Author: Jessica Leigh Hester / Source: Atlas Obscura
When the Princeton University geologists Akshay Mehra and Adam Maloof, Mehra’s advisor, wanted to learn more about Cloudina—a fossilized organism that lived 545 million years ago—they decided to pulverize it.
As part of their work for a recent study, published in the Proceedings of the National Academy of Sciences, the researchers had collected samples from rocky outcroppings in Namibia and the Canadian Rockies that were once reefs. The haul was varied—the scientists had hacked off pieces of different colors and textures. Back in the lab, “we cut them down, sawed them into blocks, stuck the blocks on a metal plate using some epoxy, and then we just started grinding away,” Mehra says.
Spinning at 3,000 rpm, GIRI (short for the Princeton Grinding Imaging and Reconstruction Instrument) cuts the material into slices just a few microns thick—that’s about one-third as thick as a single strand of hair. A dribble of water-based coolant soothes the friction and flushes the ground material away. As it whirs, the machine captures a high-resolution image, “a recording of what exactly is in the rock, including color and texture information,” Mehra says. The researchers can rotate the image and get a close-up look at how the different structures relate to each other. (Watch a video of a sample from Namibia, above, which shows only the fossil tubes, and no surrounding stone.) When GIRI has chewed its way through the rock, there’s nothing left but finely ground dust.
It might seem startling to knowingly make smithereens out of millions of years…
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