MICHAEL MANGA: Recent Refereed Publications
Abstracts
Jellinek, A.M, A. Lenardic, and M. Manga (2002)
The influence of interior mantle temperature on the structure of plumes:
Heads for Venus, Tails for the Earth
Geophysical Research Letters, vol. 29, paper number
10.1029/2001GL014624.
Abstract:
To form mantle plumes with large heads and narrow trailing conduits requires
large (factor >102) viscosity variations within the hot thermal boundary
layer at the plume source. However, if a layer of fluid with a
temperature-dependent viscosity is heated from below and cooled from above,
convection occurs beneath a stagnant lid, and the interior fluid temperature
remains close to that of the hot boundary. Consequently, under conditions
of thermal equilibrium the viscosity reduction across the hot thermal
boundary layer is only around a factor of 3. Subduction of the stagnant
layer (equivalent to recycling lithospheric plates on the Earth) will cool
the interior of the mantle, thus increasing the viscosity ratio. Hence, the
existence of Earth-like mantle plumes may be a consequence of plate
tectonics. An absence of plate tectonics on Venus may lead to a flow
composed of discrete plumes, the surface expression of which are coronae, as
well as a relatively smaller core heat flux.
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