『Abstract
　Cryostratigraphy adopts concepts from both Russian geocryology and modern sedimentology. Structures formed by the amount and distribution of ice within sediment and rock are termed cryostructures. Typically, layered cryostructures are indicative of syngenetic permafrost while reticulate and irregular cryostructures are indicative of epigenetic permafrost. ‘Cryofacies’ can be defined according to patterns of sediment characterized by distinct ice lenses and layers, volumetric ice content and ice-crystal size. Cryofacies can be subdivided according to cryostructure. where a number of cryofacies form a distinctive cryostratigraphic unit, these are termed a ‘cryofacies assemblage’. The recognition, if present, of (i) thaw unconformities, (ii) other ice bodies such as vein ice (ice wedges), aggradational ice and thermokarst-cave (‘pool’) ice, and (iii) ice, sand and gravelly pseudomorphs is also important in determining the nature of the freezing process, the conditions under which frozen sediment accumulates, and the history of permafrost.

Keywords: frozen ground; permafrost; geocryology; Quaternary geology; ground ice; cryostructure』

Contents
1. Introduction
2. Frozen ground
3. Epigenetic, syngenetic and polygenetic permafrost
4. Ground ice
5. Cryostructures in bedrock
6. Cryostructures in poorly-lithified sediments
7. Cryostructures of epigenetic and syngenetic permafrost
8. Thaw unconformities
9. Aggradational ice
10. Cryostratigraphic mapping
11. Ice bodies
12. Ice, sand, and soil pseudomorphs
13. Conclusions
Acknowledgments
References