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Magma Crystals Provide “Amazing Snapshots” of Volcanic Activity

Research shedding light on the internal “plumbing” of volcanoes may help scientists better understand volcanic eruptions and unrest. The study, led by Dr Teresa Ubide of the University of Queensland and published in Geochimica et Cosmochimica Acta (https://goo.gl/wimyRR), analysed crystals in Italy’s famous Mount Etna to reveal how quickly magma moves to the surface.

“By looking at the so-called magma plumbing systems we can better interpret the signs of magma movement under our feet,” Ubide said. “The new information on magma transport prior to past volcanic eruptions can provide context to help better respond to future monitoring signals, like seismic measurements from earthquakes.”

Ubide and her team have analysed variations in the chemical composition of volcanic crystals, which form in a chemical pattern known as sector zoning. “Volcanologists and mineralogists have observed sector zoning in crystals for decades, noticing that it might develop when crystals form rapidly,” she said.

“But because the exact origin and implications of sector-zoned crystals in magma were poorly understood, they were typically disregarded in the study of pre-eruptive processes inside volcanoes. Now we’ve discovered that they not only record detailed magmatic histories and eruption triggers, but might also provide information on the velocity of magma transport to the surface.”

The research used a high-tech ultraviolet laser similar to the technology used for eye surgery to remove a thin layer from the surface of the crystals. A mass spectrometer then measured the composition of trace elements in the sample.

“We found that the changes in the trace elements in these crystals are extremely sensitive to the processes that take place inside volcanoes, like magma storage and cooling, magma mixing, magma transport and magma’s ascent to the surface,” Ubide said. “It’s an amazing snapshot of what is happening inside volcanoes, providing key insights into their internal plumbing system and helping us better understand these incredible natural wonders.”