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| Geology 370: Glacial Geology
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Home | Announcements
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| Lecture Notes | Grades
| Till types:
basal till: lodgment till or subglacial melt-out till
deformation till
ablation till: supraglacial melt-out till
Till accumulates:
on top of glaciers
on the margins of glaciers
beneath glaciers
Lateral moraines
End moraines
terminal moraines
recessional moraines
interlobate moraines
Kettle Moraine, Wisconsin
Classification based on formation
dump moraines
flow velocity
debris content
rate of ice marginal retreat
push moraines
seasonal push moraines
composite push moraines
ablation moraines
debris cored
hummocky moraine
Ground moraine
Till plains
Drumlins
characteristics
5-50 m high; 10-3000 m long
blunter end is on up-ice side
occur in fields behind end moraines
some are rock-cored; some are not
lodgment till cover
some contain fluvial sediments
may be super-imposed
hypotheses of formation
subglacial deformation: deforming layer molds around obstacles
obstacles: rigid/stiff area in deforming layer
obstacles either stationary or moving
subglacial lodgement: accretion of lodgement till around obstacles
not all drumlins are rock cored
fluvial infills/subglacial floods
scour from subglacial floods
scoured area fills in
streamlining of till by radial ice flow
Fluted moraines
lodgment till
