Polygonal patterns, with dimensions and shapes similar to modern polygons covering extensive parts of the permafrost-dominated land areas of the Arctic and subarctic, exist on the seafloor of the eastern Laptev Sea. The mapped patterns in the Laptev Sea resemble macro-scale frost polygons associated with thermal-contraction cracking of the ground (Lachenbruch 1962). The formation of these permafrost-related landforms probably occurred during the Late Pleistocene when most of the Laptev Sea shelf was sub-aerially exposed and free from ice-sheet cover (Jakobsson et al. 2014). Postglacial sea-level rise transformed these areas from a periglacial permafrost landscape into a modern shallow shelf (Gavrilov et al. 2006).