Early Volcanoes Minted Nickel

ScienceNOW Daily News ^ | 20 November 2009 | Phil Berardelli

[neverdem]

Enlarge Image

Green gold. A complex geological process produced this sample of nickel sulfide.

Credit: Marco Fiorentini, Science

Those spare nickels in your pocket might not be there without the help of ancient volcanoes that blasted sulfur dioxide into the sky billions of years ago. The discovery solves a mystery that has dogged researchers for decades, says geochemist Edward Ripley of Indiana University, Bloomington, who was not affiliated with the study.

The nickel in ore deposits is actually nickel sulfide, a compound that is rich in sulfur. The sulfur is "critically important," says geochemist Douglas Rumble of the Carnegie Institution of Washington in Washington, D.C. It concentrates nickel into a form that can be mined commercially. But no one knew where the sulfur came from. Neither the ancient seawater under which the nickel ore deposits were once buried, nor the molten magmas that welled up from Earth's mantle and originally deposited the nickel, contained very much sulfur.

Rumble, geochemist Andrey Bekker of the University of Manitoba in Winnipeg, Canada, and several other colleagues hit upon a clue to the sulfur's origins in ancient rocks from Western Australia. The rocks contained unusual ratios of two versions, or isotopes, of sulfur known as sulfur-33 and sulfur-32. Only ultraviolet (UV) light from the sun can create such an effect, Rumble says, in the course of breaking down sulfur dioxide gas. When the scientists examined nickel-bearing ore samples, also from Western Australia as well as from Canada, they found the same ratio of the sulfur isotopes.

Armed with this information and further analyses, Rumble, lead author Bekker, and colleagues propose the following scenario today in Science. Early in Earth's history, volcanic eruptions spewed massive amounts of sulfur dioxide into the atmosphere, where UV sunlight broke down the gas and created the odd sulfur isotope ratios. The sulfur descended with the rain and accumulated into sedimentary beds on the sea floor. Once there, superheated water from geothermal vents at various locations on the sea floor cooked the sulfur into sulfide. Finally, nickel-bearing magma welled up from Earth's mantle, combining with the sulfide to form nickel sulfide and encasing the compound inside volcanic rock called komatiite.

In terms of geological time scales, the whole process was lightning-fast. It may have taken as little as a few million years, Bekker says. And as soon as the sediments were assimilated by the magma, he says, it might have taken only "several decades to form the mineral deposit."

[library user]

Cool headline.

[jongaltsr]

very interesting.
like this type of science info.
keep it coming.

[Sacajaweau]

I have to think this is really very old science revisited.

[null and void]

Is the Sudbury deposit an exception?

[JimSEA]

This would mesh nicely with the location of the sulfide deposits in ancient rock in Canada and Russia. Next, where did the nickel in the oxide deposits (Cuba, New Caledonia) in very young rock come from??

[Fractal Trader]

ping

[neverdem]

Is the Sudbury deposit an exception?

I have no idea. My familiarity with earth sciences is fairly limited to what I learned in grammar and high school, except for that which I post from the net.

[dusttoyou]

A mining friend from Sudbury says the big nickel deposit was from a meteor impact.

[null and void]

That was my recollection as well. Although I think part of the nickel was of terrestrial origin from when nickel rich magma welled up to fill the crater.

[SunkenCiv]

Thanks Fractal Trader for the ping, uh, I think neverdem as well. I've had about five dozen tabs open almost since I sat down here, and they still recede into invisbility.

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[SunkenCiv]

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[AFreeBird]

Alternate headline: Acid Rain Rocks

[blam]

On a side note:

Save Your Nickels

[TheOldLady]

Hubby is allergic to nickel sulfate, the result of working with a nickel plating bath in the industrial research lab where we met in 1973. He's still in the printed wiring board business, and he jokes that he can't go near classic cars because of all that nickel under the chrome.

[bert]

I have a large polished chunk of the Sudbury ore that looks almost exactly like the photo. The fleks are silver (nickel) colored and seem to be the metallic element.

They had a stand set up and were sawing slabs for tourists. I picked up a 5 pound piece of the cutoff trash for my collection for free.

[SunkenCiv]

Sounds like a pain.

[piasa]

Might explain the interest in Mars... volcanoes, sulfur and nickel...

[Rebelbase]

[SunkenCiv]

The Meteorite That Buried Michigan | The Sudbury Impact
Alexis Dahl
9.12K subscribers
190,740 views
October 1, 2021
https://www.youtube.com/watch?v=ycQexghR61w

https://search.brave.com/search?q=sudbury+crater+youtube&source=desktop