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New Deccan Traps paper



First off, I'd love to be able to answer Ekaterina's questions on turtle
origins, but that's going to take a little more in depth research than I can
do right now.  If you are able to hunt up the Laurin & Reisz, Rieppel and
DeBraga, and Lee papers, they will be able to answer a fair number of those
questions.

New paper just out:
Hofman, C., G. Féraud & V. Courtillot.  2000.  40Ar/39Ar dating of mineral
separates and whole rocks from the Western Ghats lava pile: further
constraints on duration and age of the Deccan traps.  Earth and Planetary
Science Letters 180: 13-27.
(available online at
http://www.elsevier.nl/gej-ng/10/18/23/84/25/26/article.html).

New argon/argon dates suggest that at least the bottom two-thirds of the 2.5
km depth of the Deccan traps erupted in a short (less than 1 Myr) interval
of time close to 65.5 Ma.

Furthermore, they find that the paleomagnetism of most of these samples are
reversed (contary to some previous studies), consistent with being in Chron
29R (the short magnetic reverse chron which brackets the K-T boundary).
(They did find normal paleomag data in the uppermost flows above these
samples, which would be consistent with a C29N (early Danian Age, Early
Paleocene Epoch) date.

                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): 301-314-7843