1. Weathering, Erosion, and Soil Notes

2. Weathering
Notes

3. Weathering - The surface processes that break down rock into small pieces called sediment.

4. Two Types of Weathering
MECHANICAL WEATHERING –
Physical processes that break rock into fragments with the same makeup and characteristics as the original rock.
Examples:
1. Plant Roots
2. Burrowing Animals
3. Ice Wedging - occurs when water enters cracks of rocks, freezes and expands, and breaks rock apart.

5. Mechanical - Plant Roots

6. Mechanical – Burrowing Animals

7. Mechanical – Ice Wedging

8. Two Types of Weathering
2. CHEMICAL WEATHERING –
Chemical reactions dissolve minerals in rocks or change them into different minerals.
Example: Oxidation - chemical process that occurs when iron is exposed to oxygen in the air causing the rock to break down.

9. Chemical - Oxidation

10. Chemical – Dissolving

11. Factors that Affect Rate of Weathering
Effects
Climate
Chemical Weathering - is rapid in warm, wet climates. Heat or high temperatures speed up chemical reactions that occur in water.
Mechanical Weathering – is often rapid in colder climates that have frequent freezing and thawing.
Rock Type
 Some types, such as granite, weather slowly in warm wet climates than others, such as marble.

12. Erosion
Notes

13. Erosion - The wearing away and moving of surface materials by gravity, water, wind, or glaciers.
4 Agents of Erosion:
Wind
Water
Gravity
Glaciers

14. Types of Erosion
Mass Movement- occurs as gravity moves materials down a slope as one large mass.
Transportation- the carrying of sediments from one place to another.
Deposition- when erosion agents drop sediments as they lose energy.

15. Types of Mass Movement
Types
Description
Slump
A mass of sediment slips along a curved surface.
Mudflow
A mixture of sediment and water flows down a slope.
Creep
Sediment moves downhill slowly.
Rock Fall or Rock Slide
Layers or blocks of rock break loose and move downhill suddenly.

16. MUDFLOW
SLUMP

17. CREEP

18. ROCK SLIDE

19. Erosion Causes Consequences Prevention Agricultural Cultivation
Forest Harvesting
Overgrazing
Urban Construction
Weather
Building Problems
Poor Soil
Damage to buildings and land
Contour Farming
Terracing
Slopes
Manage Crops

22. Soil
Notes

23. SOIL- A mixture of weathered rock, decayed organic matter, mineral fragments, water, and air.
It may take soil up to 1000’s of years to form.

24. The formation of soil is influenced by:
Time affects soil formation because rocks are being weathered constantly and new soil is being added on top of old soil. This takes 1000’s of years but the layers of soil help determine how much water and
nutrients a soil
sample
contains.
Formation of Soil
Climate
Slope – (Topography)
Types of Rock –(Parent Material)
Biota
Length of TIME rock weathered
Hot climates can speed up chemical weathering, while cold weather can lead to ice wedging.
Topography is the shape and steepness or slope of the land. If the land is flat, water enters the soil and can speed up weathering. If the area is on a hill or slope the soil can be washed away or eroded.
Biota means, “all the living organisms in an area”. This includes plants, animals even bacteria and decomposers. Biota helps speed up soil formation.
Parent material
is the rock or sediment that forms soil when it is weathered. Bedrock is parent material that forms in the same place where the soil forms.

25. C. Soil may be made up of:
Particles of sediment such as clay, silt, and sand.
Humus - decaying, dark-colored plant and animal matter.
Water and air, which fill in the space between soil particles.
A soil profile consists of several horizons, or layers

26. HORIZON CHARACTERISTICS A Topsoil B Subsoil C Bedrock
Top layer
Fertile
More humus, less rock B
Subsoil
Middle Layer
Less Humus
Lighter in Color
Minerals through leaching C
Bedrock
Bottom layer
Rocky
Little organic matter
Affected by glaciers

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