What is a glacial moraine?

As a glacier moves, it acts like a giant conveyor belt, scraping up rock, sand, and boulders from the land and carrying this debris along and within the ice. When the glacier melts or retreats, it dumps this material in characteristic piles and ridges called moraines. Different types form in different places: lateral moraines run along the sides of a glacier, medial moraines form where two glaciers merge, and terminal moraines mark the farthest point the glacier reached before retreating. Moraines are important clues for scientists because they reveal how far glaciers once extended and how the climate has changed. Many landscapes shaped by past ice ages are dotted with moraines.