Weathering and Erosion

landforms created by wave erosion

-Sea stack -Sea arch -Sea cave

factors that affect chemical processes:

-acidity -chemicals used -temperature -surface areas

What five factors determine the amount of runoff in an area?

-amount of rain -vegetation -type of soil -shape of the land -how people use the land

deposits by waves

-beaches (longshore drift) -spits -sandbars and barrier beaches

Compare landslides and slumps

-both involve the movement of soil and rock downhill -landslides the rock and soil are loose -slumps the rock and soil moves as a single mass

Weathering

-breakdown of rocks -physical or chemical process -no movement -causes: ~atmoshpere ~living organisms ~water

What is chemical weathering?

-breakdown of rocks and minerals through chemical reactions -ex: weathering caused by carbonic acid

How does climate affect the rate of weathering?

-cold climates, the freezing and thawing that occurs causes rapid mechanical weathering through the process of ice wedging -warmer climates, chemical weathering is more rapid because the chemical reactions that dissolve rocks and minerals are accelerated by warm temperatures

construction and deconstruction forces

-erosion -sediment -deposition

Describe how a valley glacier forms

-form high in mountain valleys. because the temperatures rarely rise above freezing, ice and snow build up year after year. As more snow falls, the ice and snow below become compacted.

mass movement

-landslides -mudflows -slump creep

Erosion

-movement of broken down rock -physical process -requires movement of rock or something moving over the rock -causes/agents: ~running water (streams, rivers, etc) ~glaciers ~water

five agents of erosion

-wind -gravity -waves -running water -glaciers

all treatments

15 minutes

In Figure 7-2, which picture shows ice wedging: A, B, or C?

A

continental glacier

A large mass of moving ice and snow on land that covers much of a continent or large island

Present day glaciers are found primarily in _______________

Antarctica and Greenland

In Figure 7-2, which picture shows weathering that involves carbonic acid: A, B, or C?

C

What is one main difference between continental glaciers and valley glaciers?

Continental glaciers are much larger and thicker

Compare and contrast the way the two types of glaciers move

Continental glaciers can cover most of a continent or large island. As they move, they can spread out in all directions. In contrast, valley glaciers move down mountain valleys previously cut by rivers. The sides of mountains prevent valley glaciers from spreading in all directions as continental glaciers do.

A valley glacier spreads out over a large island or continent

F

Ice wedging is a form of chemical weathering

F

Mechanical weathering is more rapid in warm, wet climates

F

Mudflows are most common in swampy areas

F

Once the depth of snow and ice reaches more than 30 to 40 meters, the force of friction begins to pull a glacier downhill

F

Plants can only cause mechanical weathering

F

Sandbars are formed through erosion by waves

F

The process that lays down sediment in a new location is erosion

F

Millions of years ago, the Appalachian Mountains were towering, craggy mountains. Describe the processes that resulted in the lower, more gentle mountains that we know today.

Over millions of years, weathering broke down the rock in to small pieces. This process included both chemical and mechanical weathering. The small pieces of rock were then carried downhill by gravity and water.

How does the surface area of a rock affect the rate at which it weathers?

Smaller rocks have a larger surface area to volume ratio than larger rocks. This means that a larger proportion of the rock is exposed to the forces of weathering. As surface area increases, so does the rate of chemical weathering.

A spit is formed through wave deposition

T

Chemical weathering is probably faster along the Amazon River than in the Himalayas

T

Creep can occur on even very gentle slopes

T

water

The major agent of erosion that shapes the land surface of Earth

headland

a piece of land that juts out into the sea

moraine

a ridge-like deposit of sediment at the edge of a glacier

flood plain

a wide, flat area covered by water during flooding

The deposition of sediment where there is a steep drop-off into shallow, flat land can create a(n) __________

alluvial fan

The main factors that determine the amount of runoff in an area include the shape of the land, how people use the land, the type of soil, and:

amount of rain and vegetation

rate over weathering

amount remaining/time

plucking

as a glacier flows over the land, it picks up rocks in this process

Mechanical weathering ____

breaks apart rocks by physical processes

All of the following cause mechanical weathering EXCEPT ____

carbonic acid

How might small mammals cause weathering?

cause mechanical weathering as they burrow in to the ground. This breaks up sediment and pushes it to the surface. Once on the surface, other forms of weathering can act on the sediment.

