Fold Geometry

Abstract

This chapter describes methods for defining the geometry of folded surfaces in three dimensions and methods for projecting data along and within fold trends. Folds can be divided into domains where the shapes are cylindrical or conical, smoothly curved or planar. The geometries within domains are efficiently described in terms of the orientations and properties of fold axes, plunge lines, crest lines and trough lines. The relationship of these elements to bed attitudes has implications for bed thickness changes and the persistence of the folds along their trend.