We continue our study on mountain glacial landforms with the arête.
An arête is formed by two glaciers scouring away rock on two sides of a mountain. The result is a thin ridge of rock which separates two U-Shaped valleys. Weathering further erodes the rock thus shaping and sharpening the feature. Arêtes can also be formed when two cirques erode.
A TARN is a lake created in a cirque by glacial melt water, rain, river runoff or a combination.
Lake Jenny, Lassen National Volcanic Park, California
A cirque is a semicircular shaped bedrock feature high on mountainside partially surrounded on three sides by steep cliffs. Cirques are created by the advancing and retreating of glaciers. The basin becomes deeper and wider in diameter each year as it continues to be eroded. An interesting feature of a cirque is the tarn or glacial lake which results from melting glaciers.
Cirque, Grand Teton, Wyoming
Sometimes multiple cirques will form, the rock in between is an arête, a steep ridge dividing the two cirques. When three cirques form the result is a glacial horn (or pyramidal peak) such as the Matterhorn in the Alps or Irene’s Arête in the Tetons.
Cirques and arêtes, Mount Moran, Wyoming
Photos taken at Grand Teton National Park