Sedimentary Rocks

1
Sedimentary Rocks

• Section 6.3

2
Classification of Sedimentary Rocks

• Clastic rocks are formed from fragments of other
  rocks.
• These rock fragments are bonded together by
  minerals that fill the space between the
  fragments. This is called cementation.
• There are three types of clastic sedimentary
  rocks. Conglomerate, sandstone, and shale.

3
Chemical rock

• Minerals, such as salts that are deposited out of
  a water solution to form the rock.
• An example is halite in rock salt flats.

4
Organic Rock

• These rocks are formed from organic sediment.
• Organic sediments are made of the remains or dead
  plants and animals.
• The white cliffs of Dover, England are an example.

5
Features of sedimentary Rock

• Stratification are changes in the composition of
  rock layers laid down on top of each other.
• Fossils are found only in sedimentary rock.
• Sometimes ripple marks or mud cracks are
  preserved in the sedimentary rock.

6
Features of sedimentary Rock Cont.

• Limestone sometimes contains spheres of silica
  rock called geodes.
• Geodes have crystals inside. These crystals are
  usually quartz or calcite.
• Geodes may be formed from pockets of water in the
  rock.