Weathering- breaking down materials  There are 2 main types of weathering:  ____________________________WEATHERING- physical forces break down the rock  _____________change the rock’s chemical composition (think tearing a piece of paper)  Examples: _________________________, unloading, biological activity  ___________________________WEATHERING- transformation of the rock into __________________________________________________  _____________________________________________________ (dissolving a marble gravestone, rusting)  Examples: dissolution, reactions with oxygen, reactions with water

M.W.- Frost Wedging  Water can split rocks in 2!  When water freezes, it’s volume ________________(it expands)

M.W. - Biological Activity  The __________________of organisms, including ______________, burrowing ____________________, and ______________, can also cause mechanical weathering.

C.W.- Dissolution, reactions with water, reactions with air  Remember, the weathered materials are being CHEMICALLY CHANGED  Can involve acid precipitation  When ________________________combines with water it can form a ____________________  ____________________________- ______________________________________ __ many substances and reacts with many minerals like marble  ___________________________- over time, _______________________________to form oxides- _______ is IRON-OXIDE exposed to water

Chemical Weathering Example  A marble tombstone is exposed for many years and reacts with __________and ___________in the air to become __________________ __________________

Rate of Weathering  How quickly something is weathered depends on:  The _______________________  Chemical weathering is most effective ___________ ________________________________________  Heat speeds up chemical reactions  Reactions with water are one of our chemical weathering types!  The _________________________  Some rocks and minerals are more likely to be weathering than others  ______________________________  The ______________________________to outside forces, the ______________________________________

Check Ins 1.Define mechanical weathering 2.Define chemical weathering 3.What is frost wedging? 4.What happens to the volume of water when it freezes? 5.What atmospheric gas forms a mild acid when dissolved in water? 6.What factors affect the rate of weathering?

Soil  One of the MOST IMPORTANT products of weathering is soil  Soil is part of the _______________that _________________ _____________________________________________________  Regolith is the _____________________________________fragments that covers most of the Earth’s surface  Soil has 4 main components 1.________________________________ 2.________________(decayed remains of organic material)  The main source is _______________ 1._________________ 2.____________

Soil Formation  The most important factors affecting soil formation are  Parent material- where does the soil originate?  ____________- the longer it’s been forming, the thicker it becomes  _________________- has the _______________________ - best climate is warm and wet  Organisms- living and dead affect the nutrients in the soil  _____________- the ______________the slope, the ________________________________it is for soil to stay in place and accumulate

Soil Texture  What is the difference between these two soils? THEY HAVE DIFFERENT _____________________

Soil Texture  Texture is determined by the ___________________________________  Sand (______________)  Silt  Clay (____________)  _______________is a mixture of all three sizes- it’s the __________________________ _____________________

Soil Texture Soil pyramids are used to determine soil type based upon texture and vice- versa No matter what, the percentages of sand, silt, and clay add to _____________%

How to read a soil triangle Percent ________ is read across here  Percent __ _______is read diagonally down here  Percent _______ is read diagonally up here 

Groundwater movement  Remember that soil supports plant life and that it contains the following 4 components  Air  ___________________  Humus  Mineral matter  How water moves through soil is very important and depends on two factors  ____________________: the ____________________________________________  Determines how much ______________________________________  _____________________: the _______________________________________through interconnected spaces  Determines ____________________________________________________

Soil Erosion  Erosion = the ____________________ of weathered materials  _____________and ___________are two major erosional agents  The rate of erosion depends on the ______________, the _____________of slopes, and type of _________________in the area  _________________and animals have a huge effect on rates of erosion.

Soil Erosion  Do you think the rates of erosion have increased or decreased because of humans?  What are some human activities that you think have accelerated the rates of soil erosion? (brainstorm with a partner)

Soil Erosion  Human activities that accelerate erosion:  ___________________of natural __________________________through  _____________________  Sediment Deposition  Reservoirs fill with sediment  Since humans have appeared the amount of _______________carried by rivers and streams has ______________________________

Soil Erosion  Soil Erosion Control  Continue brainstorming with your partner: What are some ways we can control erosion? 1.Planting rows of ______________called ____________________ 2.Terracing __________________ 3.Plowing along the contours of hills 4.________________________________

Mass Movements  Erosion is the movement of _____________________materials  When LARGE amounts of material move it’s a ________________________  Look at the different types of mass movements on the following slides…

Mass Movements  The ________________of rock and soil ______________due to ___________________is a mass movement  What is the force behind mass movements?  ___________________

Triggers of Mass Movements  Mass movements can be triggered by  ___________________of surface materials with ______________  _____________slopes  _______________________________  Earthquakes  Why can the removal of vegetation trigger mass movements?  ____________________________________________ ____________________________________________ ___________________________________________.

Triggers of Mass Movements  Climate affects mass movements  The greatest threat of mass movements comes during a __________spring _________________vegetation is growing.  Why?  _____________________to hold soil in place  Mass movements can be triggered by ___________________________

Types of Mass Movements  Mass movements are classified based on  Type of ____________________  How it moves  _______________________of movement  Types  Rockfall  Slides  _________________

Mass Movements Summary  Rockfalls  A rockfall occurs when rocks or rock fragments __________________________ through the air  Slides  In a slide, a _______________of material moves ______________________along a flat, inclined surface  Slides that include segments of bedrock are called _______________________  Slumps  A slump is the downward movement of a block of material along a ___________________surface

Mass Movement Summary  Flows  Flows are mass movements of material containing a large amount of _______________  Mudflows _________________and carry a mixture of soil, rock, and water that has a consistency of wet concrete  Earthflows _________________________and carry clay-rich sediment  Creep is the _______________________ movement of soil and regolith

Check-in questions Check In Questions 3 (Soil Erosion and Mass Movement) 1.How have human activities affected the rates of soil erosion? What are some activities that have the greatest effect? 2.What is the force behind mass movements? 3.Explain how the removal of vegetation triggers mass movements. 4.Why might you expect mass movements to be greatest during a wet, early spring? 5.Describe the following mass movements: (a) slide, (b) creep, (c) slump, and (d) flow.

Slump

Creep