than a separate discipline of archaeology. In Renaissance Europe , philosophical interest in the remains of Greco - Roman civilization and the rediscovery of classical culture began in the late Middle Ages , with humanism . Cyriacus of Ancona

6435-628: The Spanish military engineer Roque Joaquín de Alcubierre in the ancient towns of Pompeii and Herculaneum , both of which had been covered by ash during the Eruption of Mount Vesuvius in AD 79 . These excavations began in 1748 in Pompeii, while in Herculaneum they began in 1738. The discovery of entire towns, complete with utensils and even human shapes, as well the unearthing of frescos , had

6552-767: The UK, metal detectorists have been solicited for involvement in the Portable Antiquities Scheme . Regional survey in underwater archaeology uses geophysical or remote sensing devices such as marine magnetometer, side-scan sonar , or sub-bottom sonar. Archaeological excavation existed even 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

6669-426: The ability to use fire, the development of stone tools , the discovery of metallurgy , the beginnings of religion and the creation of agriculture . Without archaeology, little or nothing would be known about the use of material culture by humanity that pre-dates writing. However, it is not only prehistoric, pre-literate cultures that can be studied using archaeology but historic, literate cultures as well, through

6786-634: The above-ground nuclear tests of the 1950s and 1960s. Though the extra C generated by those nuclear tests has not disappeared from the atmosphere, oceans and biosphere, it is diluted due to the Suess effect . Carbon-14 is produced in coolant at boiling water reactors (BWRs) and pressurized water reactors (PWRs). It is typically released into the air in the form of carbon dioxide at BWRs, and methane at PWRs. Best practice for nuclear power plant operator management of carbon-14 includes releasing it at night, when plants are not photosynthesizing . Carbon-14

6903-593: The amount of C in tooth enamel , or the carbon-14 concentration in the lens of the eye. In 2019, Scientific American reported that carbon-14 from nuclear testing has been found in animals from one of the most inaccessible regions on Earth, the Mariana Trench in the Pacific Ocean. The concentration of C in atmospheric CO 2 , reported as the C/ C ratio with respect to a standard, has (since about 2022) declined to levels similar to those prior to

7020-425: The amount of C in the atmosphere and subsequently the biosphere; after the tests ended, the atmospheric concentration of the isotope began to decrease, as radioactive CO 2 was fixed into plant and animal tissue, and dissolved in the oceans. One side-effect of the change in atmospheric C is that this has enabled some options (e.g. bomb-pulse dating ) for determining the birth year of an individual, in particular,

7137-408: The archaeological excavations being conducted at Pompeii and Herculaneum . He was one of the founders of scientific archaeology and first applied the categories of style on a large, systematic basis to the history of art He was one of the first to separate Greek art into periods and time classifications. Winckelmann has been called both "The prophet and founding hero of modern archaeology " and

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7254-434: The area surveyed is deemed sterile . Aerial survey is conducted using cameras attached to airplanes , balloons , UAVs , or even Kites . A bird's-eye view is useful for quick mapping of large or complex sites. Aerial photographs are used to document the status of the archaeological dig. Aerial imaging can also detect many things not visible from the surface. Plants growing above a buried human-made structure, such as

7371-560: The artifacts they had found in chronological order. A major figure in the development of archaeology into a rigorous science was army officer and ethnologist Augustus Pitt Rivers , who began excavations on his land in England in the 1880s. Highly methodical by the standards of the time, he is widely regarded as the first scientific archaeologist. He arranged his artifacts by type or " Typology (archaeology) ", and within types chronologically. This style of arrangement, designed to highlight

7488-422: The atmosphere. C and C are both stable; C is unstable, with half-life 5700 ± 30 years. Carbon-14 has a specific activity of 62.4 mCi/mmol (2.31 GBq/mmol), or 164.9 GBq/g. Carbon-14 decays into nitrogen-14 ( N ) through beta decay . A gram of carbon containing 1 atom of carbon-14 per 10 atoms, emits ~0.2 beta (β) particles per second. The primary natural source of carbon-14 on Earth

