Download Chapter 2, Section 1 Rocks: Mineral Mixtures

Chapter 2, Section 1
Rocks: Mineral Mixtures
Facts
A Rock is a solid
mixture of
crystals of
one or more
minerals.
Rocks can be classified by
observing their characteristics
and properties
What are some
characteristics of rocks?
The Uses and
History of Rocks
Early humans used rocks as tools.
Some rocks were used as
hammers, while others were used
to sharpen rocks into sharp tips
that could be used for arrows,
knives, and scalpels
Rocks have been used in
architecture in the past as well
as in the present.
Examples: granite, marble,
sandstone, and slate
Rocks can help
scientists
answer
questions
about our
Earth and
solar system
Fossils found in
rocks allow
scientists to
learn more
about evolution
and about the
history of the
Earth
What are some other
uses of rock?
The Rock Cycle
The rocks in the Earth are
constantly changing their
shape and composition. This
process is known as the rock
cycle.
The way a rock changes
determines its type. There are
3 main types of rocks: igneous,
sedimentary, and metamorphic
The Rock Cycle
SEDIMENTARY ROCK: grains of
sand and sediment erode from
the mountain and wash down
into a water body. Overtime as
the layers build up, they are
pressed into a cement-like form.
Formation of Sedimentary Rock
The Rock Cycle
METAMORPHIC ROCK: when pieces
of the Earth collide, sometimes large
pieces of rock are forced downward.
The sedimentary rock changes state
due to the intense heat and pressure
Formation of Metamorphic Rock
Metamorphic Rock
The Rock Cycle
MAGMA: when metamorphic
rock completely or partially
melts.
Magma
The Rock Cycle
IGNEOUS ROCK: Rock that
forms as the magma rises to
the Earth’s crust and cools
Formation of Igneous Rock
Igneous Rock
The Rock Cycle
SEDIMENT: When igneous
rocks on the Earth’s crust
begins to erode, it breaks
down into grains of sand and
clay
Sediment
Classifying Further
The 3 types of rock can be
classified further based upon
their characteristics
Rocks can be classified based
upon their composition. The
composition of a rock is
determined by the minerals
that make up that rock
Rocks can also be classified by
their texture. The texture of a
rock is created based upon the
sizes of the grains it contains
• fine-grained: contains small
particles
• medium-grained: contains average
sized particles
• coarse-grained: contains large
particles that are easily visible
Fine-Grained texture
Medium-Grained texture
Coarse-Grained texture
Composition/Texture of Igneous
Rock
• The amount of time it takes for magma or
lava to cool determines the texture of
igneous rock
• FELSIC- lighter colored and less dense.
Rich in silicon, sodium, aluminum,
potassium
• MAFIC- dark colored and more dense.
Rich in iron, magnesium and calcium
IGNEOUS ROCK
FORMATIONS
INTRUSIVE – when magma cools beneath
Earth’s surface
• Ex. Plutons- large balloon shaped
structures formed in deep areas
EXTRUSIVE-igneous rock formed at the
Earth’s surface
Ex. Volcanic rock
SEDIMENTARY ROCK
• Formed at or near Earth’s surface without
the heat and pressure.. Layers are
deposited and compacted together. Layers
of sedimentary rock are known as
STRATA. The way in which layers are
formed is called STRATIFICATION, or
layering
Sedimentary rock is classified by the way it
is formed
Classification of Sed Rocks
• 1. CLASTIC- made from fragments of
rocks and other minerals
• 2. CHEMICAL- forms from solutions of
minerals and water
• 3. ORGANIC- forms from the remains of
once living things
METAMORPHIC ROCK
• How does the rock change?
• CONTACT METAMORPHISM- occurs
when rock comes in contact with magna
and changes the surrounding rock
• REGIONAL METAMORPHISM- occurs
when a lot of pressure builds up or when
large pieces of the earth collide
TEXTURE OF MET ROCK
• FOLLIATED- has mineral grains that are
aligned by pressure.
• Ex. Shale changed into slate , then
phyllite, etc
NONFOLLIATED- does not have a regular
pattern of how the minerals are arranged
• Ex. Sandstone changed to quartzite