jäämuodot

Jäämuodot refers to the various landforms created by the action of ice, primarily glaciers and ice sheets. These geological features are shaped by processes such as erosion, transportation, and deposition of glacial material.

Glacial erosion carves out distinct landforms. Cirques, which are bowl-shaped depressions, are formed at the head of a glacier. As glaciers move down valleys, they widen and deepen them, creating U-shaped valleys. Arêtes are sharp, knife-edge ridges that form between two adjacent cirques or glacial valleys. Horns, such as the Matterhorn, are pointed mountain peaks that are sculpted by the erosive action of multiple glaciers. Fjords are long, narrow inlets with steep sides, formed when glaciers carve out valleys that are later flooded by the sea.

Glacial transportation moves vast amounts of rock and sediment, known as till. Deposition of this till creates a variety of landforms. Moraines are ridges of till deposited at the edges or the snout of a glacier. Terminal moraines mark the furthest extent of a glacier's advance, while lateral moraines form along the sides. Drumlins are elongated hills, often teardrop-shaped, formed by glacial ice overriding and reshaping deposited till. Eskers are long, winding ridges of sand and gravel deposited by meltwater streams flowing within or beneath a glacier. Kettle lakes are depressions formed when blocks of ice melt after being buried in glacial till.

The study of jäämuodot is crucial for understanding past climates and glacial history, as well as for landscape evolution.