Learning volcanoes – advanced students
In many descriptions of volcanoes and their eruption histories we stumble upon the terms Tuff, Tufa or Ignimbrite. Most every self-respecting volcano has one or all of them. Generally it becomes obvious from the context that they refer to widespread deposits of volcanic materials. But what exactly is an ignimbrite?, is it different to tuff?, and where do they all come from?
Tuff and ignimbrite are clastic rocks composed of volcanic Continue Reading
Intro: I wrote this some 12 months ago, a couple months after our M7.1 intraplate earthquake here in Anchorage. This seems a good time to revisit what happened and why. As usual, there are more questions afterwards than before. Cheers –
Update, Aug. 2019:
In the five years since this was first posted, science continues to grind away, answering a few questions which in turn create a bunch more questions. The Baillie tree ring / ice core team is increasingly of the opinion that the 535 – 540 AD global cooldown was caused by huge volcanic eruptions, at least two of them bracketing the period. A team including Robert A Dull published a paper August 16 entitled “Radiocarbon and geologic evidence reveal ilopango volcano as the source of the colossal ‘mystery’ eruption of 539/40 CE” that appears to nicely define the most recent end of that bracket.