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Published byCamron Webster Modified over 9 years ago
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~1X
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The highest resolution models resolve about 20 discrete LLVAs below the usual LVZ
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Heated from below gives narrow upwellings and broad downwellings. Cooling from the top and internal heating give the opposite. Fig. 11. Numerical simulation of convection in a fluid with viscoelastic rheology and a yield stress showing temperature (top) and the second invariant of stress rate (bottom). For a suitable range of Rayleigh number and yield stress the surface velocity, vx, breaks up into a number of distinct ‘plates’.
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Heated from below gives narrow upwellings and broad downwellings. Cooling from the top and internal heating give the opposite. Fig. 11. Numerical simulation of convection in a fluid with viscoelastic rheology and a yield stress showing temperature (top) and the second invariant of stress rate (bottom). For a suitable range of Rayleigh number and yield stress the surface velocity, vx, breaks up into a number of distinct ‘plates’. Hawaii ridge superswell
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Ridge Related Upwellings Shallow lateral flow (fingers) either away from ridges (ridge centered upwellings) or toward ridges/thin spots (off axis upwellings).
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Cooled from above…
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Low sound speed(?) but dense
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1, Hawaii; 2,Samoa; 3, Marquesas; 4, Tahiti 5, Pitcairn; and 6, Macdonald.
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Hawaii Galapagos Easter
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fingers superswell 42 S.Of Alaska W. Of Calif. -2% +3%
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Downwellings?
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cold warm cool cold Most hotspots, backtracked LIPs & kimberlites fall within the ~ -2% contour surrounding ridges (p=10 -8 ) Harvard In spite of being ‘passive’, ridge-related upwellings are not ambient or ‘representative’ shallow mantle Dziewonski&Ekstrom
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Hawaii Tonga ridge 800
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