Melty magma hints at coming big eruptions

• Autores: Colin Barras
• Localización: New scientist, ISSN 0262-4079, Nº. 2957, 2014, pág. 16
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • Before volcanoes erupt, they must "defrost". The magma beneath some of the most dangerous volcanoes may be relatively cool and solid for most of the time. That means evidence that magma is melting could be a sign of an imminent eruption. To find out, Karl Cooper of the University of California, Davis, studied solidified lavas from Mount Hood, a potentially active volcano in Oregon that last erupted 220 years ago. With Adam Kent of Oregon State University in Corvallis, she isolated crystals from the lava. They were at least 21,000 years old, based on the radioactive decay of uranium, a "clock" that began ticking when they formed. There was far more strontium in the crystals' cores than near their margins. That is odd, because at 750°C, the temperature at which lava begins to melt, strontium would diffuse throughout crystals within a few thousand years. As it hadn't done so, the crystals can have spent no more than 2800 years above 750°C, and maybe just 140 years.