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Re: The Permian-Triassic Extinction
I'm not sure if I'm responding with another non sequitur, but with the
continents jammed together to form one giant landmass (Pangaea), the
terrestrial biotas were exposed to harsher, drier environments that
from a drastic decrease in the ratio of coastline to the vast interior.
This would not mean an increase in global average temperatures, and that's
what Dora seems to be saying.
A sudden drop in global temperature followed by global warming
is usually attributed to the Siberian Traps.
The drop would require sulfate aerosols, and these would require explosive
volcanism -- that's the opposite of effusive volcanism which by definition
must have produced the traps.
The bolide hypothesis does not have much
support when it comes to the Permian/Triassic extinction.
At least the supposed craters aren't published yet.
No Permian dinosaurs (as others have pointed out, with admirable
There were dinosaurian ancestors back then, in the form of basal
archosauromorphs (and maybe archosauriforms).
Only one archosauriform -- the proterosuchid *Archosaurus rossicus* -- is
known from the (very latest) Permian.