Dirt cone

Sand cone, sometimes called glaciers, ice or melting cones, are a phenomenon on the surface of some glaciers. Often the existing ice and covered with a layer of sand structures of circular cross-section and have, depending on the development stage of a pronounced peak. The cones reach in the Alps a height of 1-5 m, rarely to 10 m. From Iceland have been reports of up to 30 m in front of high sand cone.

Formation

Prerequisite for the formation of a sand cone is initially the existence of a glacial mill, which has been partially filled with sand (stage A). This has typically been registered by superficial glacial melt water.

By the summer melting and evaporation of the ice, the glacier surface is lowered. Here, the sand in the uppermost glacier mill slips off the side and forms a cluster ( stage B).

The sand pile has against the sunlight shielding and insulating effect. As a result, the ice melts beneath the sand pile slower than all around, so that the surface of the ice ring lowers faster to the sand pile as under the cluster itself (stage C).

When the ice cylinder continues to grow under the pile of sand by lowering its environment, lack of its sides, the insulating effect of the sand. When it begins to melt from its upper edges forth, its shape is transformed into a truncated cone (stage D), the sides of which are covered by herabrutschendem sand.

This process continues until the frustum has become a cone (stage E). This stage is more stable because of the cone of sand again isolated from melting. The slope of the cone is typically 40 °, the thickness of the coating sand 1-30 cm, 100 cm and more rare.

Typically comes and goes a sand cone in the course of a summer. However, larger can survive two to three summers.