Exam 19: Glaciers and Glaciation

A worldwide decrease of at least _____ ^$\circ$ C in temperature would bring about a new glacial age.

Where tributary glaciers come together the adjacent lateral moraines join to form a ______ moraine.

The compacted mass of granular snow,transitional between snow and ice,is called firn.

A(n)_____ is the sharp peak that remains after cirques have cut back into a mountain on several sides.

The upper part of a glacier,the part with perennial snow and ice,is called the __.

___ are the product of past glaciations.

The primary control of glacial-interglacial episodes seems to be variation in the Earth's orbit and inclination to the sun.

The theory of _____ states that at times in the past,colder climates prevailed during which much more of the land surface was glaciated than at present time.

A U-shaped valley (in cross section)is characteristic of glacial erosion.

Glaciers are part of the hydrosphere.

When an ice block that was buried in sediment finally melts a depression called a ___ forms.

If a moving glacier reaches a body of water ______ float free.

____ are landscape features that indicate a mountainous area has been glaciated.

Bodies of till shaped into streamlined hills are called ___.

A large trunk glacier carves a deeper valley than smaller tributaries.After the glacier disappears the tributary valley remains as _____ high above the main valley.

Above the rigid zone,glacial ice movement is due to __.

Striations and grooves in bedrock indicate the direction of ice movement.

Open fissures called ___ develop in the brittle surface ice of glaciers.

A(n)___________ is an ice-transported boulder that was not derived from the underlying bedrock.

Bodies of till shaped into streamlined hills are called drumlins