Changes to Earth’s Surface.

Changes to Earth’s Surface.

What Processes Change Landforms?

Changing LandformsThe earth’s surface is always changing

around you.Flowing water, waves, wind, ice, internal

movements all change existing landforms.Def:

Landforms-physical features on the earth’s surface

What are some of the forces that change landforms?

Write your answer in your notes.

A: What are some of the forces that change landforms?

Flowing water waves wind icemovements inside the Earth transform the

landforms or Earth’s surface

WaterMuch of the earth’s surface is made of

rock.Shaping occurs when weathering wears

away rockDef: Weathering- the process of breaking

rock into silt, sand, clay, and other tiny pieces called sediment.

Water

After weathering has broken rock into sediment, erosion and deposition move the sediment to new places.

Def: erosion-the process of moving sediment from one place to another.

Def: deposition- the process of dropping or depositing sediment in a new location.

Water

Some rivers deposit sediment in wide areas at their mouths, which are called deltas.

Wind

Wind also causes weathering and erosion.

Like a sandblaster, it uses particles to erode surfaces.

Wind also carries sediment from place to place.

Wind erodes dry surfaces easier than wet or damp rock.

Wind

Sand can be blown into large mounds called dunes.

Beach dunes are built by the constant blowing sea breezes.

Sleeping Bear Dunes in Michigan.

Ice

Glaciers can also change landforms.Def: Glaciers- thick sheets of ice, formed

in areas where more snow falls in the winter than melts in the summer.

Glaciers are actually moving.Because of their size and weight, glaciers

erode everything under them.

Ice

There are two kinds of glaciers:

1.valley glaciers-found in high mountains valleys, and flow slowly down mountainsides. Only a few left in North America, and even those are melting rapidly.

Ice

2. Continental glaciers- ice sheets that cover large areas of Earth. These are the glaciers that thousands of years ago covered Europe, Canada, and the Northern United States.

Mass Movement

When large amounts of soil and sediment move quickly.

Two examples of mass movement are mudslides and landslides.

Def: mudslides- move wet soil.Def: landslides- move dry soil and rock.Both occur when gravity becomes stronger than

the friction holding the soil in place on a hill.

Mass Movement

Def: creep- occurs when soil moves slowly downhill because of gravity.

Creep can occur so slowly that it is hardly noticeable.

Most of the time, it is noticed when things seem out of place, like fences, utility poles, roads, and railroad tracks. Or then a sinkhole can form.

Mass Movement

A sinkhole forms when the rock under the soil dissolves or erodes away.

Def: sinkhole- a large hole in the ground that opens suddenly.

New Landforms

Glaciers are a major way new landforms occur.They push mounds of sediment in front of them,

and when they melt, the rock and soil leave ridges of new landforms.

Def: terminal moraines- when glaciers melt and leave ridges of sedimentary rock and soil to mark their leading edge of movement.

New Landforms

New islands can be formed by volcanic eruptions, especially underwater volcanoes.

Underwater volcanoes increase their height by depositing melted rock and ash.

The Hawaiian islands formed this way.A new island called Loihi is forming this

way, growing slowly on the ocean floor.

Questions to answer

What is erosion?What is deposition?What is weathering?Describe how water, wind, and ice cause erosion,

deposition, and weathering.What are glaciers?What is mass movement?How do terminal moraines form?How did the islands of Hawaii form?How does an oxbow lake form?

Questions to answer

What is erosion?Answer:The process that picks up

sediment and moves it elsewhere.

Questions to answer

What is deposition?Answer: The process that leaves sediment

in other places.

Questions to answer

What is weathering?Answer: the process of breaking rock into

silt, clay,and other tiny pieces, called sediment.

Questions to answer

Describe how water, wind, and ice cause erosion, deposition, and weathering.

Answer: Water causes weathering,erosion, and deposition when water runs over land formations for a long period of time. When the water flows slows or stops, it deposits the particles that broke off.

Questions to answer

Describe how water, wind, and ice cause erosion, deposition, and weathering.

Answer: Wind causes weathering and erosion when it picks up loose particles of soil and rock and blows it around. When the wind stops blowing, it deposits the particles.

Questions to answer

Describe how water, wind, and ice cause erosion, deposition, and weathering.

Answer: Ice causes weathering and erosion when the giant glaciers slide against the ground. Deposition occurs when the ice begins to melt and the soil and rock particles it has moved get left behind.

Questions to answer

What are glaciers?Answer: Glaciers are thick slabs or

sheets of ice that form in areas of the Earth where it snows more than is able to melt away in the summer.

Questions to answer

What is mass movement?Answer: Mass movement occurs when the

gravitation pull overcomes the friction holding the soil in place.

Questions to answer

How do terminal moraines form?Answer: When glaciers melt away, they

leave behind long ridges of soil and rock.

Questions to answer

How did the islands of Hawaii form?Answer: Underwater volcanoes formed

these islands by building up melted rock and ash until it appears above sea level.

Questions to answer

How does an oxbow lake form?Answer: An oxbow lake forms when a

slow moving river forms a broad loop, which eventually closes off and the river forms a new path through the land. The leftover loop forms a crescent shaped body of water.