What term describes a large mass of ice that moves over land due to gravity?

A continental glacier refers to a massive body of ice that flows over land and is primarily driven by gravity. These glaciers cover vast areas, often extending over 50,000 square kilometers, and are found mainly in polar regions, such as Antarctica and Greenland. The immense weight and thickness of a continental glacier cause it to flow outward from its center, reshaping the landscape beneath it through erosion and deposition processes.

This term is distinct from others; for example, a valley glacier, while also a type of glacier, specifically flows down a mountain valley rather than across large expanses of land. A caldera is a large depression formed when a volcano erupts and collapses, and a laccolith is a type of igneous intrusion that causes the overlying rock layers to bulge upward. Understanding these differences highlights why continental glacier is the correct answer, as it specifically pertains to large ice masses moving across land.