about: the geological formation

A glacier is a large, slow-moving mass of ice, formed from compacted layers of snow, that slowly deforms and flows in response to gravity and high pressure. The word glacier comes from French via the Vulgar Latin glacia, and ultimately from Latin glacies meaning ice.

Glacier ice is the largest reservoir of fresh water on Earth, and second only to oceans as the largest reservoir of total water. Glaciers cover vast areas of the polar regions and are found in mountain ranges of every continent except Australia, although there are glaciers on New Zealand. In the tropics glaciers are restricted to the highest mountains. The processes and landforms caused by glaciers and related to them are referred to as glacial. The process of glacier growth and establishment is called glaciation. Glaciers are sensitive monitors of climate conditions and are crucial to both world water resources and sea level variation.

Types of glaciers

main: Glacier morphology

Ice sheets are the largest glaciers, enormous masses of ice that are not visibly affected by the landscape and that cover the entire surface beneath them, except possibly on the margins where they are thinnest. Antarctica and Greenland are the only places where continental ice sheets currently exist. These regions contain vast quantities of fresh water. The volume of ice is so large that if the Greenland ice sheet melted, it would cause sea levels to rise some six meters (20 ft) all around the world. If the Antarctic ice sheet melted, sea levels would rise up to 65 meters (210 ft). Ice shelves are areas of floating ice, commonly located at the margin of an ice sheet. As a result they are thinner, have limited slopes and reduced velocities.* Ice streams are fast moving sections of an ice sheet.. They can be several hundred kilometers long. Ice streams have narrow margins and either side ice flow is usually an order of magnitude less. In Antarctica many ice streams drain into large ice shelves. Although some drain directly into the sea, often with an ice tongue, e.g. Mertz Glacier. In Greenland and Antarctica ice streams ending at the sea are often referred to as tidewater glaciers or outlet glaciers, such as Jakobshavn Isbræ ( ).