quote:
They dropped, dramatically (about 50 m), in connection with the ice age, but it is hard to tell whether this was cause, effect, or both.
from:
Palaeos: Page not found
I think you are jumping to conclusions without enough information.
For one thing what is "most of North America"? There was a large shallow inland sea up the middle of NA during, IIRC, the cretaceous too. I would not call that transgression "most" but it was a lot of NA.
Also, at this time, there were a lot of other areas that were not mostly underwater so how much extra water is required (beyond 150 m)?
If if we removed the tectonic uplift from current NA and raised sea levels 150m how much transgression would there be?
After you have these details then we can see if the water problem is equivalent for the two models. Not until then can you make any statements.
ABE
from:
Ordovician
It appears, eyeballing only, that perhaps 2/3 of NA was wet. Since the current NA (as shown on this map) did NOT EXIST (part of it was added from Europe later. It is hard to calculate "most" under these circustances.
It is my understanding that the basic creton of NA is about the part shown on the above referenced map. Where do we draw the boundaries of NA when it was in bits and pieces at the time.
I do know that the north pacific coast (to 100's of kms inland from the current coast) was added 100's of millions of years after the Oldevician. The picture shows it as underwater and part of NA but that is incorrect.
This message has been edited by NosyNed, 06-21-2005 09:09 PM