Erosion and WeatheringErosion and Weathering

What is erosion?What is erosion?

• (geology) the mechanical process of wearing or grinding something down (as by particles washing over it)

• The wearing away of the earth’s surface by natural processes

• corrosion: erosion by chemical action

Types of ErosionTypes of Erosion

• Water

• Wind

• Glacier

• Soil

• Sea

WaterWater

• Occurs from chemicals in the water and the force and flow of water

• Chemicals break down certain rocks like limestone or chalk

• Force of water creates cracks and crevasses

• These get bigger and bigger as it gets eroded, particles of the rock get carried in the water and further aid erosion

WindWind

• The wind picks up smaller particles of rock (pebbles and sand)

• These hit landforms and take pieces off them

• This friction causes the break up of landforms

Glacier ErosionGlacier Erosion

• What is a GLACIER?: A huge mass of ice slowly flowing over a land mass, formed from compacted snow in an area where snow accumulation exceeds melting

• These large bodies of ice that pick up rocks and earth and erode the earth’s surface

• Powerful eroding machine, picking up pieces of rock the size of houses in some places

• Glaciers are so powerful they can carve valleys and create landforms

Sea ErosionSea Erosion

• Salts and other chemicals in the water erode coastal rocks

• These are dragged out to sea and deposited in other areas (Long shore Drift)

• Wave power creates erosion. Also particles of rock and sediment aid to the erosion process

Soil ErosionSoil Erosion

• Biggest problem for farmers

• Wind and rain remove topsoil and nutrients

• Makes the soil infertile and it breaks up leaving dongas

TASKTASK• You are a forester in South Africa and you have just acquired some land and you are faced with a

problem with soil erosion due to poor farming techniques:

YOUR PROBLEM: YOUR PROBLEM: • DONGAS CASUED BY EROSION HAVE TAKEN UP CRITICAL SPACE FOR YOU TO PLANT AND GROW

TREES

• WHAT STEPS ARE YOU GOING TO TAKE TO REPAIR THE DONGAS?• WHAT IMPROVED PLANTING TECHNIQUES ARE YOU GOING TO USE?

RUBRICRUBRICRubric for task 1 2 3 4 5

Steps to combat problem

Just outline Just points No steps good points Good outline good points Very good step by step outline with relevant points and techniques

Repair Dongas Just technique no explanation

No technique vague explanation

Adequate technique and vague explanation

Good technique, adequate explanation

Relevant techniques and clear explanation of techniques

Improved faming methods

Little effort made Adequate methods no explanation

Adequate methods and adequate explanation

Good methods and good explanation

Excellent methods and explanations

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