3.3 Sedimentary Rocks

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Todays Objective What Makes Sedimentary Rocks
Special?
Sedimentary Rocks - are one of the three main
rock types
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• A sedimentary rock can form one of three ways
• by the deposition of the weathered remains of
  other rocks
• by the deposition of the results of biologic
  activity
• by precipitation from solution.

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Important Vocab!

• Compaction is a process that squeezes, or
  compacts, sediments.
• Cementation glue - takes place when dissolved
  minerals are deposited in the tiny spaces among
  sediments.

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Important Vocab!

• Weathering - is a process in which rocks are
  physically and chemically broken down by water,
  air, and living things.
• Erosion - involves weathering and the removal of
  rock.
• Deposition - when an agent of erosion water,
  wind, ice, or gravity lose energy, it drops the
  sediments.

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Please add

• Agents of Erosion Water, wind, ice/glaciers, and
  gravity

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Classification of Sedimentary Rocks

• Can be classified into two main groups according
  to the way they form.

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• Inorganic Land Derived

(AKA) Clastic Sedimentary Rock - composed of
weathered bits of rocks And minerals. These
rocks are classified by particle size.
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Conglomerate
EXAMPLES of Inorganic Land Derived
Shale with Plant Fossils
Large grain size
Small grain size
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• Chemical Sedimentary Rocks
• Forms when dissolved minerals
• precipitate from water solutions.
• (water usually evaporates or boils)
• Ex Limestone rock salt.

Salt Flat
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• Organically Formed Sedimentary Rocks
• Forms when shell fragments are cemented
  together or when plant remains are compacted into
  rock.
• Ex Fossiliferious Limestone Bituminous Coal

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Features only found in Sedimentary Rocks

• 1. The Law of Superpositioning - In undisturbed
  rocks, the oldest layers are found on the bottom
  and the youngest at the top.

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Please add

• Lithification Physical and chemical processes
  that transform sediments into sedimentary rocks
  (compaction cementation)

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• 2. Ripple Marks rock formed along
• the beach or stream bed.
• 3. Mud Cracks - formed when wet mud or
• clay dried and shrank, leaving a rock
• record of a dry environment.
• 4. Fossils traces of remains
• of ancient life.
• Trilobite

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Where is the oldest layer located on this picture?
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