CCHS Glaciers Brown (copy)

Alpine / Valley Glacier

A glacier confined to a valley

Ice Cap

a dome shaped mass of ice that covers less than 50,000 square miles

Ice Shelf

A thick, floating platform of ice that forms where a glacier or ice sheet flows down to a coastline and onto the ocean surface.

Snow line

The elevation above which snow remains all year long

axial precession (wobble)

The direction Earth's axis of rotation is pointed

Obliquity

The angle Earth's axis is tilted with respect to Earth's orbital plane

eccentricity

The shape of Earth's orbit

continental glacier

Dome shaped glacier of at least 50,000 square miles

Firn

partially compacted granular snow that is the intermediate stage between snow and glacial ice.

glacial advance

when a mountain glacier's terminus extends farther down valley than before. usually associated with glacial periods (ice ages).

glacial retreat

a glacier that loses more water than it gains. usually associated with interglacial periods (warm periods).

glacier

A large, dense body of ice that is constantly moving due to its own weight

Ice Age

A period of time lasting tens of thousands of years, where Earth's temperature drops very low and the polar ice caps and glaciers grow toward the equator.

glacial period (ice age)

times with large ice sheets

interglacial period

times without large ice sheets

Louis Agassiz

the father of glaciology

Milankovitch cycles

changes in Earth's position relative to the Sun that are believed to be a strong driver of Earth's long-term climate, and are responsible for triggering the beginning and end of glaciation periods (Ice Ages).

rigid zone

the upper brittle zone (top 130 ft) of a glacier where the ice cracks into crevasses

zone of plastic flow

the lower section (deeper than 130 ft) of a glacier that behaves like a plastic

zone of accumulation

the part of a glacier that receives more mass by accumulation than loses by melting (above the snow line)

zone of wastage

The area on a glacier where there is a net loss of snow and ice (below the snow line)