1. The Rock Cycle Rocks vs Minerals Three Types of Rock Earth’s Layers
Rock Formation
The Rock Cycle
Rock Identification

2. Diamond, a mineral, embedded in a rock
Rocks vs. Minerals
Minerals
Homogeneous
Naturally-occurring
Inorganic
Defined chemical composition
Crystalline structure
Single element or compound of elements
Rocks
Composed of one or more minerals
Diamond, a mineral, embedded in a rock

3. Three Types of Rock

4. Three Types of Rock Igneous Cooled molten rock Extrusive Intrusive
Formed by volcanic processes
Cool quickly at or near Earth’s surface
Intrusive
Cool slowly beneath Earth’s surface

5. Three Types of Rock Sedimentary
Particles of other rock (“clasts”) cemented together
Can be made from gravel, sand, silt, mud, or living things

6. Three Types of Rock Metamorphic
Existing rock subjected to intense heat and pressure beneath Earth’s surface

7. Earth’s Layers

8. Rock Formation Rocks are recycled in Earth’s layers
Molten rock from the mantle cools beneath the surface or rises up onto the crust and cools, forming igneous rock

9. Rock Formation Intrusion Sill Dike/dyke
Formation of intrusive igneous rock within layer of other rock
Sill
Magma cools between layers, forming sheet of igneous rock; horizontal
Dike/dyke
Magma intrudes through cracks in rock, approaching surface; vertical or diagonal

10. Rock Formation

11. Rock Formation
Batholith
Wide intrusion

12. Rock Formation
Uplift
Rocks of Earth’s crust rise up due to tectonic movement, forming hills and mountains

13. Rock Formation Erosion
Wind and water break off pieces of surface rock and transport it

14. Rock Formation Clasts: pieces of surface rock
Clasts are deposited in an area, then compacted and cemented into sedimentary rocks
Lithification: process of compaction and cementation

15. Lithification Sediments are deposited
More sediments are deposited on top
Upper layers compact lower layers, squeezing out any water in them
Minerals left behind cement clasts together
Result is solid sedimentary rock

16. Rock Formation Rock becomes buried deeper beneath the surface
Pressure and heat increase with depth
Instead of melting, rocks change, or metamorphose, into another rock
Metamorphism
Minerals move and align
New minerals form
Metamorphic rocks also form when existing rocks come into contact with molten rock

17. Rock Formation Deeper within the Earth, existing rocks melt
Melted rock rises to or near the surface and becomes igneous rock

19. The Rock Cycle

20. The Rock Cycle Any rock type can become any other type of rock
Fill in the label numbers for the image
Magma
Cooling
Igneous rock
Erosion
Sedimentation
Sediments & sedimentary rock
Burial and metamorphism
Metamorphic rock
Melting

21. Rock Identification Igneous Often contain crystals
But, if cooling too fast, crystals don’t form (e.g. obsidian)
Some have holes from the formation of air bubbles during cooling
Obsidian
Granite
Pumice

22. Rock Identification Igneous Extrusive Intrusive
Rapid cooling allows formation of small crystals or no crystals
Examples: basalt, obsidian, pumice, rhyolite
Intrusive
Slow cooling allows formation of large crystals
Examples: granite, gabbro, peridotite, diorite
Basalt
Granite

23. Rock Identification Sedimentary Types Particle type
Clastic: form from eroded particles
Chemical: form from dissolved minerals that fall out of what they are dissolved in (precipitate)
Organic: form from plant or animal debris
Particle type
Clasts include those from rock and volcanic ash
Living organisms form limestone (calcium carbonate), chert (silicon dioxide), and coal (mostly carbon)

24. Rock Identification Sedimentary: Clast size
Silt -> siltstone (very small particles)
Mud -> mudstone (very small particles)
Sand -> sandstone (intermediate size particles)
Gravel: 2 mm to 4 meters
Forms conglomerate or breccia
Conglomerate: rounded
Breccia: sharp and angular
Siltstone
Sandstone
Conglomerate
Breccia

25. Rock Identification Sedimentary
Crustal layers predominantly sedimentary rock
Sedimentary rocks sometimes have fossils embedded in them

26. Rock Identification Metamorphic
Foliated: layered/banded due to direct pressure
Some break into flat pieces
Some have a shiny surface
Examples: gneiss, schist, slate
Non-foliated: not layered or banded
Examples: marble, quartzite, hornfels
Gneiss
Slate
Marble