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Re: SVP press coverage



At 8:11 AM -0500 11/25/04, John Bois wrote:
> > Gerta Keller has been saying the KT impact and the extinction
>> don't match for so long I don't consider it news, and that account sounds
>> like it was based on a paper published sometime in the past year. She's
>> insistent enough and contrary enough to offer the potential of a good
>> story, so her claims do get picked up by some reporters.
>
>But what is the quality of her evidence?  If it is good, this is a _big_
>story, right?  I fear many writers are afraid to report it because they
>have already led off stories with sentences like: "The asteroid that
>killed off dinosaurs..."  Sometimes evidence can spoil a good narrative.

Her evidence is largely based on forams and their position relative to the 
iridium layer and the Chicxulub crater. The problem is that forams can easily 
be redeposited. At first glance, finding Maastrichtian forams in the Chicxulub 
crater would argue that the impact came before the boundary, but an impact 
would seriously stir up the oceans (the impact was on the continental shelf), 
so quite a bit of recently deposited sediment would be stirred up, eventually 
settling down as late-Maastrichtian deposits on top of the crater (or the 
iridium layer).

Keller has been pushing this view for over a dozen years. She has come up with 
a few new deposits that show the same pattern, notably -- she claims -- in the 
cores from Chicxulub. In my judgement -- and like much of paleontology this is 
a judgement call -- she has yet to provide the compelling level of evidence 
needed to offset the evidence correlating the impact with the extinction of the 
dinosaurs.

That said, we still are far from understanding the dynamics of the KT 
extinctions. You do not have to kill every single dinosaur at the instant of 
impact to cause their extinction. The aftermath of the event has to reduce 
their population below a viable level for species survival in the post-impact 
conditions. It's conceivable that a handful of dinosaurs staggered on for years 
after the impact, scratching out enough food to survive, but not enough to 
reproduce sufficiently to repopulate. If the stragglers died out within a 
century or two after the impact, I would say the impact killed them all.

>From a journalist's standpoint, I'll add another point. With limited time and 
>space available to cover news, we have to decide what to cover, and we have to 
>sort through a lot of garbage and routine reports to pick the best news. A 
>recent article in the Columbia Journalism Review argued that loud and 
>insistent contrarians in areas like climate change are getting more coverage 
>than they deserve because journalists are striving to balance the claims of 
>opposing sides even after the science has come down strongly on one side. If I 
>was writing a scholarly review or a book, I might devote a paragraph or two 
>describing the contrarian ideas and why they are dubious. There's no place for 
>that in a 400-500 word news story.
-- 
Jeff Hecht, science & technology writer
jeff@jeffhecht.com; http://www.jeffhecht.com
Boston Correspondent: New Scientist magazine
Contributing Editor: Laser Focus World
525 Auburn St., Auburndale, MA 02466 USA
v. 617-965-3834; fax 617-332-4760