Rock of Ages: The Evolution of Minerals

Living organisms, according to The Economist, don’t have a monopoly on evolution. Minerals, too, evolve. The gist of the article is that rocks are showing characteristics of evolution. When the Earth first came to be, few minerals existed; however, today there are more than 4,000 different minerals on the planet.

The article cites a study, just published in American Mineralogist, by Robert Hazen of the Carnegie Institution in Washington, DC, and a team of colleagues. The researchers worked to identify “how much of the diversity was created by the rocks alone and how much of it was created by the evolution of life.”

Of course, the researchers admit that minerals do not have genes and can’t mutate like living organisms. Still, they suggest that “when life appeared, the evolution of minerals and the diversity of life became entwined.” Hazen explains that contemplating minerals in evolutionary terms allows us to identify how far a planet has developed geologically. “Moreover,” he explains, “it can tell you whether life was present at some point—and even whether it is present now.”

Here’s a little nugget to track the thinking of Hazen and his crew:

With NASA’s Messenger probe now going into orbit around Mercury, Dr Hazen predicts that it will find only 300 or so minerals on the planet. If there are 500-1,000 detected, then it will suggest that there is a lot more to Mercury than anyone originally thought. And if minerals that depend upon life for their formation show up, then researchers will be flummoxed. The same is true for Mars and other planets—including the exoplanets that have been known about but which have just been seen for the first time orbiting stars outside the Solar System (see article).

Apologies to anyone trying to access the The Economist — it might be subscription only.

Laura Moorhead