Using the Canadian Light Source (CLS) at the University of Saskatchewan and its BMIT-ID beamline, he discovered much larger pores in samples from the Earth’s crust than predicted.
“I expected nanometer-sized pores, whereas I ended up finding pores up to 200 microns — so several orders of magnitudes larger,” said Pujatti, a scientist in the University of Calgary’s Department of Geoscience who recently defended his PhD. “This was very, very puzzling to me.”
Three-dimensional CLS imaging techniques allowed him to see the rocks’ internal structure. There, he found the pores in a mineral called olivine, which is made up largely of silica and magnesium.
As in other geologic systems, he thought the olivine would form new minerals — basically clays — as it dissolved “but I didn’t see that,” he said. “I could only see pores.”
“Finally, I realized the types of fluids that percolated through these rocks were too cold to lead to the formation of new minerals.” The ‘culprit’ was simply sea water.
“Classically, we always consider the oceanic crust as a sink for magnesium,” he said. “Instead, interactions between fluids and these olivine-rich rocks release magnesium.”
Read more on the Canadian Light Source website
Image: Simone Pujatti (right) and Benjamin Tutolo.