7605-400: The best preserved and are still 13 metres (43 ft) tall; it is not clear how many brochs originally stood so high. A frequent characteristic is that the walls are galleried: with an open space between, the outer and inner wall skins are separate but tied together with linking stone slabs; these linking slabs may in some cases have served as steps to higher floors. It is normal for there to be

7722-563: The best-known; they are open to the inquiry of historians for centuries, while the study of pre-historic cultures has arisen only recently. Within a literate civilization many events and important human practices may not be officially recorded. Any knowledge of the early years of human civilization – the development of agriculture, cult practices of folk religion, the rise of the first cities – must come from archaeology. In addition to their scientific importance, archaeological remains sometimes have political or cultural significance to descendants of

7839-632: The construction of a wooden first floor (spotted by the antiquary George Low in Shetland in 1774), and excavations at Loch na Berie on the Isle of Lewis may show signs of a further, second floor (e.g. stairs on the first floor, which head upwards). Some brochs such as Dun Dornaigil and Culswick in Shetland have unusual triangular lintels above the entrance door. As in the case of Old Scatness in Shetland (near Jarlshof ) and Burroughston on Shapinsay , brochs were sometimes located close to arable land and

7956-421: The date of death or fixation can be estimated. The initial C level for the calculation can either be estimated, or else directly compared with known year-by-year data from tree-ring data ( dendrochronology ) up to 10,000 years ago (using overlapping data from live and dead trees in a given area), or else from cave deposits ( speleothems ), back to about 45,000 years before present. A calculation or (more accurately)

8073-554: The decay of radioactive material in surrounding geologic strata. In connection with building the Borexino solar neutrino observatory, petroleum feedstock (for synthesizing the primary scintillant) was obtained with low C content. In the Borexino Counting Test Facility, a C/ C ratio of 1.94×10 was determined; probable reactions responsible for varied levels of C in different petroleum reservoirs , and

8190-674: The distant past. Carbon-14 is produced in the upper troposphere and the stratosphere by thermal neutrons absorbed by nitrogen atoms. When cosmic rays enter the atmosphere, they undergo various transformations, including the production of neutrons . The resulting neutrons (n) participate in the following n-p reaction (p is proton ): The highest rate of carbon-14 production takes place at altitudes of 9 to 15 kilometres (30,000 to 49,000 ft) and at high geomagnetic latitudes . The rate of C production can be modeled, yielding values of 16,400 or 18,800 atoms of C per second per square meter of Earth's surface, which agrees with

8307-473: The early 20th century, many archaeologists who studied past societies with direct continuing links to existing ones (such as those of Native Americans , Siberians , Mesoamericans etc.) followed the direct historical approach , compared the continuity between the past and contemporary ethnic and cultural groups. In the 1960s, an archaeological movement largely led by American archaeologists like Lewis Binford and Kent Flannery arose that rebelled against

8424-643: The empirical evidence that existed for the understanding of the past, encapsulated in the motto of the 18th century antiquary, Sir Richard Colt Hoare : "We speak from facts, not theory". Tentative steps towards the systematization of archaeology as a science took place during the Enlightenment period in Europe in the 17th and 18th centuries. In Imperial China during the Song dynasty (960–1279), figures such as Ouyang Xiu and Zhao Mingcheng established

8541-644: The established cultural-history archaeology. 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 postmodern movement arose led by the British archaeologists Michael Shanks , Christopher Tilley , Daniel Miller , and Ian Hodder , which has become known as post-processual archaeology . It questioned processualism's appeals to scientific positivism and impartiality, and emphasized

8658-633: The evolutionary trends in human artifacts, was of enormous significance for the accurate dating of the objects. His most important methodological innovation was his insistence that all artifacts, not just beautiful or unique ones, be collected and catalogued. William Flinders Petrie is another man who may legitimately be called the Father of Archaeology. His painstaking recording and study of artifacts, both in Egypt and later in Palestine , laid down many of

