LINGERING QUESTIONS ON VOLATILES,
VOLCANOES, AND THE FUTURE OF
YELLOWSTONE
It now seems quite certain that abundant basaltic magma
intrudes the crust beneath the Yellowstone Caldera, stoking
the fires beneath the silicic magma and flooding the overlying
hydrothermal system with gas. Yet important and
fascinating questions remain. How variable is the surface
gas flux at timescales ranging from daily to millennial? Is it
possible that current emissions result from a temporary
(postglacial?), increased rate of hydrothermal discharge that
reflects shallow hydrothermal processes more than the deep
intrusions discussed above? If so, increased hydrothermal
flow might be cooling the underlying magma and decreasing
the long-term volcanic hazard. It is also possible that
Yellowstone has remained dormant for so long because its
magmas and hydrothermal system are very efficient at
releasing their heat and volatiles, thus preventing buildup
of magmatic pressure. Ultimately, we cannot assess these
issues without greater understanding of the origin, variability,
and significance of measured geochemical fluxes and
their relationship to the geophysical data that have been
collected for decades. Monitoring of heat and volatile flux
is only beginning, but it holds great promise to aid us in
deciphering the signals emitted by Earth’s giant calderas:
someday, that ability may save our lives.