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1/  Mountain belts have high topography because they involve the thickening of the continental crust, and therefore a drop in the average density of the continental lithosphere.

2/ MORs have a high elevation because isostasy is acting on an extremely attenuated oceanic lithosphere.  The maximum elevation for a MOR is the neutral buoyant level of the asthenosphere.

3/ The B&R province has a high elevation because isostasy is acting on an extremely attenuated continental lithosphere.

4/ Tibet formed following the collision between the Indian-Australian plate with the Eurasian plate.

5/ The Altiplano results from the subduction of the Nazca plate underneath the South Amerian plate.

6/ The average elevation of Tibet is nearly 5000 m.

7/ Collision between the Indian-Autralian plate and the Eurasian plate started about 50 Ma ago.

8/ Transform faults and overlapping spreading centres are the two major discontinuities affecting MORs.

9/ The stress ellipsoid characterises the state of stress acting on a material point.

10/ σ1 is the longest axis of the stress ellipsoid.  

 11/ When the state of stress is homogeneous (=hydrostatic), σ1=σ2=σ3 and the stress ellipsoid is a sphere.

12/  A non-homogeneous state of stress has two components: hydrostatic and deviatoric.

13/ Deformation results from the deviatoric component of the stress ellipsoid.

14/ The three main tectonic regimes are: contraction, extension, and transcurrent.

15/ Contraction: σ3 vertical.
Extension: σ1 vertical.
Transcurrent: σ2 vertical.

16/ Ridge Push and Slab Pull are the two main forces driving the displacement of plates.

17/ The large variability in tectonic regimes in the western US can be explained by the interference between plate tectonic forces acting on the western margin of the North American plate, and gravitational forces related to lateral variations in gravitational potential energy.

18/ A linear relationship between stress and strain characterises elastic deformation.

19/ Elastic deformation is recoverable, plastic deformation is permanent.

20/ The yield point is the treshold beyond which the relationship between stress and strain is no longer linear.