Section 15.1 What is a glacier?

Compare a River to a Glacier Fast flow Liquid: rain or snow <1% of hydrosphere Anywhere on earth warm climates Living things Low elevation People can pollute Slow flow Solid ice (firn) 10% of hydrosphere Poles or high elevations Cold climates (year-round) No living things in them Larger in size H 2 O hydrosphere Fresh water Gravity pulls Transport materials Erodes valleys Tributaries Change over time Level/size changes

Glacier- a large mass of compacted snow and ice that moves due to gravity Where are some areas that you think glaciers can form?

Glaciers Facts Cover 10% of Earth’s land 75% of earth’s fresh water is in glaciers! Glaciers change land by eroding, transporting and moving huge amounts of sediment. Glaciers are part of both the water cycle & rock cycle

The Earth’s Water Cycle

The hydrologic cycle Figure 5.3

Where do they form? Glaciations are based on the snow line –Snow line is the elevation at which permanent snow occurs during the summer Closer to the poles = Closer to sea level

Snowline The lowest elevation at which permanent snow occurs in the summer

Height of the snowline (glaciers formation) decreases as the latitude increases Pg. 318

Where Glaciers are Located Cold climate year-round North and south poles High elevations in mountains.

How Glaciers Form 1.When more snow falls in the winter than can melt in the summer. 2. Layers of snow accumulates year after year (above the snowline) 3. The snow compacts and re-crystalizes 4. Until the mass moves, slowly down hill due to gravity Seasonal migration of snow

Types of Glaciers pg ContinentalAlpine or Valley Where? Size/shape? How many?

Valley glaciers hundreds of small glaciers found high in the mountains where streams once ran. Also called “Alpine” glaciers. They flow slowly downhill between valley walls. They also have tributaries like streams or rivers.

Piedmont When a valley glacier emerges from the confining walls of a mountain valley and spread out into broad sheets. Alluvial fan of sediment

Continental Glaciers Cover very large landmasses like in Greenland and Antarctica. Can be a mile thick in places. Mostly circular or oval in shape Spreads out in all directions Also called an ice sheet Some places the ice reaches the sea and can break off into icebergs.

Greenland ice sheet

The weight of the accumulating snow pushes the glacier out in all directions ike pancake batter

Antarctica Earth’s largest continental glacier