The Helium Conundrum (4)
DAVID Hilton, a geochemist with the Scripts Institution of Oceanography, in California, predicts that the new ocean will appear (roughly) 50 million years hence—after the superplume has split the African tectonic plate into “Somalia” and “Nubian” segments.
It needs to be emphasized though, that heat—not helium—is driving this process. You can call it “guilt by association”. Helium is implicated, because it is always on the scene: Associated, geologically, with the convectional, heat-carrying magma that is causing the upheaval.
There are, Wikipedia apprises, eight isotopes of helium. But only He-3 and He-4 are stable; and only they occur naturally. Being primordial, He-3 originates from deep in Earth’s interior.
No new He-3 is forming in the solid Earth—because it is a decay product of tritium, a rare isotope of hydrogen. Hilton thus used the ratio of He-3 to He-4 in rock he collected from active African volcanoes, to pinpoint a single superplume as the culprit.
Scientifically, helium has always harbored surprises. This was driven home painfully in 1903, to the mayor of Dexter, Kansas—a town in the expansive Great Plains region of the American Mid-West.
A newly drilled well was gushing out nine million cubic feet of gas daily. “To celebrate their good fortune,” a commemorative booklet of the American Chemical Society (ACS) records, “the people of Dexter planned a huge [ceremony], complete with band music, patriotic speeches, and games”.
The mayor dutifully delivered a rousing speech; and the escaping gas was to be lit, as a grand finale. A promotional circular, the booklet says, promised residents that “a great pillar of flame” from the burning well would “light the entire countryside for a day and a night”.
The crowd watched excitedly, the booklet continues, as a burning bale of hay was pushed into the gushing gas. But the gas did not ignite. Instead, “the burning bale [was] quickly extinguished. Undaunted, the mayor repeated the process several times, but with the same results”.
Another anomalous incident had occurred 35 years earlier, in India, during a solar eclipse. A French astronomer was observing the Sun’s reddish chromosphere, through a spectroscope, when he noticed a bright yellow spectral line—situated near the “D” lines of sodium.
Yet it denoted a different element, one unknown on Earth: Until 1895, when helium was isolated in the U.S.A. and Europe. The U.S. investigator thought he’d found “nitrogen”. So credit went to a Scotsman, who named the element after the Greek Sun god, “Helios”.
Dexter’s “dud” gas well contained only 15 percent combustible methane which, the ACS booklet noted, “would not burn in the presence of 72 per cent inflammable nitrogen,” plus an “inert residue” of 12 per cent.
Two chemists at the University of Kansas, David F. McFarland and Hamilton P. Cady, later isolated a gas in the residue, with a spectral line similar to that seen earlier on the Sun. “The total amount of helium present in the Dexter gas,” the publication said, “was an astonishing 1.84 per cent”.
Ultimately, events at Dexter would add spiraling economic and political dimensions to the helium conundrum. “The gas helium,” wrote G. Sherburne Rogers, of the U.S. Geological Survey, in 1921, “…at first regarded as one of the rare elements, was found…to occur… in natural gas, from many localities in Kansas.”
But not just Kansas: Indeed, most of the world’s helium-rich natural gas fields (with He-4 content above three per cent), says the American Physical Society, are in the U.S. states Kansas, Oklahoma, Texas and Wyoming and to a lesser extent, neighboring Canada.
This dominance has been a stabilizing factor. Yet U.S. policy has also contributed greatly to the current helium crisis.
To be continued.
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