Archaeology Wordsmith

Results for correlation:

autocorrelation: CATEGORY: typology
DEFINITION: An instance when two variables appear to be correlated, not because of any causal relationship between them, but because they are subdimensions" of some other variable."
correlation: CATEGORY: technique
DEFINITION: The use of various methods, often multiple methods, to demonstrate the equivalency of stratigraphic units. This term refers to the relation of one stratigraphical unit to another, by petrological, osteological, lithographic, cultural, chronological, or palaeontological means. For example, stratigraphic units may be correlated using palaeontological criteria, absolute dating methods, relative dating methods, cross-dating methods, and position relative to the glacial-interglacial cycle by examining physical and biological attributes. Correlation of fossil inclusions is a principle of stratigraphy: that strata may be correlated based on the sequence and uniqueness of their floral and faunal content.
spatial autocorrelation: CATEGORY: term
DEFINITION: The tendency for items found close to one another in space to be highly similar with respect to characteristics that are not independent of location.
archaeoastronomy: SYNONYMS OR RELATED TERMS: astroarchaeology
CATEGORY: branch
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.
balk excavation method: CATEGORY: technique
DEFINITION: The excavation of an area of a site leaving vertical pillars or walls in place, thus allowing better correlation between excavations with predefined strata.
calendar: SYNONYMS OR RELATED TERMS: calendrics
CATEGORY: term
DEFINITION: A cyclical system of measuring the passage of time. The day is the fundamental unit of computation in any calendar. Most ancient civilizations (and perhaps some non-literate prehistoric societies) developed calendrical systems to mark the passage of time and various methods have been employed by different peoples. Where these were both carefully calculated and written down, as in Egypt, Mesopotamia and Mesoamerica, they are of considerable assistance to archaeologists for dating purposes. In the Americas, the origins of calendrics are still obscure, but evidence from Monte Albán suggests that the 52-year Calendar Round was known by the 6th century BC. The Long Count system was in use by c 1st century BC if not before. Ancient Near Eastern calendars varied from city to city and from period to period. In most cities the year started in the spring and was divided into 12 or 13 months. In some places the months were of fixed length; in others they were lunar months starting at the first sighting of the crescent of the new moon. As there are more than 12 lunar months in a solar year additional, or intercalary, months were included so that every third year contained 13 months. The earliest Egyptian calendars were based on lunar observations combined with the annual cycle of the Nile inundation, measured with nilometers. On this basis, the Egyptians divided the year into 12 months and three seasons: akhet (inundation), peret (spring/ crops), and shemu (harvest). The Egyptians had 30-day months and 5 intercalary days in their solar or civil calendar. For agricultural purposes and for determining religious festivals, they used a different calendar based on observations of Sirius, the dog star. The calendar in use in ancient Mesopotamia and the Levant was lunar, based on 12 months of 30 days each. This produced a year of only 354 days, about 11-1/4 days short of the true solar year; the necessary correction was made by the addition of seven months over a period of 19 years. This type of calendar is still used in both Judaism and Islam for religious purposes, though many countries now also employ the Gregorian solar calendar for secular purposes. The origin of the calendric system in general use today -- the Gregorian calendar -- can be traced back to the Roman republican calendar, which is thought to have been introduced by the fifth king of Rome, Tarquinius Priscus (616-579 BC). This calendar was likely derived from an earlier Roman calendar -- a lunar system of 10 months -- that was supposedly devised about 738 BC by Romulus, the founder of Rome. In the year 46 BC, Julius Caesar corrected the calendar by having a year of 445 days (known as the ultimus annus confusionis' or 'the last year of the muddled reckoning'). He then adapted the Egyptian solar calendar for Roman use, inserting extra days in the shorter months to bring the total up to 365, with the addition of a single day between the 23rd and 24th February in leap years. This calendar, known as the Julian Calendar, remained in use until the time of Gregory XIII in 1582, who made a further correction (of eleven days) and instituted the calendar which is in general use today. Very useful to Mesoamerican archaeologists is the Maya Long Count or Initial Series, which was a means of recording absolute time. Its starting date of 3113 BC (using the Goodman-Thompson-Martinex correlation) marks some mythical event in Maya history and itself stands at the beginning of a cycle 13 Baktuns long. A Baktun at 144,000 days in the largest unit of time in the calendar and is further divided into smaller units: the Katun (7200 days); the Tun (360 days); the Uninal (20 days) and the Kin (a single days). Thus Long Count dates are expressed in terms of these units in a five place notation. Therefore the date 9.18.0.0.0. indicates the passage of 9 x 144,000 plus 18 x 7200 days since the initial date of 3113 BC. In cultural contexts, however, the dates are inscribed as a series of hieroglyphs which incorporate numeration via bars (units of five) and dots (units of one). Short count dating replaced the Long Count after 900 AD and the Katun replaced the Baktun as the largest unit. It is less precise, however.
