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Resurrection of the Quaternary (was RE: Precisely Dating The KT Boundary)

> From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu]On Behalf Of
> Jerry D. Harris
> >The mass extinction of dinosaurs occurred about 66 million years ago, at
> >the end of the Cretaceous Period (K) and the beginning of the Tertiary
> >Period, known as the K-T boundary.<
>      Unfortunately, this is (a) wrong, (b) wrong, (c) wrong, and (d) all of
> the above.  Not in terms of the dating, but in the nomenclature.  As of
> 2004, there is no more Tertiary.  It's gone, period.


>  (So is Quaternary.)

False. Or rather, it's gone but has been recommended for return in a rather (in 
my opinion) ugly form. Here is the short form of the
recommendation by the "Quaternary Task Group jointly of the International 
Commission on Stratigraphy (ICS, of the International
Union of Geological Sciences, IUGS) and of theInternational Union for 
Quaternary Research (INQUA)":

The Quaternary Task Group recommends that the Quaternary be:

(1) An officially ratified geochronologic/chronostratigraphic unit of the 
international geologic
time scale,
(2) Defined as the interval from the GSSP base of the Gelasian Stage 
(approximately 2.59 Ma)
of the late Pliocene Epoch to the Present, and
(3) Assigned the geochronologic rank of Period or Sub-Era within the Cenozoic 
Era. [A
majority (6 of 8) considered Period acceptable, and a lesser majority (5 of 8) 
Sub-Era to be acceptable.]

Here's the complete recommendation at the ICS website

Bad, BAD Cenozoic stratigraphers! We let you get away with too much for too 
long! And now you want a period (or Sub-Era) whose
boundaries are NOT CONGRUENT with Stage boundaries!?!?

> They were discarded because they were remnants of the really old time
> division into "Primary, Secondary, Tertiary, and Quaternary" periods.  Now,
> for the Cenozoic, there are only the Paleogene (Paleocene-Oligocene) and
> Neogene (Miocene-Recent).  Thus, there is no more K/T boundary -- there is
> only the K/P boundary.

K/Pg.  P = Permian. Pg is the new symbol for the Paleogene.

>  This was decided by the International Stratigraphic
> Commission, so it's not like it's just one person's opinion -- this is, a la
> the ICZN, the "rules" that stratigraphers must follow.

                Thomas R. Holtz, Jr.
        Senior Lecturer, Vertebrate Paleontology
Department of Geology           Director, Earth, Life & Time Program
University of Maryland          College Park Scholars
        Mailing Address:
                Building 237, Room 1117
                College Park, MD  20742

Phone:  301-405-4084    Email:  tholtz@geol.umd.edu
Fax (Geol):  301-314-9661       Fax (CPS-ELT): 301-405-0796