Types Of Glaciers
Ice sheets- They are only found in Antarctica and Greenland, ice sheets are enormous masses of glacial ice and snow expanding over 50,000 square kilometres. The ice sheet on Antarctica is over 4200 meters thick in some places, which cover nearly all land areas.
Ice shelves- They happen when ice sheets extend over the sea, and float on the water. Their thickness ranges from 200 meters to over 1000 meters. Ice shelves surround most of the Antarctic continent.
Ice caps- They are miniature ice sheets, covering less than 50,000 square kilometres.
Ice Streams and Outlet Glaciers- They are channelized glaciers that flow more rapidly than the surrounding body of ice.
Ice Fields- Ice fields are similar to ice caps, except that their flow is influenced by the underlying topography, and they are typically smaller than ice caps.
Mountain Glaciers- These glaciers develop in high mountain regions, often flowing out of ice fields that span several peaks or even a mountain range. The largest mountain glaciers are found in Arctic Canada, Alaska, the Andes in South America, the Himalayas in Asia, and on Antarctica.
Valley Glaciers- It commonly origins from mountain glaciers or ice fields, these glaciers spill down valleys they look much like giant tongues. Valley glaciers may be very long, often flowing down beyond the snow line and sometimes reaching sea level.
Piedmont Glaciers- They occur when steep valley glaciers spill into flat plains, where they spread out.
Cirque Glaciers- They are found high on mountainsides and tend to be wide rather than long.
Hanging Glaciers- These glaciers cling to steep mountainsides. Like cirque glaciers, they are wider than they are long. Hanging glaciers are common in the Alps, where they often cause avalanches due to the steep inclines they have.
Tidewater Glaciers- They are valley glaciers that flow far enough to reach out into the sea.
How Glaciers Affect Land?
Glaciers don’t just transport material as they move, but they also sculpt and carve away the land beneath them. A glacier's weight, combined with its movement, can drastically reshape the landscape. Over hundreds or even thousands of years, the ice changes the landscape. The ice erodes the land surface and carries the broken rocks and soil far from their original places, which results with glacial landforms.
Cirques are created when glaciers erode backwards, into the mountainside, creating rounded hollows shapes like a shallow bowls.
Aretes are jagged, narrow ridges created where the back walls of two cirque glaciers meet, eroding the ridge on both sides.
Horns are created when several cirque glaciers erode a mountain until all that is left is a steep, pointed peak with sharp, ridge like aretes leading up to the top.
Fjords are long, narrow coastal valleys that were originally carved out by glaciers. They have steep sides and rounded bottoms. Because of glacial erosion on the below sea level land surface, when glaciers finally disappear, sea water covers the valley floor.
Fjords, glaciated valleys, and horns are all erosion types of landforms, created when a glacier cuts away at the landscape. Another type of glacial landform is created by deposition, or what a glacier leaves as it retreats or melts away.
Till is material that is deposited as glaciers retreat, leaving behind mounds of gravel, small rocks, sand and mud. It is made from the rock and soil ground up beneath the glacier as it moves.
Material a glacier picks up or pushes as it moves forms moraines along the surface and sides of the glacier. As a glacier retreats, the ice melts away from underneath the moraines, so they leave long, narrow ridges that show where the glacier used to be. Glaciers don't always leave moraines behind; because sometimes the glaciers own melt water carries the material away.
Streams flowing from glaciers often carry some of the rock and soil debris out with them. These streams deposit the debris as they flow.
Kettle lakes form when a piece of glacier ice breaks off and becomes buried by glacial till or moraine deposits. Over time the ice melts, leaving a small depression in the land, filled with water.
Glaciers leave behind anything they pick up along the way, and sometimes this includes huge rocks.
Drumlins are long, tear drop shaped sedimentary formations. What caused drumlin to form is poorly understood, but scientists believe that they were created sub glacially as the ice sheets moved across the landscape during the various ice ages. Theories suggest that drumlins might have been formed as glaciers scraped up sediment from the underlying ground surface, or from erosion or deposition of sediment by glacial melt water, or some combination of these processes. Because the till, sand and gravel that form drumlins, are deposited and shaped by glacier movement, all drumlins created by a particular glacier face the same direction, running parallel to the glacier's flow.
