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Sedimentary Rocks. Bits and Pieces. Sedimentary rocks form as sediment is: l Deposited l Buried l Compacted l Cemented. Sedimentary rocks fall into 3 groups:. Clastic/inorganic Organic Chemical. Physical Weathering.

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Sedimentary rocks

Sedimentary Rocks

Bits and Pieces


Sedimentary rocks form as sediment is:

lDeposited

lBuried

lCompacted

lCemented


Sedimentary rocks fall into 3 groups
Sedimentary rocks fall into 3 groups:

  • Clastic/inorganic

  • Organic

  • Chemical


Physical weathering
Physical Weathering

  • Clastic sediments are produced when rock physically weathers, which means it breaks apart.

  • Big rocks break into smaller rocks.

  • Weathering is an extremely slow process.


There are 6 sizes of clastic sediments
There are 6 sizes of clastic sediments.

  • Boulders

  • Cobbles

  • Pebbles

  • Sand

  • Silt

  • Clay


Particles are collected and transported by running water
Particles are collected and transported by running water.

http://www.youtube.com/watch?v=fATA1SOLICo


Abrasion
Abrasion

  • Sediments become smoothed and rounded as they bounce along the bottom of the stream and hit against each other.


Deposition and sorting
Deposition and Sorting

  • A stream loses velocity when entering quiet waters so its ability to transport sediment decreases. Particles drop to the bottom. This is deposition.

  • Large particles settle first. Other particles settle according to size. Smallest particles last. This is sorting.


Burial and compaction
Burial and Compaction

  • As more sediments accumulate, the bottom ones are buried.

  • This increased weight of the top sediments physically squeezes the lower sediments together which compacts them.

Heavy Weight

OUCH!


Cementation
Cementation

  • All the waters of the Earth contain dissolved minerals. These dissolved minerals and sometimes clay fill up spaces between the rock fragments and bind them together. This is cementation.


Stratification
Stratification

  • Sedimentary rocks often form in horizontal layers called strata.


Fossils
Fossils

  • These layers or strata often contain fossils.

  • Only sedimentary rocks contain fossils.


Fossil structures
Fossil Structures

  • Mud cracks and ripple marks give evidence of environment at formation.


Organic bioclastic sediments
Organic(Bioclastic)Sediments

  • The remains of plants and animals. The two most common are shells and plant material.


Chemical sediments
Chemical Sediments

  • Chemical sediments form when water evaporates and the materials dissolved in the water precipitate (settle).


Bonneville salt flats
Bonneville Salt Flats

  • Home of the land speed record.

Thrust SSC –

763 mph

http://www.youtube.com/watch?v=LKQ-xj5C2m8


Yucca Mountain

  • Nuclear waste depository

http://www.youtube.com/watch?v=tbq9a2oyMAo

http://www.youtube.com/watch?v=Q41vzLjwZqM


Characteristics of sedimentary rocks
Characteristics of Sedimentary Rocks

  • Sedimentary rocks are the most common type of rocks on Earth’s surface.

  • Sedimentary rocks usually form underwater.

  • Sedimentary rocks may contain fossils.

  • Sedimentary rocks often form in layers or strata.

  • Sedimentary rocks are our keys to the past.


Nature s palette
Nature’s Palette

Antelope Canyon




Clastic sedimentary rocks
Clastic Sedimentary Rocks

  • Breccia – angular

  • Conglomerate - rounded


Clastic sedimentary rocks1
Clastic Sedimentary Rocks

  • Sandstone – can be various size grains.



Clastic sedimentary rocks3
Clastic Sedimentary Rocks

  • Shale – breaks along bedded planes.


Bioclastic sedimentary rocks
Bioclastic Sedimentary Rocks

  • Bituminous coal – plant remains = carbon


Bioclastic sedimentary rocks1
Bioclastic Sedimentary Rocks

  • Limestone – cemented shell fragments or precipitates of biologic origin = calcite


Chemical sedimentary rocks
Chemical Sedimentary Rocks

  • Rock salt - Crystalline texture composed of halite.


Chemical sedimentary rocks1
Chemical Sedimentary Rocks

  • Dolostone – Crystalline texture composed of dolomite.

Fossil


Chemical sedimentary rocks2
Chemical Sedimentary Rocks

  • Rock Gypsum – Crystalline texture composed of gypsum.


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