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Lithospheric strength vs TMoho |
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| As any material, the strength of rocks decrease as temperature increases. The graph on the left shows the evolution of the integrated strength of the continental lithosphere as the temperature at the moho (TMoho) increases. This graph shows that when the temperature increases from 500 to 700ºC, the strength decreases by a factor of ~20. |
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This suggests that for similar composition and thickness, the continental lithosphere in the Archaean was much weaker that its modern counterpart. It shows also that abobe ~700ºC the strength does not change much as the TMoho increases. |
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The graph on the left shows two strength profiles for the continental lithosphere. In blue is the kind of strength profile one can get for a modern geotherm (TMoho=540ºC). Modern continental lithosphere have a very strong Sub-Continental Lithospheric Mantle (SCLM). In red is the strengh profile obtained for a warmer geotherm with TMoho=~700ºC. The strongest layer as now disappeared and the stronger layer of the continental lithosphere is the upper crust.
The strength of the continental lithosphere depends so much on the temperature at the Moho (TMoho) that the Moho temperature can be used as a proxy for the lithospheric strength.
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