May 26, 2011
NASA-FUNDED SCIENTISTS MAKE LUNAR WATERSHED DISCOVERY
MOFFETT FIELD, Calif. -- A team of NASA-funded researchers has
measured for the first time water from the moon in the form of tiny
globules of molten rock, which have turned to glass-like material
trapped within crystals. Data from these newly-discovered lunar melt
inclusions indicate the water content of lunar magma is 100 times
higher than previous studies suggested.
The inclusions were found in lunar sample 74220, the famous
high-titanium "orange glass soil" of volcanic origin collected during
the Apollo 17 mission in 1972. The scientific team used a
state-of-the-art ion microprobe instrument to measure the water
content of the inclusions, which were formed during explosive
eruptions on the moon approximately 3.7 billion years ago.
The results published in the May 26 issue of Science Express raise
questions about aspects of the "giant impact theory" of how the moon
was created. That theory predicted very low water content of lunar
rock due to catastrophic degassing during the collision of Earth with
a Mars-sized body very early in its history.
The study also provides additional scientific justification for
returning similar samples from other planetary bodies in the solar
"Water plays a critical role in determining the tectonic behavior of
planetary surfaces, the melting point of planetary interiors and the
location and eruptive style of planetary volcanoes," said Erik Hauri,
a geochemist with the Carnegie Institution of Washington and lead
author of the study. "I can conceive of no sample type that would be
more important to return to Earth than these volcanic glass samples
ejected by explosive volcanism, which have been mapped not only on
the moon but throughout the inner solar system."
In contrast to most volcanic deposits, the lunar melt inclusions are
encased in crystals that prevent the escape of water and other
volatiles during eruption.