McGill geology researchers' discovery of high concentrations of CO2 at mid-ocean ridges confirms explosive nature of certain volcanic eruptionsBetween 75 and 80 per cent of all volcanic activity on Earth takes place at deep-sea, mid-ocean ridges. Most of these volcanoes produce effusive lava flows rather than explosive eruptions, both because the levels of magmatic gas (which fuel the explosions and are made up of a variety of components, including, most importantly CO2) tend to be low, and because the volcanoes are under a lot of pressure from the surrounding water. Over about the last 10 years however, geologists have nevertheless...