contingency table: CATEGORY: technique
DEFINITION: A table for classifying elements of a population according to two variables -- recording the relationship between two classes of items, each entry counting the number of specific occurrences of the possible combinations. The rows correspond to one variable and the column to the other. The classes compared in such a cross tabulation might be, for instance, sites in different ecological zones, artifacts in different contexts, or the coincidence of different decorative traits and fabric types in a pottery assemblage. Various statistics can be calculated from such a table, especially to test the significance of the observed correlations; the chi-square test is often used to do this.
cross-dating: SYNONYMS OR RELATED TERMS: cross dating
CATEGORY: technique
DEFINITION: A correlation dating technique that can yield a relative or absolute age or chronology. The basis of cross-dating is the occurrence of finds in association. The assumption is that a particular type of artifact, for example a type of sword, when found in an undated context will bear a similar date to one found in a dated context, thus enabling the whole of the undated context to be given a chronological value. The method is based on the assumption that typologies evolved at the same rate and in the same way over a wide area or alternatively on assumptions of diffusion. Many of the chronologies constructed before the advent of chronometric dating techniques were based on cross-dating. New techniques such as radiocarbon dating showed some of the links established by cross-dating to be invalid, so the method has become somewhat discredited. However, its use is still helpful where recognizable products of dateable manufacture are found in undated contexts with no possibility of using a chronometric dating technique. So in the absence of geochronology, two cultural groups can only be proved contemporary by the discovery of links between them. If in culture A an object produced by culture B is found, A must be contemporary with, or later than, B. The term cross-dating ought strictly to be used only when an object of culture A is also found in proved association with culture B, when overlap of at least part of the time span of each is proved. Items having an established date, such as dated coins or buildings, or ceramics of known manufacture are most often used. By itself, a cross-dated chronology does not give absolute dates, but it may be calibrated by reference to other dating methods. A type of cross-dating has always been used in geology and stratigraphical sequences are often correlated by the assemblages of fossils they contain; this is known as biostratigraphy. The archaeological versions of cross-dating may have been developed directly out of the geological method and may have been based on a false analogy between biological fossils and archaeological artifacts.