8775-538: The father of the discipline of art history . The father of archaeological excavation was William Cunnington (1754–1810). He undertook excavations in Wiltshire from around 1798, funded by Sir Richard Colt Hoare. Cunnington made meticulous recordings of Neolithic and Bronze Age barrows , and the terms he used to categorize and describe them are still used by archaeologists today. Future U.S. President Thomas Jefferson also did his own excavations in 1784 using

8892-765: The fifteenth century, and the general accuracy of his records entitles him to be called the founding father of modern classical archeology." He traveled throughout Greece and all around the Eastern Mediterranean, to record his findings on ancient buildings, statues and inscriptions, including archaeological remains still unknown to his time: the Parthenon , Delphi , the Egyptian pyramids , the hieroglyphics . He noted down his archaeological discoveries in his diary, Commentaria (in six volumes). Flavio Biondo , an Italian Renaissance humanist historian, created

9009-528: The first history books of India. One of the first sites to undergo archaeological excavation was Stonehenge and other megalithic monuments in England. John Aubrey (1626–1697) was a pioneer archaeologist who recorded numerous megalithic and other field monuments in southern England. He was also ahead of his time in the analysis of his findings. He attempted to chart the chronological stylistic evolution of handwriting, medieval architecture, costume, and shield-shapes. Excavations were also carried out by

9126-402: The funding required, estimated at £1m–£3m, had not yet been arranged. Archaeology Archaeology or archeology is the study of human activity through the recovery and analysis of material culture . The archaeological record consists of artifacts , architecture , biofacts or ecofacts, sites , and cultural landscapes . Archaeology can be considered both a social science and

9243-561: The global carbon budget that can be used to backtrack, but attempts to measure the production time directly in situ were not very successful. Production rates vary because of changes to the cosmic ray flux caused by the heliospheric modulation (solar wind and solar magnetic field), and, of great significance, due to variations in the Earth's magnetic field . Changes in the carbon cycle however can make such effects difficult to isolate and quantify. Occasional spikes may occur; for example, there

9360-475: The ideas behind modern archaeological recording; he remarked that "I believe the true line of research lies in the noting and comparison of the smallest details." Petrie developed the system of dating layers based on pottery and ceramic findings , which revolutionized the chronological basis of Egyptology . Petrie was the first to scientifically investigate the Great Pyramid in Egypt during the 1880s. He

9477-472: The importance of a more self-critical theoretical reflexivity . However, this approach has been criticized by processualists as lacking scientific rigor, and the validity of both processualism and post-processualism is still under debate. Meanwhile, another theory, known as historical processualism , has emerged seeking to incorporate a focus on process and post-processual archaeology's emphasis of reflexivity and history. Archaeological theory now borrows from

9594-443: The increasing number – albeit still pitifully few – of radiocarbon dates for the primary use of brochs (as opposed to their later, secondary use) still suggests that most of the towers were built in the 1st centuries BC and AD. A few may be earlier, notably the one proposed for Old Scatness Broch in Shetland, where a sheep bone dating to between 390 and 200 BC has been reported. The other broch claimed to be substantially older than

9711-720: The inner face of the wall. Also there is a spiral staircase winding upwards between the inner and outer wall and connecting the galleries. Brochs vary from five to fifteen metres (16 to 49 ft) in internal diameter, with three-metre-thick (9.8 ft) walls. On average, the walls only survive to a few metres in height. There are five extant examples of towers with significantly higher walls: Dun Carloway on Lewis , Dun Telve and Dun Troddan in Glenelg , Mousa in Shetland and Dun Dornaigil in Sutherland, all of whose walls exceed 6.5 metres (21 ft) in height. Mousa's walls are

