New research suggests that the largest volcanoes (supervolcanoes) can take as little as hundreds of years to form. Previously, it was believed that supervolcanoes existed for as much as 200 000 years before they released their molten rock. This information, and the little other that is known about supervolcanoes, comes from the study of crystals of zircon, which contain small amounts of radioactive elements which allows their age to be determined. Studies from these crystals showed the time between formation and eruption was hundreds of thousands of years. However, in a recent study the team targeted crystals of quartz, from which they suggested the pools of magma lasted as little as to 500 years before eruption (this information was determined by studying how long it took the quartz crystals to form, which was between 500 and 3000 years). This was learned through the study of the supervolcano site of Long Valley in California, which is estimated to have erupted 760 000 years ago and cover half of North America in ash. The eruptions of supervolcanoes are believed to release more debris that any eruption seen by humanity and to release enough ash to effect the global weather for years.
The only problem posed in the research of volcanoes and supervolcanoes is that magma formation occurs in historical time, instead of geological time. However, a greater understanding of pool development and the ability to predict eruption will be sought. Future research might not only broaden our understanding, but provide us with different information once again depending on what crystal is studied.
http://www.bbc.co.uk/news/science-environment-18269593