Sedimentary Rocks

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Student Concept Map
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Sedimentary Rocks

• Dr. David Steer

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Rock Cycle
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Group discussion time

• Given
• Bag of sedimentary rocks

Group these rocks in some manner.
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Grouping items

• Remember this exercise?

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Grouping items

• Group these objects in some logical way.

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Grouping items
Depositional setting (3) Texture

• Group these objects in some logical way.

Throw
Target
Use only hands
Hit with a stick
Kick
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Sedimentary Rocks Deposition

• Clastic (detrital) sedimentary rocks
• composed of sediments, rock and mineral fragments
  formed when rocks disintegrate at or near the
  earth's surface.
• Chemical sedimentary rocks
• precipitated from a solution (e.g. sea-water) as
  the result of changing physical conditions (e.g.
  evaporation).
• Biochemical sedimentary rocks
• formed by the actions of living organisms or
  composed of the remains of dead organisms.

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Clastic or Detrital Sedimentary Rocks

• Clastic sediments Classified based on
• coarse grain size particles
• (gravel, includes pebbles, cobbles and boulders),
  
• medium grain size
• (sand)
• fine grain size
• (silt) gritty feel of sample
• very fine sediment
• (clay) too fine to see

May appear layered
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Clastic Rocks Classified
Sediment Grain Size (diameter) Sedimentary Rocks
Clay less than 0.0039 mm Shale, Mudstone
Silt 0.0039 to 0.0625 mm Siltstone
Sand 0.0625 to 2 mm Sandstone
Gravel more than 2 mm Conglomerate
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Review

• Which rock is most likely sedimentary?

Temperature when formed
A
B
Depth
C
E
D
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Examples of clastic sedimentary rocks

• Mudstone
• Fine grained low energy

• Sandstone
• Medium grained moderate energy
• Individual grains visible in samples

• Conglomerate
• Medium to coarse grained high energy

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Chemical Sedimentary Rocks

• Chemical sedimentary rocks
• precipitated from a solution (e.g. sea-water) as
  a result of changing physical conditions (e.g.
  evaporation).
• May be difficult to see layers
• Biochemical sedimentary rocks
• formed by the actions of living organisms or
  composed of the remains of dead organisms.
• Fossils usually apparent

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Examples of Biochemical Sedimentary Rocks

• Limestones
• form when marine organisms die and their
  skeletons accumulate.

• Coal
• forms when land plants die and their organic
  tissue accumulate.

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Concept Map

• Construct a concept map that guides you through
  classifying a sedimentary rock.

Classify these rocks.