19 Feb '15, 3pm

The mystery of the offset chronologies: Tree rings and the volcanic record of the 1st millennium

The mystery of the offset chronologies: Tree rings and the volcanic record of the 1st millennium

One could also re-examine the hypothesis that frost rings are useful volcanic markers. In fact, it is possible to have some frost rings without any evidence of explosive volcanism, presumably occurring due to extremes in local weather, but, as shown above, they do seem to record large volcanic eruptions in recent times very well indeed. Why would that change in the 1st millennium? Furthermore, when a space analysis is performed between historically-dated severe dust veils between the 1st century BC and the 7th century AD, these compare well with frost rings, but again volcanic horizons in Greenland ice appear to be too old by 7-years (see Figure 3). Accepting, of course, that historical documentation is correct, the dated bristlecone pine frost rings agree perfectly as a response to the volcanically induced climatic events. We conclude then that these early ice core chrono...

Full article: http://www.realclimate.org/index.php/archives/2015/02/the...

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