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Generation of plumes under a localized high viscosity lid in 3‐D spherical shell convection
Author(s) -
Yoshida Masaki,
Iwase Yasuyuki,
Honda Satoru
Publication year - 1999
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/1999gl900147
Subject(s) - plume , prandtl number , convection , rayleigh number , geology , mechanics , geophysics , spherical shell , enceladus , viscosity , lithosphere , natural convection , physics , shell (structure) , materials science , thermodynamics , composite material , paleontology , tectonics , astrobiology
We conduct numerical simulations of incompressible infinite Prandtl number convection in a spherical shell with a single localized high viscosity lid (HVL) on the top surface to understand the possible effects of the continental lithosphere on plume generation. The temperature under the HVL increases rapidly after the emplacement of the HVL on constant viscosity convection with internal and bottom heatings. Later, upwellings at the bottom merge into a large scale flow and a large plume emerges under the HVL. This time‐scale depends on the existence of phase changes. In our model, whose Rayleigh number is 10 6 , the large plume is formed on a time‐scale of 1 Gyr. A simple scaling suggests that this time‐scale may be reduced by a several times, if the Rayleigh number is around 10 7 . Despite the complicated 3‐D thermal structure, it is dominated by an l = 1 pattern controlled by the position of the HVL.