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Re: Everything you know about the Iren Dabasu age is wrong...




--- Phil Bigelow <bigelowp@juno.com> wrote:

> 
> 
> On Sun, 25 Sep 2005 02:45:42 -0700 (PDT) Tim Donovan
> <uwrk2@yahoo.com>
> writes:
> > 
> >  No. If Mesolanistes is found from North America
> all
> > the way to southern China (I presume Shuvalov
> meant
> > the Maastrichtian Pinging formation)it should be
> > present between these regions,
> 
> 
> It doesn't have to be present in the areas between
> the localities. 
> Different paleoenvironmental conditions can create
> huge geographic gaps
> in the range of snails.

 Naturally I assume it was absent in the desert areas
but as  I wrote before, the paleoenvironment of Iren
Dabasu was similar.


> > and it is known from
> > the Nemegt. If Iren Dabasu
> > were really of Nemegtian
> > age, Mesolanistes should be
> > present there too(the
> > paleoenvironments were
> > similar).
> 
> 
> Paleo drainage patterns may have limited the spread
> of Mesolanistes into
> new areas. 

  It spread much farther south into China, and farther
inland into Outer Mongolia.


> Besides, it is probably unwise to base
> such sweeping
> generalizations on the occurrence or absence of one
> taxon.

  Not just one.
 
> What does the palynology of these localities
> indicate?

  The palynological record of Mongolia is very poor.


> 
> <pb>
> --
> 
> 
> 
> 



                
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