Date and Time Scheme Sources identifies formats for formulating date and time data in standardized ways for consistent retrieval.  The purpose of this list is to enable the date and time coding schemes used in metadata records to be identified by a code.  For code assignment, general structure, usage, and maintenance guidelines see Introduction.

Arrangement of the list

Entries in the list are arranged in alphabetical order by the code and consist of the source code followed by the bibliographic citation for the source documentation.  The citations are linked to the online source for some codes.

Code structure

Each code consists of a maximum of 12 characters, including lowercase alphabetic characters, numeric characters 0 through 9, and the hyphen (-).  Possible additions to codes are described in Source Code Maintenance.

Date and Time Scheme Source Codes


Extended Date/Time Format


Code identifies formatted dates allowed in ISO 8601 which use the alternative described as "basic" (i.e., with minimum number of separators) rather than "extended" (i.e., with separators).  This alternative specified in the standard uses the following date patterns:  YYYY; YYYY-MM if only year and month given; YYYYMMDD if year, month, and day are included (hours, minutes, seconds may also be added:  Thhmmss.s).  It is also used for other encodings specified in ISO 8601, e.g., date ranges, which are in the form of <date/time>/<date/time>.


Code identifies dates formatted according to MARC 21 rules in field 008/07-14 for dates of publication/issuance.  Examples include:  YYYY (for year), MMDD (for month and day), 19uu (MARC convention showing unknown digits in a year date), 9999 (MARC convention showing that the end year date has not occurred or is not known).  See Legal Characters under field 008/06 of MARC Bibliographic.


Temporal Enumerated Ranges (August 2007)


Code identifies dates following the W3C profile of ISO 8601, Date and Time Formats, that specifies the pattern: YYYY-MM-DD.  If hours, minutes, and seconds are also needed the following pattern is used: YYYY-MM-DDThh:mm:ss.

Usage in MARC 21

 Bibliographic records

046 $2 (Special Coded Dates / Source of date)

 Authority records

046 $2 (Special Coded Dates / Source of date scheme)

 Community Information records

046 $2 (Special Coded Dates / Source of date)

MODS/MADS Elements

 mods: originInfo / dateIssued @encoding

 mods: originInfo / dateCreated @encoding

 mods: originInfo / dateCaptured @encoding

 mods: originInfo / dateValid @encoding

 mods: originInfo / dateModified @encoding

 mods: originInfo / copyrightDate @encoding

 mods: originInfo / dateOther @encoding

 mods: subject / temporal @encoding

 mods: part / date @encoding

 mods: recordInfo / recordCreationDate @encoding

 mods: recordInfo / recordChangeDate @encoding

 mads: authority / temporal @encoding

 mads: related / temporal @encoding

 mads: variant / temporal @encoding

 mads: affiliation / dateValid @encoding

 mads: recordInfo / recordCreationDate @encoding

 mads: recordInfo / recordChangeDate @encoding

See also:

Source Codes for Vocabularies, Rules, and Schemes:  Contents