Tertiary Dinosaurs

[smithjb@sas.upenn.edu (Joshua Smith)]

> They've found as much dinosuar material in the tertiary as they have pinnant
> material pre-Archae - but not many people say "Oh - geology is too
> complicated, and you can't trust statistics, can you?  No, there may have
> been be dinos in the tertiary."
> 
        The problem with Tertiary dinosaurs is this:

        The remains are all remains (e.g., tooth crowns) that are robust 
and handle reworking and weathering quite well.  They are durable and 
last for a long time, even in situations (e.g., oxisols) that tend to 
beat up on bone material.

        These elements are ALL (I think this is true, correct me if I am 
wrong) found in fluvial channel deposits.  It is such a bad idea to run 
around calling something found in a Tertiary river lag that cuts into 
Cretaceous bedrock Tertiary.  Especially if that Cretaceous bedrock is 
fluvial in character as well.  I am pretty sure that everything I have 
heard about that has been found that is being called a Tertiary dinosaur 
is a durable element found in a fluvial deposit.  These elements are by 
definition allochthonous.  Also, as far as I know, the provenance studies 
done on the matrix in which these fossils are found TEND to SUGGEST (not 
data that indicate, much less concrete than that...) that the matrix has 
a good deal of material that SEEMS to be traceable to the Cretaceous 
sediments which these Tertiary streams drain.  That doesn't do much to 
support the idea that these fossils started out in the Tertiary...


-- 
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Josh Smith
University of Pennsylvania
Department of Earth and Environmental Science
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