[Image: Nevada test site, Google Maps, filtered through Instagram.]
There’s a great line in Tom Zoellner’s book Uranium: War, Energy, and the Rock That Shaped the World where he describes the after-effects of underground nuclear tests. Zoellner writes that, during these tests, “a nuclear bomb buried in a deep shaft underneath a mountain would vaporize the surrounding rock and make a huge cathedral-like space inside the earth, ablaze with radioactivity.”
[Image: Nevada test site, Google Maps, filtered through Instagram.]
They suggest that these detonations produce spaces—such as collapse cones and debris fields—that have “no direct natural analogue,” although they do helpfully contrast weapon-test craters with meteor-impact sites. (The authors also break underground nuclear test sites down into “zones,” which include a “zone of irreversible strain,” which is an amazing phrase.)
The larger purpose of their paper, though, is to look at long-term “signatures” that humans might leave behind in our underground activity, from nuclear tests to mineralogical carbon-capture to deep boreholes to coal mines. Will these signatures still be legible or detectible for humans of the far future? On the whole, their conclusion is not optimistic, suggesting instead that even vast subterranean mines and sites of underground nuclear weapons tests will fade from the terrestrial archive.
“Many of the physical and chemical products of human subsurface intrusion either do not extend far from the source of intrusion, lack long-term persistence as a signal or are not sufficiently distinctive from the products of natural processes to make them uniquely recognisable as of anthropogenic origin,” they write. “But the scope and complexity of the signals have increased greatly over recent decades, both in areal extent and with increasing depths, and seem set to be a fundamental component of our technological expansion. There will be some clues to the geologist of the far-future, when historical knowledge records may not be preserved, that will help resolve the origin.”
Nevertheless, it is totally fascinating to imagine what future archaeologists might make of Zoellner’s “huge cathedral-like space[s] inside the earth, ablaze with radioactivity,” long after they’ve collapsed, and where sand has been fused into unnatural glass and anomalous traces of radiation can still be found with no reasonable explanation for how they got there.
Could future archaeologists deduce the existence of nuclear weapons from such a landscape? And, if so, would such a suggestion—ancient weapons modeled on the physics of stars—sound rational or vaguely insane?
[Image: An otherwise unrelated photo of a cave in China, taken by @PhailMachine, via wallhere].
An interesting story that re-emerged during recent coverage of the Thai cave rescue is that a team of British cavers trapped underground in central Mexico for “more than a week” back in 2004 had been accused of having an ulterior motive.
The conspiracy seems to have begun when someone noticed a particular piece of equipment in a photo of the caving team: “someone spotted radon dosimeters being used. This wasn’t a military training exercise; it was a bunch of guys on holiday, some of whom happened to be in the armed services.”
What the British team would even have done with such materials, if they had found them, including how they would have safely transported uranium out of the underworld in their caving gear—not to mention how they would have exploited this knowledge later, perhaps by developing a vast, illegal, underground mine in the middle of central Mexico?—is difficult to imagine, but, wow, would I like to read that novella.
Six British soldiers descend into the Earth beneath Mexico looking for the infernal materials of war, part of a much larger, secret global mission for subterranean weapons-prospecting, slipping into caves in Central America, the U.S. Southwest, the Namibian desert, and beyond, combining raw international espionage, classified satellite reports, weaponized mineralogy, advanced underground mapping techniques, and every gear-head’s camping equipment fantasy turned up to 11.
“In 1972,” the Curtin University of Technology explains, “the very well preserved remains of several ancient natural nuclear reactors were discovered in the middle of the Oklo Uranium ore deposit.” The university adds that each of these equatorial African reactors “operated on an intermittent basis for a period ranging from a few years to hundreds of thousands of years. The total time period over which the reactors operated is thought to be about a million years.”
In one specific case, we read in a report published five years ago by Physical Review Focus, a chain reaction in the uranium-rich rocks “cycled on and off every three hours.”
