JIM BRACE-THOMPSON
View of the Mid-Atlantic Ridge at Þingvellir National Park, Iceland’s first national park.
SUE GARDNER, WIKI MEDIA COMMONS
A recent issue of the journal Science noted how volcanic eruptions follow from magma stored deep underground. Such storage and build-up can last from thousands to hundreds of thousands of years, particularly for silica-rich volcanoes like Mount Pinatubo in the Philippines. Until recently, there was somewhat less understanding surrounding the timing of mechanisms driving basaltic magma, such as that underlying the island nation of Iceland that sits astride the Mid- Atlantic Ridge. A new study suggests such magma may be stored for just hundreds to thousands of years at the so-called “crust-mantle boundary.” By the way, thanks to magma welling up and sea-floor spreading, Iceland is said to grow wider by some 9 centimeters every year. Half of the island is part of the North American Plate and the other half is part of the Eurasian Plate, which makes for a lot of volcanic activity!