Geol 101 Exam 4 Review

Final Review

Types of glaciers, examples

- Valley (Alpine) Glaciers: Advance slowly, only a few centimeters per day. Can be long, short, narrow, single or with branching tributaries. Ex, Hubbard Glacier (Alaska)

- Ice Sheets: Much larger than valley glaciers, Ex: Greenland & Antarctica

- Sea Ice: frozen seawater , floats because it is less dense than liquid water

- Ice Shelves: Forms when a glacier or ice sheet flows into the adjacent ocean (is grounded in shallow water)

- Ice Caps: covers uplands and plateus- masses of glacial ice.

- Outlet glaciers: avenues for ice movement from an ice cap or ice sheet

- Piedmont glaciers: occupy broad low lands at the bases of steep mountains and form when one or more alpine glaciers emerge from the confining walls of mountain valleys.

How glaciers form

- Glaciers begin to form when snow remains in the same area year-round, where enough snow accumulates to transform into ice. Each year, new layers of snow bury and compress the previous layers. This compression forces the snow to re-crystallize, forming grains similar in size and shape to grains of sugar

Firn

- Granular, recrystallized snow. A transitional stage between snow and glacial ice. Commonly found making up old snow banks near the end of winter

Snowline

- The lower limit of perennial snow. The elevation above which snow remains throughout the year

Crevasse

- The large gaps in between glaciers that form as a glacier moves. These form in the zone of fracture in a glacier.

Horn

- A pyramid-like peak formed by glacial action in three or more cirques surrounding a mountain summit. Sharp, pyramid-like peaks that were shaped by alpine glaciers.

Arête

- Sharp-edged ridges

Cirque

- An amphitheater- shaped basin at the head of a glaciated valley produced by frost wedging and plucking. Bowl-shaped depressions and have precipitous walls on three sides but are open on the downvalley side.

Hanging valley

- A tributary valley that enters a...