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Rock and Roll!
 A rock is a solid mixture of crystals of one or more
minerals.
 Uses:
 Early humans used rock to make tools
 Buildings (concrete)
 Science: helps us with the history of the Earth
Rock Types and Magma
 Igneous
 Sedimentary
 Metamorphic
 Magma is the hot liquid that forms when rock partially
or completely melts.
The Rock Cycle
 The rock cycle is the process by which one rock type
changes into another.
 Weathering
 Erosion
 Deposition
 Compacting
 Metamorphism
 Melting
 Cooling
 Solidification
Classifying Rocks
 Composition – the minerals the rock is made of.
 Texture – sizes, shapes, and positions of the grains of
which it is made.
 Fine grained
 Medium-grained
 Coarse-grained
Igneous Rock
 When magma or lava cools down enough, it solidifies
to form igneous rock.
 Igneous means “fire” in Latin.
 3 ways igneous rock can form
 heat
 Pressure released
 Composition change
Igneous rock formations
 Intrusive Igneous rock forms when magma cools
beneath the Earth’s surface.
 Usually coarse grained.
 Cools slowly
 Plutons are large, balloon shaped intrusive formations
that result when magma cools slowly at great depths.
Igneous rock formations
 Extrusive Igneous rocks form on the Earth’s surface.
 Cools quickly
 Can form from volcanoes or from fissures (long cracks
in the Earth’s surface)
Sedimentary Rock
 Through weathering and erosion, sediment (rock
fragments) is deposited in layers and becomes
compacted.
 Weathering, erosion, deposition, compaction
 Layered rock – strata
 Stratification – the layering of sedimentary rock. (tells
us a lot about history)
Sedimentary Rock compositon
 Clastic – made of fragments of other rocks and minerals.
(ex. Sandstone)
 Chemical – made of solutions of minerals and water.
(ex. Chemical limestone)
 Organic – made of remains of animals that once lived in
the ocean. (limestone)
 Fossils are formed in sedimentary rock.
Metamorphic Rock
 Meta means changed and morphos means shape in
Latin.
 Rock undergoes metamorphism through heat or
pressure or both.
 All 3 types of rocks can change into metamorphic rock.
Types of Metamorphism
 Contact: when a rock comes in contact with magma.
 Regional: when enormous pressure builds up in a rock
that is deeply buried under other rock formations.
Textures of Metamorphic Rock
 Foliated – has minerals that are aligned like pages in a
book.
 Nonfoliated – does not have a regular pattern.
 Usually made of one or a few minerals.