Library of Congress >> MARC >> Authority >> Names and Terms  >> X48

X48 - Chronological Terms-General Information


MARC 21 Authority
October 2014

"Full" documentation refers to the MARC 21 Format for Authority Data that contains detailed descriptions of every data element, along with examples, input conventions and history sections.

"Concise" documentation refers to the MARC 21 Format for Authority Data that contains abridged descriptions of every data element, along with examples.


First Indicator Second Indicator
Undefined
# - Undefined

148/448/548 - Undefined
# - Undefined

748 - Thesaurus
0 - Library of Congress Subject Headings
1 - LC subject headings for children's literature
2 - Medical Subject Headings
3 - National Agricultural Library subject authority file
4 - Source not specified
5 - Canadian Subject Headings
6 - Répertoire de vedettes-matière
7 - Source specified in subfield $2



Subfield Codes

Main term portion

  • $a - Chronological term (NR)

Tracing and linking subfields

  • $i - Relationship information (R)   [448/548/748]
  • $w - Control subfield (NR)   [448/548/748]
  • $0 - Authority record control number or standard number (R)   [548/748]
  • $2 - Source of heading or term (NR)   [748]
  • $4 - Relationship code (R)   [448/548/748]
  • $5 - Institution to which field applies (R)   [448/548/748]
  • $6 - Linkage (NR)
  • $8 - Field link and sequence number (R)

Subject subdivision portion

  • $v - Form subdivision (R)
  • $x - General subdivision (R)
  • $y - Chronological subdivision (R)
  • $z - Geographic subdivision (R)


GUIDELINES FOR APPLYING CONTENT DESIGNATORS

Content designators identify the subelements occurring in chronological term headings constructed according to generally accepted thesaurus-building conventions (e.g., Faceted Application of Subject Terminology (FAST)). Chronological terms include dates that are used as the lead element of subject or added entry access fields in bibliographic records. A chronological term that is authorized for use only as a subject subdivision part of an extended subject heading is contained in a 182 (Chronological Subdivision) field.

Only generally-applicable content designators are described in full in this section. A small number of content designators with field-specific instructions are described in the Tracings and References-General Information section (for fields 448 and 548) and the 7XX Heading Linking Entries-General Information section (for field 748).

INDICATORS

First Indicator - Undefined

Undefined and contains a blank (#).

Second Indicator

In fields 148, 448, and 548, the second indicator position is undefined and contains a blank (#). For field 748, the second indicator position contains one of the values described in the 7XX Heading Linking Entries-General Information section.

SUBFIELD CODES

$a - Chronological term

Chronological term used as an entry element.

748 #7$a1710-1714$2fast
748 #7$a1500-1700$2fast
148 ##$a1863

$i - Relationship information   [448/548/748]

Designation of a relationship of the entity in a 448, 548, or 748 field to the 1XX entity in the record or a textual reference instruction phrase. For fields 448 and 548 the phrase may be system-generated from the field tag or from the codes defined for subfield $w (Control subfield). Subfield $i is appropriate only in fields 448, 548, and 748. Guidelines for using subfield $i in fields 448 and 548 are provided in the Tracings and References-General Information section. Guidelines for using subfield $i in field 748 are provided in the 7XX Heading Linking Entries-General Information section.

$v - Form subdivision

Designates a specific kind or genre of material as defined by the thesaurus being used. Subfield $v is appropriate in the X48 fields only when a form subject subdivision is added to a main term to form an extended heading.

$w - Control subfield   [448/548/748]

Codes in one or more character positions defined to control the display of information and specify relationships, restrictions, and status. Subfield $w is appropriate only in fields 448, 548, and 748. Character position definitions and guidelines for applying the codes defined for subfield $w in fields 448 and 548 are provided in the Tracings and References-General Information section. Character position definitions and guidelines for field 748 are provided in the 7XX Heading Linking Entries-General Information section.

748 #7$a1710-1714$2fast$wna

$x - General subdivision

Subject subdivision that is not more appropriately contained in subfield $v (Form subdivision), subfield $y (Chronological subdivision), and subfield $z (Geographic subdivision). Subfield $x is appropriate in the X48 fields only when a general topical subject subdivision is added to a main term to form an extended heading.

$y - Chronological subdivision

Subject subdivision that represents a period of time. Subfield $y is appropriate in the X48 fields only when a chronological subject subdivision is added to the main term to form an extended heading.

$z - Geographic subdivision

Appropriate in the X48 fields only when a geographic subject subdivision is added to a main term to form an extended heading.

$0 - Authority record control number or standard number   [548/748]

See description of this subfield in Appendix A: Control Subfields.

$2 - Source of heading or term   [748]

Code that identifies the source of a heading or term when the second indicator position contains value 7. Subfield $2 is appropriate only in field 748. Guidelines for applying subfield $2 are provided in the 7XX Heading Linking Entries-General Information section.

748 #7$a1900-1999$2fast
748 #7$a1800-1899$2fast

$4 - Relationship code   [448/548/748]

Contains in coded form the designation of a relationship of the entity in a 448, 548, or 748 field to the 1XX entity in the record. Guidelines for using subfield $4 in fields 448 and 548 are provided in the Tracings and References-General Information section. Guidelines for using subfield $4 in field 748 are provided in the 7XX Heading Linking Entries-General Information section.

$5 - Institution to which field applies   [448/548/748]

See description of this subfield in Appendix A: Control Subfields.

$6 - Linkage

See description of this subfield in Appendix A: Control Subfields.

$8 - Field link and sequence number

See description of this subfield in Appendix A: Control Subfields.


INPUT CONVENTIONS

Punctuation - Punctuation of the subelements of a heading is generally dictated by subject heading system/thesaurus rules. These input conventions clarify MARC punctuation practices. An X48 field does not end with a mark of punctuation unless the field ends with an abbreviation, an initialism, or data that ends with a mark of punctuation.

Spacing - No spaces are used in initialisms, acronyms, or abbreviations. One space is used between preceding and succeeding initials if an abbreviation consists of more than a single letter. A data element that contains an open-ended date ends with one space when it is followed by a subject subdivision.

Display Constant

- [dash associated with the content of subfield $v, $x, $y, and $z]

Dash (-) that precedes a subject subdivision in an extended subject heading is not carried in the MARC record. It may be system generated as a display constant associated with the content of subfield $v, $x, $y, and $z.


CONTENT DESIGNATOR HISTORY

$i - Reference instruction phrase [448/548] [REDEFINED, 2009]
$i - Relationship information [748] [NEW, 2014]
$0 - Record control number [548/748] [REDEFINED, 2010]
$4 - Relationship code [448/548] [NEW, 2009]
$4 - Relationship code [748] [NEW, 2014]

Library of Congress >> MARC >> Authority >> Names and Terms  >> X48
(10/20/2014)
Contact Us