Weathering & Erosion Choose OK. What is weathering? Weathering is the process that breaks down rock and other substances on Earth’s surface. The forces.

Weathering & ErosionWeathering & Erosion

Choose Choose OKOK

What is weathering?What is weathering?

Weathering is the process Weathering is the process that breaks down rock and that breaks down rock and other substances on Earth’s other substances on Earth’s

surface . The forces of surface . The forces of weathering breaks rocks into weathering breaks rocks into smaller and smaller piecessmaller and smaller pieces

What is Erosion?What is Erosion?

Erosion is the removal of these small Erosion is the removal of these small particles of rock by wind , water ice or particles of rock by wind , water ice or gravity.gravity.

Weathering and erosion work together Weathering and erosion work together to continuously wear down and carry to continuously wear down and carry away the particles, constantly away the particles, constantly changing the surface of Earth.changing the surface of Earth.

There are two main types of There are two main types of weathering:weathering:

Mechanical [sometimes called Mechanical [sometimes called physicalphysical]] ChemicalChemical

Both types of weathering act slowly, but over time, Both types of weathering act slowly, but over time, they break down even the biggest, hardest rocks.they break down even the biggest, hardest rocks.

Mechanical weathering Mechanical weathering breaks breaks rocks down into smaller pieces. rocks down into smaller pieces.

Types of mechanical weathering Types of mechanical weathering include freezing and thawing, include freezing and thawing,

release of pressure, pant growth, release of pressure, pant growth, actions of animals and abrasion. actions of animals and abrasion.

Let’s investigate Let’s investigate mechanical weatheringmechanical weathering

first.first.

In mechanical weathering, a In mechanical weathering, a rock is broken down into rock is broken down into smaller pieces without smaller pieces without changing its mineral changing its mineral

composition.composition.

There are several different There are several different processes that cause processes that cause

mechanical weathering. mechanical weathering. View Website

Observe the effects of Observe the effects of mechanical weathering mechanical weathering

View Website

Enchanted Enchanted rock is a rock is a

huge huge example of example of mechanical mechanical weathering. weathering.

Now, let’s look at Now, let’s look at chemical weatheringchemical weathering. .

Chemical weathering Chemical weathering breaks rocks breaks rocks down rock through chemical down rock through chemical

changes . The causes of chemical changes . The causes of chemical weathering include:weathering include:

WaterWater

OxygenOxygen

Carbon dioxideCarbon dioxide

Living OrganismsLiving Organisms

Acid RainAcid Rain

Chemical weathering Chemical weathering happens when the minerals happens when the minerals

that make up a rock are that make up a rock are changed, leading to the changed, leading to the

disintegration of the rockdisintegration of the rock

EXAMPLES OF CHEMICAL EXAMPLES OF CHEMICAL WEATHERINGWEATHERING

OXIDATION OCCURSOXIDATION OCCURS when free when free oxygen combines chemically with oxygen combines chemically with metallic elements (usually iron) metallic elements (usually iron)

AKA AKA RUSTRUST

CARBONATIONCARBONATIONWater containing carbonic acid Water containing carbonic acid

dissolves minerals (all rain water is dissolves minerals (all rain water is slightly acidic)slightly acidic)

Most strongly affected are Most strongly affected are calcite minerals:calcite minerals:

limestone and marblelimestone and marble

CARBONATIONCARBONATION

Stalagmites and Stalagmites and stalactitesstalactites

Acid RainAcid Rain

Acid rain causes rapid chemical Acid rain causes rapid chemical weatheringweathering

Lichens on Lichens on rocks cause rocks cause

chemical chemical weathering weathering by secreting by secreting an acid that an acid that breaks down breaks down

the rock.the rock.

View the following websites to View the following websites to learn more about chemical learn more about chemical

weatheringweathering 1.) 1.) Feldspar to clay

Now let’s move on toNow let’s move on toEROSIONEROSION

What is erosion?What is erosion?

Erosion is the process by which Erosion is the process by which natural forces move weathered natural forces move weathered rock and soil from one place to rock and soil from one place to

another.another.

Some of these forces include Some of these forces include glaciers, wind, water, earthquakes, glaciers, wind, water, earthquakes, volcanoes, tornadoes, hurricanes, volcanoes, tornadoes, hurricanes,

mud flows, and avalanches.mud flows, and avalanches.

As soon as a rock particle (loosened by one As soon as a rock particle (loosened by one of the two weathering processes) moves, we of the two weathering processes) moves, we

call it call it erosionerosion . .When it comes to rest , or lay down, we call it When it comes to rest , or lay down, we call it

deposition.deposition.

Weathering, erosion, and deposition act Weathering, erosion, and deposition act together in a cycle that wears down and together in a cycle that wears down and

build up Earth’s surface. build up Earth’s surface.

Water is the most Water is the most important erosional agent important erosional agent and erodes most often as and erodes most often as

running water in streams or running water in streams or rivers.rivers.

FloodingFlooding

Sea ArchesSea Arches

Beach ErosionBeach Erosion

River ErosionRiver Erosion

Observe river erosion Observe river erosion causing waterfallscausing waterfallsVisit this Visit this website

Waves in oceans and other large Waves in oceans and other large bodies of water cause coastal bodies of water cause coastal

erosion. erosion.

The power of ocean waves is The power of ocean waves is awesome; large storm waves awesome; large storm waves can produce 2000 pounds of can produce 2000 pounds of pressure per square foot. The pressure per square foot. The

pure energy of waves along with pure energy of waves along with the chemical content of the the chemical content of the

water is what erodes the rock of water is what erodes the rock of the coastline. the coastline.

Wave action in Calvert County Maryland

Watch wave erosion on Watch wave erosion on this websitethis website

Erosion by wind is known as Erosion by wind is known as aeolian erosion (named after aeolian erosion (named after

Aeolus, the Greek god of Aeolus, the Greek god of winds) and usually occurs in winds) and usually occurs in deserts. Aeolian erosion of deserts. Aeolian erosion of

sand in the desert is partially sand in the desert is partially responsible for the formation responsible for the formation

of sand dunes.of sand dunes.

Painted Desert National Painted Desert National MonumentMonument

Sahara DesertSahara Desert

Gobi Desert in ChinaGobi Desert in China

Kalahari DesertKalahari Desert

Dust Bowl, the man-caused Dust Bowl, the man-caused environmental disaster of the environmental disaster of the

1930s1930s

The erosive power of moving ice is The erosive power of moving ice is actually a greater than the power actually a greater than the power of water. However since water is of water. However since water is

much more common, it is much more common, it is responsible for a greater amount responsible for a greater amount of erosion on the earth's surface. of erosion on the earth's surface.

Athabasca Glacier - Jasper, Canada

Hubbard Glacier in Alaska Hubbard Glacier in Alaska

valley glaciervalley glacier

Observe landscapes Observe landscapes formed by erosion click on formed by erosion click on

the websitethe website

Let’s look at some more Let’s look at some more examples of erosion.examples of erosion.

Website Website

The End!The End!