Results for absolute dating:
- absolute dating
- SYNONYMS OR RELATED TERMS: chronometric dating; absolute dates; absolute chronology; absolute age determination (antonym: relative dating)
CATEGORY: chronology; technique
DEFINITION: The determination of age with reference to a specific time scale, such as a fixed calendrical system or in years before present (B.P., BP), based on measurable physical and chemical qualities or historical associations such as coins and written records. The date on a coin is an absolute date, as are AD 1492 or 501 BC.
- chronometric dating
- SYNONYMS OR RELATED TERMS: absolute dating; chronometry
DEFINITION: Any technique of dating that relies on chronological measurement such as calendars, radiocarbon dates, etc. and which give the result in calendar years before the present, or B.P. Most of these techniques produce results with a standard deviation, but they have a relationship to the calendar which relative dating techniques do not. Among the most useful chronometric dating techniques are radiocarbon dating, potassium argon dating, and thermoluminescence dating. Dendrochronology, the relationship of dated ancient trees with live trees has no standard deviation and is the most accurate of all, though not universally applicable. Chronometric dating has developed in the last 30 years and has revolutionized archaeology.
- calendrical age determination
- CATEGORY: technique
DEFINITION: An absolute dating technique used when an object has been inscribed with a date from an ancient calendrical system or is associated with calendrical inscriptions that can be correlated with a modern calendar.
- 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.
- SYNONYMS OR RELATED TERMS: chronology
DEFINITION: The process by which an archaeologist determines dates for objects, deposits, buildings, etc., in an attempt to situate a given phenomenon in time. Relative dating, in which the order of certain events is determined, must be distinguished from absolute dating, in which figures in solar years (often with some necessary margin of error) can be applied to a particular event. Unless tied to historical records, dating by archaeological methods can only be relative -- such as stratigraphy, typology, cross-dating, and sequence dating. Absolute dating, with some reservation, is provided by dendrochronology, varve dating, thermoluminescence, potassium-argon dating, and, most important presently, radiocarbon dating. Some relative dating can be calibrated by these or by historical methods to give a close approximation to absolute dates -- archaeomagnetism, obsidian hydration dating, and pollen analysis. Still others remain strictly relative -- collagen content, fluorine and nitrogen test, and radiometric assay. Other methods include: coin dating, seriation, and amino-acid racemization. The methods have varying applications, accuracy, range, and cost. Many new techniques are being developed and tested.
- CATEGORY: culture
DEFINITION: Archaeological cultures that represent similar levels or technological advance with other cultures, regardless of a difference derived in absolute dating methods. This is the principle behind the Three Age System.
- ice cores
- CATEGORY: technique
DEFINITION: Borings taken from the Arctic and Antarctic polar ice caps, containing layers of compacted ice, useful for the reconstruction of paleoenvironments and paleoclimatology and as a method of absolute dating. Continuous cores, sometimes taken to the bedrock below, allow the sampling of an ice sheet through its entire history of accumulation. Because there is no melting, the layered structure of the ice preserves a continuous record of snow accumulation and chemistry, air temperature and chemistry, and fallout from volcanic, terrestrial, marine, cosmic, and man-made sources. Actual samples of ancient atmospheres are trapped in air bubbles within the ice. This record extends back more than 300,000 years.
- ridge and furrow
- CATEGORY: feature
DEFINITION: A pattern of parallel ridges resulting from the plowing of strip fields in medieval and later open field systems. The fossilized remains of ancient plowmarks are a common sight in England, having the appearance of long, rounded parallel ridges with alternating ditches. There is no absolute dating for the ridge and furrow field; a few contentious examples could be Roman in date, while others are as late as the 17th and 18th centuries.
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