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Balanced cross sections

A cross section with internally consistent geometry: Concepts of balancing cross sections applies to all kinds of faulting and deformation, but was first developed in thrust systems. Removal of finite strain from deformed rocks can give rise to their shapes in undeformed state. The fig is reproduced after Ramsay and Huber 1987. Morcles nappe, the lowest of the Helvetic nappes is taken as an example and a very simplified method is shown to find the initial shape of the nappe before its collapse under gravity.Balance occurs when bed lengths and cross-sectional area are equal in both deformed and undeformed state (except with volume loss due to consolidation and dissolution.

  • Structures drawn on section should be those observed in outcrop or limited to geologic structures expected in a particular environment.
  • Cross section must be able to be restored to undeformed state. That is, removal of deformation should result in group of undeformed sedimentary rocks with expectable geometry
  • Line-length and area balancing Depth to detachment calculation--an outcome of area balancing. Fault displacement established. Section may be correct