Glacial Depositional Landforms

en glacial meaning

material buried within glacier

supra glacial meaning

material on surface

sub glacial

material at base

where does deposition usually occur

at snout due to meltwater and when glacier slows down

till meaning

material deposited directly by glacier

characteristics of glacial dep. till

unsorted mix

shows passage of ice

large and angular due to uneroded

lodgement till meaning

subglacial material deposited by actively moving glacier

ablation till meaning

at snout when ice melts

features of moraines

lines/ series of mounds of material

elongated at right angles to direction of ice advance

crescent shaped

lateral moraines

build up of sediment at edge of glacier against of valley wall

push moraines

previously deposited moraine shunt forward

recessional moraines

formed during glacial retreat, creates marking point

terminal/end moraines

found at snout of glacier- furthest point down valley when ice melts during snout sandstill

temporal changes to moraines

last a medium amount of time- can be displaced through retreat (not terminal ones though) or weathering

drumlins characteristics

formed of till- bigger than rouche mountonnees

steeper upstream end

elongated in direction of advance

formation of drumlins

ice shapes pre existing glacial drift landscape

moving glacier deposits round nucleus of uneven ground- swarms

ice overloaded with sediment- deposits and elongated with ice movement

temporal changes to drumlins

last a long time- vegetation can grow on them so can be unnoticed especially due to size

erratics characteristics and formation

boulder different to bedrock sitting in

transported and deposited by glacier

indicators of patterns of former ice flow

erratics temporal change

last a long time due to size- cannot be displaced

till plains formation and characteristics

terminal moraines

wide areas and flat relief

underlying bedrock covered by till

material compact so poorly drained and leads to lakes etc

temporal changes to till plains

last a medium amount of time- can be disrupted by meltwater/ weathering/ periglacial features but usually large enough to remain

where can you find these these in the world

switzerland

ireland

canada

us

where can you find moraines

switzerland- Zermatt

where can you find drumlins

Ireland- Clew Bay

where can you find erratics

Canada- Okotoks

where can you find till plains

midwest us eg ohio