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Sedimentary Rocks

S6E5. Students will investigate the scientificview of how the earths surface is formed.

c. Classify rocks by their process offormation.Enduring Understanding: Rocks are groupedbased on how they formed and their mineralcomposition.

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Sedimentary Rocks

http://www.fi.edu/fellows/payton/rocks/create/sedi

ment.htm

Sedimentary rocks are layers ofsediment

cemented together. The sedimentary processbegins with igneous, sedimentary andmetamorphic rocks weathered which is thebreaking down of rocks followed by erosionthe movement from the Earth's surface by

natural processes such as wind or water flow,through the act of transportation. Thetransfer of sediments (soil particles) from oneplace to another followed by deposition thelayering after layering of the sediment. Then

Compaction occurs after the sediments havebeen deposited. Cementation the finalprocess acts as glue or cement to bind thesediments together forming sedimentary rocks.

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Sedimentary Rock

Sedimentary Rocks are formed at ornear the Earths surface

No heat and pressure involved

Strata layers of rock

Stratification the process inwhich sedimentary rocks are

arranged in layers

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Origin

Comprise 75% of the Earths surface

Formed when sediments becomecompacted and cemented together

Usually has layers called strata

The highest layer has theleast pressure.

The lowest layer has themost pressure.

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Compaction

What does

compactionmean? Layer upon layer of

sediment builds up andthe pressure from theupper layers pushesdown on the lower layers.

Only SMALL sedimentswill stick together to formrock

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Cementation

What does it mean?

Water soaks through soil and rock.The water dissolves minerals in soiland rock.

The solution ofminerals and water

moves between the sediments.The sediments stick together when the

minerals crystallize.

Common with LARGE sediments

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Classification

Sedimentary rocks are classified in3 ways (formed)

1. Clastic Sedimentary Rocks

2. Chemical Sedimentary Rocks

3. Organic Sedimentary Rocks

Its by the way they are formed!!!

WHAT?

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1. Clastic Sedimentary Rock

Made from broken fragments ofother rocks.

Conglomerate = large/round fragments

Breccia = large/sharp fragments

Breccia Conglomerate

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Sedimentary Rock

Clastic

made of fragments of rockcemented together with calcite or quartz

Breccia is a term most

often used for clasticsedimentary rocks thatare composed of largeangular fragments(over two millimeters

in diameter).

The spaces betweenthe large angularfragments can be filledwith a matrix ofsmaller particles or a

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2. Chemical Sedimentary

Rock

Formed from minerals crystallizingout of a solution

The solution is made ofmineralsand water.

Halite (Rock Salt)

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Sedimentary Rock

Chemical sedimentary minerals crystallizeout of solution to become rock

Limestone is asedimentary rockcomposed primarily ofcalcium carbonate(CaCO3) in the form of themineral calcite. It most

commonly forms in clear,warm, shallow marinewaters.

It is usually an organicsedimentary rock that

forms from theaccumulation of shell,

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3. Organic Sedimentary Rock

Rocks formed from once-living(organic!) things.

Organic LimestoneOcean animals called coral createhuge deposits of limestone. As they

die, their skeletons collect on theocean floor.

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Sedimentary Rock

Organic sedimentary remains of plants andanimals

Coal is an organicsedimentary rock thatforms from theaccumulation andpreservation of plantmaterials, usually in a

swamp environment.

Coal is a combustiblerock and along withoil and natural gas itis one of the three

most important fossilfuels.

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Stratification

The process in which sedimentaryrocks are arranged in layers.

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