dendrochronology: SYNONYMS OR RELATED TERMS: tree-ring dating
CATEGORY: technique
DEFINITION: An absolute chronometric dating technique for measuring time intervals and dating events and environmental changes by reading and dating the pattern (number and condition) of annual rings formed in the trunks of trees. The results are compared to an established tree-ring sequence for a particular region with consideration to annual fluctuations in rainfall which result in variations in the size of the rings laid down by trees on the outside of their trunks. These variations, given favorable conditions, form a consistent pattern; and sections or cores taken from beams in ruins have been matched to provide a long chronology over large areas. The method is based on the principle that trees add a growth ring for each year of their lives, and that variations in climatic conditions will affect the width of these rings on suitable trees. In a very dry year growth will be restricted, and the ring narrow, while a wet and humid year will produce luxuriant growth and a thick ring. By comparing a complete series of rings from a tree of known date (for example, one still alive) with a series from an earlier, dead tree overlapping in age, ring patterns from the central layers of the recent tree and the outer of the old may show a correlation which allows the dating, in calendar years, of the older tree. The central rings of this older tree may then be compared with the outer rings or a yet older tree, and so on until the dates reach back into prehistory. Problems that arise are when climatic variation and suitable trees (sensitive trees react to climatic changes, complacent trees do not) are not be present to produce any significant and recognizable pattern of variation in the rings. Another problem is that there may be gaps in the sequences of available timber, so that the chronology 'floats', or is not tied in to a calendrical date or living trees: it can only be used for relative dating. Also, the tree-ring key can only go back a certain distance into the past, since the availability of sufficient amounts of timber to construct a sequence obviously decreases. Only in a few areas of the world are there species of trees so long-lived that long chronologies can be built up. This method is especially important in the southwestern United States, Alaska, and Scandinavia, dating back to several thousand years BC in some areas. Dendrochronology is of immense importance for archaeology, especially for its contribution to the refining of radiocarbon dating. Since timber can be dated by radiocarbon, dates may be obtained from dendrochronologically dated trees. It has been shown that the radiocarbon dates diverge increasingly from calendrical dates provided by tree-rings the further back into prehistory they go, the radiocarbon dates being younger than the tree-ring dates. This has allowed the questioning of one of the underlying assumptions of radiocarbon dating, the constancy of the concentration of C14 in the atmosphere. Fluctuations in this concentration have now been shown back as far as dendrochronological sequences go (to c 7000 BC), and thus dating technique is serving the further research on another. In 1929, A.E. Douglass first showed how this method could be used to date archaeological material. The long-living Bristlecone Pine (Pinus aristata) of California has yielded a sequence extending back to c 9000 bp. In Ireland, oak preserved in bogs has produced a floating chronology from c 2850-5950 bp.
factor analysis: CATEGORY: technique
DEFINITION: A multivariate mathematical technique which assesses the degree of variation between artifact types, and is based on a matrix of correlation coefficients which measure the relative association between any two variables. This statistical technique calculates the relative importance of a set of factors that together are assumed to influence some observed set of values or properties.
glaciation: SYNONYMS OR RELATED TERMS: glacial
CATEGORY: chronology; geography
DEFINITION: The process by which land is covered by continental and alpine glacier ice sheets or the period of time during which such covering occurred; several glaciations are required to make up an Ice Age (as the Pleistocene). The land is subject to erosion and deposition by this process, which occurred repeatedly during the Quaternary; the process modifies landscapes and affects the level of ocean basins. These periods of colder weather are also called glacials, and the warmer periods between them interglacials. At the onset of colder weather, water is taken up into the ice-sheets and glaciers, causing a drop in sea level. Landscapes covered by ice can be recognized by the smooth rock surfaces and the U-shaped valleys formed by the ice-sheets and glaciers and the rock rubble carried along in them. As the climate warmed, the glaciers retreated, the ice melted, and the sea-level rose. The ice also deposited various forms of boulder clays, and banks of debris at the sides and ends of glaciers, known as moraines. Beyond the limits of glaciers and ice-sheets, extensive layers of outwash sands and gravels were deposited; where these deposits occur in lakes they are called varves. The periglacial zone around the margin of an ice sheet has permanently frozen subsoil, and is occupied by cold-loving plants and animals. Erosion was mainly brought about by solifluxion. The low temperatures and the constant freezing and thawing also affect the soil; these frost effects are called cryoturbation. Particularly characteristic are ice-wedges, polygonal cracks in the ground frequently recognizable in air photographs. They were caused by the shrinking of the ground at low temperatures and the filling of the cracks with water, which subsequently expanded on freezing to open the crack still further. The last two million years have been marked by a series of such glaciations. Broad correlations between the glaciation schemes in different parts of Europe and North America exist. Four Ice Ages have been figured; in Europe, the First Glaciation was at a climax 550,000 years ago. This gradually gave way to the First Interglacial (Gunz-Mindel) Period lasting about 60,000 years in which warm conditions again prevailed. The Second Glaciation came along with its climax 450,000 years ago, and the Second Interglacial Period (Mindel-Riss) followed, lasting 200,000 years. The Third Glacial Period (Riss) climax 185,000 years ago was relieved by 60,000 years of interglacial warmth. The Fourth (Wurm) and last Ice Age was at its height 72,000 years ago. The term has also commonly been used to describe the periods of generally cold climate which occurred at intervals during the Quaternary period. It is, however, now clear that ice-sheets grew only during parts of these so-called 'glacials' (e.g., the Devensian). For this reason, the term 'cold stage' is preferable.
