1. Rocks

2. What are Rocks?
Rocks are a combination of minerals that are bonded together in some way.
All rocks are made of minerals
Monomineralic- contain one mineral Polymineralic- contain more than one mineral
Rocks are classified into three groups by how they are formed

3. 3 types of Rocks
Metamorphic Rocks: are formed when old rocks change by heat and pressure.
Sedimentary Rocks: Form from sediments (pieces of other rocks) that are cemented together.
Igneous Rocks: Form from molten rock that cools and hardens.
Rocks are classified by how they form

4. Classification of igneous rocks- 2 types
Intrusive
Form from magma
Cooled and solidified (hardened) slowly deep underground
Large crystal size
Extrusive
Form from lava
Cooled and hardened quickly at or near the surface of the earth.
Small or no crystals

5. Igneous rocks are also formed causing the magma to rise
when volcanoes erupt,
causing the magma to rise
above the earth's surface.

7. Types of igneous rocks Granite- most abundant igneous rock
Can be made up of feldspar, quartz, mica, and hornblende

8. Obsidian
Obsidian rocks are igneous rocks that form when lava cools quickly above ground.
Obsidian is actually glass and not a mixture of minerals. The edges of this rock are very sharp.

9. Pumice
Pumice rocks are igneous rocks which were formed when lava cooled quickly above ground.
This rock is so light, that many pumice rocks will actually float in water.
Pumice is actually a kind of glass and not a mixture of minerals.

10. Extrusive
Insrusive

11. Igneous Rocks
Can be:
Felsic: light colored rocks that are rich in elements such as aluminum, silicon. Lower density
Mafic: dark colored rocks that are rich in iron and Mg. Higher density
Coarse-grained texture: takes longer to cool, larger visible mineral crystals
Fine-grained texture: cools quickly with small mineral crystals
Glassy Texture: cools the quickest, no mineral crystals form
Vesicular texture: Gas pockets (holes)
(note) Texture refers to the size/appearance of the minerals

13. II. Sedimentary Rocks

14. How are they formed? Fragments of rock get broken down into sediments
ARE USUALLY FORMED IN A WATERY ENVIRONMENT.
OFTEN LAYERED
ARE THE ONLY ROCKS THAT CONTAIN FOSSILS
Fragments of rock get broken down into sediments
Sediments are
transported, compacted, and cemented into
rock

15. Sedimentary Rocks: Are the only type of rocks that contain fossils.
Fossil formation

16. Clastic Rocks – fragments cemented together and include the sediments: sand, silt, clay, pebbles, and boulders

17. Chemical rocks (crystalline) result of evaporation
Generally these rocks are formed from one mineral
Rock salt
(halite)
Rock gypsum- made
from gypsum

18. Organic rocks (contain remains of living things)
Or Bioclastic
Limestone- made from
Mineral calcite and
Fragments of shells
Bituminous coal- fossil fuel
Formed from plant remains in
Swampy areas- most are millions
Of years old

20. 3. Metamorphic rocks

21. Metamorphic rocks are rocks that have "morphed" into another kind of rock. These rocks were once igneous or sedimentary rocks.
The rocks are under tons and tons of pressure, which fosters heat build up, and this causes them to change.

22. These pre-existing rocks are called parent rocks
How are they formed?
Metamorphic rocks are pre-existing rocks that have been changed by heat and/or pressure without melting.
These pre-existing rocks are called parent rocks

23. Classification- 2 groups
Foliated
Mineral crystals are aligned, or arranged in bands or layers.
Banding: High grade metamorphism. Alternating layers of dark and light minerals.
Non-foliated
Mineral crystals do not have mineral crystals arranged in bands of layers. Example marble and quartzite.

25. Metamorphism Regional Metamorphism Contact Metamorphism
Caused by extreme pressure and heat.
Happens over wide “regions”.
Contact Metamorphism
Caused by contact with extreme heat.

26. Holey schist!

28. Rock Cycle
Rock must go through melting and solidification to become an igneous rock
Rock must go through weathering and erosion to become sedimentary rock
Rock must go through heat and pressure to become a metamorphic rock

31. Based on the characteristics, what kind of rock is A. B. C. D. E
Based on the characteristics, what kind of rock is A? B? C? D? E? Write the key word that led you to this conclusion.