Earth's Mantle
				
Earth's mantle, the region of solid but viscously deformable rock between the
surface and a depth of approximately 3000 km, is vigorously convecting.  The
most obvious surface manifestations of convection are subduction zones and
seafloor spreading.  This figure examines the development of a mantle plume,
a concentrated area of hot upwelling material believed to be responsible for
hotspots such as the Hawaiian island chain.

This three-dimensional numerical model tracks the development of thermal
instabilities at the base of an already convecting mantle and the interaction
of the resulting plume with the larger scale mantle circulation associated
with plate tectonics.  In the calculation depicted, we capture the three-
dimensional nature of assumed whole-mantle convection but simplify the
geometry using a rectangular box with stress-free an insulating side
boundaries.  The calculation is visualized with two semi-transparent surfaces
of constant temperature (red, hot; blue, cold) and two slices, one vertical
and one horizontal, where color varies according to the temperature of the
slice.

The image was produced using the interactive graphics package Advanced Visual
Systems (AVS) at Los Alamos National National Laboratory, Institute of
Geophysics and Planetary Physics (IGPP).


Acknowledgements:
	C.W. Gable, LANL, IGPP
	C. Kincaid, U. Rhode Island
	S. Sacks, Carnegie Inst. Of Washington