Go Back



In any profile of a fold, the shape is that of a partial or semicircular or semielliptical cone. Such folds are noncylindrical since none of the folded surfaces contains a straight line parallel to the fold hinge. The fold dies out when traced along the hinge.

  • fold surface reconstructed by rotating one line about another.
  • cone axis and apical angle are important descriptors.
  • change in serial cross sections (smaller amplitude).
    as apical angle approaches 0 the fold form approaches cylindrical.
  • these folds die out along their length. - nonplanar strain.
  • often a good approximation of the end of doubly plunging fold
  • small circle girdle of poles on a stereonet.