Re: impacts are cool!

["Thomas R. Holtz, Jr." <th81@umail.umd.edu>]

At 10:50 PM 10/29/97 -0500, Michael Teuton wrote:

>The amount of iridium favors a comet strike.

In point of fact, the amount of iridium favors an *asteroid* strike, not a
cometary one.  Whereas the bulk of a comet's mass is frozen gasses,
asteroids are mostly metal and silicate.

Comets got into the picture due to the (still very questionable) periodic
extinction theory, which is not necessarily supported by the data.

Thomas R. Holtz, Jr.
Vertebrate Paleontologist     Webpage: http://www.geol.umd.edu
Dept. of Geology              Email:th81@umail.umd.edu
University of Maryland        Phone:301-405-4084
College Park, MD  20742       Fax:  301-314-9661