RE: Climate Changes Mid-late Dinosaur era.

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

> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
> Daniel Bensen
>
> Global temperatures must have been quite warm indeed, and the temperature
> differences between latitudes very low. Palm trees grew on Spitsbergen aka
> Svalbard, champsosaurs thrived on Bylot island in the northern Canadian
> Arctic (Nunavut meanwhile)...<<
>
> Hey!  How does that work?  A homogeneous global climate?  I
> thought that was
> only in science fiction.  What could explain such a thing?
>
Homogenous, no.

Much reduced latitudinal gradient, yes.

Factors that allowed for a reduced difference between poles and equator:
        *Many epieric seas, so changes in global albedo AND ameliorating 
affects of
water (reduced seasonal extremes) reach much more of the land area
        *Increased CO2 levels
        *Possibly different style circulation in oceans

One important thing to remember about historical geology is that although
"the present is the key to the past", many aspects of the
Earth-Ocean-Atmosphere system are variable through time (i.e., continental
configuration, atmospheric composition, sea level, etc.).

                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