News – Kamchatka, a remote peninsula in northeastern Russia just across the Bering Ocean from Alaska, is sparsely populated by an impressive population of brown bears and the world’s most erupting volcano.
There have been more than 40 brutal eruptions in the Kamchatka Shiveluch volcano over the past 10,000 years. The last gigantic explosion occurred in 1964, creating a new crack and covering an area of nearly 100 square kilometers with pyroclastic currents. But Shiveluch is definitely exploding, as it has been for more than 20 years. So why would anyone be in danger of getting too close?
Researchers from the University of Washington at St. Louis, including Michael Krawczynski, assistant professor of earth and planetary sciences in Arts & Sciences and graduate student Andrea Goltz, reassures Kamchatka of the difficult circumstances because by understanding what makes Shiveluch tick scientists could understand the earth’s water cycle and get insights into the plumbing systems of other volcanoes.
In a recent study published in the journal Contributions to Mineralogy and Petrology, researchers from the Krawczynski laboratory looked at small nodules of erupted and preserved primitive magma among other materials.
“The minerals in these nodules bear names for what happened early in the magma evolution, deep in the Earth’s crust,” said Goltz, the paper’s lead author.
The researchers found that the conditions inside Shiveluch contain about 10% -14% water by weight (wt%). Most volcanoes contain less than 1% water. For subduction zone volcanoes, the average is usually 4%, rarely higher than 8 wt%, which is considered superhydrous.
Of particular interest is a mineral called amphibole, which acts as a substitute or fingerprint for high water content at known temperatures and pressures. The special chemistry of the mine tells researchers how much water is deep beneath Shiveluch.
“When you change the chemistry of these two minerals, amphibole and olivine, to the temperature and water content as we do in this paper, the results are amazing both in terms of the amount of water and so on. low and that temperature we are recording, ”Krawczynski said.
“The only way to get prime, pristine products at low temperatures is to add a lot of water,” he said. “Adding water to a rock has the same effect as adding salt to ice; you reduce the melting point. In this case, there is so much water that the temperature is reduced to a point where amphibians can crystallize. ”
Read more on the Department of Earth and Planning Sciences website