Rocks & The Rock Cycle
I. Background Information
A. Rock: A mixture of minerals, that make up the Earth’s crust
B. Rock Types
a. Igneous Extrusive: * Forms above ground
(aka Volcanic) * Cools quickly
* Consists of small, fine grains, air, and gas bubbles
1. Igneous: Rock formed by cooling magma or lava
b. Igneous Intrusive: * Forms under ground
(aka Plutonic) * Slow cooling
* Consists of large, coarse grains
2. Sedimentary: Rock formed by compaction and cementation of sediments that were deposited by wind or water.
•Sediments are fragments of rocks formed from erosion and weathering
•Often have visible rock fragments, shells and fossils
3. Metamorphic: * Any rock changed by heat & pressure
* Foliation Bands of rock formed by
heating and squishing
crystals
Igneous
MetamorphicMagma or Lava
Sedimentary
Erosion
Melting
Heat & PressureMelti
ng
Heat &
P
ressu
re
Ero
sio
n
Meltin
g
Coolin
g
THE STRUCTURE OF THE EARTH
UPPER MANTLE
CRUST
INNER CORE
OUTER CORE
LOWER MANTLE
III. Inside the Earth
A. CRUST 1. AKA…THE LITHOSPHERE2. 70 KM THICK3. TWO TYPES:
OCEANIC: DENSE, MADE OF BASALT (EXTRUSIVE)CONTINENTAL: LESS DENSE, MADE OF GRANITE
(INTRUSIVE)
B. MANTLE1. UPPER: 330 KM THICK; HOT, MOVING ROCK
(THINK OF SILLY PUTTY)2. LOWER: 2500 KM THICK; RIGID, DENSE ROCK
C. CORE1. OUTER: 2250 KM THICK, A THICK LIQUID2. INNER: 1250 KM THICK, A SOLID METAL BALL