RE: The Western Interior Seaway (and computers)

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

> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
> David Marjanovic
>
>
> > No exit to the Artic basin? How do you know that? The
> > channel between Norway and Greenland was open (passive
> > margin) according to the map I'm looking at...
> > <http://www.scotese.com/cretaceo.htm>
>
> According to that map, this was an epicontinental sea, except for a narrow
> crack in its middle.
>
> Is there actually any evidence for this epicontinental sea? *Normapolles* is
> found both in eastern North America and in Europe but not in Asiamerica...
>
Paleogeographers are pretty secure on this one. I do not know the details about 
this, but first order approximation would be that
they have Cretaceous marine sediments from that area...

You'd have to check the literature for details. Note: this is probably a good 
idea for EVERYONE who has been posting about these.
Let's just say that you folks are not the first people to address this issue, 
and there are a lot of good scientists out there who
have been working on the topic for a while. The paper I mentioned yesterday is 
simply the physically closest one I had at hand;
there are plenty of other studies out there. Paleoceanography is a very 
well-supported science with far more researchers than
dinosaur paleontology, and the Cretaceous is one of the more interesting (and 
economically significant; ever heard of "petroleum"?
;-) Periods for study.

One brief comment, though: the North Atlantic Conveyor Belt is extraordinarily 
young, possibly no older than the mid-Pliocene. The
development of the Isthmus of Panama was critical in bringing it up to strength 
(previously there was a strong central
Atlantic->central Pacific current in that region).

A second brief comment: global circulation patterns in the Cretaceous were 
dominated by a circumequatorial current (between bits of
Laurasia and bits of Gondwana), something we do not have today.

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

http://www.geol.umd.edu/~tholtz/
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