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Re: extinction



> > > Volcanic debris can float for long
> > > distances via marine currents.
> >
> > But certainly not uphill to the purely terrestrial Nanxiong Basin. You'd
> > need a second impact to create the gihugrongous tsunami necessary to
wash
> > seawater into that basin, and I _am_ taking paleogeography into account.
>
> Re the K-T transition iridium spikes, are you advocating that the
> splendid works of Zhao, and other Chinese scientists be disregarded
> because they do not fit your notions of K-T science?

No, I advocate the idea that marine currents cannot have caused the multiple
Ir spikes in the Nanxiong basin. That's all.

I don't know how to say this in a polite way, but... please don't read
between my lines. There is nothing in there.

> "Therefore, it seems logical to reason that the trend toward more
> negative C-13 values of the eggshells in the two studied sections
> could be an indirect consequence of a lasting increase in CO2
> concentration in air during the K/T transition. This

requires the _presence_ of such an increase, and that ought to be researched
first, before drawing further conclusions. -- Needless to say, that trend is
not predicted by an impact, and therefore of course deserves more study.

> seems to agree with the model developed
> by McLean [22-24] who proposed that CO2-induced
> greenhouse warming was caused by the Deccan Traps
> volcanism during the K-T transition."

Well, now we have Ravizza & Peucker-Ehrenbrink showing that the Deccan Traps
volcanism did cause such a greenhouse, but also that it ended quite some
time before the K-T boundary.