045  Time Period of Content (NR)  (Variable Data Fields)

Codes

First indicator - Type of time period in $b or $c

#  Subfield $b or $c not present

0  Single date/time

1  Multiple single dates/times

2  Range of dates/times

Second indicator:

#  Undefined

Subfields:

a  Time period code (R)

b  Formatted 9999 B.C. through A.D. time period (R)

c  Formatted pre-9999 B.C. time period (R)

6  Linkage (NR)

8  Field link and sequence number (R)

NOTE:  See MARC 21 Format for Bibliographic Data (045 Time Period of Content) for code definitions not given below.

Description/Instructions

Field 045 is used to record the time period of the content of the work.  The subfields enable users to isolate material covering a particular time span.  The date may be given in coded form in subfield $a or in formatted form in subfields $b and $c.

This field may be used alone or in conjunction with other fields to retrieve items with specific subject characteristics.  For example, material on New Hampshire at the time of the American Revolution can be identified by searching field 043 (Geographic Area Code) or field 052 (Geographic Classification Code) for New Hampshire and field 045 subfield $a (Time period code) for the appropriate century and decade.  Material covering a particular city in New Hampshire in 1776 can be identified by searching the field 052 for the city in New Hampshire and field 045 subfield $b (Formatted 9999 B.C. through A.D. time period) for 1776.

For serials, this field indicates the period depicted by the content of the item, e.g., a current serial about the 16th century would be coded $a t-t- or $b d1500 $b d1599.

First indicator - Type of time period in $b or $c

This indicator shows whether or not subfield $b or $c is present, and if it is present, shows the type of date/time recorded.

045 ## w2w5

[no dates/times recorded]

045 0# $b d1975

[single dates/time]

Subfields

$a  Time period code.

The time period consists of four alphanumeric characters assigned according to the codes given below

For B.C. dates, a lowercase alphabetic character represents the millennium and a digit represents the century.  If the century is not known, a hyphen is used instead of a number.

For A.D. dates, a lowercase alphabetic character represents the century and a digit represents the decade.  If the decade is not known, a hyphen is used instead of a number.

If a single year or period within a decade is recorded, the appropriate two-character code is repeated to create the four character code.

If more than one chronological code applies, input each in a separate subfield $a.

$b  Formatted 9999 B.C. through A.D. time period.

Only as much detail as is needed is recorded in this subfield.  The subfield may contain a minimum of five characters and a maximum of eleven characters.

The subfield may consist of one alphabetic (a "c" for B.C. dates or a "d" for A.D. dates) and ten numerics.  Information in the subfield should appear in the following order:

1)   Gregorian calendar indication

"c" - B.C. dates

"d" - A.D. dates

2)   Year (format:  YYYY)

3)   Month (format:  MM)

4)   Day (format:  DD)

5)  Hour (format:  HH)

Leading zero ("0") fill is used for months and days.  The 24 hour clock is used for hours.  If more than one date is needed, subfield $b is repeated.  The first indicator should always be set to other than "#".

If subfield $a is not present, the field must start with subfield "$b".

1984

code as:

045 0# $b d1984

1972 and 1975

code as:

045 1# $b d1972 $b d1975

$c  Formatted pre-9999 B.C. time period.

The pre-9999 B.C. formatted time period consists of numeric characters representing the number of years B.C.

A work about the time period 1000 B.C. to 100 A.D. code as:

045 2# $c 10000 $b d0100

Related fields, etc.

045 Time Period of Content  (MARC 21 Format for Bibliographic Data)

See also:

01X-09X  Numbers and Codes

Variable Data Fields

Section E.  MARC 21 Format for Serials as Applied Within CONSER

CONSER Editing Guide:  Contents