Re: Fwd: Re: extinction at the K/T boundary

[Jeffrey Martz <martz@holly.ColoState.EDU>]

> The idea that a comet did in the dinos of course presumes that there 
> was an
> unusually big impact at the K/T boundary. In the latest Geology 
> tentative
> evidence that the Mexican crater was formed before the K/T was 
> presented. I
> hope it proves to be true. Besides, no good impact mechanism for 
> killing off
> ALL the few hundred dinosaur species of which - most were probably weed
> species with very high rates of reproduction and independent juveniles 

     I attended the PJ symposium at DMNH this weekend.  Phil Currie 
delivered the talk on Mesozoic vertebrates (all the talks were broad and 
focused on a particular group of organisms in a particular time frame, 
moderately technical to pretty technical) In which he noted the Latest 
Cretaceous decline, and also the reapearance of more primitve forms like 
the protoceratopsians.  He suggested that the more advanced Maastrichtian 
dinosaurs were having problems of some sort (allowing the primitive forms 
to creep in from wereever they were holding out, possibly upland 
environments) and then the asteroid happenmed to hit at an unusually  bad 
time, "adding insult to injury".
 
LN Jeff