Results for alignment:
- CATEGORY: structure
DEFINITION: An arrangement of single or multiple rows of standing stones (menhirs) at a site once occupied by humans. They are found mainly in Brittany and the British Isles' highland zones and are often aligned on cairns, henge monuments, or stone circles. Some others are found in Corsica. The rows do not provide much dating evidence, but they were probably set up in the 2nd and 3rd millennium BC (Neolithic, Bronze Age).
- rock alignment
- CATEGORY: feature
DEFINITION: A design created by an arrangement of rocks, typically found across desert plains; usually the complete image can be discerned only aerially.
- SYNONYMS OR RELATED TERMS: astroarchaeology
DEFINITION: The study of the relationship between prehistoric knowledge of astronomical events through calendars, observatory sites, and astronomical images in art and past cultural behavior. The field includes the study of mathematical correlations between archaeological features and the movements of celestial bodies. Some sites (Stonehenge, New Grange) show a definite interest in simple solar observations. Ancient astronomical knowledge can be inferred through the study of the alignments and other aspects of these archaeological sites.
- archaeomagnetic dating
- SYNONYMS OR RELATED TERMS: archaeomagnetic intensity dating, archaeomagnetism, palaeointensity dating, archaeomagnetic age determination
DEFINITION: A chronometric method used to date objects containing magnetic materials -- especially for buried undisturbed features such as pottery kilns, earthen fireplaces, and brick walls -- which can be compared to known schedules of past magnetic alignments within a region and fluctuations in the earth's magnetic field. Clay and rocks contain magnetic minerals and when heated above a certain temperature, the magnetism is destroyed. Upon cooling, the magnetism returns, taking on the direction and strength of the magnetic field in which the object is lying. Therefore, pottery which is baked in effect fossilizes" the Earth's magnetic field as it was the moment of their last cooling (their archaeomagnetism or remanent magnetism). In areas where variations in the Earth's magnetic field are known it is possible to date a pottery sample on a curve. This method yields an absolute date within about 50 years."
- CATEGORY: related field
DEFINITION: Most ancient civilizations studied the skies for astronomical knowledge. Ancient astronomy has been studied by archaeologists in prehistoric Europe through monuments and in Central America through inscriptions and documents. Studies of prehistoric astronomy in Europe have concentrated on the megalithic monuments and stone circles, which have been proven to incorporate alignments of the sun, moon, and brighter stars -- especially significant points in their cycles. Solar alignments occur at New Grange and Stonehenge, lunar orientations at the Recumbent Stone Circles of Aberdeenshire and the Carnac stones in Brittany. Many theories are discussed as to the accuracy of measurements and the degree of astronomical understanding achieved by these early societies. The ability to predict astronomical events would have enhanced political power, which is something suggested in Mesoamerica. The ability to predict events by the governing elite class increased their credibility as able rulers. The Mesoamerican people put great emphasis on the calendar and astronomy and were able to make extremely accurate measurements of the solar year, the appearance of eclipses, and the phases of the Moon. Buildings seen as observatories occur at Chichen Itza and at Palenque, and the Dresden codex is a detailed collection of calculations tracing the eclipses of the Moon and Sun and the cycles of Venus and possibly Mars and Jupiter. The Maya were even aware of the impreciseness of the 365-day year in their Calendar Round and added a correction factor to account for the quarter-day per year discrepancy. The cycle of the Moon, in comparison, was calculated with amazing accuracy (29.5302 days compared to the actual figure of 29.5306). The cycle of Venus (calculated at 583.92) was also pinpointed as accurately as measurements taken by modern astronomical methods. The ancient astronomers' awareness of long-term astronomical phenomena was astonishing.
- CATEGORY: site
DEFINITION: A site in Wiltshire, England, at which stands one of Britain's finest megalithic monuments (known as henges) and one of the largest ceremonial structures in Europe. It was built c 2000 BC in the Neolithic, where the ridgeways of southern England meet, a natural site for tribal gatherings. It consists of a large bank with internal ditch (1.2 km long) with four equally spaced entrances. Inside the ditch was set a circle of 98 sarsen stones, weighing as much as 40 tons each. In the center were two smaller stone circles, each c 100 meters in diameter. The northern circle contains a U-shaped setting of three large stones, and the southern inner circle once had a complex arrangement of stones at its center. The Ring Stone, a huge stone perforated by a natural hole, stood within the earthworks and main stone circle at the southern entrance. The southern entrance leads out to two parallel rows of sarsens forming an avenue 15 m wide and 2.5 km long which ends at a ritual building (the so-called Sanctuary) on Overton Hill. Traces of a second avenue remain on the opposite side of the monument. From the bottom of the ditch came sherds of Neolithic Windmill Hill, Peterborough, and Grooved Ware styles, while higher up were fragments of South British (Long Necked) Beaker and Bronze Age pottery. Burials with Beaker and Rinyo-Clacton wares have been excavated at the bases of some of the stones. Near the southern end of the Avenue was an occupation site with Neolithic and Beaker sherds. The complex geometry of the site is studied, especially the possible astronomical alignments built into it. The circles at Avebury and the wooden structure on Overton Hill were all probably built at the same time by Neolithic communities.
