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>How would a supernova be linked to the observed absence of
>terrestrial vertebrate fossils for a meter or so below the
>K/T boundary? This blank, errasing the fossil remains of
>dinosaurs (which did not survive) and mammals (which did),
>but not of plants, is now laid at the foot of acid rain due
>to a huge quantity of sulfur thrown into the atmosphere.
One problem I've always had with the "acid rain" explanation of the missing
meter problem is the following: If the acidity of ground fluid rose enough
to dissolve buried bone, how could any amniote which laid calcified eggs
survive the boundary event? Surely acid rain that intense could percolate
through an sauropsid or monotreme nest as well as it could clays, sands,
and soils? Amphibians, fresh water fish, etc. could concievably survive if
their nesting environment (lakes, ponds, rivers) were buffered by
underlying carbonates, but turtles, squamates, champsosaurs, crocs,
neornithine birds, and monotremes all survived as well.
Maybe we have to chalk up the missing meter to the Signor-Lipps effect.
And, to add to the problem of testability of the supernova hypothesis,
several astrophysicists suggest that it is the neutrino pressure, not gamma
rays, which would be the killing agent from a supernova blast. How this
would be reflected in the fossil or geologic record, I really don't know.
Thomas R. Holtz, Jr. tholtz@geochange.er.usgs.gov
Vertebrate Paleontologist in Exile Phone: 703-648-5280
U.S. Geological Survey FAX: 703-648-5420
Branch of Paleontology & Stratigraphy
MS 970 National Center
Reston, VA 22092
U.S.A.
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