Forget metal detectors and drilling rigs. Some of the best clues about what lies beneath the earth’s surface are being delivered by creatures that weigh only a fraction of an ounce.
Termites are helping geologists search for buried gold and other valuable minerals by doing something they have been doing for millions of years: digging. In parts of Africa and Australia, these industrious insects can excavate deep into the ground in search of moisture and material for their nests. Depending on the species and environment, termites can reach surprisingly deep layers of soil and rock, sometimes tens of meters below the surface.
As they tunnel and build, termites bring particles from those deeper layers back to the surface and incorporate them into their mounds. The material can contain tiny chemical traces — a kind of underground fingerprint — associated with mineral deposits hidden below. To a termite, it is simply building material. To a geologist, it can be a valuable sample of what lies beneath.
That makes termite mounds a natural form of geological sampling. Exploration companies can collect small amounts of mound soil and have laboratories analyze its chemical composition. Elevated levels of gold or other elements can indicate that a potentially valuable mineralized zone lies somewhere beneath or nearby. Geologists can then use those clues to determine where expensive exploratory drilling and other machinery should be deployed.
The approach has been scientifically tested for more than a decade. Research by Australia's Commonwealth Scientific and Industrial Research Organisation (CSIRO) found elevated concentrations of gold in termite mounds above known gold deposits in Western Australia. The research showed that even relatively small mounds could provide useful clues about mineralization several meters underground.
More recent studies have broadened and strengthened the case. A 2023 study of "Macrotermes falciger" termite mounds in the Democratic Republic of Congo found that mound material reflected characteristics of the underlying geological formations and concentrated metals including copper, cobalt, nickel, lead and zinc in fine particles. The researchers concluded that termite mounds can provide useful information about subsurface geological anomalies for mineral exploration.
The method is appealing because it can help explorers narrow a search area before bringing in costly equipment. It also requires collecting samples from existing mounds rather than extensively disturbing the landscape.
It turns out that some of nature's best prospectors don't earn a paycheck and aren't required to wear a hard hat.
Credits: Fanciful image by The Jeweler Blog using aichatapp.ai. Termite mound photo by Oratile Leipego, CC BY-SA 4.0, via Wikimedia Commons.
