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.
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.
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
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
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