1. Earth’s Materials and Processes-Part 7 Rocks and the Rock Cycle

2. Rocks
An aggregate of one or more minerals; or a body of differentiated mineral matter (ex: obsidian); or of solid organic matter (ex: coal).
Appearance controlled by composition, size, and arrangement of aggregate grains (texture).

3. Rock Types Igneous: form by solidification of molten rock (magma).
Sedimentary: form by lithification of sediment (sand, silt, clay, shells).
Metamorphic: form by transformations of preexisting rocks (in the solid state).

4. Igneous Rocks
Can be intrusive or extrusive.

5. Igneous Intrusive Rocks
Form within the Earth
Slow cooling
Interlocking large Crystals
Ex: Granite

6. Igneous Extrusive Rocks
Form on the surface of the Earth as a result of volcanic eruption.
Rapid cooling
Glassy or fine-grained texture
Ex: Basalt

7. Igneous Intrusive vs. Extrusive

8. Sedimentary Rocks
Sediment produced by weathering and erosion or by precipitation from solution.
Clastic sediments are derived from the physical deposition of particles produced by weathering and erosion of preexisting rock.
Chemical and biochemical sediments are precipitated from solution.

9. Clastic
Chemical/Biochemical

10. Lithificaton The process that converts sediments into solid rock.
Compaction
Cementation

12. Metamorphic Rock
Regional Metamorphism: metamorphism affecting rocks over an extensive area as a result of the large-scale action of heat and pressure.
Contact Metamorphism: metamorphism due to contact with or proximity to an igneous intrusion.

14. Examples
Conglomerate
Metaconglomerate

15. The Rock Cycle
The rock cycle is a model that describes the formation, breakdown, and reformation of a rock as a result of sedimentary, igneous, and metamorphic processes.

16. The Rock Cycle