What discriminates loess from other soil types is lack of stratification, as well as uniformity of their particles, which makes them to be easily identified in field. An area of approximately 388,000 hectares of Golestan province in Iran is covered by three types of loess with sedimentology and geotechnical characteristics. A group of geological properties and transfer processes, sedimentation manner, along with physical, mechanical, and chemical characteristics of loess, which control its geotechnical properties, have been considered as engineering geology criteria. Among such criteria, those such as mechanism and distance of transfer, texture, dry density, plasticity properties, void ratio, compressibility, mineral and chemical composition, and structure of loess can be mentioned. Based upon these criteria, properties of loess in three zones have been evaluated and it was indicated that the conditions of geological origin and sedimentation considerably control the geotechnical soil behavior. Structure and skeleton of loess in the three zones were completely different in comparison with each other, which provide a suitable and easy field criterion for recognition.

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