The nickel we use today might not be here if it wasn't for ancient volcanoes spewing sulfur dioxide into the sky. A study reported today in Science hypothesizes how these nickel sulfide deposits came to be.

The nickel ore in mineral deposits is nickel sulfide; the sulfur makes the nickel into a compound that can be commercially mined. It was not known where this sulfur came from because neither the magma that deposited the nickel nor the prehistoric seas where the nickel deposits were once buried contain high levels of sulfur.

Researchers were clued into the possible source of sulfur by ancient rocks in Western Australia. These rocks contained unusual ratios of two sulfur isotopes, sulfur-32 and sulfur-33. The only way to generate such an unusual ratio of isotopes is UV light breaking down sulfur dioxide says geochemist Douglas Rumble of the Carnegie Institution of Washington in Washington.

Researchers propose that this sulfur dioxide with an odd isotope ratio was deposited into sedimentary beds on the sea floor by rain. Superheated water from geothermal vents on the sea floor changed the sulfur into sulfide, which then combined with nickel in magma as it spilled onto the sea floor to form nickel sulfide. The whole process was extremely rapid by geological standards, taking as little as a few million years.

(Sourced from www.examiner.com)