| ablation
area
part of the glacier at lower altitudes
at which ablation exceeds accumulation; grey area of glacier
tongue
in
photo |
accumulation
area
part of the glacier at higher
altitudes at which snow stays throughout melting season; | |
| arête
sharp, narrow ridge formed as result
of glacial erosion from two sides; |
calving
detachment of blocks of ice from
a glacier
into water; | |
 | cirque
armchair-shaped
hollow with
steep
sides and backwall due to glacial erosion high on a mountainside; flat basin containing
often a lake (tarn); |
crevasse
deep V-shaped cleft formed in the
brittle part of a
glacier; result of the fracture
of ice undergoing extension; |  |
| dropstone
relatively
large clast that falls through
the water column into soft sediment; released from icebergs; indicated by d in
photo |
drumlin
streamlined hillock, commonly elongated
parallel to former ice-flow direction;
composed of glacial debris; gently
inclined, smooth slope facing down-valley
and a steep, rough slope
facing
up-valley | |
 | erratic
boulder or large block of bedrock
transported away from its source by a glacier; |
esker
long,
commonly sinous ridge of sand &
gravel; deposited by a stream in a subglacial
tunnel; seen cutting through the lakes in the lower left of photo and in
cross-section | |
 | fiord
long, narrow steep-sided arm of the sea;
formed as a result of glacial erosion; |
glacier
karst
debris-covered
stagnant ice; typically
with many lake-bearing caverns and
tunnels; found at the snout of a retreating
glacier; | |
| glacier
table
boulder
sitting on a pedestal of
ice; resulting from protective effect of the rock mass on ablation of the
ice surface; still existing one in the lower right, previous one in the upper
middle of the photo |
glacial
trough
U-shaped
valley with steep sides
and a flat bottom; formed by
glacial erosion; |
 |
| | groove
glacial abrasion form with striated (photo on right) and
or polished sides and base; oriented parallel
to the ice-flow direction, up to several
meters wide and deep; |
hanging
glacier
glacier that spills out from
a high.level cirque
od clings to a
steep
mountain side; after retreating further
up-valley building hanging valleys; |  |
| horn
steep-sided, pyramid-shaped
peak;
formed due to erosion on three or more
sides; |
iceberg
piece of ice that has been shed by a
glacier into a lake
or the sea; | |
 | ice
cliff
vertical face of ice; normally at the
terminus of an advancing glacier; |
icefall
steep, heavily crevassed portion of a
glacier; | |
| jökulhlaup
sudden and catastrophic outburst
of water from a glacier; photo shows mega-ripples after flooding of Alsek River
valley |
kame
steep-sided mound of stratified sand & gravel
deposited supra- or intraglacial by streams; | |
| kame
terrace
as kame, but deposited
along
the margin of a glacier; flat or
gently sloping; |
kettle
bowl-shaped depression within an area
covered by glacial debris; forms as a result
of the burial of a mass of glacier ice
and
subsequent melting; | |
| loess
wind-blown sedimentof silt grade; often
the result of winnowing of fines from glacial
outwash plains; |
moraine
distinct ridges or mounds of debris
laid down directly by a glacier or pushed
up by it; unsorted loose material
is till; subdivided into lateral, medial, ground,
terminal
and push moraines; |  |
 | nunatak
rocky outcrops projecting above the
ice sheet surface; |
ogives
arcuate bands with the apex pointing
down-glacier, which develop in icefalls;
each band representing one year's movement
through the icefall; seen in the right half of photo | |
|
portal
open archway through which a meltwater
stream emerges; |
roches
moutonnée
rocky hillock with gently
inclined, smooth slope facing
up-valley
resulting from glacial abrasion, and
a steep,
rough slope facing down-valley
resulting from glacial plucking | |
| rock
flour
pulverized bedrock; carried in suspension
gives water the typical milky appearance; |
| sandar
extensive flat plains of sand & gravel
with braided
streams of glacial meltwater; | |
| sérac
tower of unstable ice; in regions of fast
glacier movement; |
| surge
short phase of accelerated glacier flow;
periodic; between surges often stagnation;
indicated
by distorted medial moraine in photo | |
| till
unsorted morainal sediment; |
| varve
sequence of laminae, deposited in lakes;
representing a year's sedimentation; | |
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