1. Introduction to Geology
Chapters 13-15

2. The Earth’s Structure
Inner core: solid core of iron and nickel, ,000 degrees F
Outer core: liquid layer of iron and nickel, degrees F
Mantle:
Lithosphere – upper mantle (solid) plus crust, forms rocky plates that make up earth’s surface
Aesthenosphere – below lithosphere, softer
Lower mantle: semi-liquid rock, material rises and sinks

3. Mohorovicic discontinuity (the Moho) – slippery layer in the lithosphere that forms the boundary between the crust and the mantle
Crust: outer layer, solid, about 7 miles thick

4. Rocks

5. Three types of rocks
Sedimentary – Eroded sediments are carried by water, then drop and are compacted by heat and pressure.
Igneous – Formed by the cooling of molten rock
Metamorphic – Sedimentary, igneous, or other metamorphic rocks that have been changed by heat and pressure into a new kind of rock

6. Sedimentary Rocks Most common type of rock
Typically form layers called strata
Two types: clastic and non-clastic

7. Clastic Sedimentary Rocks
Appear to contain fragments eroded from other rocks
Form when rocks get broken up then cemented together with heat and pressure
Examples: conglomerate, sandstone, shale

8. Nonclastic Sedimentary Rocks
Form from minerals dissolved in water
Examples: limestone and halite

9. Fossils and Sedimentary Rock
A fossil is any trace or remains of a living organism that has been preserved by natural means.
Fossils are almost always found in sedimentary rock. Why?

10. Fossil Fuels
Appear to come from fossilized remains of plants and animals
Can be solid, liquid, or gas.

11. Coal Sedimentary rock that appears to have been laid down by water.
Appears to have been formed rapidly by plant life being deposited under large quantities of flowing water. Heat and pressure changed them to rock.

12. Oil Liquid fossil fuel formed from ocean-dwelling creatures
Found with sedimentary rocks of marine origin, sometimes with marine fossils in them

13. Natural Gas Gaseous fossil fuel often found with oil
May be a by-product of oil formation

14. Where fossil fuels are found

15. Igneous Rocks

16. Igneous rocks Appear to have been molten in the past
Magma – molten rock found beneath earth’s surface
Lava – molten rock that flows out onto earth’s surface

17. Two types of igneous rocks
Extrusive – formed when lava solidifies above earth’s surface
Intrusive – formed when magma solidifies after squeezing into other rocks

18. Metamorphic Rocks

19. Metamorphic rocks
Appear to have changed in structure or chemical composition since their formation

20. Two types of metamorphic rock
Foliated – banded or layered
Nonfoliated – no bands or layers