The Techniques of Modern Structural Geology. Volume 1: Strain Analysis / Методы современной структурной геологии. Том 1: Анализ деформаций

Structural geology, a branch of earth science, has leapt ahead over the past decade. This rapid development has come about for several reasons. First has been the realization that naturally deformed rocks seen in field outcrops contain a fantastic range of small scale features which relate directly to large-scale orogenic deformation systems. No longer is it wise for the geologist interested in largescale crustal structure to write off such small-scale features as trivia. It has become clear today that the understanding and interpretation of these geometric features enables the investigator to build up a much more comprehensive understanding of the subtle but very important features of an orogenic zone. The field structural geologist with a developed “eye” for these features can often work over large areas to much more effect than was possible in the past. No longer is it adequate to determine the fold trends, or to map a structural lineament, or even to realize that here we have a suture between two moving continental masses. Today we can and should go much further—we can use our studies of strain state to say exactly how much deformation and how much displacement have occurred. When we have made an assessment of the overall strain pattern of a region we are in a good position to say what the relative movement directions between large and small sections of the crust were, whether the great bends in the major orogenic zones of the earth for example are primary features, or result from secondary bowing of a previously rectilinear zone. <...>