grey ware: SYNONYMS OR RELATED TERMS: greyware
CATEGORY: ceramics
DEFINITION: The typical household and ceremonial ceramic ware of Monte Albán and the Valley of Oaxaca, Mexico, made from a fine gray paste in the middle Pre-Classic period. Grey ware occurs throughout Monte Albán's occupation, with some variations in shape and ornamentation. In the latter periods in the Oaxaca sequence, after the collapse of Monte Albán, Mixtec grey ware was distributed through the Valley. The Zapotecs' merge with the Mixtecs is suggested by the correlation between the distribution of the Mixtec ceramics in Zapotec households, c 1250-1521 AD.
index fossil: SYNONYMS OR RELATED TERMS: index fossil concept; index species
CATEGORY: artifact; technique
DEFINITION: A fossil with widespread geographical range but which is restricted in time to a brief existence. In archaeology, it is a theory that proposes that strata containing similar fossil assemblages will tend to be of similar age. This concept enables archaeologists to characterize and date strata within archaeological sites using diagnostic artifact forms, making an animal species the basis for dating by faunal association. Artifacts that share the attributes of index fossils are useful in the cross-dating and correlation of deposits that contain them and in the construction of chronologies.
Le Vallonet: CATEGORY: site
DEFINITION: A cave on the Mediterranean coast of Provence, France, which has yielded what may be the oldest tools in Europe. In sediments with fauna of Upper Villa-Franchian type were five pebble tools and four flakes. Both the animal bones and the tools suggest a correlation with the early part of the Olduvai sequence.
Pleistocene Series: CATEGORY: chronology
DEFINITION: A division of the Quaternary System defined by its deposits. It is a worldwide division of rocks deposited during the Pleistocene Epoch (1,600,000-10,000 years ago). It overlies rocks from the Pliocene Epoch (5.3-1.6 million years ago) and is itself overlain by rocks of the Holocene Series; together these two latter divisions make up the Quaternary System. These deposits contain evidence of humans and their development throughout glacial and interglacial conditions. . By international agreement, the global stratotype section/point for the base of the Pleistocene Series is in the Vrica section in Calabria, Italy. The Pleistocene's boundary with the Pliocene occurs just above the position of the magnetic reversal that marks the Olduvai Normal Polarity Subzone, thus allowing the worldwide correlation of Pleistocene rocks with reference to the magneto-stratigraphic timescale.
stratigraphic relationships: CATEGORY: term
DEFINITION: Relationships of a superpositional nature, where one deposit lies above another, or they are made up of correlations, where strata or features have been cut into isolated parts by later digging.
