1. Sedimentary Rocks - Today’s Objective:
What Makes Sedimentary Rocks Special?
Sedimentary Rocks -
are one of the three main rock types

2. A sedimentary rock can form one of three ways:
by the deposition of the weathered remains of other rocks
by the deposition of the results of biologic activity
by precipitation from solution.

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. 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.

5. Please add…
Agents of Erosion: Water, wind, ice/glaciers, and gravity

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

7. Inorganic Land Derived
(AKA) Clastic Sedimentary Rock - composed of weathered bits of rocks
And minerals.
These rocks are classified by particle size.

8. EXAMPLES of Inorganic Land Derived
Shale with
Plant Fossils
Conglomerate
Large grain size
Small grain size

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

10. Organically Formed Sedimentary Rocks –
Forms when shell fragments are cemented together or when plant remains are compacted into rock.
Ex: Fossiliferious Limestone & Bituminous Coal

11. Features only found in Sedimentary Rocks
1. The Law of Superpositioning - In undisturbed rocks, the oldest layers are found on the bottom and the youngest at the top.

12. Please add…
Lithification: Physical and chemical processes that transform sediments into sedimentary rocks (compaction + cementation)

13. 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

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