There’s something incredibly satisfying about the fact that the appropriately named Kola Superdeep Borehole (KSB) wasn’t created out of a need to find oil. This colossus is only 23 centimeters (9 inches) wide, but it’s 12,262 meters (40,230 feet) deep, easily making it the deepest artificial point on planet Earth – and it came about thanks to a scientific duel.
As explained by Atlas Obscura, American and Soviet engineers were trying to outdo each other in the subterranean realm just as they were trying to beat each other into orbit and to the Moon. America may have won the race to the Moon, but their 1958-initiated “Project Mohole” off the Pacific coast of Mexico lost funding and stopped drilling in 1966 – but the Russians, from 1970 to the early 1990s, kept on going.
The result was the KSB, which consisted of several boreholes attached to a single original hole. The deepest is termed SG-3, and extends a decent way through the continental crust of the Kola Peninsula.
If you’re having difficulty visualizing how deep it is, no worries. You could say it’s 37.8 Eiffel Towers deep. No? Well, alternatively, you could say it’s the same length as 13,045 large adult skunks stacked head to toe.
As you’d expect, plenty of new geological data was obtained through SG-3, but it’s safe to say that the palaeontological revelations took everyone by surprise. The Smithsonian explains that around 6.4 kilometers (roughly 4 miles) down, 2-billion-year-old microscopic plankton fossils were found fairly intact, regardless of the intense environmental conditions down there.
We also found out that a major interpretation of seismic data – that at a certain depth, granitic rock transitioned into basalt – was incorrect, and that slow changes in pressure and temperatures over time were responsible for the phantom geological layer.
It was also discovered that free-flowing water existed down there, squeezed from the rocks and trapped by the incredible pressures.