Broadly speaking, a glacier is said to have three parts:
1.-
ACCUMULATION ZONE OR GLACIAL CIRQUE: It is the highest area of the glacier where snow
accumulates and turns into ice. More snow accumulates in this area in winter
than melts in summer. The addition of snow in this area is what promotes
movement.
2.- PERPETUAL SNOW LINE: it is the external limit of the accumulation zone. It
can vary a lot, for example in a polar region it may be at sea level and in a
tropical mountainous area it would be at an altitude above 4500 m.
3.-
ABLATION ZONE: After the perpetual snow line is the ablation zone, which is an area in
which there is a net loss of the glacier. Snow from the previous winter and
some glacial ice melt. It is the area where the processes of fusion and
evaporation occur, and where equilibrium is reached. The concept "Balance
of a glacier" refers to the balance or imbalance between the
accumulation of ice in the accumulation zone and its loss in the ablation zone.
When accumulation exceeds ablation, the glacier will advance until the two
factors balance. In equilibrium, the end of the glacier would remain
stationary. When the ablation is greater, the glacier retracts and goes into
recession.
https://www.nps.gov/glba/learn/nature/images/glacierbudget.jpg
Large chunks of ice can break off in the ablation zone in a process called DISMEMBERMENT. When the dismemberment
occurs in a sea or lake area, icebergs are generated.
ICEBERGS:
/ These are less dense than water so they float and move through it
following currents.
/ They have more than 80% of their mass submerged, they can have diameters
of several kilometers, thicknesses of more than 600 meters and diameters of
several kilometers.
/ They can be very dangerous for maritime navigation, in the North Atlantic
there are many icebergs coming from the Greenland ice cap glacier.
https://media.istockphoto.com/photos/iceberg-floating-in-arctic-sea-picture-id693474546?k=20&m=693474546&s=612x612&w=0&h=5uoEMUjdisC1054odAuKrXRbLVro8uRe0tMA9NaG5_U=
