List B - Age-dating methods
List B Absolute and relative age-dating methods
These thesaurus lists, lists A-R, are used by GeoRef indexers for selecting index terms and by searchers for additional information on the hierarchies not necessarily found in individual term records in the body of the Thesaurus. In most cases, an hierarchical list is given. In some cases, an alphabetical or other list is provided.
The notes under Searching attempt to guide the searcher in the use of the list. Searchers might also read the notes on Indexing for further clues but should be aware that these notes reflect current practice which in some cases differs from past practice. Further notes on specific terms are in the body of the Thesaurus and additional notes on searching are in the GeoRef Thesaurus, 11th edition Introduction section on searching beginning on page x. Information specific to searching and the individual list topics is included, e.g., a section on age-dating methods begins on page xi.
Under Indexing the current indexing practice is given. These notes should be read along with the instructions under the individual terms in the body of the Thesaurus.
Age-dating methods are divided into two major groups: absolute-age and relative-age methods.
The methods can be searched in combination with a specific age term, see List E, or a material. For reference to methodology, search in combination with methods, for references to actual date measurements, search in combination with dates. Some of the relative age methods may be used for other purposes besides dating.
To limit a search to age-dating, search in combination with geochronology in the category. See List A.
Searching some age-dating methods may require special formatting. See searching instructions for the search platform you are using.
Absolute-age methods are entered in the standard form most commonly found in the geologic literature. Example: Ar/Ar instead of Ar-40/Ar-39. Relative-age methods should be entered along with the term geochronology. In addition, either the term methods or dates should be included. Other relevant terms to consider include "catalogs" and "instruments". Specific Age terms should be included as well as the material dated.