Upwardly Mobile

Natural History, April, 2001 by Henry S. F. Jr. Cooper

Every volcano is different, of course. But Webster and his associates continue to gather data suggesting that an increase of sulfur relative to chlorine in the inclusions could well indicate that an explosive eruption might be in the works at Vesuvius--and possibly elsewhere. Why the ratio of chlorine to sulfur is a factor, however, is not understood.

Another feature of volatiles in magma is that they attach themselves to a number of metals, determining which metals a particular magma will carry along and deposit in underground pipes, veins, and cracks. "So in studying how these hot gases drive volcanic eruptions, one can also see how they concentrate metals like gold and silver and tin and molybdenum," Webster says. In fact, when he first joined the staff of the Museum in 1990, two years after receiving his doctorate from Arizona State University, his research focused on ore and mineral deposits and their transport underground via the same volatiles that make magmas upwardly mobile.

As Webster tells it, "My grandfather, my father's father, was a miner, so whenever we went to visit him in Georgia--and later in Dutchess County, New York--I would go off with Grandpa to the marble or limestone quarries. What was really neat was that in pockets in the rock I could find crystals. He got me started with rocks and minerals, and I've been hooked ever since".

Henry S. E Cooper Jr., a former staff writer for the New Yorker, has been visiting the Museum since he was four years old, when his father sat him in a cavity of the Willamette meteorite.