Post on 26-Mar-2015
I. Minerals and Rocks
A. Early Earth
1. Early surface was a violent place
2. Full of molten lava and no atmosphere; it
took time for Earth to cool and appear as it does now.
3. As surface cooled, patches of solid minerals began to form.
4. These lightweight minerals formed the first rocks.
A. Minerals1. All rocks
composed of minerals
2. Mineral-natural, inorganic solid
3. Inorganic – was never alive
4. Usually composed of crystals
5. 95% rocks made up of minerals
B. 3 Types of Rocks
1. Rocks – a group of minerals bound together.
2. 3 Types:a. Igneous - Most of Earth’s crust is made of
igneous rock
b. Sedimentary - The most common rock in uppermost portion of Earth’s crust
c. Metamorphic – near volcanoes and plate boundaries
C. Igneous Rock
1. Rock formed from cooled and hardened magma or lava
2. Two Typesa. Extrusive – cools quickly on Earth’s surface
1. Usually out of volcano or crack in Earth’s surface
b. Intrusive – cools slowly while trapped beneath Earth’s surface
1. The surrounding hard rock acts like a blanket, allowing it to cool slowly
3. Lava cools quickly – few crystals4. Magma cools slowly – lots of crystals
Igneous Rocks
What type of igneous is pictured below?
C.Igneous rocks cont.
5. Basalt – extrusive
6. Obsidian - extrusive
7. Granite – intrusive*
Igneous movie
D. Sedimentary Rocks1. Rocks broken down by
weathering and erosion
2. Pieces accumulate and are compressed and cemented together to form sedimentary rock
3. Pieces can contain fossils (plant or animal) **ONLY ONES!!
4. Sediment must be compressed or cemented together.
E. Sedimentary Formed in 2 ways
1. Rocks made of broken pieces (clasts) of other rocks.
a. Pieces of rock appear to be glued together.
2. Pieces/fine grains brought together by:
a. Compaction - is a process that squeezes, or compacts sediments.
b. Cementation -takes place when sediments are glued together by tiny minerals.
F. Common sedimentary rocks
1. Conglomerate – pebbles glued together
2. Sandstone - sand
3. Mudstone - mud
4. Shale – mudstone that breaks apart into
layers
5. Limestone – fossils from sea
G. Metamorphic rock1. Metamorphic – preexisting rocks that are
transformed by high temperature and/or pressure; their properties change.
2. Metamorphism often gives rock a distinctive banding pattern
a. Their unique colors and patterns make them ideal for sculptures.
G. Metamorphic cont.
3. Formed in 2 ways:a. heat alone caused by hot magma of igneous
intrusions.b. both heat and pressure: can occur over entire
region
4. Rock undergoes chemical change over millions of years without melting
5. Fossils are destroyed by heat and pressure.
What type of metamorphism?
What type of metamorphism?
H. Common Metamorphic rocks
1. Marble –comes from limestone
2. Slate – comes from shale
Metamorphic rock
I. Rock cycle1. Explains the sequence of events in which
rocks are weathered, melted, altered, and formed.
2. Geological processes of the earth’s crust recycling one type of rock into another.
3. Rock formation occurs SLOWLY, often over thousands of years.
Magma
Cools and hardens
Weather and Erosion
Compaction and CementationHeat and Pressure
IGNEOUS ROCKS
SEDIMENT = SAND
SEDIMENTARY ROCK
METAMORPHIC ROCK
MELTING
Convection currents
Granite cliffs
Devils tower
Importance of Rocks and Minerals
Metamorphic movie
Rock Cycle movie