Glaciers

Question 1

Compare a glacier to an ice age

Answer 1

Glacier is a mass of slowly moving ice

Ice age is a period of time during which glaciers existed

Question 2

How many ice ages were there? When was the most recent ice age?

Answer 2

Evidence for 4 ice ages; the most recent was about 10,000 years ago

Question 3

how is a glacier formed?

Answer 3

1. in colder regions of the Earth, snow that falls during the winter does not melt during summer
2. Collected snow becomes deeper over time and lower layers are compressed by weight of upper layers
3. compression causes the ice to melt; it flows downhill and refreezes, forming roughly textured ice (glacier ice)

Question 4

How does a glacier move?

Answer 4

Pressure of the top layer of ice causes lower layers of snow to ice and melt. These layers lubricate the base and extend the area of the glacier. Gravity makes the glacier flow downhill

Question 5

2 main types of glaciers

Answer 5

Alpine/mountain

Continental

Question 6

Alpine Glacier

Answer 6

Formed in mountain valleys; small V-shaped streams erode valleys into a U-shaped glacier valley (found in the Alps and Rocky Mtns)

Question 7

Continental Glacier

Answer 7

Covers large areas of land; made of huge ice sheets

Ex: Greenland, Artarctica, northern-N. America during Pleistocene era

Question 8

Horn

Answer 8

Sharp edged, pyramid-shaped mountain peak present in areas where there are many alpine glaciers (Matternhorn in the Alps)

Question 9

Cirque

Answer 9

Circular scoop high in a mountain area formed by erosion by frost; usually where alpine glaciers begin. Cirques on several sides of the mountain create horns

Question 10

Moraine

Answer 10

Mass of rocks that are collected by glaciers as they move

Question 11

3 basic types of moraine

Answer 11

ground
lateral
medial

Question 12

Lateral Moraine

Answer 12

Material along valley walls; found on the side of a glacier

Question 13

Medial Moraine

Answer 13

It is formed when two glaciers join; the lateral moraines of both glaciers collect in the center of the new one

Question 14

Ground moraine

Answer 14

Rocks at the bottom of a glacier; these rocks cut deep grooves as they are dragged along the bedrock

Question 15

Terminal moraine

Answer 15

A long ridge formed when rock fragments collect as the front of the glacier melts; they can be hundreds of feet high, and miles long and wide (ie Long Island has two large and long terminal moraines)

Question 16

Outwash plain

Answer 16

Meltwater carries sand and other fine particles away from the front of a glacier. As it is deposited it forms an outwash plain that can have a several mile radius (ie southern shore of Long Island)

Question 17

Erratic

Answer 17

Lg. boulder deposited by a glacier far from its place of origin

Question 18

Drumlin

Answer 18

Small oval hill formed under a glacier as it moves (like Bunker hill, Boston)

Question 19

Kettle hole

Answer 19

Glacier melts leaving a block of ice surrounded by moraine. There is a hole in the ground when the ice melts

Question 20

Kettle lake

Answer 20

A lake formed when a kettle hole created by a glacier fills with water

Question 21

Glacial lake

Answer 21

Glacial moraine builds up in a valley and forms a natural dam as it blocks the flow of water. Lakes are formed.

Ex: Finger Lakes, NY

Question 22

Tarn

Answer 22

A small lake occupying a rock basin in a cirque; created by a glacier

Question 23

How does wind erode and change the land?

Answer 23

If the surface of land is loose (sand, loose soil, silt, etc.) the action of wind will move it from one location to another

Question 24

Wind abrasion

Answer 24

When strong winds pick up sand, the sand abrades and erodes surfaces it comes in contact with

Question 25

Sand dune

Answer 25

Sandhill formed when wind carrying sand slows down due to obstruction. Sand falls and collects near obstruction and over time may form a large hill (like dunes on Cape Cod, White Sands, Sahara Desert)

Question 26

Loess

Answer 26

A loamy deposit formed by wind, usually yellowish and calcareous, common in the MI Valley and in Europe and Asia; good for growing crops. Ex: topsoil in Missouri and other Midwestern states

Question 27

Subduction

Answer 27

Type of plate movement where one plate dives down into the mantle beneath the more buoyant plate