| Rheological profile of the continental lithosphere | ||||||
| The continental crust displays a wide range of compositional variation from mafic rocks (gabbros, amphibolites) to quartz dominated composition (granites). This contrast with the relative homogeneity the mantle (peridotite with 60%<olivine<95%). The figure on the right illustrates the dependence of the rheology of the lithosphere on its composition. All rheological profiles involve the same geotherm with a temperature at the Moho of 540ºC (dashed line TMoho = 600ºC). Depending of the composition and the rheological parameters the integrated strength in contraction of the continental lithosphere varies over one order of magnitude from 790 MPa down to 78MPa. In extension the integrated strength ranges from 255 MPa down to 50 MPa. The large variability of the rheological properties of common crustal and mantellic rocks, prevents the definition of a standard rheology for the continental lithosphere. |
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