DYNAMIC EARTH: GLACIERS

How did "Snowball Earth" affect plate tectonics?

distribution of continents toward hihg latitudes

In glacial budgets, ice always flows _____, even during _____.

downhill, retreat

What are long, aligned hills of till called and what is their form?

drumlins, asymmetric

What are long, sinuous ridges of sand and gravel called?

eskers

What is the intersection of a tributary glacier with a main glacier called?

hanging valley

The zone of accumulation is the area of what?

net snow addition

What are the 2 zones of glacial budgets?

zone of accumulation, zone of ablation

Calving is when an iceberg is _____ _____ the water. An example?

4/5 beneath, Titanic

In equatorial regions, glaciers form above what?

5km elevation

Where do 2 major ice sheets remain on Earth?

Antarctica, Greenland

A low amount of what 2 greenhouse gases causes the Earth to be cooler?

CO2, CH4

What are U-shaped glacial troughs flooded by the sea called?

Fjords

What are hills of bedrock abraded smooth on the upstream side by steep and rough on downstream side due to ice plucking called?

Roche Mountonee

What is it called when ice slips over water flowing along the base of the glacier?

basal sliding

During glacial plucking, rock fragments are dragged along the _____ of the _____. Water seeps into cracks, freezes, and mechanically breaks up the _____.

base, glacier, bedrock

How do greenhouse gases trap heat?

by absorbing solar energy

"Snowball Earth" affected atmospheric chemistry by changing what 2 greenhouse gas concentrations?

carbon dioxide (CO2), methane (CH4)

What are bowl-shaped basins high on a mountain called?

cirques

What are 2 possible conditions for glacier formation?

cold climate (polar latitudes or high elevation), wet climate

What are boulders dropped by glacial ice called and what are they different from?

erratics, underlying bedrock

When water is stored on land during an ice age, sea level _____. When deglaciation returns water to the oceans, sea level _____.

falls, rises

During glacial abrasion, pulverizations produces what and polishes what?

fine-grained "rock flour", bedrock

Varves have the finest silt and clay from what? And they have coarser silt and sand from what?

frozen winter months, summer meltwater

What is it called when there is a "sandpaper" effect on substrate?

glacial abrasion

What is sediment transported in meltwater called?

glacial outwash

During what process are the broken bedrock fragments plucked out by glacier?

glacial plucking

What is it called when rock is surrounded by frozen water and carried off?

glacial plucking

Valley glaciers flow from _____ to _____ in mountain settings.

high, low

What is a pointed mountain peak called?

horn

What are 3 types of ice rock?

igneous, metamorphic, sedimentary

What are depression formed from stranded ice blocks called?

kettle lakes

An arête are a "_____-_____" ridge with two glaciers _____ _____ one another.

knife-edge, eroding towards

What are 3 characteristics of thick masses of recrystallized ice?

last all year long, flow via gravity, 2 forms of glaciers

For a glacier to sustain elevation, it must be controlled by what?

latitude

What is wind-transported rock flour called? Ex. in LA?

loess, Tunica Hills

The zone of ablation is the area of what? And through what 3 things?

net ice loss, melting & evaporation & calving

What is year-round frozen soil called? And what do its free-thaw cycles generate?

permafrost, unusual patterned ground

Long-term causes of "Snowball Earth"? affected what 2 major things?

plate tectonics, atmospheric chemistry

Glacial tills are _____ sorted, _____ sediment dropped by glacial ice that consists of _____ grain sizes.

poorly, unstratified, all

Ice ages cause sea level to do what?

rise and fall

In polar regions, glaciers form at _____ _____.

sea level

Ice shelfs are thin ice sheets floating where and are attached to what?

sea, main glacier

What are 2 characteristics of glacial outwash sizes? Grains?

sizes - graded, stratified grains - abraded, rounded

In order for a glacier to form in a wet climate, what needs to occur?

snow must be abundant; more snow must fall than melts

What is the gouging of bedrock by large rocks that show direction of ice movement called?

striations

In what 2 ways were weather patterns different during ice ages?

the American SW was much wetter, all climate changed + vegetations belts shifted southward

During basal sliding, water lubriacates what?

the base

In continental glaciers, the ice flows outward from what part of the sheet?

thickest

What are 2 forms of glaciers?

valley, continental

What is a seasonal glacial lake-bed sediment called?

varve

When did the most recent ice age end?

~11 ka

During ice ages, glacier coverage is what percentage?

~30%

"Snowball Earth", when a large % of Earth was covered in ice, occurred how many years ago and where can evidence be found?

~700 million, equatorial latitudes