1. Rocks and the Rock Cycle
Igneous, Sedimentary, and Metamorphic varieties

2. Where do all rocks come from?
All rocks basically come from magma (molten rock from the earth’s interior, which provides the parent material for igneous, sedimentary, and metamorphic rocks)
The only exception are rocks composed of organic material ( a certain variety of sedimentary and metamorphic rocks)

3. The Rock Cycle

4. The Rock Cycle

5. The Rock Cycle

6. How the rock cycle works
Relatively all rocks start out as igneous rocks.
IGNEOUS ROCKS are formed from volcanism
When igneous rocks are weathered, deposited elsewhere and then solidified, they are then classified as SEDIMENTARY ROCK (lithified sediment)
If an Igneous rock or a Sedimentary rock somehow gets buried and undergoes an extensive change in temperature and/or pressure, the rock will then become metamorphosed, so classified as METAMORPHIC ROCK

7. Igneous Rock Rock formed when magma cools and hardens via volcanism
Two types – intrusive igneous and extrusive
Intrusive – when magma doesn’t quite make it to the surface, but crystallizes and cools below the surface
Extrusive- magma that makes it to the surface, now lava, that crystallizes and cools above the surface

8. Some cool intrusive sites

9. Yosemite, CA

10. Devil’s Postpile (Mammoth, CA)

11. Some typical intrusive igneous rocks

14. Some Cool Extrusive Igneous Sites
Obsidian dome (Mammoth, CA)

15. Not Cool extrusive

16. Structures Related to Igneous Rocks
Batholith- a large mass of intrusive igneous rock, sometimes called a pluton (think Sierra Nevada)

18. A pretty cool dike

19. For tomorrow……
We will talk about and look at various igneous compositions (What’s chemistry and viscosity got to do with it?)
Also, we will start to examine Sedimentary and Metamorphic Rocks and Structures