Lateral moraine
Topic: Landforms and their Evolution: Rivers, Groundwater, Glaciers, Waves and Wind · NCERT: Class 11, Ch 6 "Landforms and their Evolution"
Meaning
A lateral moraine is a ridge of glacial till along the side of a glacial valley. It runs parallel to the glacier. Frost and weathering break rock off the valley walls, and it falls onto the edges of the moving ice. The glacier carries this debris along its sides. As the ice melts, it leaves the debris behind as long ridges, one on each side. Lateral moraines may curve round at the glacier's end and join the terminal moraine in a horseshoe shape. They show how wide and thick the glacier once was.
Example
The Gangotri glacier in Uttarakhand has high lateral moraine ridges along both sides of its valley. They stand well above today's shrinking ice, which shows how much the glacier has thinned.
Don't confuse with
- Medial moraine: a medial moraine runs down the middle of a valley where two glaciers merge. A lateral moraine lies along the valley's sides.
- Terminal moraine: a terminal moraine lies across the valley at the glacier's snout. A lateral moraine runs along its length.