The idea that radioactive deposits beneath the Earth could self-react and undergo fission was first proposed by physicist Paul Kazuo Kuroda. The internal clock of a geological formation, Kuroda suggested, given contact with water, could simply start ticking away:
In 1956, nuclear chemist Paul Kazuo Kuroda of the University of Arkansas in Fayetteville predicted that a chain reaction could develop in natural uranium deposits, generating heat just as the reactor in a nuclear power plant does. His suggestion proved prophetic when, in the 1970s, others discovered several burned-out natural reactors in the Oklo uranium mines in Gabon.
Amazingly, “researchers still don’t know precisely how the fossil reactors managed to burn slowly for more than 150,000 years, when they could have exploded violently.” The presence of underground water seems especially fortuitous in that regard—it helped to avoid a nuclear detonation.
That’s plausible because the water molecules would collide with neutrons whizzing through the uranium and slow them down, a process called moderation. Because slower neutrons more efficiently split the uranium nuclei in a chain reaction, the water would promote the reaction and cause the reactor to heat up. Eventually, however, the heat would boil away the water, shutting the reaction down until more water could collect.
It was a pulsing rhythm, a geologic throb: based on present-day chemical measurements taken of specific isotopes in the nearby rocks, “the researchers estimate that the reactor ran for 30 minutes and then shut down for two and a half hours.”
I’m reminded again here of William Burroughs’s extraordinary and haunting suggestion, from his novel The Ticket That Exploded, that, beneath the surface of the earth, there is “a vast mineral consciousness near absolute zero thinking in slow formations of crystal.” Here, though, it is a mineral seam, or ribbon of heavy metal—a riff of uranium—that stirs itself awake in a regularized cycle of radiative insomnia that disguises itself as a planet. Brainrock.
Gabon’s “natural nuclear fission reactors,” according to Wikipedia, “are the only known sites in which natural nuclear reactors existed. Other rich uranium ore bodies would also have had sufficient uranium to support nuclear reactions at that time, but the combination of uranium, water and physical conditions needed to support the chain reaction was unique to the Oklo ore bodies.”
Of course, this process created what we would now call nuclear waste—including plutonium. These otherwise extraordinarily dangerous waste products, however, have been entombed within the earth for two billion years. The Curtin University of Technology points out that “this is so long that all of the radioactive waste products (even those with million year half lives) have decayed away.” They have also hardly even moved: the plutonium, according to the U.S. Department of Energy, “has moved less than 10 feet from where it was formed almost two billion years ago.”
Are there thus structural lessons to be learned from the rocks at Oklo? “By analyzing the remnants of these ancient nuclear reactors and understanding how underground rock formations contained the waste, scientists studying Oklo can apply their findings to containing nuclear waste today,” the DOE goes on to suggest. This is another way of saying that the Oklo uranium deposits are being studied as natural analogues for how high-level nuclear waste might behave in an artificial repository like Yucca Mountain (watch for a long and fascinating interview with a geophysicist from Yucca Mountain here on BLDGBLOG next week).
We might say, then, that a geological formation, like some nuclear version of Spanish architect Vicente Guallart’s notion of geologics, has partially inspired an architectural form.
The timescales are all wrong for this, meanwhile, but if geomythology is the study of ancient folk tales, oral traditions, and regional myths to see if they contain camouflaged references to real, but prehistoric, geological events—earthquakes, tsunamis, volcanic eruptions, and more—what geomythological influence might the throbbing and automechanized Oklo uranium mines play? How extraordinarily interesting would it be to come across a series of old myths about an intelligent presence in the rocks of equatorial Africa, a kind of mineralized Mother Nature winking at everyone from below—and to realize that they’re referring to the reactions at Oklo. A spirit in the Earth.
Finally, do these naturally occurring reactions come with the implication that our present-day nuclear reactors are, in a sense, simulated geological processes, not unlike artificial diamond-creation chambers? Nuclear reactors become models of already existing natural events. They are terrestrial reenactments, you might say.
Scientific American has a five-page article about the Oklo phenomenon, if you’d like to read more.