Glaciers and Mass Movement Flashcards
What are glaciers?
Thick masses of ice that form over thousands of years
What are the two types of glaciers?
Valley Glaciers and Ice Sheets
What are Valley Glaciers?
Ice that flows down mountain valleys at high latitude
Example: Alaska
What are ice sheets?
Ice that covers a large region where the climate is extremely cold
Example: Antartica
What is an iceberg?
A large piece of floating ice usually broken off from a glacier
What is an ice age?
A long period of very cold climate conditions
In what two ways do glaciers erode?
Plucking and Abrasion
What is plucking?
When frost action loosens blocks of rock and glacier then lifts them away
What is abrasion?
When the ice slides over the rocks like sandpaper
What are striation?
Scratches left on the bedrock as the glacier moves over it
Deposition due to glaciers is usually…
Unsorted/random and has angular sediments
In what order do glaciers deposit sediment?
They drops the sediments in the reverse order to which they were picked up
How are U shaped valleys formed?
Ice carves a wide valley pushing everything in its way and when the glacier melts it leaves behind a U shaped valley.
What type of a valley does a glacier leave? What type of valley does a river leave?
A glacier leaves behind a U shaped values and rivers leave a V shaped values
What is till?
Unsorted sediments left behind from a glacier
What is a moraine?
Ridges of till
What is a drumlin?
An oval shaped mound of hill
How does a drumlin reveal which direction the glacier moved?
Whatever direction the pointy side of drumlin is facing is the direction the glacier moved
What is a glacial lake?
A lake formed when the glacier begins to melt
What is a kettle lake?
A small lake formed when a chunk of ice becomes dislodged and then melts
What is a glacial erratic?
A large boulder dropped by melting ice
What was Long Island formed by?
Long Island was formed by glaciers
What split Long Island into the North and South shores?
Two moraines
What are the difference between glaciers and rivers?
Rivers-
U shaped valleys
Unsorted-random angular fragments
Streams-
V shaped valley
Sorted from large (on bottom) to small (on top)
Rounded fragments
What is mast movement?
The movement of loose materials down slope under the influence of gravity
What are some parts of gravity/glaciers?
-not sorted
-angular
-not layered
-opposite of water
What is talus?
Rock fragments that have been weathered from a cliff and pulled down by gravity. They come from piles at the base of the slope.
What are the six types of Mass movement?
Creep, landslides, slump, mudflow, earth flow, and avalanche
What is creep?
The unseen movement of soil down slope and is unseen.
Where is creep only noticiable?
It’s only noticeable by fences, poles, trees that lean down hill
What are landslides?
The sudden movement of a mass of bedrock or loose rock that is triggered by earthquakes or addition of large amounts of water (makes it easier for materials to flow).
What is slump?
Small blocks of land that move downhill along curved surfaces and occurs when the slope is too steep and the bottom of the slope cannot support the top. Movement makes the slope stable.
What is mudflow?
The rapid movement of water that can carry large amounts of sediments (suspended clay and silt). They can travel at 60+ mph that can move rocks, boulders, and houses
What is earth flow?
A mass of material that has been saturated with water a flows down hill
What is an avalanche?
A landslide composed of masses of ice, snow, soil, and rock (large scale mass movement)