9828-695: The interiors often modified and changed, and that they underwent many phases of habitation and abandonment. The Crucible of Iron Age Shetland 's Mousa, Old Scatness and Jarlshof sites are on the United Kingdom "Tentative List" of possible nominations for the UNESCO World Heritage Programme list of sites of outstanding cultural or natural importance to the common heritage of humankind . This list, published in July 2010, includes sites that may be nominated for inscription over

9945-462: The kinds of pottery found inside them that most resembled south British styles were local hybrid forms. The first of the modern review articles on the subject (MacKie 1965) did not, as is commonly believed, propose that brochs were built by immigrants, but rather that a hybrid culture formed from the blending of a small number of immigrants with the native population of the Hebrides produced them in

10062-444: The lives and interests 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, assumptions, cultural values and possibly deceptions of a limited range of individuals, usually a small fraction of the larger population. Hence, written records cannot be trusted as

10179-671: 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 artifacts. (Nevertheless, surveying

10296-578: The lower C levels in methane, have been discussed by Bonvicini et al. Since many sources of human food are ultimately derived from terrestrial plants, the relative concentration of C in human bodies is nearly identical to the relative concentration in the atmosphere. The rates of disintegration of potassium-40 ( K) and C in the normal adult body are comparable (a few thousand decays per second). The beta decays from external (environmental) radiocarbon contribute about 0.01  mSv /year (1 mrem/year) to each person's dose of ionizing radiation . This

10413-484: The main tower. Examples include Howe, near Stromness , Gurness Broch in the north west of Mainland, Orkney , Midhowe on Rousay and Lingro near Kirkwall (destroyed by a farmer in the 1980s). There are "broch village" sites in Caithness, but elsewhere they are unknown. Most brochs are unexcavated. The end of the broch building period seems to have come around AD 100–200. Those that have been properly examined show that they continued to be in use for many centuries, with

10530-458: The maximum distance traveled is estimated to be 22 cm in air and 0.27 mm in body tissue. The fraction of the radiation transmitted through the dead skin layer is estimated to be 0.11. Small amounts of carbon-14 are not easily detected by typical Geiger–Müller (G-M) detectors ; it is estimated that G-M detectors will not normally detect contamination of less than about 100,000 decays per minute (0.05 μCi). Liquid scintillation counting

10647-673: The most effective way to see beneath the ground. Magnetometers detect minute deviations in the Earth's magnetic field caused by iron artifacts, kilns , some types of stone structures , and even ditches and middens. Devices that measure the electrical resistivity of the soil are also widely used. Archaeological features whose electrical resistivity contrasts with that of surrounding soils can be detected and mapped. Some archaeological features (such as those composed of stone or brick) have higher resistivity than typical soils, while others (such as organic deposits or unfired clay) tend to have lower resistivity. Although some archaeologists consider

10764-425: The neutrons in carbon-14 decays to a proton and the carbon-14 ( half-life of 5700 ± 30 years ) decays into the stable (non-radioactive) isotope nitrogen-14 . As usual with beta decay, almost all the decay energy is carried away by the beta particle and the neutrino. The emitted beta particles have a maximum energy of about 156 keV, while their weighted mean energy is 49 keV. These are relatively low energies;

10881-409: The next 5–10 years. The Caithness Broch Project was set up in 2013 as a project in experimental archaeology to build a broch using traditional techniques such as drystone walling. Purposes of the project include possible insights into the purpose of brochs, preservation of local skills in techniques such as drystone wall building, and to attract tourists. As of 2022 a site had not been acquired, and

10998-646: The northern Highlands and the Islands, a few examples occur in the Borders (for example Edin's Hall Broch and Bow Castle Broch ), on the west coast of Dumfries and Galloway , and near Stirling . In a c.  1560 sketch there appears to be a broch by the river next to Annan Castle in Dumfries and Galloway. This small group of southern brochs has never been satisfactorily explained. The original interpretation of brochs, favoured by 19th-century antiquarians,

