Brown University | 2015 Aug 24
Scientists have found traces of carbon in volcanic glass collected from the Apollo missions to the Moon. The finding may not only explain the driving force behind ancient “fire fountain” eruptions on the Moon but also suggest that some volatile elements on the Moon and Earth have a common origin.
[img3="Volcanic evidence: Super-tiny bits of molten magma became trapped in tiny crystals of olivine, preserving evidence of volatile gasses. Credit: Saal Lab/Brown University"]https://news.brown.edu/files/Moonwater1.jpg[/img3][hr][/hr]Tiny beads of volcanic glass found on the lunar surface during the Apollo missions are a sign that fire fountain eruptions took place on the Moon’s surface. Now, scientists from Brown University and the Carnegie Institution for Science have identified the volatile gas that drove those eruptions.
Fire fountains, a type of eruption that occurs frequently in Hawaii, require the presence of volatiles mixed in with the erupting lava. Volatile compounds turn into gas as the lavas rise from the depths. That expansion of that gas causes lava to blast into the air once it reaches the surface, a bit like taking the lid of a shaken bottle of soda.
“The question for many years was what gas produced these sorts of eruptions on the Moon,” said Alberto Saal, associate professor of earth, environmental, and planetary sciences at Brown and corresponding author of the new research. “The gas is gone, so it hasn’t been easy to figure out.”
The research, published in Nature Geoscience, suggests that lava associated with lunar fire fountains contained significant amounts of carbon. As it rose from the lunar depths, that carbon combined with oxygen to make substantial amounts carbon monoxide (CO) gas. That CO gas was responsible for the fire fountains that sprayed volcanic glass over parts of the lunar surface. ...
Carbon content and degassing history of the lunar volcanic glasses - Diane T. Wetzel et al
- Nature Geoscience (online 24 Aug 2015) DOI: 10.1038/ngeo2511