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A terminal moraine, also called an end moraine, is a type of moraine that forms at the Glacier terminus (edge) of a glacier, marking its maximum advance. At this point, debris that has accumulated by plucking and abrasion, has been pushed by the front edge of the ice, is driven no further and instead is deposited in an unsorted pile of sediment. Because the glacier acts very much like a conveyor belt, the longer it stays in one place, the greater the amount of material that will be deposited. The moraine is left as the marking point of the terminal extent of the ice.
are formed when a glacier retreats from a previously deposited terminal moraine, only to push proglacial sediment or till into an existing terminal moraine. This process can make the existing terminal moraine far larger than its previous size.
Dump moraines occur when rock, sediment, and debris, which accumulate at the top surface of the glacier, either slide, fall, or flow off of the Glacier terminus of the glacier. The accumulation of till will form a terminal moraine as the glacier retreats.
Ablation moraines form when a large piece of ice, containing an accumulation of sediment and debris, breaks from the snout of the glacial. Once it is separated and begins to melt, the debris found throughout this glacial piece is deposited to form a new terminal moraine. The more debris that is found within the ice, the longer it will take for complete melting to occur.
Climate plays an important role in the formation of terminal moraines. As temperatures increase, glaciers begin to retreat faster, causing more glacial till to be deposited in the form of terminal moraines. However, when temperatures decrease, zone of accumulation goes into overdrive. This starts a process where the accumulation of snow, in the zone of accumulation is greater than loss due to melting or ablation.
Rocks and sediment not native to one area could be found in a region completely foreign to that from which they were formed. This is the result of a prior terminal moraine being picked up and deposited by a newer glacial event. The terminal moraines resulting from the Last Glacial Maximum are the most informational features about glacial advance still present today.
Another landscape feature formed by terminal moraines are kettle lakes. These are produced during glacial recession when Boulder or blocks of ice are left in place as the glacier recedes from the newly deposited terminal moraine. As the ice boulders melt, they begin to pool to form kettle lakes in the glacial outwash plain.
In North America, the Outer Lands is a name given to the terminal moraine archipelago of the northeastern region of the United States (Cape Cod, Martha's Vineyard, Nantucket, Block Island and Long Island). According to geologist George Frederick Wright some of the most prominent examples of terminal moraines on Long Island are "the most remarkable in the world". Other prominent examples of terminal moraines are the Tinley Moraine and the Valparaiso Moraine, perhaps the best examples of terminal moraines in North America. These moraines are most clearly seen southwest of Chicago.
In Europe, virtually all the terrain in the central Netherlands is made up of an extended terminal moraine. In Switzerland, alpine terminal moraines can be found, one striking example being the moraine at the end of the valley of the Forno Glacier in the south-eastern canton of Graubünden near St. Moritz and the Italian border.
In New Zealand the Franz Josef Glacier on the West Coast has created the terminal moraine called the Waiho Loop.
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