CONICAL FOLDS
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.
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