very slow movement of rock downhill

creep

In the diagram, above, marker D is pointing to a __________, which is a landform that forms when a river slows down as it flows into an ocean or lake. As the river slows, it drops its sediment load, gradually creating a network of small channels and islands

delta

sediment

deposited material

Deltas are built up by

deposition

kettle

depressions left by melted blocks of ice in glacial deposits

amount remaining

easy comparison for rates of weathering

The process by which natural forces move weathered rock and soil from one place to another is called

erosion

Wind and water are agents of ____________________ that move sediment from one location to another

erosion

In areas where freezing and thawing occur frequently, rocks weather rapidly because of the ____ of freezing water

expansion

lowest % remaining

fastest rate

spit

formed through longshore drift

Mass movement is caused by

gravity

The force that moves sediment in a landslide or mudflow is ____________________

gravity

As rock is worn away by waves on a coastline, the land that takes a little longer to wear away can form a:

headland

How waves erode

headland

rate

how quickly something happens

The times in the past when continental glaciers covered large parts of Earth's land surface were the ____________________

ice ages

Which of the following is NOT an example of chemical weathering?

ice wedging in rock

After the last ice age, stranded ice blocks left behind by the continental glacier melted and formed

kettles

karst topography

landscape in which limestone is eroded to form deep valleys and caverns

most destructive kind of mass movement

landslide

As waves repeatedly hit a beach, some of the beach sediment moves down the beach with the current, in a process called ______

longshore drift

In the diagram, above, marker E is pointing to a __________, which is the "winding" shape that a river can take and its shape is determined by the hardness of the rock the flowing water meets

meander

A river flowing across a wide flood plain begins to form looplike bends called

meanders

In Figure 7-2, are the animal burrows in B an example of chemical or mechanical weathering?

mechanical

What material will oxidize when it is exposed to oxygen and water?

metal

Describe what a moraine is made of and explain how this glacial feature forms

moraine is made up of till, the mixture of sediment deposited by a glacier. A moraine forms when a ridge of till is deposited at the edges or at the lower end of a glacier. A terminal moraine forms at the farthest point reached by the glacier as the glacier begins melting back.

Glaciers can only form when

more snow falls than melts

In which of the following does the land being moved contain approximately 60% water?

mudflow

What causes a mudflow?

occur when soil that is usually dry become soaked with water. If the soil is especially high in clay content, mudflows con occur on very gentle slopes -earthquakes can also trigger mudflows

What occurs during a slump?

occurs when a large piece of a steep hill breaks away and falls

How do glaciers cause deposition?

occurs when glaciers retreat, leaving behind rocks and soil known as till

In the diagram, above, marker F is pointing to a __________, which are formed when meanders wear away at a narrow point and a pool of water forms

oxbow lake

Glacial erosion, the picking up and movement of earth beneath a glacier, is also referred to as ____________________

plucking

What processes lead to glacial erosion?

plucking and abrasion. Plucking is the process by which a glacier picks off rocks as it blocks over the land. The rock fragments freeze to the bottom of the glacier, gouging and scratching the bedrock as the glacier advances in the process of abrasion.

How are kettle lakes formed?

retreating glaciers often leave behind large chunks of ice in the soil. When these ice chunks melt, depressions in the landscape are left. Kettle lakes are formed when these depressions fill with water.

what chemical weathering called oxidation causes

rust

Both weathering and erosion produce

sediment

delta

sediment deposited where a river flows into an ocean or lake

A mass movement called ____________________ occurs when sediment suddenly slips downhill in one large mass

slump

Mass movement that involves rock and soil moving as a single unit

slump

groundwater

term used by geologists for water that soaks into the ground, fills the openings in the soil, and trickles into cracks and spaces in rock layers

deposition

the process by which worn away soil and rock settle out of the water

gradient

the rate at which something changes over a distance or time

erosion

the removal of soil and rock from one area to another

velocity

the speed of an object in a particular direction

As the energy of a wave moves through the water, what happens to the water particles themselves?

they move up and down, but do not move forward

The mixture of sediments deposited directly by a glacier is called ____________________

till

A stream or river that runs into another stream or river is called a

tributary

In the diagram, above, marker B is pointing to a __________, which is a small stream or river that runs into a larger stream or river

tributary

A kind of glacier called a(n) ____________________ forms when ice and snow build up in a mountain valley

valley glacier

What is the main agent of erosion that has shaped much of Earth's surface?

water

In the diagram, above, marker A is pointing to a __________, which is formed by water eroding away soft rock around harder rock, creating a steep drop-off

waterfall

Where a river flows from an area of harder rock to an area of softer rock, the softer rock may wear away, eventually forming a drop called a(n)

waterfall