Download igneous rocks - Mrs. Wisniewski

IGNEOUS ROCKS
Vocab to know:
Intrusive igneous rock
Extrusive igneous rock
MAGMA AND LAVA FORM DIFFERENT TYPES
OF IGNEOUS ROCKS
 Igneous rocks form from ________ rock.
 This molten rock is called _________
o Molten rock that reaches the surface of the
Earth is called _________
 An __________ rock is classified on the basis of its
mineral composition and the size of its mineral
crystals.
o A rock formed from magma can have the
same composition as a rock formed from lava
but the rocks will have different _______ sizes.
Origin of Igneous Rocks
Igneous rocks are classified according to where they
are ___________
INTRUSIVE IGNEOUS ROCKS Examples: Granite, gabbro, diorite
 They can reach the surface as deeper rocks are
uncovered by weathering or when forces inside
the Earth push rocks up to the surface
EXTRUSIVE IGNEOUS ROCK-
Examples: Rhyolite, pumice, basalt, obsidian
Textures of Igneous Rocks
The texture of an igneous rock-the size of its mineral
crystals- depends on how ________ the magma or lava
is __________.
INTRUSIVE- these rocks form ________ the surface of
the Earth so they can form _________ crystals.
WHY? Because The interior of the Earth is very hot
 These high temperatures allow magma to cool
____________
 This ________ cooling allows time for _______
mineral crystals to form
EXTRUSIVE- these rocks form ______________ of the
Earth so they form very _________ crystals
WHY? Because The surface of the Earth is cooler than Earth’s
interior
 These lower temperatures cause lava to COOL
____________
 This does not allow large crystals to form
Some igneous rocks can contain crystals of very
different sizes. These rocks formed from ____________
________________________________________________
Composition of Igneous Rocks
Texture is not enough to identify an igneous rock so you
have to also consider their composition.
 Most igneous rocks are made up mainly of
_________ minerals (the most common mineral
group in Earth’s crust)
 Remember silicates are compounds that contain
___________ and ____________
 Geologists classify the rock on the basis of how rich
it is in silica
 You can estimate the amount of silica in an igneous
rock by looking at its ___________
o _______ levels of silica in rocks typically
create a ___________________
 Granite
o _______ levels of silica typically create a
______ COLOR
 Basalt
Read pages A86-A87 and answer question 3 on page
A87