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RE: New date for Chicxulub?
Highly recommended reading:
Smit, J. 1999. The global stratigraphy of the Cretaceous-Tertiary boundary
impact ejecta. Annual Review of Earth and Planetary Sciences 27:75-113.
> -----Original Message-----
> From: email@example.com [mailto:firstname.lastname@example.org] On
> Behalf Of Tommy Tyrberg
> Sent: Thursday, April 06, 2006 9:35 AM
> To: email@example.com; DML
> Subject: Re: New date for Chicxulub?
> At 15:44 2006-04-06, David Marjanovic wrote:
> >>The above claim that the data in support of a direct relationship
> >>the spherules and the iridium layer "doesn't make sense" seems
> much ado
> >>about nothing.
> >Better yet: The GSA abstract doesn't mention any radiometric
> dating. So
> >when there are several spherule layers plus the boundary spread
> over 10 m,
> >why can't they all (except the lowest), including the boundary, be
> Or even more likely the whole ensemble formed in something more like
> minutes than 300,000 years. This seems to be yet another case of
> gradualism. It seems that many geologists simply cannot conceive
> that near
> a 200 km impact crater in the hours after the impact sediments might
> settle out slowly and peacefully in neat stratigraphic order.
> It is worth noting that outside the Caribbean area nobody has ever
> any trace of "multiple impacts" or that the impact layer is 10
> meters below
> the K-T boundary.
> Tommy Tyrberg