REVIEW OF WEATHERING AND EROSION

WHAT WORD(S) SIMPLY DESCRIBE “WEATHERING”

• Breaking down

• Remember this is different from erosion

• There are two types of weathering:

CHEMICAL AND MECHANICAL

CHEMICAL WEATHERING ACID RAIN

DISSOLVE IN WATER

CARBON DIOXIDE

ORGANISMS OXIDATION

MECHANICAL WEATHERINGABRASION

PLANTSANIMALS

TEMPERATURE CHANGE

RELEASE OF PRESSURE

WHAT WORD(S) WOULD SIMPLY DESCRIBE “EROSION”

• MOVEMENT

• Erosion occurs after weathering• Types of erosion include:

WATER/ICEWINDGRAVITY

EROSIONWATER WIND

GRAVITY

NEW IMPORTANT TERM…

Principle of UniformitarianismPrinciple of Uniformitarianism

• States that the same processes that operate today operated in the past.

• All the types of weathering and erosion we’ve studied that occur today have ALWAYS BEEN OCCURRING since the beginning of the Earth.

• A principle is basically a LAW (description of how nature works).

Deposition and the Weathering-Erosion-Deposition

Cycle(WED Cycle)

What is Deposition?What is Deposition?

• The process in which sediment is laid down in new locations.

WINDWINDEROSION

EROSIONFINISHFINISH

STARTSTART

DEPOSITIONDEPOSITION

What causes Deposition?What causes Deposition?

• All the types of erosion: water, wind, gravity, etc.

What is the WED cycle?What is the WED cycle?

• The Cycle of Weathering, Erosion, and Deposition that occurs now and has been occurring all around the world at all times.

• Because of this cycle, the Earth’s surface has changed greatly over time.

• It is what fills in lakes, shortens mountains, made the grand canyon, etc.

WED CYCLEWED CYCLE

WEATHERING

EROSION

DEPOSITION

WED CYCLEWED CYCLE

BEATS UP ROCKS

MOVES ROCKS

DROPS ROCKS IN NEW PLACE

Here is a section of the Earth’s surface 100,000 years ago. There is a mountain and a nicelittle lake.

Here is the same section after10,000 years after weathering,erosion, and deposition haveoccurred.

Here is the same sectiontoday; weathering, erosion,and deposition haveoccurred and will continue to occur.

Consider this…

The Appalachian mountains are the oldest mountains in the world. They were formed300 million years ago. The Rocky Mountains were formed between 65 and 100 million years ago. The highest part of the AppalachianMountains is Mt. Mitchell (in North Carolina) at 6,684 ft. The highest part of The Rocky Mountains is Mt. Elbert (in Colorado) at 14,440 ft. Can you explain why?