Cryostructures in permafrost Tuktoyaktuk Coastlands, Western Artic Canada

The shape and distribution of ice and sediment within frozen ground constitute its cryostructure. Observations on perennially frozen sediments in the Tuktoyaktuk coastlands enable six cryostructures to be identified: (1) structureless, (2) lenticular, (3) layered, (4) reticulate, (5) crustal, and (6) suspended. These cryostructures can be transitional or composite. Five cryofacies types can also be identified according to volumetric ice content and grain size. They can be grouped into cryofacies assemblages. The utility of the descriptive classification of ice-rich sediments is illustrated from a palaeothaw layer at Crumbling Point.