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From:
owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of Gavin
Rymill
> >This is only
tenuously a list topic but the BBC website still managed to make it a dinosaur
headline!!
>
>
>Still interesting
though.
> Cool
stuff. Apparently preliminary data suggests that the Earth's magnetic
field during the Long Cretaceous Normal (C34n, running from the lower Aptian (c.
120 Ma) to the beginning of the Campanian (c. 83.5 Ma)) was three times the
present intensity.
This
mid-Cretaceous is an interesting time for a number of (quite possibly
interrelated) reasons:
*Highest sea levels since the Cambrian (at least), making it the highest
in post-Pangaean history
*Higher activities of the mid-ocean ridges
*Faster rates of sea-floor spreading
*Extremely low temperature gradient from equator-to-pole (that is,
climate at the equator and climate at the poles were very similar, and
hot)
*Greater total separation of landmasses than at present, due to the net
effects of plate tectonics and oceanic highstands
*REALLY big South American and African dinosaurs
*Fins,
fins, fins, fins...
*Arrival of Asian-style dinosaurs into the Western Interior of North
America (latest Albian/earliest Cenomanian)
Thomas R. Holtz,
Jr. |