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- Chapter 4 : Weathering, Erosion, Deposition, and Landscapes.

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Do Now: Name several useful functions of soil.Do Now: Name several useful functions of soil.

Serves as a home for animals and insects.

It is used to filter waste and water.

Has the ability to store and heat water.

Produces and stores gases (like carbon dioxide).

Provides nutrients for & sustains plant life.

Absorbs rain to prevent flooding. Contributes to vegetation.

Several Functions of Soil Consist Of :

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Layer:Layer:

Topography:Topography:

Weathering:Weathering:

Microorganisms:Microorganisms:

Soil:Soil:

A single thickness of some material covering asurface.

The shape and configuration of a

surface/land.

The alteration of rock to more stable material

from their exposure to the agents of air, water,and organic fluids.

A living thing (organism) of microscopicsize that has the ability to act or function

independently.

Material in the top layer of the surface of the earth

in which plants can grow.

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Soil is the mixture of weathered rock,

microorganisms and/or organic remains

on the primary surface of the Earth that

usually covers bedrock. Soil serves as anatural medium for the growth of land

plants. The composition of soil depends

on the rocks which it weathered and the

surrounding climate.

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There are several factors that determine howThere are several factors that determine howsoils are formed. Some of them are:soils are formed. Some of them are:

1. Parent materialParent material The composition of the soil and what it is madeup of.

2. ClimateClimate - Heat, wind, and ice affect how fast or slow the soil

processes.

3. OrganismsOrganisms - These are the things that live on or in the soil.

4. TopographyTopography - The location of soil changes how the soil is affected

by climate. For example, soil at the bottom of a hill will get morewater than the soil at the top of a hill.

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Soil CompositionSoil CompositionSoil is made up of both living and dead organisms which consist of plantsSoil is made up of both living and dead organisms which consist of plants

and animals , air, water, and mineral particles such as sand, silt, and clay.and animals , air, water, and mineral particles such as sand, silt, and clay.The diagram below shows the four main ingredients of ideal soil.The diagram below shows the four main ingredients of ideal soil.

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Soil FormationSoil FormationPhysical weathering breaks solid rock into smallparticles. Chemical weathering changed theminerals, often increasing the clay content. Plantsand animals add organic materials in the form of

waste products and the remains of dead organisms.The decay of organic remains produces organic

acids which accelerate chemical weathering.Burrowing animals, such as earth worms, androdents help air and water circulate through the soil

and mix mineral and organic matter.

- Reviewing EarthScience: The Physical Setting ( Page 84 )

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Soil LayersSoil LayersComplete the Following Diagram:Complete the Following Diagram:

OO-- HorizonHorizon

EE-- HorizonHorizon

BB-- HorizonHorizon

CC-- HorizonHorizon

RR-- HorizonHorizon

AA-- HorizonHorizon

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Chemical weathering turns hard minerals into soft ones.

Mechanical weathering breaks solid rock into smaller pieces.

Plant & animals add organic materials in the form of wasteproducts & dead organisms .

The decay of organic matter produces acids which acceleratechemical weathering.

Burrowing Animals, such as earthworms, insects, & rodents, helpcirculate air and water through the soil & mix mineral & organicremains.

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O HorizonO Horizon: litter layer;forested areas

A Horizon:A Horizon: top soil; highorganic content

EH

orizon:EH

orizon: eluviations of clay, iron,

aluminum

sand & silt left behind

B Horizon:B Horizon:

eluviations: accumulation ofexuviated materials

C Horizon:C Horizon: unconsolidatedparent material

RHorizon:RHorizon: solid rock

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Soil LayersSoil Layers

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CH

orizon

RHorizon

A Horizon

B Horizon

C Horizon

RHorizon

A Horizon

C Horizon

RH

orizon

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Which two processes are most important inWhich two processes are most important inthe formation of soils?the formation of soils?

(1)Weathering and biological events(2)Crystallization and metamorphism

(3)Evaporation and condensation(4)Erosion and sublimation

(1)W

eathering and(1)W

eathering andbiological eventsbiological events

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--Taylor Campbell Allen (Period 4)Taylor Campbell Allen (Period 4)