Moraines can be classified either by origin, location with respect to a glacier or former glacier, or by shape.
Lateral moraines , Alberta, Canada. Lateral moraines are parallel ridges of debris deposited along the sides of a glacier. The unconsolidated debris can be deposited on top of the glacier by
frost shattering of the valley walls or from tributary streams flowing into the valley, or may be subglacial debris carried to the surface of the glacier, melted out, and transported to the glacier margin. , Zermatt, Switzerland. The
lateral moraine is the high snow-free bank of debris in the top left hand quarter of the picture. The
medial moraine is the double line of debris running down the centre-line of the glacier. Lateral moraines can rise up to over the valley floor, can be up to long, and are steeper close to the glacier margin (up to 80 degrees) than further away (where slopes are typically 29 to 36 degrees).
Rogen moraines Rogen moraines or ribbed moraines are a type of basal moraines that form a series of ribs perpendicular to the ice flow in an
ice sheet. The depressions between the ribs are sometimes filled with water, making the Rogen moraines look like
tigerstripes on
aerial photographs. Rogen moraines are named after
Lake Rogen in
Härjedalen,
Sweden, the landform's type locality.
de Geer moraines Closely related to Rogen moraines, de Geer moraines are till ridges up to 5 m high and 10–50 m wide running perpendicular to the ice flow. They occur in large groups in low-lying areas. Named for
Gerard De Geer, who first described them in 1889, these moraines may have developed from crevasses underneath the ice sheet.
End or terminal moraines of the Okanogan Lobe. Cascade mountains in the background. End moraines, or
terminal moraines, are ridges of unconsolidated debris deposited at the snout or end of the glacier. They usually reflect the shape of the
glacier's terminus. Glaciers act much like a conveyor belt, carrying debris from the top of the glacier to the bottom where it deposits it in end moraines. End moraine size and shape are determined by whether the glacier is advancing, receding or at equilibrium. The longer the terminus of the glacier stays in one place, the more debris accumulate in the moraine. There are two types of end moraines: terminal and recessional. Terminal moraines mark the maximum advance of the glacier. Recessional moraines are small ridges left as a glacier pauses during its retreat. After a glacier retreats, the end moraine may be destroyed by postglacial erosion.
Recessional moraine Recessional moraines are often observed as a series of transverse ridges running across a valley behind a terminal moraine. They form perpendicular to the lateral moraines that they reside between and are composed of unconsolidated debris deposited by the glacier. They are created during temporary halts in a glacier's retreat.
Arctic push moraines , Grant Land In permafrost areas an advancing glacier may push up thick layers of frozen sediments at its front. An arctic push moraine will then be formed.
Medial moraine ,
Greenland. A medial moraine is a ridge of moraine that runs down the center of a valley floor. It forms when two glaciers meet and the debris on the edges of the adjacent valley sides join and are carried on top of the enlarged glacier. As the glacier melts or retreats, the debris is deposited and a ridge down the middle of the valley floor is created. The
Kaskawulsh Glacier in the
Kluane National Park,
Yukon, has a ridge of medial moraine 1 km wide.
Supraglacial moraines Supraglacial moraines are created by debris accumulated on top of glacial ice. This debris can accumulate due to ice flow toward the surface in the
ablation zone, melting of surface ice or from debris that falls onto the glacier from valley sidewalls.
Washboard moraines Washboard moraines, also known as
minor or
corrugated moraines, are low-amplitude geomorphic features caused by glaciers. They consist of low-relief ridges, in height and around apart, accumulated at the base of the ice as
lodgment till. The name "washboard moraine" refers to the fact that, from the air, it resembles a
washboard.
Veiki moraine A Veiki moraine is a kind of hummocky moraine that forms irregular landscapes of ponds and plateaus surrounded by banks. It forms from the irregular melting of ice covered with a thick layer of debris. Veiki moraine is common in northern
Sweden and parts of
Canada. ==See also==