11115-443: The now-destroyed archaeology and is used in describing and interpreting the site. Once artifacts and structures have been excavated, or collected from surface surveys, it is necessary to properly study them. This process is known as post-excavation analysis , and is usually the most time-consuming part of an archaeological investigation. It is not uncommon for final excavation reports for major sites to take years to be published. At

11232-529: The original research objectives of the archaeologists. It is then considered good practice for the information to be published so that it is available to other archaeologists and historians, although this is sometimes neglected. Before actually starting to dig in a location, remote sensing can be used to look where sites are located within a large area or provide more information about sites or regions. There are two types of remote sensing instruments—passive and active. Passive instruments detect natural energy that

11349-413: The past. Since its early development, various specific sub-disciplines of archaeology have developed, including maritime archaeology , feminist archaeology , and archaeoastronomy , and numerous different scientific techniques have been developed to aid archaeological investigation. Nonetheless, today, archaeologists face many problems, such as dealing with pseudoarchaeology , the looting of artifacts,

11466-698: The people who produced them, monetary value to collectors, or 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 unrealistic subjects are treated more seriously, accusations of pseudoscience are invariably levelled at their proponents (see Pseudoarchaeology ) . However, these endeavours, real and fictional, are not representative of modern archaeology. There

11583-521: The positions, dimensions and likely status of broch in the various areas in which brochs are found. For example, the broch "villages" which occur at a few places in Orkney have no parallel in the Western Isles . Generally, brochs have a single entrance with bar-holes, door-checks and lintels. There are mural cells and there is a scarcement (ledge), perhaps for timber-framed lean-to dwellings lining

11700-550: 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 (also see Primary Laws of Archaeology ). Likewise, their association , or relationship with nearby objects and features , needs to be recorded for later analysis. This allows the archaeologist to deduce which artifacts and features were likely used together and which may be from different phases of activity. For example, excavation of

11817-479: The same meaning. Brochs are often referred to as dùns in the west, and they are the most spectacular of a complex class of buildings found in northern Scotland. There are approximately 571 candidate broch sites throughout the country, according to the Royal Commission on the Ancient and Historical Monuments of Scotland . The origin of brochs is still subject to ongoing research. While most archaeologists believed 80 years ago that brochs were built by immigrants, there

11934-620: The same meaning. Place names in Scandinavian Scotland such as Burgawater and Burgan show that Old Norse borg is the older word used for these structures in the north. Brochs are often referred to as dùn in the west. Antiquarians began to use the spelling broch in the 1870s. A precise definition for the word has proved elusive. Brochs are the most spectacular of a complex class of roundhouse buildings found throughout Atlantic Scotland. The Shetland Amenity Trust lists about 120 sites in Shetland as candidate brochs, while

12051-408: The sheer number of brochs, sometimes in places with a lack of good land, makes it problematic. Brochs' close groupings and profusion in many areas may indeed suggest that they had a primarily defensive or even offensive function. Some of them were sited beside precipitous cliffs and were protected by large ramparts, artificial or natural: a good example is at Burland near Gulberwick in Shetland , on

12168-475: The sub-discipline of historical archaeology . For many literate cultures, such as Ancient Greece and Mesopotamia , their surviving records are often incomplete and 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 of aristocrats has sometimes been restricted to deeds and contracts. The interests and world-view of elites are often quite different from

12285-519: The temples of Šamaš the sun god, the warrior goddess Anunitu (both located in Sippar ), and the sanctuary that Naram-Sin built to the moon god, located in Harran , but he also had them restored to their former glory. He was also the first to date an archaeological artifact in his attempt to date Naram-Sin's temple during his search for it. Even though his estimate was inaccurate by about 1,500 years, it

12402-476: The term archaeology means "the study of ancient history". The discipline involves surveying , excavation , and eventually analysis of data collected, to learn more about the past. In broad scope, archaeology relies on cross-disciplinary research. Archaeology developed out of antiquarianism in Europe during the 19th century, and has since become a discipline practiced around the world. Archaeology has been used by nation-states to create particular visions of

