Cirque Floor Geology

Author s edition boston mass.

Cirque floor geology.

The floor of the cirque ends up bowl shaped as it is the complex convergence zone of combining ice flows from multiple directions and their accompanying rock burdens. True cirque growth only occurs once the thickness of snow patches increases to a point at which glacier ice can form by compaction. Corrie combe cwm 1855 robert browning childe roland to the dark tower came in men and women london. Cirques are bowl shaped amphitheater like depressions that glaciers carve into mountains and valley sidewalls at high elevations.

Hence it experiences somewhat greater erosion forces and is most often overdeepened below the level of the cirque s low side outlet stage and its down slope backstage valley. The granite creek tarn wrangell st. Once formed glaciers widen and deepen cirques by subglacial abrasion and quarrying of the hollow floor and lower headwall 3 see diagram below. Chapman and hall 193 piccadilly oclc 1561924.

Ticknor and fields 1856 oclc 187461130 stanzas 22. Elias national park alaska sits in a classic bowl shaped cirque. Often the glaciers flow up and over the lip of the cirque as gravity drives them downslope. The floor of the cirque is bowl shaped because of the convergence zones of combining ice flows from a different direction and the debris accompanying them.

Cirques subjected to seasonal melting often form small lakes. Circle amphitheatre shaped basin with precipitous walls at the head of a glacial valley it generally results from erosion beneath the bergschrund of a glacier a bergschrund is a large crevasse that lies a short distance from the exposed rock walls and separates the stationary from the moving ice.