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Ch 3 Rocks Notes
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3.1 The rock cycle shows how rocks change
A) Most rocks are made of minerals
1) Rocks are naturally formed _________________ that are usually made up of
one or more minerals.
Example: Obsidian and Coal, are 2 rocks that contain no minerals, rather they are
made of natural glass or ancient plant remains that have been buried and
compacted.
B) Our world is built of rocks
1) The Earth’s layers are made up of either _____________ or _____________
rocks
2) Buildings, statues and roads are all made of rocks. We get our _____________,
such as Iron, Aluminum and Cooper from rocks.
Example: The Great Wall of China is made of granite. The Great Pyramid
of Egypt is made of limestone and the faces of 4 US presidents who make up Mt.
Rushmore are made of granite.
3) Geologic maps show the _____________ of _______________ in an area and
specifically where they are located.
C) Rocks change as they move through the ______________ __________________
1) The rock cycle is a set of natural processes that form, _____________________,
break down and re-form rocks.
2) There are 3 types of rocks: _____________________________________________
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3.2 Igneous rocks form molten rock
A) Magma and lava form different types of igneous rocks.
1) Temperatures within the Earth reach
up to 1250°C and can melt rock into
magma. When magma reaches the
Earth’s surface it becomes lava.
a) ____________________ igneous
rocks form large crystals, because
they cool slowly.
b) ____________________ igneous
rocks form very small crystals,
because they cool quickly.
3) Most igneous rocks are made up of ________________________ minerals (a
compound of silicon and oxygen) and the amounts vary per rock.
a) Rocks with high levels of silica are _______________ in color.
b) Rocks with low levels or silica are ________________ in color.
3.3 Sedimentary rocks form from earlier rocks
A) Some rocks form from rock particles
1) _______________________ are materials
that settle out of air or water and can
sometimes be mixed with rocks, minerals
and pieces or plants and/or animal remains.
a) Sediments eventually press
together to form rocks as more and
more layers from on top of them.
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B) Some rocks form from plants or shells
1) Coal forms from dead wood, bark, leaves, stems and roots in ______________,
tropical climates that deposit and then sediment buries the material and
pressurizes it into a rock.
2) Limestone is made up of _________________ minerals, such as calcite. Shells
and skeletons of ocean organisms are formed from these minerals and when
these creatures die, they deposit on the sea floor and are buried, forming
limestone.
a) Coral reefs are also made of limestone.
C) Some rocks form when dissolved minerals re-form from water
1) Water runs over rocks and _____________________ minerals which eventually
make it into oceans, lakes, rivers and streams.
D) Sedimentary rocks show the action of wind and water.
1) When rocks have sediments layered from ______________ to ______________,
this shows that water carried them.
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3.4 Metamorphic rocks form as existing rocks change
A) Heat and pressure change rocks
1) Metamorphism is the process of _______________ one rock into another by
heat and pressure.
Example: Schist came from Shale, Marble came from Limestone
B) Metamorphic changes occur over large and small areas.
1) When large blocks of rock are heated and pressurized (regional), the ________
the rocks the greater the change.
Example: A sedimentary rock can turn to Slate near the surface, but can become
gneiss when within a mountain.
2) When _____________ pushes up through rock layers (contact), it recrystallizes
the surrounding rock.
C) Most metamorphic rocks develop bands of minerals.
1) Foliated rocks have flat or wavy _______________ bands of minerals.
a) They are common with regional metamorphism.
2) Nonfoliated rocks are usually made up of ____________ __________ type of
mineral with low pressure.
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