- burial orientation
- CATEGORY: term
DEFINITION: The direction or alignment of the body at the time of burial, especially the direction toward which the head is positioned. Burial orientation may vary according to the culture involved.
- CATEGORY: site
DEFINITION: A village in western France near the Atlantic coast that is the site of more than 3,000 prehistoric stone monuments of the alignment type. These menhirs are arranged in three groups of 10-13 parallel rows, which ended at semicircles or rectangles of standing stones. The single stone menhirs and multistone dolmens were made from local granite and are worn by time and weather and covered in white lichen. The area also has a series of long cairns of mid-Neolithic to Early Bronze Age which covers funerary chambers and secondary cists. The grave goods included polished axes of rare stones such as jadeite and fibrolite, stone boxes containing charcoal, cattle bones, and pottery. The area was clearly an important ritual center, venerated by the Bretons until fairly recent times, and adopted by the Romans for religious purposes. Christians added crosses and other symbols to the stones. In 1874, James Miln uncovered the remains of a Gallo-Roman villa one mile east of the village. The Musée Miln-Le Rouzic in Carnac has an important collection of artifacts.
- SYNONYMS OR RELATED TERMS: Nasca lines; Nazca Lines
CATEGORY: artifact; lithics
DEFINITION: Any ground-constructed example of rock art, such as intaglios or rock alignments; straight lines, geometric shapes, and other representative designs found on the desert plain. Geoglyphs can be formed by piling up materials on the ground surface or by removing surface materials and most suggest a largely ceremonial function.
- lateral section
- CATEGORY: artifact
DEFINITION: A cross section in which the cut is made perpendicular to the base line of the artifact drawing and the outline of the section is oriented like a profile view but in horizontal alignment with the points through which the cut was made
- ley line / ley-line
- SYNONYMS OR RELATED TERMS: ley
DEFINITION: A hypothetical straight line connecting prehistoric sites, frequently regarded as the line of an ancient track and credited by some with paranormal properties. The term also refers to the alignment of diverse features, usually taken from small-scale maps rather than from the ground, assumed to have some ancient esoteric significance.
- magnetic dating
- SYNONYMS OR RELATED TERMS: paleomagnetic dating
DEFINITION: Any theoretically chronometric dating technique which uses the thermo-remanent magnetism of certain types of archaeological material. These methods use the known changes have taken place in the direction and intensity of the earth's magnetic field. Magnetic minerals present in clay and rocks each have its own magnetic orientation. When heated to the so-called blocking temperature, the original magnetic orientation of the particles is destroyed, and they will take on the orientation of the earth's magnetic field in a fixed alignment -- which does not alter after cooling. These methods are most suitable for kilns and hearths. Once the direction of the archaeological sample has been determined, it may be possible to date it by fitting it to the secular variation curve established for the local area. There is no universal curve, since not only the earth's main field varies, but there are also local disturbances. Since the dating of the curve has to be constructed through independent dating techniques, and these are not available for every area, there are not established curves for every region. As a dating technique, it is strictly limited to those areas where dated curves have been established. A more recent dating technique using thermo-remanent magnetism is palaeointensity dating (archaeomagnetic intensity dating). The principle is that the thermo-remanent magnetism in burnt clay is proportional to the intensity of the magnetic field acting on the clay as it cools down. The measurement of its intensity, and a comparison with the intensity revealed by reheating in today's magnetic field, gives a ratio for the past and present fields which can be used to establish a curve of variation in the earth's magnetic field intensity. The method promises to be useful since direction in situ is not required and it can therefore be used for pottery and other artifacts as well as hearths and kilns.
