Transcript What are the layers and characteristics of Earth`s Interior?

Key Terms: weathering, mechanical weathering,
chemical weathering, sediment, erosion, deposition,
compaction, cementation.
Sediment
 Please turn to page 52 in your textbook.
 Sedimentary rocks form from sediment.
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Sediment is any small solid piece of material
that come from:
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pre-existing rock broken down into smaller pieces
remains of living things (organic material) such as
shells, bones, leaves, dead wood, etc.
crystallized dissolved minerals.
Stop :
Complete Formation of Sedimentary Rocks
Activity Worksheet Number 1
Before Continuing
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Weathering
 Weathering is the process that breaks down rock and
other substances at Earth’s surface.
 The process of mountain building thrusts rock up to
the Earth’s surface.
 There the rock becomes subject to weathering.
 There are two types of weathering
 Mechanical Weathering
 Chemical Weathering
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Mechanical Weathering
 Mechanical weathering occurs when rock is broken
down into smaller pieces by physical changes.
 The forces of mechanical weathering that breaks rock
into pieces are
 Freezing and thawing (frost wedging)
 Release of pressure
 Growth of Plants
 Actions of animals
 Abrasion
 These forces are called the agents of mechanical weathering.
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Chemical Weathering
 Chemical weathering occurs when rock is broken
down through chemical changes.
 The agents of chemical weathering that break down
rock are
 Water
 Oxygen
 Carbon dioxide
 Living organisms
 Acid Rain
Stop :
Complete Formation of Sedimentary Rocks
Activity Worksheet Number 2, 3, and 4 Before
Continuing
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From Sediment to Rock
 Different processes occur in a specific order that turn
sediment into sedimentary rock.
Erosion- the movement of sediment.
 Deposition- the depositing of the
sediment.
 Compaction- pressing the sediment
together.
 Cementation- binding the sediment.
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Erosion
Erosion occurs when sediment is
moved.
Sediment can be moved by:
Gravity
 Rivers and Streams
 Glaciers
 Wind
 Waves
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 These are known as agents
of erosion.
Stop
:
Complete Formation of Sedimentary Rocks Activity Worksheet Number 5
Before Continuing
Deposition
Deposition is the process by which
sediment settles out of the agent of
erosion that had been carrying it.
Sediment is deposited in:
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Horizontal layers
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layers become very thick after a long periods
of time.
Oldest layers on the bottom
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Law of Superposition.
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Erosion and Deposition Animation
 Observe how sediment is eroded and
deposited
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Compaction
After being deposited, thick layers
of sediment build up.
These layers are heavy and press
down on the layers beneath them.
Compaction then occurs.
Compaction is the process that
presses sediments together.
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Cementation
 Minerals are dissolve in water.
 The water containing the dissolved minerals seep
into the spaces between the sediment.
 The water evaporates, leaving behind the
crystallized minerals.
 Cementation then occurs.
 Cementation is the process in which dissolved
minerals crystallize and glue particles of sediment
together.
 Often takes millions of years for compaction and
cementation to transform loose sediments into
solid sedimentary rock.
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Compaction and Cementation Animation
 Observe how sediment is compacted
and cemented.
Stop :
Complete Formation of Sedimentary Rocks
Activity Worksheet Number s 6 and 7
Before Continuing
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Classifying Sedimentary Rock
 Geologists classify sedimentary rock
according to the type of sediment that make
up the rock.
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Clastic Sedimentary Rock
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Organic (Biochemical) Sedimentary Rock
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Sediment type: Rock fragments
Sediment type: Remains of Biological/Organic
material. Mainly fossil shells or plant fragments.
Chemical Sedimentary Rock
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Sediment type: dissolved mineral crystallization.
Mainly chemically precipitated crystals
Stop:
Complete Formation of Sedimentary Rocks Activity Worksheet Number 8 and turn in your activities sheet when finished.
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