Golden moments

Volcanic eruptions normally release molten lava, water vapour and hot gases. But the Galeras volcano in Colombia is one with a difference. It spits out gold dissolved in its dense mix of gases; this gold melts out as magma from crustal rocks hundreds of miles beneath the surface. Fraser Goff, a geologist with the Los Alamos National Laboratory in New Mexico, US, found that the veins in old volcanic rocks of this area contained tiny flecks of gold. Parts of the veins contained 7.8 ounces of gold per tonne (t) of rock; gold mines in western US have been known to yield a mere ounce per t. Goff estimates that if the volcano remains moderately active for 10,000 years, some 200 t of gold would get accumulated. The crater gases of Galeras contain four times as much gold as those of White Island, a similar volcano in New Zealand ( Earth , Vol 4, No 2 ).

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