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.”
I thought of Zoellner’s vision of a “huge cathedral-like space inside the earth” recently while reading a paper by Colin N. Waters et al., called “Recognising anthropogenic modification of the subsurface in the geological record.” Among other things, the authors describe the long-term “structural effects of subsurface weapon detonations.”
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?
(Vaguely related: “fossil reactors” underground in Gabon.)