From diamonds to plastic, humanity’s impact on the history of earth’s mineral evolution
Source: James St. John
Once upon a time, diamonds were the only rocks in the universe.
These minerals of compressed carbon formed from supernovas, and over time more minerals formed, created chondrites and eventually planets. Scientists speculate that the early earth started with approximately a dozen minerals during formation, which increased to 1,500 as plate tectonics contributed to high-pressure metamorphic changes. However, now the Earth hosts over 5,000 different minerals, with some caused by humans.
As Earth evolved, minerals evolved.
The planet was first formed with about a dozen minerals, but as time progressed factors such as oxygenation and tectonic movement led to the synthesis of new minerals. Life on Earth has also affected minerals in ways that haven’t been seen anywhere else in the universe. In fact, even if another inhabited planet was found formed with the same elements as ours, at least a quarter of the minerals would be wildly different. In a series of papers by R. M. Hazen and colleagues, they determined that oxygenation opened the doors to thousands of new minerals. What would happen to a planet where the inhabitants relied mostly on hydrogen? What new minerals would come into being?
The ability of life alone are not the only factors when it comes to new minerals. Human’s interactions with the earth has caused new formations. Some only occur in specific situations, like calclacite– which only forms in old oak drawers in museums. New uranium minerals have begun to form in abandoned mines exposed to oxygen; and a bright blue, powder-like mineral was found on ancient Egyptian bronze artifacts as well as mines in other arid areas around the world.
Then there’s a slightly more harmful side of human contribution.
A new “mineral” dubbed plastiglomerates have formed in areas like Kamilo Beach, Hawaii. These plastiglomerates are formed when plastic melts with other materials, be it shells, netting, or other trash, to form a substance harder than plastic. They can form from forest fires, lava flows, otherwise extreme temperatures, or when plastic is thrown into camp fires, and are classified as either clastic (free-formed) or in situ (adhered to rock outcrops). Scientists suggest that the more dense plastiglomerates will become a part of the future geological record, though opinions differ on if they will last very long or revert back to oil.
Despite all the changes that humanity has inflicted on the earth, it could be the plastiglomerates the official marker for humankind’s impact on the Earth.
Plastiglomerate found on Kamilo Beach, Hawaii
Source: Patricia Corcoran, University of Western Ontario