tundform

Tundform is a geomorphological term used to describe landforms that are characteristic of tundra landscapes, produced by periglacial processes in regions where permafrost is present. The term emphasizes surface forms created by freeze‑thaw cycles, ground ice, and gelifluction in cold, dry climates with limited moisture.

In such environments, soils remain cold enough to support permafrost, and ice segregation concentrates within sediments. Over time, frost action and ice growth deform and relocate material, creating a variety of surface patterns. Ice wedges can form and widen, leading to polygonal ground; frost heave and differential subsidence produce hummocky and hollow relief; and ice-rich cores in certain ridges or mounds can drive the development of pingos.

Common tundforms include ice-wedge polygons and the broader patterned ground that features stone nets and polygonal rings formed by sorting of surface materials; hummocks and hollows that create a checkerboard-like microtopography; and pingos, which are raised, ice-cored mounds that emerge in areas of ongoing permafrost dynamics. The precise morphology depends on local climate, soil properties, groundwater flow, and the presence or absence of liquid water within the permafrost.

Geographically, tundforms are found in Arctic and subarctic regions and in high-elevation tundra worldwide, including parts of North America, Eurasia, Greenland, and some mountainous regions. They are sensitive to climate change, with permafrost degradation and altered freeze-thaw regimes affecting the persistence and appearance of tundform landscapes.