The strength of continental lithosphere: "jelly sandwich" or "crème-brûlé"?

The strength of the continental lithosphere and how it responds to long-term geological loads is a topic of much current interest in the Earth Sciences. Flexure studies suggest a rheological model, dubbed the "jelly sandwich" model, in which the strength of the lithosphere is attributed to both the upper crust and mantle. Studies of the thickness of the seismogenic zone, however, suggest a model, dubbed the "crème-brûlé" model, in which the strength resides in the crust, but that the mantle has no strength. This essay will review the evidence in support of each model and will attempt to reconcile between these fundamentally different views of the mechanical behaviour of the lithosphere.

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Jackson, J., 2002, Strength of the continental lithosphere: Time to abandon the jelly sandwich ?: GSA Today, v. September, p. 4-10.

Lamb. S., 2002, Is it all in the crust ?: Nature, doi:10.1038/420130a, November, No 6912.

Watts, A. B., and E. B. Burov, 2003, Lithospheric strength and its relationship to the elastic and seismogenic thickness: Earth Planet. Sci. Letts., v. 213, p. 113-131.

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