HIGH-TEMPERATURE SILICATE VOLCANISM ON JUPITERS MOON IO

Infrared wavelength observations of lo by the Galileo spacecraft show that at Least 12 different vents are erupting lavas that are probably hotter than the highest temperature basaltic eruptions on Earth today. In at least one case, the eruption near Pillan Patera, two independen t instruments on Galileo show that the lava temperature must have exce eded 1700 kelvin and may have reached 2000 kelvin. The most likely exp lanation is that these lavas are ultramafic (magnesium-rich) silicates , and this idea-is supported by the tentative identification of magnes ium-rich orthopyroxene in Lava flows associated with these high-temper ature hot spots.