Sedimentary Rocks

1
Sedimentary Rocks
2

• 1) Formation of Sedimentary Rocks-
• Sediments- loose materials such as rock
  fragments, mineral grains, and bits of shell that
  have been moved by wind, water, ice, or gravity.
• Sedimentary rocks form when sediments are pressed
  and cemented together.
• A. Stacked rocks-
• Sedimentary rocks are often formed in layers.
• The older layers are on the bottom because they
  were deposited first.
• 2) Classifying Sedimentary Rocks-
• Sedimentary rocks are usually classified as
  Detrital, Chemical, or Organic.

3

• 3) Detrital Sedimentary Rocks-
• Detrital- to wear away.
• A. Weathering- The process that breaks rocks
  into smaller pieces.
• B. Erosion- When a rock is exposed to air,
  water, or ice, it is unstable and breaks down
  chemically or mechanically.
• C. Compaction- When sediments build up in layers
  and pressure is added to those layers, they are
  pushed and compacted to form solid rock.
• D. Cementation occurs when water soaks through
  soil and rock.
• E. Shape and size of sediments-
• Detrital rocks are named according to the shape
  and sizes of the sediments that form them.
• If the sediments are rounded, the rock is called
  conglomerate.
• If the sediments have shape angles, the rock is
  called breccia.

4

• 4) Chemical Sedimentary Rocks-
• Chemical sedimentary rocks form when dissolved
  minerals come out of solution.
• Examples- Limestone and Rock Salt.
• 5) Organic Sedimentary Rocks-
• A. Rocks made from the remains of once living
  things.
• Examples- Chalk and Coal.