November 15, 2013
NOTE: BUILDING 34, ROOM W150
GODDARD SPACE FLIGHT CENTER
"Volcanism on Io: Implications for a Subsurface Magma
Jupiter’s moon Io is the most
volcanically active body in the Solar System, with a mean
surface heat flux that is 20 times larger than on the Earth.
However, unlike the Earth, extreme volcanism on Io is primarily
due to the dissipation of tidal energy and not from radiogenic
sources. This study uses the first 1:15,000,000-scale global
geologic map of Io to examine the spatial distribution of its
volcanic systems and test a range of tidal dissipation models.
Results show that clusters of volcanic centers exhibit a
statistically significant 30–60° eastward offset relative to the
patterns of volcanism predicted by currently favored tidal
dissipation models. These models assume that interior heating
within Io occurs primarily in the asthenosphere due to the
deformation of solid mantle material. However, the observed
offset between volcanism and predicted surface heat flux maxima,
raises the possibility that there is a missing component in our
understanding of melt production and/or magma ascent within Io.
One such factor may involve the excitation of fluid tides within
a subsurface “magma ocean” (i.e., an extensive region of
interconnected silicate partial melt). The existence of Io’s
magma ocean is supported by recent re-examination of Galileo
magnetometer data, which provides evidence of an electromagnetic
field induced within a globally continuous magma layer with at
least 20% partial melt and 50 km thickness. If so, fluid tidal
dissipation may help to explain Io’s observed patterns of
volcanism and provide a new insight into the moon’s interior
About the speaker:
Dr. Christopher Hamilton is a Research Associate within the
Planetary Geodynamics Laboratory (Code 698), where he carries
out research focused on planetary volcanology and terrestrial
analog studies. His research focuses on lava flow emplacement,
magma‒water interactions, and the spatial analysis of volcanic
landforms to better understand the geologic history of the Solar
System’s terrestrial planets and moons. Work presented in this
study also includes contributions from Code 698 colleagues, Dr.
Robert Tyler and Dr. Wade Henning.
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