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Rocks
ESPS
Hagen
Vocabulary List
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1. Rock Cycle
2. Igneous rocks
3. Magma
4. Lava
5. Intrusive rocks
6. Extrusive rocks
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7. Metamorphic rocks
8. Sedimentary rocks
The Rock Cycle
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Rocks form from a mixture of minerals,
mineraloids, glass and or organic matter
The rock cycle shows how the 3 types of rock
form and change
The 3 types of rocks are metamorphic, igneous
and sedimentary
The processes that form and change rocks are:
weathering, erosion, compaction, cementation,
melting and cooling
The Rock Cycle
Igneous Rocks
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Igneous rocks form when
magma or lava cools and
hardens
Magma is liquid rock
below the Earth’s surface
Depths range from 60 to
200km and temperatures
reach about 1400°C
Lava is liquid rock that
flows from volcanoes on
the surface of the Earth
Igneous Rocks
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When magma cools
inside the Earth’s surface
the rocks are called
intrusive rocks
These rocks tend to have
large mineral grains that
you can easily see (like
granite) because the
magma cools slowly and
the minerals have time to
group together and form
Common Intrusive Igneous
Rocks
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Granite
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Diorite
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Gabbro
Igneous Rocks
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When lava cool on the Earth’s
surface the rocks are called
extrusive rocks
Because the air is so much
cooler on the Earth’s surface
extrusive rocks cool very
quickly
Because they cool so quickly
the minerals do not have time
to come together and cool you
cannot see the different
minerals that make up
extrusive rocks
Common Extrusive Igneous
Rocks
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Obsidian
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Pumice
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Scoria
Classifying Igneous Rocks
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The first step to classify an igneous rock is
to determine if it is intrusive or extrusive
The second step to classify an igneous
rock is to determine what type of magma
or lava it formed from
3 types of magma or lava are: basaltic,
andesitic or granitic
Classifying Igneous Rocks
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Basaltic rocks: they are dense
and heavy, dark colored and
rich in iron and magnesium
(these are common in the
Hawaiian Islands)
Granitic rocks: they are light
colored, have lower density
than basaltic rocks and they
contain a lot of silicon and
oxygen
Andesitic rocks: they have
mineral combinations between
granitic and basaltic
Igneous rocks are the most
abundant rock on the planet
Metamorphic Rocks
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Metamorphic rocks undergo
change due to intense heat
and pressure (but do not melt!)
Metamorphic rocks can form
from igneous, sedimentary or
other metamorphic rocks
The heat and pressure come
from deep inside the Earth
The amount of heat and
pressure determine what type
of metamorphic rock will form
Common Metamorphic Rocks
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Slate
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Gneiss
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Marble
Classifying Metamorphic Rocks
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The main way to classify a
metamorphic rock is to
determine if the rock is foliated
or nonfoliated
Foliated rocks have flatten
parallel bands that are easily
separated along the bands
Common foliated rocks are
slate and gneiss
Nonfoliated rocks do no have
bands
Common nonfoliated rocks are
quartzite and marble
Sedimentary Rocks
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While most of the rocks on
Earth are igneous rocks
chances are you have seen
mostly sedimentary rocks on
the surface
Sedimentary rocks form when
sediments are pressed or
cemented together
Sediments form from other
rocks or even living things that
have been broken apart by
wind or water
These processes are called
weathering and erosion
Sedimentary Rocks
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Sedimentary rocks get
packed together by
compaction or
cementation
Compaction occurs by
erosion moves sediments
to a new location, where
they are deposited, over
time sediments get piled
up and the layers of
sediment push down to
form a rock
Sedimentary Rocks
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Cementation occurs when
water flows through the
sediment and dissolved
minerals that naturally form a
cement causing the remaining
sediment to form a rock
Sedimentary rocks often form
layers that are easily seen
The older rocks are on the
bottom and the newer rocks on
top
These layers can tell the
history of the area
Common Sedimentary Rocks
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Shale
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Conglomerate
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Sandstone
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Siltstone
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Limestone
Classifying Sedimentary Rocks
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Sedimentary rocks are mainly
identified by the composition of
the sediments from the original
rocks
Sedimentary rocks are
classified as: detrital, chemical
or organic
Detrital rocks are made from
fragments of other rocks that
have been cemented together
(these rocks are called clasitc
because of their texture)
Classifying Sedimentary Rocks
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Detritial rocks are named
according the shape and
size of the sediments
If the sediments are large
and round they are called
conglomerate rocks, but if
they are large and sharp
they are called brecca
rocks
If the sediments are sand
size the rock is called
sandstone
Classifying Sedimentary Rocks
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Chemical sedimentary rocks
form when minerals are
dissolve by water and the
water evaporates leaving the
rock behind
Limestone is formed from
ocean water
Rock salt is formed from lakes
and seas
Organic sedimentary rocks
from from the remains of living
things
Coal is an example of a
chemical sedimentary rock