Chapter 10: Weathering & Soil Formation...Chapter 10 Section 3 From Bedrock to Soil The Source of Soil •What Is Soil? Soil is a loose mixture of small •mineral fragments, •organic

< Back Next > Preview Main

Chapter 10: Weathering & Soil Formation Section 2 & 3: Rates of Weathering & From Bed Rock to Soil


Section 2 Rates of Weathering Chapter 10

Differential Weathering • What Is Differential Weathering? Differential

weathering is a process by which softer, less weather resistant rock wears away and leaves harder, more weather resistant rock. The image below is an example of differential weathering.



The Shape of Rocks • Surface Area: The more surface area of a rock

that is exposed to weathering, the faster the rock will be worn down.

• Increasing the Rate of Weathering: If a large rock is broken down into smaller fragments, weathering of the rock happens much more quickly.





Weathering and Climate • What Is Climate? Climate is the average weather

condition in an area over a LONG period of time.

• Temperature and Water: The rate of chemical weathering happens faster in warm, humid climates. Water also increases the rate of mechanical weathering.



Weathering and Elevation • High Elevations: Rocks at higher elevations, as

on a mountain, are exposed to more wind, rain, and ice than rocks at lower elevations.

• Steep Slopes: The steepness of mountain slopes increases the effects of mechanical and chemical weathering. Steep slopes cause water and sediments to quickly run down the side of the mountain.


Section 3 From Bedrock to Soil Chapter 10

The Source of Soil

• What Is Soil? Soil is a loose mixture of small • mineral fragments, • organic material, • water and air that can support the growth of vegetation.

• Residual and Transported Soil: Soil that

remains above its parent rock is called residual soil. Soil that is blown or washed away from its parent rock is called transported soil.



Soil Properties

• Soil Texture and Soil Structure: • Soil texture is the soil quality that is based on the

proportions (ex. size & shape) of soil particles. • Soil structure is the arrangement of soil particles

(ex. smaller pieces on top & larger on the bottom.)


Chapter 10 Section 3 From Bedrock to Soil



Soil Properties, continued

• Soil Fertility: A soil’s ability to hold nutrients and to supply nutrients to a plant is described as soil fertility.

• Soil Horizons: Because of the way soil forms, soil often ends up in a series of layers called horizons.

• Soil pH: Soils can be acidic or basic. The pH scale is used to measure how acidic or basic a soil is.



Soil and Climate • Tropical Rain Forest Climates: The warm soil in

tropical rain forest climates allows dead plants and animals to decay easily. This provides rich humus to the soil.

• Desert Climates: The lack of rain in desert climates leads to low rates of chemical and mechanical weathering.



Soil and Climate, continued • Temperate Forest and Grassland Climates:

Temperate forest and grassland climates get enough rain to cause a high level of chemical weathering, but not too much that nutrients are leached out.

• Arctic Climates: In arctic climates, as in desert climates, chemical weathering occurs very slowly. Low temperatures slow the formation of humus.


** Show SOIL Brain Pop

Video**

Documents

Chapter 10: Weathering & Soil Formation...Chapter 10 Section 3 From Bedrock to Soil The Source of Soil •What Is Soil? Soil is a loose mixture of small •mineral fragments, •organic