Tectonic structures are produced in rocks in response to stresses generated, for the most part, by plate motion within the Earth, and include different kinds of faults and folds, along with other structures. They make up to tectonics framework of the Earth. The kinds of structures that form in different parts of the crust are determined by:
- prevailing temperature and pressure,
- contrast in properties with direction between and within individual layers (anisotropy) or the lack of contrast (isotropy), and
- amount and character of fluids within the rock mass.
How rapidly the mass is deformed and the orientations of stresses applied to it also influence the kinds of structures produced. These factors determine whether deformation will be: