week 7 ~ glacial

what is this?

glacial trough/U-shaped valley

what is this?

hanging valley

what is this?

fjord → U-shaped valley with sea level high enough to fill

what are these?

grooves

what are these?

plastically moulded forms (p-forms)

diff lithology causing diff levels of abrasion

what are these?

striations

what is this?

glacial polish

how are partly streamlined landforms produced?

combination of abrasion and rock fracturing

what is this?

roche moutonnee

how are roche moutonnees formed?

stoss - striated surface due to abrasion from moraine at glacier base

lee - materials plucked from lee side

what is this?

crag and tail

how is crag and tail formed?

stoss - plucking and abrasion erode side

lee - less resistant moraines deposited giving it a tail

what is this?

cirque and tarn

what is this?

horn → pyramidal peak

what are these?

arete → saw tooth like ridges

what is this?

nunatak (glacial islands) → high elevated bed rock that has not been glaciated

what is the low lying area between horns and aretes?

col

what is this?

erratics → pieces of material transported from glacier, vary in size

what is a moraine?

mound of till

what are the types of moraines?

lateral → formed along edge of valley

medial → joining of 2 lateral moraines

end → formed at end of glacier

terminal → type of end glacier, furthest one formed

recessional → end moraine marking times of temp pauses

what is this?

drumlin → stream lined, formed through subglacial deposition

what are the types of glacial sediment?

glacial till → from ice directly

glaciofluvial → from melted glacial water rivers

glaciolacustrine → from melted glacial water lakes

what are these?

eskers

how are eskers formed?

when rivers/lakes are formed under or right at the edge of a glacier and leave behind a pile of material when the ice melts

what are these?

kames

what are these?

kettle lakes

how are kames formed?

formed when supraglacial sediment is deposited on top and the ice melts leaving a mound of debris

how are kettle lakes formed?

formed when you have a block of ice that eventually melts surrounded by outwash material or tills

what is permafrost?

zones of permanently frozen ground (more than 2 years)

what is continuous vs discontinuous ground ice?

cont → entire thing frozen

discont → pockets of frozen/unfrozen

what is an active layer?

seasonally thaws/freezes

what is a permafrost table?

line where permanent ice begins

what is this?

frost cracking

what is frost heave?

when ice lens layers thickens and the frozen zone experiences volume expansion/shrinkage due to frost heaving/thawing

what are these?

frost wedges

what are these?

melted ice wedges

formed when series of ice wedges are formed in the same area

what are these?

frost mounds. → pockets of soil filled with icea

what are these?

pingos

how are pingos formed?

giant ice mounds

formed when there is a pocket of water underneath which pushes the ground upwards as it freezes

what is this?

thermokarst → irregular terrain with depressions and hummocks between them

how is thermokarst formed?

thawing of ground ice and material collapsing

what are these?

stone circles

what are these?

polygons

what are these?

stone stripes

what are these

hummocks