Glacier Formation Glaciers are formed from layer after layer of compacted snow. As the snow compacts, it loses trapped air, becoming harder and more dense.

Slides:



Advertisements
Similar presentations
Glaciers Chapter 8, Section 2.
Advertisements

Glaciation of Canada.
The movement of sediments by wind, water, ice, or gravity.
Form in high mountains where snow accumulates to sufficient depths so that it is compressed, compacted and recrystallized. For this reason glacial.
Erosion and Deposition by Glaciers Created By: Belinda Schmahl.
Glaciers and Glacial Landforms
Glaciers.
Chapter 7: Erosion and Deposition
Glaciation. "What causes ice sheets to expand and contract? Are the present ice sheets growing or shrinking? How will global warming impact the ice sheets?
‘S‘S. VOCABULARY GLACIER - LARGE MOVING MASS OF ICE THAT FORMS NEAR EARTH’S POLES AND IN MOUNTAINOUS REGIONS AT HIGH ELEVATIONS. GLACIER - LARGE MOVING.
Earth Science: 7.1A Glaciers. Glaciers  As recently as 15,000 years ago, up to 30 percent of earth’s land was covered by an glacial ice.  Earth was.
Glaciers.
Chapter 3 Section 4 Glaciers. Moving mass of ice and snow Form when more snow falls than melts Agent of erosion.
Lithosphere: Glaciated Uplands
Glaciers Moving Ice Formation of Glaciers A glacier is defined as a mass of moving ice. A glacier is defined as a mass of moving ice. There are several.
Ch 15: p  Enormous masses of moving ice created by the accumulation and compaction of snow.  Powerful agents of erosion ~ have carved some.
Glaciers Glaciers formed much of the landscape that exists presently in the northern United States and elsewhere in the world. Glaciers Today, scientists.
Chapter 21: The Glacier Systems and the Ice Age Presentation.
Glaciers UNIT 5 STANDARDS: STATE OBJECTIVES: NCES 2.1.1, 2.1.3, LESSON 6.
Glaciers and Erosion Chapter 7 Section 1.
Glacier Notes.
Glacial Landscapes Glacier = large moving mass of ice. Glacier = large moving mass of ice. Glaciers erode, transport and deposit massive amount of sediment.
Glaciers. Geologists define a glacier as any large mass of ice that moves slowly over land. There are two types of glaciers: Continental glaciers Valley.
GLACIERS.
Glaciers We wouldn’t be here without them.. A Glacier is an accumulation of snow that is large enough to survive the summer melt. What are glaciers?
Chapter 8 Erosional Forces Section 8-2 Glaciers Note Guide.
Chapter 3 Erosion and Deposition Section 4 Glaciers
Glacier: Any large mass of ice that moves slowly over land.
Chapter 7.3 Glaciers. Glacier Any large mass of ice that moves slowly over land. Two kinds: – Continental Glaciers – Valley Glaciers.
D. Evan Stribling  a larger mass of compacted snow and ice that moves under the force of its own gravity (weight)  They erode in some places deposit.
Glaciers Landmarks of the Past. Glaciers: Large mass of ice, air, rock debris.Glaciers: Large mass of ice, air, rock debris. –At least partially formed.
Agenda Check In Review notes Glaciers WATER Who’d’a Thunk: Karaoke means “empty orchestra” in Japanese.
- In some places it is too cold for all the snow to melt - This snow begins to pile up - The weight of all the snow piling up causes the crystals to reform.
 As much as plate tectonics builds up the Earth’s surface, forces in nature are also working to wear it down. One major force of erosion happens due.
Glaciers Erosive forces.
EROSION: The force that shapes the Earth!
Glacier Review.
How Do Glaciers Shape the Land?
Mass Movements, Wind, and Glaciers
AIM: How do Glaciers change the landscape? Do Now:
Glaciers Pg. 79.
Like running water, gravity is the driving force
Rocks & Landforms I-7 Notes
Do Now: Start vocab on Notes packet
Erosion and Depistion BY GLACIERS!.
An agent of erosion, weathering, and deposition
Chapter 8 – Mass movements, Wind and Glaciers
Prairie School Earth Science
Glaciers and Mass Movements
How Glaciers Modify the Landscape
Glaciers Section 9.4.
Glacier Terms.
Glaciation of Canada.
Aim: How do Glaciers affect the land?
Glacial Erosion Chapter 4.2.
Erosion and Deposition
Wind Erosion Wind can erode both soil and rocks.
Erosion & Deposition by Glaciers
Chapter 15 Glaciers Glacier Large mass of compacted snow and ice.
Erosion and Depistion BY GLACIERS!.
Glaciation.
Earth Science Chapter 8 Section 3
Earth Science Notes Glaciers.
Security Briefing and Background Check
Glacial Erosion Chapter 4.2.
Mass Movements, Wind, and Glaciers
Glaciers.
This valley glacier has bands that look like ripples
Security Briefing and Background Check
What are Glaciers? Masses of ice formed on land by the compaction of snow.  Factor of glacier movement: gravity (caused by weight of ice)
Presentation transcript:

