Hello Erika
I thought both were being used for dates if you check:
 
    http://www.loc.gov/marc/authority/ad100.html
 
you will see that $d is still active.
 
The RDA approach to name authority is a little bit over elaborate - so duplication of data does occur. As this is an LC record - I wonder if some kind of decision has been made that for certain authors the date is not significant for the information searcher - or that there will be links via the bibliogrpahic 100 field to the authority record that makes the dates available to display and / or search.
 
Good observation!
 
Best wishes
 
Keith
Keith Trickey
Sherrington Sanders
From: Erika Janette Charles Nino (CABU) <[log in to unmask]>
To: [log in to unmask]
Sent: Monday, 14 May 2012, 16:26
Subject: [MARC] 046-100 AUTHORITY RECORD

Hi all, I would like to know why now with RDA is used now Tag 046 instead of $d in Tag 100?
With this practice, such information is accessible only to librarians that review the authorities being that that 046 is not recovered in OPACs
 
Thanks,
 
LC control no.:      n 79038532
LCCN permalink:    http://lccn.loc.gov/n79038532
HEADING:     Cortázar, Julio
000     01055cz a2200277n 450
001     4215160
005     20120407074810.0
008     790424n| acannaabn |b aaa
010     __ |a n 79038532 |z n 88637611
035     __ |a (OCoLC)oca00272052
040     __ |a DLC |b eng |c DLC |d DLC |d OCoLC |d DLC |d OCoLC |d CSt |d UPB
046   __ |f 1914 |g 1984
053     _0 |a PQ7797.C7145
100   1_ |a Cortázar, Julio
374     __ |a author
400     1_ |a Кортасар, Хулио
400     1_ |a קורטאסר, חוליו
400     1_ |a קןרטאזאר, חוליו
667     __ |a Machine-derived non-Latin script reference project.
667     __ |a Non-Latin script references not evaluated.
667     __ |a The following pseudonym is a valid AACR 2 heading: Denis, Julio
670     __ |a His Los reyes, 1949.
670     __ |a Prego, O. La fascinación de las palabras, c1985: |b t.p. (Julio Cortázar) p. 9-10 (died Feb. 12, 1984)
670     __ |a BNE Web OPAC, Oct. 30, 2006 |b (Cortázar, Julio (1914-1984); wrote poetry under the pseudonym Julio Denís)
952     __ |a RETRO
953     __ |a xx00 |b ta30
 
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...las bibliotecas han liberado a más personas que todas las guerras del mundo.
 
Erika Charles Niño.
Procesos Técnicos. Procesamiento Documental.
Capilla Alfonsina Biblioteca Universitaria
Universidad Autónoma de Nuevo León
(52) + (01 81) 83 29 40 15 ext. 5392