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Glacial deposition
landforms -
Moraines
- Lateral moraines
- Ridge of till running along
edge of glacial valley,
orientated parallel to direction
of ice flow
- Example at Athabasca
Glacier 1.5km long and
124m high
- Material which has been frost shattered from the exposed valley
sides above the level of ice, falls onto the sides of the glacier by
rockfall and accumulates on top of ice.
- As glacier retreats the material is
gradually lowered and deposited
on ground at sides of valley.
- As glacier retreats the material is
gradually lowered and deposited
on ground at sides of valley.
- Ridge of till running along
edge of glacial valley,
orientated parallel to direction
of ice flow
- Medial moraine
- Found on the floor of previously glacial valley.
These features are aligned with the direction of
ice movement
- Length 1-20km width 50-100m
- Formed where two glaciers meet where the
lateral moraines (debris on edges) of two
adjacent valley sides converge and is then
carried on top of middle of enlarged glacier.
- Consists of angular and poorly sorted materials.
- Found on the floor of previously glacial valley.
These features are aligned with the direction of
ice movement
- Terminal moraines
- A ridge of material
stretching across glacial
valley at the farthest
extent of the ice
- Elongated at right angles to direction of
ice advance. Usually steep sided,
particularly ice contact side
- Angular and poorly sorted material
- Width 20-500m
- Often crescent shaped, moulded to form of snout
- Crescent shape due to position of snout-
the centre of glacier advances further as
friction with the valley side causes more
rapid melting at the sides.
- Steeper up-valley side is result of the
behind supporting deposits making
them less likely to collapse
- Steeper up-valley side is result of the
behind supporting deposits making
them less likely to collapse
- A ridge of material
stretching across glacial
valley at the farthest
extent of the ice
- Recessional moraines
- Series of ridges of material that are parallel to
each other and to the terminal moraine, found up
valley of the terminal moraine. Rarely greater
than 100m in height
- Form during standstill in glacier's
retreat when material is deposited in
front of re-positioned snout.
- Size of the ridge is dependent on the pause of the glacier.
- For significant ridges to develop there needs to be
long pause in glacier movement, hence seldom
greater than 100m
- For significant ridges to develop there needs to be
long pause in glacier movement, hence seldom
greater than 100m
- Size of the ridge is dependent on the pause of the glacier.
- Series of ridges of material that are parallel to
each other and to the terminal moraine, found up
valley of the terminal moraine. Rarely greater
than 100m in height
- Push moraine
- Same outward appearance
as terminal or recessional
moraine but stones in till
tilted upwards
- Formed during ice
advancement, pushing
previous moraine deposits
such as terminal/recessional
moraines forward in front of
snout and pushes stones up
- Faster the advance, the greater the angle of tilt of the orientation of the stones
- Same outward appearance
as terminal or recessional
moraine but stones in till
tilted upwards
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