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Contents of 11.6 How does strength vary in the lithosphere?

• The significance of composition and crust thickness
• Mantle rock under oceanic crust is probably dry, whereas continental lithospheric mantle contains water and water-bearing minerals. Wetter mantle under continental crust is weaker than drier mantle under oceans.
• Continental crust is thicker than oceanic and experiences higher temperatures that reduce rock strength and enhance plastic flow.
• The wetter continental crust is very weak below ~15 km in contrast to the same depth of dry mantle under oceanic crust at that depth. Continental lithosphere becomes weaker below 12-15 km while oceanic lithosphere becomes stronger until about 40 km.

11.6 How does strength vary in the lithosphere?