COMPELLING EVIDENCE

We take it that one of the things that you are not overly worried about is why Lake Kivu in East Africa has 50 million tons of methane dissolved in it.

Yet this is one of a goodly number of strong indications that may point the way to a vast, world-wide reservoir of natural gas, and that may change the energy industry's approach to prospecting for it.

That theory is not disputed by Cornell astronomy professor Thomas Gold and his research assistant Steven Soter; but they propose an additional, and probably more important, mechanism: methane (natural gas) of non-biological origin deep in the interior of the earth. It seeps to the surface in certain places, and it is liberated during an earthquake.

Lake Kivu is one of several places with much methane in it without any organic rock to explain it. And there are other such places: the permafrost region of the Arctic, and the mid-ocean ridge of the Pacific.

And then comes the clincher: our old friend radon gas. As we reported earlier [Sept 79], the Japanese, and now others, measure the radon concentration in deep well water. If it suddenly increases, an earthquake may be imminent. But radon has a halflife of only 3.8 days, so that it could not by itself diffuse very far upward before it decayed into its (solid) daughters. Evidently the radon is merely a tracer for a much more abundant gas that sweeps it along while it remains itself undetected.

Three guesses which one.

The whole fascinating story is told by the two scientists in "The Deep-Earth-Gas Hypothesis," Scientific American, June 1980; and in the 14 months for which it lay in our "This Month" file (displaced by matters we considered more urgent), we learned about the work of Dr Harmon Craig of California's Scripps Institute of Oceanography, who found that in the methane-rich regions of the Pacific Ridge, the concentration of helium 3 is also extremely high (3,000 times higher at Lake Kivu than in ordinary river water). Helium is rare, inert, and helium 3 is not produced by radioactive decay. It is another primordial gas tagging the primordial methane.

[Astronomers will, quite rightly, call me an ignoramus in their field, but I must confess that I never believed the craters on the moon were made by meteors. True, they look like the crater made by a meteor in the Arizona desert; but for every large meteor there are zillions of small ones, and there is no lunar atmosphere to burn them up. If the big ones made craters, the small ones would have mashed it to dust; yet the astronauts hopped around on good solid rock. What the craters always did remind me of were the rings that you see on the surface of mud when gas bubbles up through it...]