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Re: Bagarataan environments?



--- David Marjanovic <david.marjanovic@gmx.at> wrote:

> > Mostly desert.
> 
> Or perhaps just savanna without grass. 
> http://www.dinosauria.com/jdp/fossil/sandslide.html
> Or is this Nemegtian? 
> 
 The environment represented by Ukhaa Tolgod was
relatively wet for the Djadokhtan period. 

  I just came across a paper by Fastovsky et al and
would like to quote from it:

 "Sedimentological analysis of the dinosaur bearing
locality of Tugrik in the central Gobi desert of
Mongolia reveals unambiguous evidence of eolian
sedimentation. Th entire deposit consists of fine- to
medium -grained texturally mature sandstones.....High
angle, very large scale cross stratification between
first order bounding surfaces is preserved in
conjunction with mm-scale, coarsening upwards
sequences that distinguish each stratum.
 Although eolian sedimentary rocks are commonly
depauperate in trace and body fossils,Tugrik preserves
both in in ample abundance.....Preservation is
non-random and,in many cases,probably represents
burial during catatrophic events such as sand
storms.....The dinosaurs found at Tugrik were not lost
in the desert on their way to "greener pastures;"
rather the desert is where they made their home."

 Of course there had to have been some productivity in
Djadokhtan and Barungoyotian environments but
evidently not enough to support most large dinosaurs.






                
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