JonnyMcA Wrote:
-------------------------------------------------------

> Oh dear, I had forgotten that I had written the
> first link, and I have completely forgotten that I
> had tried to submit an article to Nature!

(You should just see the things that I forget ... )

But what does emerge from your comments below is a useful summary of the recent historiography of the subject, later changes, and the problems with GISP2.

Just goes to show how rapidly scientific fields change as fresh discoveries come to light.

> The
> memory is slowly going. It makes me wonder what
> else I have written that I have forgotten
>
> With regard the first link though
> [www.maatforum.com].
> Much has changed since then.
>
> 1) We have the NEEM ice core now, which as far as
> I can see does not reproduce the GISP2 ammonia
> signal for 1908 that has been linked to Tunguska.
> This may be a geographical thing as NEEM is much
> further north than GISP2, and so the winds might
> not have deposited the ammonium at the NEEM site.
>
> 2) We now know that GISP2 is incorrectly dated
> prior to 44 BC, but in fact it is too old, and
> must be moved forward in time, not backwards as
> described in the post. in 2012 the argument made
> was that GISP2 was wrong and the GICC05 ice cores
> (GRIP, NGRIP and DYE3) were correctly dated,
> because they appeared replicated. We now know
> that they are all too old prior to 44 BC (GISP2 is
> complicated, as it moves from being broadly
> correct back to around AD 1200, then becomes too
> old by 6 years to around 1000, then is correctly
> dated for a bit, before becoming too young to 600,
> then starts to correct itself until around 200,
> before it becomes progressively older the further
> back in time one goes).

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