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