1. Chapter 3 Rocks Why study rocks?
- rocks tell the story of your location
EX: Indiana is made of mostly limestone = formed in a shallow marine setting = so in the past Indiana was under water
How is a rock different than a mineral?
Rock = a naturally occurring combination of minerals
 Rock will show some of the properties of the minerals that make it up
EX: Limestone is made of mainly calcite so it reacts to acid

2. 3 Types of Rocks:
Igneous = rock made from cooled magma either above or below ground
EX: Granite
Sedimentary = rock formed from compacted & cemented sediments
EX: Limestone
Metamorphic = a rock that has been changed (cooked) by increasing temperature and/or pressure to form a new rock EX: Marble

3. Rocks are continually changing from one type to another = Rock Cycle

4. Igneous Rocks: Formed from cooled magma Can form at 2 locations:
1. Below Ground = Intrusive
- slow cooling of magma because ground is insulating = this allows grains/crystals to grow large
 Coarse Grained Texture
2. Above Ground = Extrusive
- quick cooling = no time for crystals to grow so extrusive igneous rocks have small grains
 Fine Grained Texture

5. Igneous Rock Fine Grained Texture Cont…
- HOWEVER……..Exceptionally quick cooling above ground can give special textures:
A. Glassy = lava instantly cooled by seawater = No grains in rock
 Very smooth/glassy feel
EX: Obsidian
B. Pyroclastic Texture = magma cooled instantly by being shot into the air (i.e. volcano)
 rock has air pockets and very rough feel
EX: Pumice & Scoria

6. How do you classify Igneous Rocks?
Texture = Coarse, Fine, Glassy, Pyroclastic
Mineral Composition = color of rock
A. Light = white, clear, light pink, light gray
B. Intermediate = equal parts black & white (salt & pepper) or dark pinks and dark grays
C. Dark = Black

7. Igneous Rock Identification Chart
MINERAL COMPOSITION
Dark
Intermediate
Light
TEXTURES
Coarse
Gabbro
Diorite
Granite
Fine
Basalt
Andesite
Rhyolite
Glassy
Obsidian
Pyroclastic
Scoria
Pumice

8. Sedimentary Rocks: Formed from compacted/cemented sediments
Weathering = process that breaks down rocks into sediments
Compaction = process that squeezes or compacts sediments
Cementation = process where smaller dissolved minerals are deposited between sediments/rocks “glues” pieces together

9. 2 Types of Sedimentary Rocks:
1. Clastic = made of weathered & broken pieces of rock
2. Chemical = form when
dissolved minerals precipitate (separate) from water
EX: lake totally dries up during the summer

10. How are Sedimentary Rocks classified?
Type = Clastic vs. Chemical
Texture = grain size (coarse  fine)
Composition = minerals
(chemical sed. rocks only)

11. Sedimentary Rock Identification Charts
Clastic Sedimentary Rocks
Texture
Rock Name
Coarse/Gravel
Conglomerate
Medium/Sand
Sandstone
Fine/Mud
Shale
Chemical Sedimentary Rocks
Composition
Calcite
Very Coarse
Coquina
Coarse
Fossiliferous Limestone
Medium
Limestone
Gypsum
Fine
Rock Gypsum
Halite
Rock Salt
Organic Matter
Medium/Fine
Coal

12. Metamorphic Rocks:
Form when pre-existing rocks are changed by heat and/or pressure
Occurs during mountain building, volcanic activity, etc…

13. 2 types of Metamorphic Rocks
1. Contact = when magma forces its way into cracks/ layers of rock
- Rise in Temperature only
- Small changes to surrounding rocks
2. Regional = occurs during large scale mountain building
(EX: 2 continental plates colliding)
- Extreme rise in Temperature & Pressure
- Large changes to surrounding rock
- Rock usually becomes layered

14. How are Metamorphic Rocks classified?
Composition of parent material
Texture = layered vs. non-layered
The longer a rock is metamorphosed, the more layered its appearance (i.e. the longer it has been cooked, the more obvious layers it has)

15. Metamorphic Rock Identification Chart
Parent Rock
Texture
Rock Name
Shale
Very Fine Layers
Slate
Fine Layers
Phyllite
Medium Layers
Schist
Coarse Layers
Gneiss
Limestone
NO Layers
Marble
Sandstone
Quartzite

16. Ch. 3 Final Assignment Worth 25 points !Pg
1, 2, 4, 5, 8 = write out questions and answers
14, 17, 19, 21, 22 = write out answers only, in complete sentences
Vocabulary Words
Cementation Metamorphic Rock
Chemical Sed. Rock Pyroclastic
Clastic Sed. Rock Regional Met.
Compaction Rock
Contact Met. Rock Cycle
Extrusive Sedimentary Rock
Igneous Rock Weathering
Intrusive

17. Put the date and SS # 8 on your paper. Copy the question & answer it.
What is the Rock Cycle?