Sedimentary Rocks

I. Sedimentary rocks are made of loose Earth materials

A. Features are many;

1. ripple marks – wavy features often found in sand stone

2. concretions – ball like objects that often form in layers

3. geodes – ball like with crystals that grow inwards in the core

B. Classifications of sedimentary rock

1. Clastics – rocks made of fragmented portions of other rocks, broken shells and minerals

2. Non-Clastic – made from sediments that are deposited by solutions or organic processes

3. Compaction – when water and air is squeezed out and the resulting rock can be impermeable such as shale

4. Cementation- substances that hold other substances together such as sandstone

5. Precipitates – when a chemical reaction forms a solid which settles such as calcite

6. Evaporites – formed when water evaporates and leaves behind a solid such a salt water evaporating and leaving salt crystals