- SYNONYMS OR RELATED TERMS: proton magnetometer
DEFINITION: A geophysical instrument that measures the intensity and sometimes direction of the Earth's magnetic field. It is used in electromagnetic surveying to identify changes in the field within soil or sediment that might be caused by subsurface features, hearths, kilns, or metal artifacts. When a current is passed through a coil in a bottle of water or alcohol the protons of the hydrogen atoms align themselves to its magnetic field. When the current is cut off, the protons realign themselves according to the earth's field, its strength being indicated by the frequency of their gyration on realignment. This sets up a weak current which is transmitted back from the bottle to the instrument and there registered on dials. The resulting figures are plotted to reveal anomalies in field strength -- usually due to buried iron, kilns, hearths, or to pits or ditches. These features can thus be rapidly located without disturbance of the ground, and excavation can be directed to the most promising areas. Magnetrometry is the use of a magnetometer for mapping subsurface anomalies. There are a number of designs, but two are particularly widely used. The proton magnetometer makes an absolute measurement of field strength, but is intermittent in operation: each reading is initiated by the push of a button, and takes some seconds to appear on the display of the instrument. Fluxgate magnetometers work on a different principle, and give a continuous reading, which makes surveying less time-consuming. Most fluxgate machines do not however measure field strength directly, but rather are gradiometers, measuring the vertical gradient of the earth's' magnetic field, i.e. how fast the field strength changes with vertical distance from the earth's magnetic field Gradient measurements can also be used in archaeological surveys and have an advantage over absolute measurements. The earth's field strength varies continuously during the day at any one location. Absolute measurements taken at different times have to be calibrated for this effect if they are to be comparable. Gradient measurements are not affected by this diurnal drift in field strength, and so do not need to be calibrated. Proton gradiometers are also available. The fluxgate, differential fluxgate, and proton gradiometer take continuous measurements of relative vertical change in the intensity of field strength.
- medicine wheel
- CATEGORY: site
DEFINITION: A kind of site in the northwest North American Plains which was comprised of stone alignments set in radiating spokes, often with central and peripheral cairns. Medicine wheels served a number of purposes and some are as old as 5500 BP. In southern Montana is a medicine wheel which is a prehistoric relic constructed of rough stones laid side by side, forming a circle 70 feet (20 m) in diameter with 28 spokes leading from the center hub, which is about 12 feet (3.5 m) in diameter.
- SYNONYMS OR RELATED TERMS: megalithic; megalithic tomb; megalithic monument
CATEGORY: feature; structure
DEFINITION: From the Greek megas 'large' and lithos 'stone', the term for a large stone and also for structures or arrangements of large stones (menhirs, stone circles, and alignments). The term is especially used for the monuments of northern and western Europe from the Mesolithic period, such as Stonehenge and Carnac in France of the late Neolithic culture of western Europe. Such a stone was sometimes free-standing, sometimes part of a structure. The term could also refer to a large tomb which used megaliths to create passages and chambers in which burials of one or more people could be placed, such as the passage graves of Brittany. Some authorities have used the term in a still wider sense to cover monuments built of Cyclopean masonry such as the Maltese Temples, the Nuraghi of Sardinia and the Navetas of Minorca. Various types of megalithic monuments have also been found in parts of Asia, Oceania, and Africa. The migration theories based on megalithic monuments are now discounted. It is now accepted that the practice of erecting these monuments arose independently in different times and places and for different reasons.
- megalithic culture
- CATEGORY: term
DEFINITION: In India, an Iron Age culture of the south from the 1st millennium BC or earlier which lasted into the early 1st millennium AD. The grave forms include urn burials and various cist, pit, and rock-cut graves. Stone alignments are also associated and graves generally contain burnished black-and-red ware, iron tools, weapons, horse and household equipment.
- megalithic yard
- CATEGORY: term
DEFINITION: A unit of measurement, 0.829 meters or 2.72 feet, deduced from the layout of stone circles and alignments in Britain and Brittany.
- CATEGORY: structure; artifact
DEFINITION: A single, vertical standing stone; any prehistoric structure consisting of a tall, upright megalith (huge stone). The name is from the Old Breton men, meaning stone" and hir meaning "long". Menhirs occur in all parts of the world where megalithic monuments are known but they are particularly profuse in prehistoric Europe. Menhirs are difficult to date but in Ireland and southwest England a few examples mark burials dating from the Neolithic to the Middle or Late Bronze Age. A similar or slightly earlier date is attested for some of the Breton menhirs. In all these areas a few of the stones bear cup marks. Such a megalith is often isolated erected by a family or tribe as a memorial stone for some deceased hero or some great event. It may have been a religious object for worship like the American Indian totem pole. Other are associated with dolmens tumuli and circles of stones. Menhirs may occur singly in rows (alignments) or in enclosures (stone circles). Anthropomorphic examples are known as statue-menhirs."
- CATEGORY: site
DEFINITION: City in Akita Prefecture, Japan, with two Late Jomon period stone circles. They have associated sundial arrangements and have been found to contain burials in shallow pits under the alignments.
