Glaciers Flashcards
How are glaciers formed from snow?
Snow falls like sediment and accumulates in layered strata.
Layers of snow recrystallizes to become metamorphic glacial ice
What is firn?
Continual compaction produces packed denser
masses of granular snow
What are the 2 types of glaciers?
Alpine (valley) Glaciers
-exist in mountainous areas
-flow down a valley from an accumulation center at the head
-form u shape valleys
* Continental Glaciers
-vast ice sheets that exist on a much larger scale then valley glaciers
Where are continental glaciers found?
Greenland and Antarctica
What is the zone of accumulation?
net gain of
snow/ice
* Colder temperatures prevent melting.
* Snow remains across the summer months
What is the Zone of ablation?
net ice loss
What is the snowline?
the area where the zones meet
How are glacial striations formed?
large rocks drag across bedrock gouging the bedrock
What is till?
sediment dropped by glacial ice
What are moraines?
unsorted layers or ridges of till deposited by a retreating glacier
What is an erratic?
boulders dropped by glacial ice
what is a drumlin?
elongated, tapered, & parallel aligned hills of molded till that formed underneath the glacier
what is a eskers?
small but long, sinuous ridges made of sand and gravel that was deposited by the meltwater of the under-glacier tunnels.
what are kettle lakes?
ce blocks calve off of glaciers and
become buried in sediment. When they
melt, they form kettle lakes
