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A piece of the bolide?
The March 29, 1996 (v. 271, p. 1806) issue of _Science_ has a short note
on the discovery of a 3 mm chip of rock from the K-T layer on the bottom
of the Pacific off the west coast of Mexico. It is rich in iridium, and
contains metallic grains that are up to 87% nickel. It is only the
second recognizeable meteorite found in all of the cores of deep sea
sediments ever taken--and "just happened" to be in the K-T layer. If
part of the bolide, it would show that it was an asteroid rather than a
comet.
Personally, I don't know why this is true, but the claim is made that the
survival of a part of the bolide (that's the word they use!) indicates
that it struck at a low angle. It is reported that earlier studies of
crater assymmetry suggest that the object came in at about a 30 degree
angle from the southeast. The core site would be downrange from the
impact.
If the impact was at a 30 degree angle, would that affect where we would
place an antipode--i.e., are the Deccan basalts still in the right place?
*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
Norman R. King tel: (812) 464-1794
Department of Geosciences fax: (812) 464-1960
University of Southern Indiana
8600 University Blvd.
Evansville, IN 47712 e-mail: nking.ucs@smtp.usi.edu