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RE: Abbreviation update



An abbreviation correction:

> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
> David Marjanovic
>
> LT, LJ, LK: Late Triassic, Jurassic, Cretaceous

LT would be an IMPROPER abbreviation for Late Triassic.

The geologic Periods have formal abbreviations used in the geologic
literature (most often on geologic maps).  The abbreviation for Triassic is
Tr (in reality, it is a non-standard character comprised of a capital "T"
with a small capital "R" attached to the vertical bar of the "T").

Although there is some sloppy misusage of abbreviations (particularly by
non-geologically oriented paleontologists and other evolutionary biologists)
in the scientific literature, these have been standardized for some time.

For those interested, here they are:
Q       Quaternary
T       Tertiary
K       Cretaceous
J       Jurassic
Tr      Triassic (see above for description of the actual character)
P       Permian
C       Carboniferous
  (in the U.S. literature,
        |P      Pennsylvanian (the character is a capital P with a vertical 
line right
next to the shaft of the "P"
        M       Mississippian
D       Devonian
S       Silurian
O       Ordovician (also sometimes a capital "Theta")
C-      Cambrian (this one I can't type: it is a capital "C" with a small
horizontal bar cutting through the midsection of the "C")

Hence, K/T for "Cretaceous-Tertiary".

For other time units there are less globally-standardized abbreviations (X,
Y, Z for various parts of the Precambrian in USGS literature, for instance).
The above list, though, is pretty darn common.


                Thomas R. Holtz, Jr.
                Vertebrate Paleontologist
Department of Geology           Director, Earth, Life & Time Program
University of Maryland          College Park Scholars
                College Park, MD  20742
http://www.geol.umd.edu/~tholtz/tholtz.htm
http://www.geol.umd.edu/~jmerck/eltsite
Phone:  301-405-4084    Email:  tholtz@geol.umd.edu
Fax (Geol):  301-314-9661       Fax (CPS-ELT): 301-405-0796