- SYNONYMS OR RELATED TERMS: palaeomagnetism, remanent magnetism; paleo-magnetism, palaeo-magnetism; archaeomagnetism
DEFINITION: The magnetic polarization acquired by the minerals in a rock at the time the rock was deposited or solidified. The permanent magnetism in rocks, resulting from the orientation of the Earth's magnetic field at the time of rock formation in a past geological age. It is the source of information for the paleomagnetic studies of polar wandering and continental drift. The field of paleomagnetism involves techniques for determining the age of rocks by analyzing the magnetic field polarity of certain minerals in the rock and its importance in archaeology lies in its use as a dating method. The ancient orientation and intensity of the earth's magnetic field is preserved by the magnetization of iron oxides in rocks and sediments and archaeological materials (archaeomagnetism). Ancient direction and intensity of the earth's magnetic field may be preserved in three ways: a) thermoremanet magnetism (T.R.M.) works through the alignment of the magnetic domains within iron minerals when heated to above the Curie point and subsequently cooling, b) detrital remanent magnetism works through the alignment of clay particles sinking down slowly through still lake or deep ocean water. A block of sediment is magnetized in the direction of the earth's field at the time when it was deposited., and c) sun-dried bricks as the bricks become magnetized in the current direction and intensity of the earth's field. Using igneous rocks, independently dated by potassium/argon, and kilns, hearths, pots etc. dated archaeologically, it has been possible to reconstruct something of the history of the earth's magnetic field. Palaeomagnetism proper is done by studying reversals in the magnetic field of the Earth, the youngest reversal dating to 700,000 bp. Measurement of the declination and inclination of the magnetic poles as it affects materials of different ages can be used to build regional chronologies. Palaeomagnetic dating has also been successfully applied to lacustrine deposits, deep sea cores, and volcanic rocks.
- random flaking
- CATEGORY: artifact
DEFINITION: The removal of flakes with no regard to the resulting aesthetic alignment of flake scars.
- stone circle
- CATEGORY: feature; structure
DEFINITION: A ring of standing stones, either circular or near-circular, found in the British Isles from the Neolithic and Early Bronze Age. There are almost 1000 stone circles, some surrounded by a ditch, with the most famous examples being Stonehenge, Avebury, and Callanish. Two atypical examples are in Brittany. The standing stones which make up these circles are widely spaced; in many examples they are incorporated into a ring-bank of smaller piled stones which has one opening as the entrance. A local variant is the recumbent stone circle of Aberdeenshire in which the entrance is marked by a large horizontal stone flanked by tall portal stones. A recumbent stone is also a feature of circles in southwest Ireland, but here the two tallest stones are placed diametrically opposite the horizontal stone. Two of the Scottish recumbent stone circles have yielded Beaker pottery, while urn burials in various 'standard' circles were of Bronze Age type. Circles are often associated with cairns, menhirs, and alignments. Many have tried to interpret the complex geometric layouts and placement of the stones within an astronomical base. There has been much discussion about the validity of various theories and there is no agreement on the subject.
- CATEGORY: site
DEFINITION: Ancient monument on Salisbury Plain, Wiltshire, England, the remains of four massive trilithons surrounded by concentric circles of megaliths, probably constructed since c 3200 BC. It was a major Neolithic and Early Bronze Age ritual monument, architecturally unique, surrounded by a whole complex of barrow cemeteries and ritual sites. It had many phases of reconstruction. Apart from a cursus, the oldest structure was a circular earthwork about 100 meters in diameter, consisting of a ditch with an inner bank broken by a single entrance. Just inside the bank was a ring of 56 Aubrey holes (pits), some of which contained cremations. There were further cremations in the ditch and on the inner plateau. The presence of grooved ware pottery, together with radiocarbon dates from a cremation suggest that Stonehenge I belongs to the end of the Neolithic. Phase II occurred in c 2200-2000 when two concentric rings of sockets were dug at the center of the site for the erection of 80 bluestones imported from the Preseli Hills of southwest Wales. To this period belongs the Avenue, two parallel banks and ditches which run from the entrance to the river Avon 3 km away. In Stonehenge's third phase, the bluestones were removed, and Sarsen stones, some weighing over 50 tons, were brought from the Downs 38 km away to the north. These blocks, unlike those of any other henge or megalithic tomb, were dressed to shape before erection, and were then set up as a circle of uprights with a continuous curving lintel, enclosing a U-shaped arrangement of five trilithons. This phase has been dated 2120 +/- 150 BC and its work was carried out by the bearers of the Wessex culture. At a later stage (phase IIIc) the bluestones were re-erected in their present positions, duplicating the sarsen structure. There is a radiocarbon date of 1540 +/- 105 BC for the early part of this final stage, and the whole of Stonehenge III probably falls within the Early Bronze Age. The final stage came in the Middle or Late Bronze Age when the Avenue was extended 2000 meters east. The function of the monument is usually held to be religious, though it had no connection with the Druids. Theories are that the northeast-southwest axis may suggest some form of sun cult, the stone settings may have been used for astronomical observations in connection with the calendar, and the Aubrey holes for calculating the occurrence of eclipses. It has also been interpreted as the temple of a sun or sky cult. Archaeologists have long been fascinated by this monument, with its evidence of massive manpower input (one calculation suggests 30 million man-hours would have been required for the phase IIIA structure), its architectural sophistication, and astronomical alignments.
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