Balanced geological cross-sections: An essential technique in geological research and exploration / Сбалансированные геологические разрезы: важный метод в геологических исследованиях и разведке

The origins of balanced sections lie in the petroleum industry in the 1950's and 19601s, most obviously in Calgary, Canada. The first published balanced sections are those by Bally, Gordy and Stewart 119661 of the Canadian Rockies. The concepts of thrust-terrain structural styles, upon which they are based, have been developing since Peach and Horne's [I9071 classic work on the Moine thrust zone in Scotland. To begin, how can we define a "balanced" section? Dahlstrom [I9691 introduced the concept into the literature and suggested two rules: 1) "A simple test of the geometric validity of a cross-section is to measure bed lengths ... these bed lengths must be consistent unless a discontinuity intervenes ..." and 2) "in a specific geological environment, there is only a limited suite of structures which can exist..." (p.743, 744). Elliott's [I9831 definition was somewhat more restrictive. ". .. the structures drawn on the section are those that can be seen in the area in cliffs, road cuts, mountain sides, etc. The use of these structures leads to an admissible cross-section. Additionally, a restored as well as a deformedstate cross-section should be constructed at the same Fime. If a section can be restored to an unstrained state it is a viable cross-section. By definition, a balanced cross-section is both viable and admissible. . . (p. 101) . <...>