Earth Science- Chapter 6-Glaciers

What are 4 agents of glacial erosion?

1) Rate of Glacial movement 2) Thickness of ice 3) Shape, abundance, and hardness of rock fragments contained in ice at base of glacier. 4)Erodibility of the surface beneath the glacier

About what percent of earth's land surface was covered by the Ice Age glaciers?

About/Nearly 30%

Under What circumstances will the front of a glacier advance, retreat, and remain stationary?

Advance: will advance if it receives more snow at the head of the glacier than the amount lost due to melting at the end of the glacier. Retreat: will retreat if melting at head of glacier is faster than the melting at the end of the glacier. Remain Stationary: Will remain stationary when the melting of the snow accumulation is equal at both ends.

How do glacier's acquire their load of sediment?

Glaciers move, and as they do, they scour the landscape, "carving" out landforms. As they move, they pick up and carry sediment particles of various sizes. A glacier can carry part of that sediment load on its bottom, its sides, or its top (sediment on top has fallen onto the glacier from the valley walls).

List 4 depositional features other than moraines

I) Drumlins II) Eskers III) Kames IV) Kettle Holes

What is "Rock Flour" and "Glacial Striations"?

Rock flower: Ground up rock produced by the grinding effect of a glacier Glacial Striations: Scratches and grooves on bedrock caused by glacial abrasion. Provides clues to direction of glacier heading.

Distinguish between a Terminal End Moraine and a Recessional End Moraine.

Terminal End Moraine: The sediment/end moraine advancing further away from the source of the glacier. Recessional End Morain: An end moraine formed as ice front ceased during glacial retreat.

What is the epicenter of an earthquake?

The epicentre of an earthquake is the point on the Earth's surface directly above the point within the Earth where the earthquake actually occurred (known as the focus or hypocentre). From this point on the surface the waves of the earthquake radiate outward like the ripples in a pond when a stone is thrown in.

How does the plate tectonics theory help us understand the cause of ice ages?

There is usually a large land mass at/near the poles (higher latitudes) before an ice age begins. Ice and snow accumulate better on land where only Glaciers can form.

Describe the formation of a medial moraine

They are formed when two valleys come together to form a single ice stream.

What is "plucking'' and "abrasion?"

Two ways glaciers erode: -Plucking: Glaciers flowing over fractured bedrock & using frost wedging to break, loosen, and lift blocks of rocks and incorporate them into the ice. -Abrasion: Ice moving over bedrock with rock fragments and "sanding" & "polishing" the surface below.

Describe how glaciers fit into the hydrologic cycle

http://www.geoclassroom.com/101online/REVQST12.html The water in ice sheets and glaciers can be viewed as removed from the oceans and temporarily stored on land. Glacial ice, like groundwater, does eventually return to the sea, but the recycling time is hundreds to thousands of years compared to months or a few years for surface water runoff from rainfall events and melting snow. Shrinking of ice sheets causes sea level to rise. As global temperatures rise, glaciers undergo net loss of ice, sea level rises, and the surface area of the oceans increases. These factors work in favor of an increase in the total amount of water evaporated into the atmosphere. With cooler temperatures and declining sea level, the total amount of water evaporated from the oceans is also expected to decrease.