PERIGLACIAL LANDFORMS IN THE KISILYAKH RIDGE

The Kisilyakh Ridge located in northern Yakutia is a minor ridge in the north-eastern part of the Chersky Range. The ridge is about 100 km long, rising at its highest point to 1726 m. Most of the Kisilyakh Ridge divides the Yana and Adycha drainage basins. The climate is extremely continental, with cold winters, relatively warm summers and low precipitation. Annual precipitation is 180-200 mm, of which 83-134 mm fall in summer. The mean annual air temperature is -15.9°C. The severe climate is responsible for the existence of continuous, cold permafrost, ranging in thickness from 200 to 500 m and in temperature from -6.0°to -10.0°C, as well as for the variety of periglacial features.Kigilyakhs, or tors, occur on summits, protruding up to 30 m.Cryoplanation terraces are found at lower elevations, representing flat surfaces bounded by steep risers up the slope.The final stage of cryoplanation terrace development are tumps, or cryopediplains, representing flat cut summits.On gentle slopes above the treeline, ploughing boulders are encountered, representing granite blocks moving faster than the surrounding slope material.