1. Sedimentary Rocks I. Formation of Sedimentary Rocks
- Sedimentary = “settling”
- Form when solids settle out of a
fluid such as water or air.
- The sediments eventually become
cemented to form rocks.

2. 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.

3. 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.

4. II. Classification of Sedimentary Rocks
Can be classified into two main groups according to they way they form.

5. Clastic Sedimentary Rocks – composed of weathered bits of rocks and minerals.
Classified by particle size.
Conglomerate – made up of rounded
particles.
Breccia – made up of angular
Ex: Shale, Sandstone, Siltstone

6. Conglomerate

7. Shale with Plant Fossils

8. 2. Chemical Sedimentary Rocks –
Forms when dissolved minerals
precipitate from water solutions.
(water usually evaporates or boils)
Ex: Limestone & rock salt.

9. Fossiliferous Limestone

10. III. Features of Sedimentary Rocks
Unique features are clues to how, when, and where they formed.
1. In undisturbed rocks, the oldest layers are found on the bottom and the youngest at the top.
Law of Superposition

11. 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

12. Where is the oldest layer located on this picture?

13. ESRT pg 7