Density Profile:
The density (in kg/m3) profile of the continental lithosphere depends mainly on the mineralogical composition of lithospheric material and also the geotherm since the density of rocks changes with temperature:
Continental crust: 2650-2900 kg/m3.
Oceanic crust: 2900-3000 kg/m3
Mantle: density about ~3370 kg/m3.
The average density of the lithosphere depends on the relative thickness of both the crustal and mantle layers.
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In the crust the density of rocks increases with depth because the rock composition evolves form felsic (lots of quartz and plagioclase: e.g. granites), to mafic (lots of amphibole, pyroxene, garnet: e.g. gabbros). In the lithospheric mantle (pale green), the density decreases through depth because of increasing temperature. |
