More on SVP/GSA

[@lepomis.psych.upenn.edu, @uga.cc.uga.edu:Schwimm@USCN.BITNET (Paleontology Columbus College, Georgia)]

Some more on the Seattle Meetings:

    I probably should not stick my neck out again on the topic,
but, there were symposia on the K/T boundary at the Geological
Society meeting in Seattle, and a fairly compelling paper by
Archibald at SVP.  My take on these is as follows:

  Everyone presenting in the GSA meetings seemed to accept the
reality of an impact around 65 M.y.  (Even Keller's group at
Princeton and Mexican associates seemed to tacitly accept it).

  -However, there were several workers who presented strong
evidence that the "megatsunami" deposits proximal to Chicxulub
are not such.  An additional talk showed that these same
"tsunami" deposits are abundantly filled with syndepositional
trace fossils. The upshot of these talks is that these deposits
are probably unrelated to the impact effects.

 -further, several papers argued that the impact deposits are
  of late Maastrichtian age (i.e., before the K/T boundary).


  Anne Weill presented a paper arguing impressively (to me) that
acid rain and acidification of terrestrial envgironments was not
a likely killing mechanisms.  She used survivorship by amphibians
across the K/T boundary as the basis for that.

  Archibald showed that taxa going extinct across the K/T
boundary are almost precisely those one would predict to be
most _unlikely_ killed off by postulated impact-generated
outcomes (acids, darkness, cold, etc).  Dinosaurs, for example,
had much wider latitudinal range (and, presumably cold-tolerance)
than, say, crocodilians; yet, crocs passed the boundary almost
intact whereas non-avian dinos bought the farm.  Ditto for many
taxa.  He plumps for a marine regression-based extinction model.

  And of course, there were a range of papers at SVP arguing
details of the impact event as an unipeachable reality and cause
of the  K/T extinctions.

  Don't shoot me: I'm only the messenger.

   By the way, John Alroy was awarded the SVP Romer Prize for the
best pre-doctoral paper.  Congratulations.

I didn't do the cruise-ship dinner, but I did climb up the trail
at Mt. St. Helens.  I bet the view was better.

David Schwimmer
Columbus College
schwimm@uscn.cc.uga.e