12519-458: The total carbon dioxide in a given region of Earth's atmosphere . Dating a specific sample of fossilized carbonaceous material is more complicated. Such deposits often contain trace amounts of C. These amounts can vary significantly between samples, ranging up to 1% of the ratio found in living organisms (an apparent age of about 40,000 years). This may indicate contamination by small amounts of bacteria, underground sources of radiation causing

12636-559: The tradition of Chinese epigraphy by investigating, preserving, and analyzing ancient Chinese bronze inscriptions from the Shang and Zhou periods. In his book published in 1088, Shen Kuo criticized contemporary Chinese scholars for attributing ancient bronze vessels as creations of famous sages rather than artisan commoners, and for attempting to revive them for ritual use without discerning their original functionality and purpose of manufacture. Such antiquarian pursuits waned after

12753-576: 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 19th-century ship wreck, and service cable location during evaluation. Metal detectorists have also contributed to archaeology where they have made detailed records of their results and refrained from raising artifacts from their archaeological context. In

12870-472: The usual term for one major branch of antiquarian activity. "Archaeology", from 1607 onward, initially meant what we would call "ancient history" generally, with the narrower modern sense first seen in 1837. However, it was Jacob Spon who, in 1685, offered one of the earliest definitions of "archaeologia" to describe the study of antiquities in which he was engaged, in the preface of a collection of transcriptions of Roman inscriptions which he had gleaned over

12987-412: The years of his travels, entitled Miscellanea eruditae antiquitatis. Twelfth-century Indian scholar Kalhana 's writings involved recording of local traditions, examining manuscripts, inscriptions, coins and architectures, which is described as one of the earliest traces of archaeology. One of his notable work is called Rajatarangini which was completed in c.  1150 and is described as one of

13104-525: Was a restlessly itinerant Italian humanist and antiquarian who came from a prominent family of merchants in Ancona , a maritime republic on the Adriatic . He was called by his contemporaries pater antiquitatis ('father of antiquity') and today "father of classical archaeology": "Cyriac of Ancona was the most enterprising and prolific recorder of Greek and Roman antiquities, particularly inscriptions, in

13221-421: Was also responsible for mentoring and training a whole generation of Egyptologists, including Howard Carter who went on to achieve fame with the discovery of the tomb of 14th-century BC pharaoh Tutankhamun . The first stratigraphic excavation to reach wide popularity with public was that of Hissarlik , on the site of ancient Troy , carried out by Heinrich Schliemann , Frank Calvert and Wilhelm Dörpfeld in

13338-423: Was borrowed from the new geological and paleontological work of scholars like William Smith , James Hutton and Charles Lyell . The systematic application of stratigraphy to archaeology first took place with the excavations of prehistorical and Bronze Age sites. In the third and fourth decades of the 19th century, archaeologists like Jacques Boucher de Perthes and Christian Jürgensen Thomsen began to put

13455-421: Was developed as a result of increasing commercial development. The purpose of archaeology is to learn more about past societies and the development of the human race . Over 99% of the development of humanity has occurred within prehistoric cultures, who did not make use of writing , thereby no written records exist for study purposes. Without such written sources, the only way to understand prehistoric societies

13572-464: Was still a very good one considering the lack of accurate dating technology at the time. The science of archaeology (from Greek ἀρχαιολογία , archaiologia from ἀρχαῖος , arkhaios , "ancient" and -λογία , -logia , " -logy ") grew out of the older multi-disciplinary study known as antiquarianism . Antiquarians studied history with particular attention to ancient artifacts and manuscripts, as well as historical sites. Antiquarianism focused on

13689-408: Was that they were defensive structures, places of refuge for the community and their livestock. They were sometimes regarded as the work of Danes or Picts . From the 1930s to the 1960s, archaeologists such as V. Gordon Childe and later John Hamilton regarded them as castles where local landowners held sway over a subject population. The castle theory fell from favour among Scottish archaeologists in

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