Landforms. In the Tuktoyaktuk Peninsula region the landscape is for the most part low, rarely rising higher than 60 metres above sea level. Approximately 30% of the land area in the Tuktoyaktuk region is covered by lakes. The flat low hummocky topography of the Landmark is only interrupted by the presence of the pingos, and the Peninsula Point bluffs. In permafrost regions, a zone of unfrozen sediments is located under most lakes. In the Tuktoyaktuk peninsula there are unfrozen sediments under every lake in which the water depth is greater than the winter ice thickness. Pingos form when a lake drains and the water’s insulating effect is removed and the lake sediments begin to freeze from the surface down. It is the expansion of this ice core which is believed to cause the upheaval of pingos. As the ice core grows, the pingo also grows in height and diameter until the overlying frozen sediments crack under the pressure. Once the summit of a pingo ruptures, the ice core is exposed to melting and the pingo begins to decay. Eventually all that remains of a decayed pingo is a crater lake. The time frame involved in the entire life cycle of a pingo is difficult to establish because of the interaction of many different processes. However, given that Ibyuk Pingo is approximately 1200 years old and on the verge of rupture, a maximum age of between 1000 and 2000 years may represent an approximate time frame.
