----- Original Message -----
From: "Tim Donovan" <uwrk2@yahoo.com>
To: <dinosaur@usc.edu>
Lehman wrote that the southern end was closed by
middle Maastrichtian time, and mentioned an incipient
Cannonball Sea. Btw, wouldn't a tsunami have wiped out
the ejecta layer if it struck immediately afterwards?
The paper about the South Dakota tsunami deposits suggests that it was still
open, and another paper about the SE Missouri deposits suggests that it was
open there as well. I don't presently have a strong opinion about that. Am
curious, though.
A tsunami wave would be expected to disrupt some or all (depending upon the
geometry) of the early ejecta deposits and then redeposit them during the
backwash wave, to give multiple ejecta layers, some segregated, some
chaotic. This could be expected to happen several times, as there would be
more than one tsunami wave associated with the event.
Jim