Information circulated on the cambridge-conference network is for scholarly use only. The attached text may not be reproduced or transmitted without prior permission of the copyright holder. In several recent contributions to this ongoing debate on impact rates and effects, it seems to me that it is being taken as given that there is almost nothing relevant in the archeological record. This would be a dangerous assumption to make.
Archaeology is incapable of dating anything well enough to see 'point events' of any kind.
I can say this with confidence as someone who has spent his career at the pointy end of chronological research in the service of archaeology. When you ask what caused these profound events, catastrophic solutions are not invoked. Workers in fields outside archaeology should also be reminded that three, possibly as few as two, consecutive failed harvests on a wide scale will reduce any agriculture-dependent population to chaos. Thirty-three papers attempt to assemble the evidence from various natural records and from archaeology. Their success is inevitably constrained by the one key factor critical in any such endeavour - chronological resolution.