Warm-up:

Warm-up:

• How are glaciers related to global warming?

• What do we need to know about glaciers to answer the question?

Set-up Cornell Notes:

This is our essential question

These are our left side questions

What is a glacier?

GlaciersA glacier is defined as a thick mass of ice that forms over land from the compaction and recrystallization of snow, and shows

evidence of past or present flow. Glaciers are part of both the hydrologic cycle and the rock

cycle.

• What is NOT a glacier?

• Is there more than one kind of glacier?

Types of GlaciersValley, or alpine glaciers form

in mountainous areas

Types of GlaciersIce sheets, or continental

glaciers, are very large. They are masses of ice covering more

than 50 000 km².For example, ice sheets cover

Greenland and Antarctica.

The only present-day continental ice sheets are those covering

Greenland and Antarctica. Their combined areas represent

almost 10% of Earth’s land area.

Figure 6.2

Types of Glaciers

An ice cap is an ice mass that covers less than 50 000 km² of land area (usually covering a

highland area.)

Types of GlaciersPiedmont glaciers are a type of glaciation characteristic of Alaska - large valley glaciers

meet to form an almost stagnant sheet of ice.

Malaspina glacier in south-eastern Alaska is considered a classic example of a piedmont glacier. Piedmont glaciers occur where valley glaciers exit a mountain

range onto broad lowlands, are no longer laterally confined, and spread to become wide lobes.

How do Glaciers Form?As air infiltrates snow, snowflakes become smaller, thicker,

and more spherical.The air is forced out of the snow.

The snow then recrystallizes into a much denser mass of small grains called firn.

Once the thickness of the ice and snow exceeds 165 feet, firn fuses into a solid mass of interlocking ice crystals, which we

call glacial ice.