[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Age of the Barun Goyot, Djadoktha and Nemegt Formations




--- "Jaime A. Headden" <qilongia@yahoo.com> wrote:

> Tim Donovan (uwrk2@yahoo.com) wrote:
> 
 
> Even pollen is likely to
> survive in a single region
> past the extinction of all other types of its kind,



 Not in Mongolia.

> such as monkey puzzles in
> South America (which were once MUCH more
> widespread), and this very
> inconsistency leads to problems in using taxa has
> strat markers. So far, all I
> see is trying to use turtles and dinosaurs 


 And Mesolanistes, conchostracans etc.


> So how long can the ghost
> lineage of *Tyrannosaurus*
> extend? How different must two different animals be
> to not mandate their
> formations of recovery are the same age? 



 Again, Norman considered S. angustirostris and S.
osborni to be virtually indistinguishable.

>What
> evidence makes anyone think that
> if the same or very similar taxon appears in two
> different formations, they are
> the same age? Using just the Santonian-Maastrichtian
> of Mongolia, for example,
> we have lizards (just using lizards) that are spread
> in either Djadokhta or
> Nemegt, some in Djadokhta and Baruun Goyot, and some
> in Baruun Goyot and Nemegt
> formations, exclusively, sans finding specimens
> otherwise. The same is true of
> small mammals. Yet no one argues each of these
> formations is the same age.



 Apples and oranges. Turnover among large dinosaurs
was faster. Saurolophus is unknown from the Campanian
or late Maastrichtian.


>   I think armchair geologists 


 Was Shuvalov an armchair geologist? Or Sukhanov,
Martinson, Russell, or Jerzykiewicz? They all
expressed views on the age of the Nemegt simlar to
mine, based on all the evidence.
 




                
__________________________________ 
Yahoo! Mail - PC Magazine Editors' Choice 2005 
http://mail.yahoo.com