Sedimentary%20Rocks

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Sedimentary Rocks
Lithification
Sediments
Deposition
Transport
Erosion
Weathering
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Weathering
The sediments that make up sedimentary rocks are
produced by
Mechanical Chemical Weathering
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Mechanical Weathering
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Chemical Weathering
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MineralStability
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Products of Weathering

• Lithic (Rock) Fragments(granite, basalt, schist,
  etc.)
• Dissolved Ions(Calcium, Potassium, Sodium, etc.)
• Rust Minerals (Hematite, Goertite, etc.)
• Clay Minerals(Bentonite, Montmorillonite, etc.)
• Residual Minerals(Quartz, Orthoclase, Muscovite,
  etc.)

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Erosion Transport
Water Wind Ice Gravity
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Deposition
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Lithification
Sediment
Rock
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Cementation

• Typical Cement
• Calcite
• Quartz

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Sedimentary Rocks
Identification
Note Use the same terms to describe sediments
sedimentary rocks. Only difference is
lithification!
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Rock Identification is based on

• CompositionWhat minerals make up the rock?

• TextureWhat is the shape, size and orientation
  of the mineral grains that make up the
  rock?Major DifferenceCrystalline vs. Clastic

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Types of Sedimentary Rocks
Detrital Rocks
Chemical Rocks
vs.
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Difference TextureDetrital (Clastic
Texture)vs.Chemical (Crystalline Texture)
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Detrital Rock Composition

• Detrital Rocks
• Lithic Fragments
• Quartz
• Clay Minerals
• Fossil Fragments
• Rust Minerals
• Orthoclase
• Muscovite / Biotite

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Detrital Rock Texture

• Clastic Texture
• Grain Size
• Grain Sorting
• Grain Rounding
• Sediment Maturity

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Grain Size

• Gravel 2mm
• Sand 1/16 mm
• Mud - Silt 1/256 mm
• Mud - Clay

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Detrital Rock Names(Based Primarily on Grain
Size)
Gravel Sized Conglomerate
Sand Sized Sandstone
Mud Sized Mudstone
Siltstone
Shale
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Sorting
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Grain Roundness
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Gravel Sized Detrital Rocks(Subdivided Based on
Grain Roundness)
Conglomerate
Breccia
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Maturity

• Immature
• Poorly Sorted
• Angular grains
• Mixed Compositionincluding clay

• Mature
• Well Sorted
• Well Rounded
• All Quartz

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Sandstones(Subdivided based on maturity)
Quartz Sandstone
Arkose (Sandstone)
Lithic Sandstone
Greywacke
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Sandstones Under a Scope
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Detrital Sedimentary Rock ID
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Chemical Rock Texture

• Crystalline Texture
• Coarse
• Fine

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Chemical Sedimentary Rocks(Names based primarily
on composition)

• Basic Rock Name
• Limestone
• Chert
• Rock Salt
• Rock Gypsum
• Peat or Coal

• Composition
• Calcite
• Quartz (silica)
• Halite
• Gypsum
• Carbon / Plant Remains

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Chemical Rocks(Names based mainly on composition)
Limestones
Crystalline Limestone
Fossiliferous Limestone
Chalk
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Chemical Rocks (cont.)
Evaportites
Chert
Rock Salt
Rock Gypsum
Coal
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Chemical Sedimentary Rock ID
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Sedimentary Rocks on Earth