stratigraphy: CATEGORY: technique
DEFINITION: The study and interpretation of the stratification of rocks, sediments, soils, or cultural debris, based on the principle that the lowest layer is the oldest and the uppermost in the youngest -- a major tool in establishing a relative dating sequence. The sequence of deposition can be assessed by a study of the relationships of different layers. Dateable artifacts found within layers, and layers or structures which are themselves dateable, can be used to date parts of stratigraphic sequences. An archaeologist has to master the skill to recognize it -- to distinguish one deposit from another by its color, texture, smell, or contents; to understand it -- to explain how each layer came to be added, whether by natural accumulation, deliberate fill, or collapse of higher-standing buildings; and to record it in measured drawings of the section. There can be problems where a feature filled with one type of material cuts into layers of the same material. Unless the later feature is recognized, objects of two different phases may appear to be stratified together. The underlying principles are: law of superposition, law of cross-cutting relationships, included fragments, and correlation by fossil inclusions. The stratigraphy principle was adopted from geology and is the basis of reconstructing the history of an archaeological site.
synchronic: SYNONYMS OR RELATED TERMS: synchronous
CATEGORY: chronology
DEFINITION: Pertaining to phenomena at one point in time, occurring simultaneously or at the same time; referring to a single period of time. This approach is not primarily concerned with change and often refers to the correlation of events or surfaces of stratigraphic units.
Thompson, Sir John Eric Sidney (1898-1975): CATEGORY: person
DEFINITION: English archaeologist and ethnographer who worked in the Maya area. He reconstructed the Temple of the Warriors at Chichen Itza and correlated the Mayan and Gregorian calendars (Goodman-Martinez-Thompson correlation between Mayan and Christian calendars which provided the basis for the chronology of Classic Maya civilization). Thompson was able to extensively decipher early Mayan glyphs, determining that they contained historical as well as ritualistic and religious records. He also worked at Lubaantun, Rio Bec and Pushilha, and he was the first to establish a chronology for the Belize Valley based on the seriation of ceramics. His books include The Civilization of the Maya" (1927) "The Rise and Fall of Maya Civilization" (1954) and "Maya History and Religion" (1970)."
varve dating: CATEGORY: technique
DEFINITION: A technique for producing chronometric dates based on the annual formation of layers of sediment on lake and river beds in glacial regions. Seasonal fluctuations in particle size and speed of sedimentation take place. During the winter, ice melting is very slow, melt-water streams do not contain much water, and they flow slowly, carrying little material. During the summer, melting accelerates, melt-water streams flow faster and carry more material. The supply of sediment to the ice-marginal lake varies with the season. A varve chronology, similar to a tree-ring chronology may be set up. But as with tree rings (see dendrochronology) the varves will vary from year to year, depending on the rapidity of the thaw, quantity of summer rain, winter snow, etc., the variations showing some correlation with the sunspot cycle. Such varve chronologies have been built up for Scandinavia and are used to date the retreat of the Weichselian ice-sheet. Varve dating has a greater significance than just for local dating, since frequently there is enough organic material to allow radiocarbon dates to be calculated. There is therefore the possibility of using the calendrical varve chronology to calibrate radiocarbon dates. Its use for archaeological dating is rather limited in that sites have to be related to the geological changes (the ice-sheet moraines or changing Baltic sea-levels) before their dates can be determined. Swedish pioneer Baron Gerard de Geer discovered in the late 19th century that these could be counted and correlated or linked over long distances, which gave him a timescale of 12,000 years and fixed the end of the Ice Age at about 10,000 years ago.
Woolley, Sir (Charles) Leonard (1880-1960): CATEGORY: person
DEFINITION: British archaeologist known for his work at Ur, Carchemish, Tell el-Amarna, Tell Atchana, Al Mina, and Al 'Ubaid. At Ur, he revealed 5000 years of history and wrote it up in a 10-volume series (Ur Excavations"). His discovery of geological evidence of a great flood suggested a possible correlation with the deluge described in Genesis and his findings in the Royal Cemetery brought the astonishing wealth and skills of the Sumerian civilization to the public's attention. He was an exacting excavator outstanding in interpretation and published popular accounts of his results. His other books include "The Sumerians" (1928) "Ur of the Chaldees" (1929) and "Digging up the Past" (1930)."

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