COMPILATION OF SOIL SALINITY MAPS FROM GEOBOTANICAL DATA

Abstract

This paper covers not only the use of vegetation for compiling soil salinity maps, but indicates that soil salinity and vegetation anamolies may lead to discoveries of oil- and gas-bearing structures. In map compilation, the author stresses the need for correlating studies of various plant associations with borehole samples. The usual method was to take samples from the bottom of the borehole, from the root horizon and from overlying horizons. The importance of defining the type of soil salinity (sulfate, chloride or sulfate chloride and also type of chloride) is emphasized. Examples are given where aerial observations of the vegetation led to further fruitful investigations. In closed basins, sulfate salts tend to be concentrated on the perimeter, chlorides at the bottom. Conditions contrary to this warrant investigation. In the Malyy Uzen region, for instance, growth of halophytes on an anticlinal structure, where drainage would be expected to create a low level of chloride salinite, led to the discovery of subsurface salt structures. On the Mangyshlak peninsula, an extensive system of faults was located by a chain of mounds of halophytic vegetation which followed one of the faults of the area. --A. Eustus.