1. Ch.6 – Sedimentary and Metamorphic Rocks

2. Formation of Sedimentary Rocks
Sedimentary Rock Formation
Weathering
Erosion
Deposition
Weathering & Erosion
The Rock breaks down or weathers into smaller fragments. This rock then mixes with water and other organic materials to form soil.
Weathering can be chemical or mechanical.
Chemical – oxidation, rusting, acids.
Mechanical – Wind or water.
The outer layers of rock weather first, changes in structure form cracks. Over time these cracks get larger, and the pieces of rock smaller.

3. Formation of Sedimentary Rocks
Mechanical Weathering
Breaks rock into pieces by:
Freezing & Thawing
Heating & Cooling
Growth of Plants
Actions of Animals
Abrasion

4. Formation of Sedimentary Rocks
Chemical Weathering
Breaks rock into pieces with:
Water
Oxygen
Carbon Dioxide
Living Organisms
Acid Rain

5. Formation of Sedimentary Rocks
Rate of Weathering
The two most important factors which determine the rate of weathering:
Type of Rock
Climate
Erosion
The removal and transportation of sediment.
Four main agents:
Wind
Water
Gravity
Glaciers

6. Formation of Sedimentary Rocks
Deposition
Transported sediment is deposited on the ground or at the bottom of a body of water.
Lithification
Compaction
Cementation

7. Formation of Sedimentary Rocks
Sedimentary Features
Bedding – 2 types
Graded Bedding
Cross Bedding
Fossils

8. Types of Sedimentary Rocks
THREE types of Sedimentary Rocks
Clastic
Chemical
Biochemical
Clastic Sedimentary Rocks
Formed from loose sediments, classified by grain size.
Coarse-grained – largest, ex: conglomerate.
Medium-grained – middle, ex: sandstone.
Fine-grained – smallest, ex: siltstone.

9. Types of Sedimentary Rocks
Chemical Sedimentary Rocks
Mineral deposits form through evaporation and precipitation.
Ex: Evaporites, such as salt deposits.
Biochemical Sedimentary Rocks
Formed from the remains of once living things.
Ex: Limestone
Grades of Metamorphism
Figure 6.19 on pg.148

10. Metamorphic Rocks Recognizing Metamorphic Rocks
Rocks change without melting, under intense temperature and pressure.
Caused by deep burial, & mountain building.
Metamorphic textures – 2 Groups
Foliated – form w/ bands of minerals.
Nonfoliated- Form w/ blocky crystal shapes.

11. Metamorphic Rocks
Types of Metamorphism
Regional
Contact
Hydrothermal

12. Metamorphic Rocks Economic Importance – Read pg.150
Metallic Mineral Resources
Non-metallic Mineral Resources
The Rock Cycle – Read pg.151
Draw Diagram – figure 6.23