Well, as far as I can tell from what I have seen of the Belfast long Chronology, there is no immediatly obvious environmental effect in growth indices of the trees in the 770's, though looking at the BLC data there, there is a small reduction in growth index lasting about 2 years from 774, but it is small and could just be coincidental noise, and is no where near as strong as the signal at 540 for example. Its within about 10% of the 150 year moving mean (lasting 1-2 years), compared with the 540 event which sees a 30% reduction from the mean for a consistent 4-5 years (and is the largest depression .

It does tie in sort of with the idea that in the past we have been subjected to extraterrestrial influences, that could potentially be encoded in myth, or effect civilisation in some form (in mentality of physically). For example, we have the old UFO fodder that in 776 at the siege of Charlamange by the Saxons that flying, fiery shields were observed in the air, which routed the Saxon Army. We also have reports that in 773 (or possible 774 or 776) a red cross appeared in teh air [www.phenomena.org.uk] (unfortunately the site is poor for giving the original reference material). The skys may have been busy at that time, be it from increased fireball flux, or an active sun, or supernova, or just an over active human imagination.

The link in the Jupiter Impact thread is here <[www.hallofmaat.com];

From my understanding there is still debate about how environmentally effective explosive volcanos can be since, but with respect to the 774-775 event, even if a large volcano did happen, it would likely not create the same 14C signal we see here, since any carbon spat out of volcanoes will typically be old stable carbon, not 14C. A volcano would likely deplete the concentration of atmospheric radiocarbon, not enrich it.

With respect to Mike's 540 AD cosmogenic event, it all comes down to the Ice core workers getting their act together and publishing evience of marker dates that categorically link acid and tephra in ice cores with Vesuvius in 79 AD (from my fading memory). Mike has proposed that the dating of the ice cores be moved by 7 years (on the basis that the acid layer supposedly of Vesuvius is wrong), which actually places a volcanic event at each tree ring at 536 and 540 ad (no comet impact required). If the dating of Vesuvius is correct, then it means that there is a volcano at 536, but none at 540, and so the cosmic hypothesis is still on the table. (I hope I have remembered this argument correctly).

This is what I like about Mikes methodology, he is perfectly happy to suggest evidence based solutions to prove his hypothisis wrong, which is what science should be about.

Jonny

The path to good scholarship is paved with imagined patterns. - David M Raup