For instance, if we find a fossil bone below the strata 3 rock level shown above, we assume that the animal most likely lived at a time before that layer was formed.However, we must be careful to note whether or not the fossil comes from the mixed strata zone of the filled in hole..
For example, if an area used for trash has modern refuse in it such as CDs and computers, and the layer underneath has cans made of tin, then it is safe to say the layer of tin cans have a greater relative age than the layer with modern refuse.
However, this does not say anything about the absolute age of the layers.
Actual samples of ancient atmospheres are trapped in air bubbles within the ice. 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.
, 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, , fluorine and nitrogen test, and radiometric assay.
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 CATEGORY: technique DEFINITION: The use of various methods, often multiple methods, to demonstrate the equivalency of stratigraphic units.
The date on a coin is an absolute date, as are AD 1492 or 501 SYNONYMS OR RELATED TERMS: absolute dating; chronometry CATEGORY: technique DEFINITION: Any technique of dating that relies on chronological measurement such as calendars, radiocarbon dates, etc.