Glacier Formation Glaciers are formed from layer after layer of compacted snow. As the snow compacts, it loses trapped air, becoming harder and more dense. The individual flakes connect to form very large ice crystals (up to a 100 m in size). This is glacial ice (which appears a blue tint.)

Which sample is from near the top of an ice core. The middle Which sample is from near the top of an ice core? The middle? The bottom?

The area on a glacier where material is added on is called the accumulation zone. This area is usually near the top of the glacier. The process of removing material from a glacier is called ablation (and occurs in the ablation zone). This occurs not only from melting (at the surface or base), but also from evaporation (at the surface) and calving. Calving is the process of forming an iceberg. The place where the accumualation zone and ablation zones meet is called the equilibrium line.

Glacier Movement Even though glaciers are very large, they can still move (albeit very slowly). Where do they get the energy? GRAVITY! They always move downhill. If the force of gravity is sufficient to overcome frictional forces, then movement will occur. This can happen in a number of ways...

Internal Deformation The glacier is “flattened”, but does not actually move. The leading edge, (a.k.a. glacier terminus, or nose) moves out away from the centre.

Basal Sliding and Deforming Substrate In order for a glacier to truly slide, friction must be reduced. In basal sliding this is done through a layer of water that results at the base due to the very high pressure. Water lubricates the contact points, easing movement. Also, if the sediment under the glacier is loose it may carry the entire glacier with it when it slides.

Is the South Pole Moving? Antarctica is a large glacier. Thus, it is capapble of moving over top of the land it’s built on. As a result, pegs inserted into the ice at the geographic south pole will actually move considerably each year!

Types and Sizes of Ice Continental Glaciers: ice sheets and ice caps completely cover the surrounding topography ice sheets are larger than ice caps Eg. Antarctica, Greenland, “Ice Age”

Types and Sizes of Ice Ice Shelves a floating ice mass that is attached to the coast along at least one edge

Types and Sizes of Ice Valley glaciers these are the fast moving glaciers that fill the contours of a valley usually steep and carry vast quantities of rock sediment

Types and Sizes of Ice Icebergs chunks of glacier that break off and float away.

Glacial Erosion Glaciers are very good at eroding rock and soil. They are 3 mechanisms in which this occurs: 1) The sheer weight of the ice allows it to penetrate deep into soil or rock. It then plows material in the direction it is moving. The is called scouring. 2) At the base of the glacier ice can melt and refreeze. When it refreezes it can trap loose rock and sediment that becomes part of the glacier and moves with it. 3) Melting water can enter cracks in rocks. If it freezes it can attach firmly to parts of the rock around the cracks. When the glacier moves, the ice in the cracks can rip the surrounding rock away. This is called plucking.

Glacial Erosion (cont.) When the glacier recedes it often leaves striations. These are distinctive “scratches” in the bedrock caused by harder trapped rocks in the base of the glacier rubbing against the underlying rock. These markings are handy for scientists because it allows them to determine the direction that the glacier was moving. Unsorted material carried by the glacier and deposited when it melts is called till.

Glacial Landforms Many common land features are a result of glacial movement. Moraines are mounds of till deposited when glaciers recede (melt). The most interesting is a terminal moraine, which is formed from till at the leading edge of the glacier.

Glacial Landforms Drumlins is thought to have formed when a new glacier moves over an old moraine. As a result they are much smaller than moraines and point parallel to the direction of glacier movement. One side is usually steeper than the other. This is the side from which the glacier came.

Glacial Landforms 3) Melted ice can flow through long ridges (like tunnels) under the glacier. Till is often carried in these streams and becomes deposited in certain points, building up to become higher than the surrounding rock. When the glacier melts, the mound that is left over will run roughly parallel to the glacial movement. This is called an esker.

There are many more formations that are related to glaciers, including many types of lakes and streams. Read about them (and review glacier concepts) in the following HW: Read section 15.1, do #1,3,4,5 p. 320 Read section 15.2, do #1,3,4,5 p. 325 Read section 15.3, do #5,6