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Generation of long wavelength heterogeneity in the mantle by the dynamic interaction between plates and convection
Author(s) -
Gurnis Michael,
Zhong Shijie
Publication year - 1991
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 - 10.1029/91gl00823
Subject(s) - plume , convection , geology , geophysics , thermal , mechanics , harmonics , wavelength , mantle convection , shear (geology) , wavenumber , mantle (geology) , physics , optics , seismology , subduction , meteorology , petrology , quantum mechanics , voltage , tectonics
Lateral variations in seismic velocity (through its dependence on temperature) can easily be generated at the gravest harmonics, including degrees one and two, by the dynamic interaction between plates and convection. Models of thermal convection with a single non‐subducting plate have been formulated in a cylindrical geometry. Plates of width one to four times times the thickness of the convecting region strongly modulate the flow by being pushed over cold downwellings and inhibiting cooling of the fluid beneath. During rapid motion off of hot regions, a large‐scale pattern of shear is developed causing small uprising limbs to be swept into the largest upwellings. Both insulation and plume‐plume collisions pump energy into the lower wavenumber harmonics.