Japan (was RE: WHAT HAPPENED AT SVPCA)(

["Thomas R. Holtz, Jr." <tholtz@geol.umd.edu>]

> -----Original Message-----
> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
> Rob Meyerson
> Sent: Friday, September 17, 1999 3:06 PM
> To: dinosaur@usc.edu
> Subject: Re: WHAT HAPPENED AT SVPCA
>
>
> Darren Naish wrote,
>
> >Paul Barrett spoke about new dinosaurs from Lower Cretaceous Japan. A
> >skull - Japans's most complete dino specimen to date - is very like
> >_Hypsilophodon_; there were also velociraptorine and tyrannosaurid
> >teeth and a possible oviraptorosaurian ungual.
>
> I am interested in the dinosaur evolution that occurred in Japan.
>  Is there any evidence to suggest that Japan was ever attached to
> the asian continent, or was it always an island?  How similar are
> the Japanese dinosaurs to the Chinese ones from the same period?
>

The geology of Japan is rather complicated.  Some of the northern parts of
the Archipelago are actually part of the North American plate, for
instance!!

In any case, the Sea of Japan (between the continent and the islands) is at
least partly a foreland basin, similar to the Cretaceous Interior Seaway of
North America, or the Cannonball Sea in the same region in the early
Cenozoic.  As subduction produces uplift of the volcanic arc (aka the
islands) there is a downwarping on the inland side of the arc, which has
filled in with water.  The actual situation is a bit (okay, a lot) more
complicated than that, but that is a major component.

So, Japan IS part of the continental mainland, and has become islands due to
continued uplift of the mountain chain (and consequently sinking on the Sea
of Japan).

Hope this helps.

                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