Scientists have discovered that humans are adding to our planet’s catalogue of mineral types at a rate never before seen.
It’s happening so fast that human-created minerals now total 208 of the 5,208 types recorded by the International Mineralogical Association (IMA)—and these are merely the ones that have been officially recognised. There are probably hundreds more currently not acknowledged.
Nor are these substances mere laboratory curiosities created by bored scientists.
“We make bricks,” says Robert Hazen, a mineralogist at the Carnegie Institution for Science in Washington DC. “We make cement. We make reinforced concrete. We have porcelain in glassware. We have all sorts of crystals in technology, batteries, and magnets. We have pigments and paints and glues and things that include mineral-like crystal substances which never before existed in the history of the world.”
Other substances are created by accident. “Many are associated with mining,” says Edward Grew, a mineralogist and petrologist from the University of Maine, who collaborated with Hazen on a paper published in the current issue of American Mineralogist.
“Mining disturbs the environment under the earth or at the earth’s surface,” he says, “and that disturbance makes for environments where new minerals can form. Some have been dated from the Bronze Age, but for the most part they are much newer.”
To figure out when minerals first appeared, the scientists went through geological databases, looking for the time when each officially recognised mineral first appeared in the geological record.
“This one formed in a mine tunnel, this one in a shipwreck, and this one in an old Egyptian statue,” Hazen says, adding that his favourite was a mineral – calclacite – that formed in a museum drawer where a mineral specimen reacted with acetic acid from the wood to create an entirely new substance. “You had a new mineral forming in a museum!” he says.
And while the wood-drawer mineral might be dismissed as a curiosity, the overall effect is important, the scientists say.
That’s because the only other time in Earth’s history when there was a remotely comparable growth in the number of mineral types was during the “Great Oxidation,” which occurred when oxygen began to build up in the Earth’s atmosphere, about 2.2 billion years ago.
This caused the oxidation of pre-existing minerals, producing the first appearances of as many as two-thirds of the minerals currently in the IMA’s catalogue (including economically important iron ores).
But the Great Oxidation event took place over the course of hundreds of millions of years. Today’s explosion in new minerals has occurred in a tiny fraction of that time. That’s important, Hazen says, because minerals are durable and the ones created in recent history will likely outlive the civilisation that produced them.
“They will be preserved for billions of years in the sedimentary record,” he says.
And that, he says, bolsters the argument for designating modern times as a new geological epoch: the Anthropocene.
The designation of geological epochs might seem arcane, but in the long-run view of geologists, it is anything but. The issue, Hazen says, is what a geologist of the future might think, going through the billion-year-future of the Grand Canyon, examining sediments laid down in our era.
“Cubic zirconium, laser crystals, silicon chips, and stuff like that are very stable materials,” he says. “Future geologists will be able to hammer out chunks of materials and say, ‘Look at this.’”
Other scientists have suggested that a similar worldwide stratigraphic layer might be created by fallout from nuclear testing, or from the fumes of leaded gasoline. But that, Hazen says, is “nothing” compared to “minerals that are being produced in huge volumes all around the world.”
Other scientists agree. J. Kelly Russell, a volcanologist and igneous petrologist at the University of British Columbia in Vancouver, notes that Hazen is “great ‘big-idea’ guy.” He didn’t have time to review the new paper for this article, but “I heard some of [his] ideas a few years ago and it was quite stimulating,” he says.
Allen Glazer, an igneous petrologist from the University of North Carolina, Chapel Hill, agrees. “I’m not an expert, but the concept make sense to me,” he says.
“If you go forward, say a million years, there will be plenty of markers showing how humans affected the landscape and the stratigraphic record. I remember as a lad going into a mine and finding beautiful blue curving crystals of chalcanthite on mine timbers. That’s a natural mineral, but was on human workings. That’s one of the sorts of things they’re talking about.”
Richard Alley, a geoscientist at Pennsylvania State University, calls the new study “one more demonstration of the large and growing human impact on the planet. “I still occasionally meet people who don’t believe that humans are powerful enough for our actions to have global consequences,” he says. “I’m not sure this paper will change those people’s minds, but [it] does re-confirm the increasingly pervasive reach of human influence.”
But Ken Caldeira, a climate scientist at the Carnegie Institution for Science’s Department of Global Ecology, Stanford, California, notes that if the future has any geologists to look back across vast spans of time, “the presence of humans on the face of this planet will be marked by the widespread extinction of many species, large mammals in particular. “It is this loss of biodiversity that I mourn. Whatever the mineralogical markers of human activity on this planet, the extinction record is the real tragedy of irrecoverable loss.”
By their names shall you know them.
Here are just a few of the 208 man-made minerals officially recognised by the International Mineralogical Association.
These ones are all associated in various ways with mines and mining.
Richard A Lovett
Richard A Lovett is a Portland, Oregon-based science writer and science fiction author. He is a frequent contributor to Cosmos.
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