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Re: Double impact at K-T boundary ?
> Typical DML reaction! Loads of discussion on whether Ukraine should
or should not be preceded by "the".
Absolutely no discussion, apart from the usual "is Shiva really an
impact?", on whether this satisfies Gerta Keller's double impact
That's because many of us are very, very skeptical about Keller's
double-impact hypothesis in the first place. The identification of the
supposed Cretaceous foraminifera in the Chicxulub crater has been
questioned, and if it's correct, it's still possible that the rock
they're in has fallen in from the walls of the primary crater.
(Impactors of that size produce a hemispherical crater that is, IIRC, 20
km deep or some other such insane number. Its walls, vertical at the
top, then collapse, leaving a much shallower and much wider crater. In
other words, Cretaceous rock with Cretaceous foraminifera in it _must_
have fallen into the primary crater and _must_ be present inside the
present crater; maybe Keller has found some of it.)