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 components1. ________________________________

2. ________________(decayed remains of organic

material) The main source is _______________

3. _________________

4. ____________

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