Re: Mesozoic snow - refined

[Jeff Hecht <jeff@jeffhecht.com>]

At 5:44 PM -0400 4/7/04, Phil Bigelow wrote:
> Did a north polar ice cap exist during the Maastrictian?  Possibly.  The
> north end of the Interior Seaway had finally closed off, and warm Tethyan
> water could no longer flow northward to moderate the Arctic Ocean
> temperatures (and cold Arctic Ocean water couldn't flow southward). [clipped]

I think we usually underestimate climatic variability on scales of 
tens of thousands of years. There is evidence of Milankovitch cycles 
that caused changes of something like 25 meters in sea level during 
parts of the Cretaceous; I forget if that includes the Maastrichtian. 
That's less dramatic change than between modern glacial and 
interglacial periods, but it does imply that climate might vary from, 
say, Atlanta to New Jersey, over an entire cycle. -- Jeff Hecht