Abstract

Small scale photography and imagery have provided the means to record a synoptic view of large areas and this information has been used primarily in structural studies. A renewed interest is observed now for the ideas of a possible global or continental basic set of lineaments and the structural control of ore deposits by regularly spaced fracture systems. The procedure which has been used performs optical Fourier analysis of linear features with the objective of presenting them in a manner which provides an accurate determination of their periodicity and a simple synthesis of their spatial distribution.

Analysis of a map of linear features is carried out by means of optical diffraction of the coherent light of a laser beam passing through a transparent reduction of the map. The diffraction pattern obtained in such a way is the two-dimensional Fourier transform of the input material. This diffraction pattern shows quantitatively the occurrence of any periodicity of linear features and their directional distribution. The results of such study can be applied to establish areas with the same tectonic style and point out linear features which indicate the main directions of a tectonic network.

This analytical procedure has been applied to a map of linear features extracted from ERTS imagery of California and an interpretation of the results is offered.