The techniques of modern structural geology. Volume 2. Folds and fractures / Методы современной структурной геологии. Выпуск 2. Складки и нарушения

After a general introduction to folding this session considers what special terms are required to describe the geometric features of folds: first those terms necessary to define features of a single folded surface, then those which describe the geometric relationships of adjacent folded layers. Special techniques to describe curvature variations based on harmonic—or Fourier—analyses are recommended and it is shown how this type of analysis is practical both for general descriptive purposes as well as for very exact analysis. The relationships of small wavelength folds in polyharmonic folds are described and practical ways of recording changing fold symmetry discussed.