Erosion and Weathering

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 Erosion Water Wind Glacier Soil Sea

Water 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

Wind 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 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 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 Erosion Biggest problem for farmers Wind and rain remove topsoil and nutrients Makes the soil infertile and it breaks up leaving dongas

TASK 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: 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?

RUBRIC Rubric for task 1 2 3 4 5 Total 15 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 Total 15