| Popis: |
Knowledge of the crustal structure is the key for understanding physical and chemical conditions of its formation and later modification by geodynamic processes. It has long been recognized that crustal structure is controlled by tectonic settings, and that the crustal thickness is one of the most important parameters that reflects the geodynamic origin of the crust. A long tectonic life of continental crust leads to its significant reworking by plate tectonics processes and crust-mantle interaction, which include mechanical extension, delamination, relamination, magmatic intra- and underplating, metamorphic reactions, sedimentation and erosion. As result, thickness of the entire crust and thicknesses of its internal layers may change significantly. In extreme cases some crustal layers can be entirely missing, as for example in the Variscan Western Europe where the lower crust is nearly absent. |
