The lithosphere under stress

I discuss thermal, rheological and compositional definitions of the Earth's lithosphere and describe the data that can be brought to bear in refining these definitions. Models of the behaviour of the lithosphere are useful in describing such diverse effects as continental basin subsidence, the flexu ral response to imposed loads such as seamounts or sediment accumulations, the partial melting of mantle beneath rifts, the composition and geochemica l signature of the melts, and the depths of seismicity. It is generally the case that oceanic lithosphere is simpler to understand than is continental lithosphere, primarily due to its usually younger age and its consistent m ode of formation at mid-ocean ridges.