Chapter 3, Section 3Sedimentary Rocks

Wednesday, December 9, 2009

Pages 82 -- 86

Objectives

• Describe how sedimentary rocks form.

• List and describe the three major types of sedimentary rocks.

Vocabulary Words

• Sediment• Erosion• Deposition• Compaction• Cementation• Clastic rock• Organic rock• Chemical rock

From Sediment to Rock

• Sedimentary rocks are formed from particles deposited by water and wind.– Sediments are small pieces of

material that come from rocks or living things.

– Water, wind, and ice can carry sediment and deposit in layers.

Ways Sediments are Turned to Rocks• Erosion

• Deposition

• Compaction

• Cementation

Erosion• Erosion occurs

when running water or wind loosen and carry away rock fragments.– Rock fragments

produced by forces breaking up and wearing away rocks on the Earth’s surface.

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Deposition

• This is the process by which sediment settles out of the water or wind carrying it.– Sediments include

rock particles, shells, bones, leaves, stems, and remains from other living things.

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Compaction• The process that

presses sediments together. – Each layer presses down

the the previous layer.– The weight of the layers

further compacts the sediments, squeezing them tightly together.

– Each layer remains visible.

• This process takes place over millions of years.

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Cementation• The process in

which dissolved minerals crystallize and glue particles of sediment together.

• This process takes place over millions of years.

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Types of Sedimentary Rock

• Clastic Rocks

• Organic Rocks

• Chemical Rocks

Clastic Rock• It is a sedimentary

rock that forms when rock fragments are squeezed together.

• They are grouped by size of the rock fragments by which they’re made.

• Examples include: Shale, sandstone, conglomerate, and breccia.

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conglomerate

Organic Rock

• Forms where the remains of plants and animals are deposited in thick layers.

• Examples include: Coal and limestone

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Coal

Chemical Rocks

• Forms when minerals that are dissolved in a solution crystallize.

• Can also form when mineral deposits left when seas or lakes evaporate.

• Examples include: gypsum and limestone.

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Gypsum

Homework

• Workbook 3.3 (due 12/16)

• Vocabulary quiz 3.3 (on 12/16)