Download Rock Mineral SG File

Study Guide
Are you taking
your notes???
Its TEST TIME!!!
Breathe deeply
It’s almost
Thanksgiving
Rocks help us discover Earth's past.
They are constantly being reworked.
A rock is an aggregate of minerals.
There are three types of rocks.
They are classified by how they form.
Igneous
Sedimentary
Metamorphic
Igneous
Igneous means, "formed by fire “
Form by the cooling and crystallization
of magma and lava
Basalt and granite are common ones.
Igneous makes up 95% of the earth's
crust


Ocean floor—basalt
Continents—granite and andesite
Sedimentary
Formed from weathered materials
(sediments) that are carried by wind,
water or ice.
Most common type on the uppermost
part of the Earth's crust.
Common types of sedimentary rx
limestone
sandstone
shale
Metamorphic
Formed from
preexisting rock
(sedimentary,
metamorphic, or
igneous)
Changed by heat,
pressure or both
Metamorphic means
"changed in form"
Two Types
Of Metamorphism
Regional
 Contact

Of Metamorphic Rocks
Foliated
 Non-foliated

Mineral Identification
Minerals are identified using their
physical properties.
These include crystal form,
hardness, cleavage, luster, color,
streak, and specific gravity

Also fizz, taste, smell
Mineral Characteristics
A mineral is a naturally occuring,
inorganic, solid with a definite chemical
composition, an orderly internal
structure (crystalline structure), and
characteristic set of physical properties
Crystal Form
Crystal form is caused by
the orderly internal
arrangement of
atoms
Quartz is the most
commonly identified
by its crystal form
Not often found because
minerals often grow
in cramped places
Two or more minerals that
have the same chemical
composition but different
crystal structures are called
polymorphs.
Fizz
If a mineral contains CO3
it will effervesce (fizz)
when you drop dilute HCl
(hydrochloric acid) on it.
Ex. Calcite CaCO3
The acid frees
CO2
(think of pop)
Origin of igneous rocks
Igneous rocks are
formed by molten
material from a
volcano or molten
material within Earth
Temps are 1600 at
60-200 km beneath
the surface
Classification of Magmas
Mafic—high in iron and magnesium
Felsic—high in feldspar and silica
(quartz)
Mafic—50% silica

Colors-- black, green, red
Intermediate—60% silica
Felsic—70% silica

Colors-- pink, white, light gray
Common Ig Rx
The continents are mainly granite
The oceans are basalt
Volcanoes
Volcanoes occur
two places:
plate boundaries
hot spots
Hawaii
is an example of a hotspot
oldest
Plate movement
youngest
Yellowstone is also located over a hotspot.
The
Cascades
are an
example of
a plate
boundary.
Three types of volcanoes:
Shield
Composite
Cinder cone
Composites are the typical
volcano shape.
Mt. Saint Helens is a composite
Most violent because of high silica content
Paracutin, Mexico: cinder cone
Steep sides, not
held together well
made of scoria
Shield volcanoes
are low with gentle slopes
They are the kind in Hawaii
The lava there is mafic
The two forms of lava are
pahoehoe and aa.
Pahoehoe is ropey
and aa is like a moving rubble field.
Sedimentary rocks
Most common rock at Earth's
surface
Thin blanket over 2/3 of the
surface covering igneous and
metamorphic rocks
Sedimentation
Volcanism builds new rocks
Weathering breaks them down
Two types of weathering:
Mechanical and Chemical
1. Mechanical
breaks rock into
smaller pieces
 Frost wedging
 Root wedging
 Gravity
2. Chemical Reactions
with water dissolve rock
H2O + CO2
H2CO3
Weak Carbonic
acid
This is what
dissolves
limestone and
makes caves
Erosion


Erosion--movement of seds
Deposition--seds are
deposited
The larger the sediment the
harder it is to move.
What can move sediments?
Wind
Water
Ice
When deposited sediment
accumulates,
it begins to transform into
sedimentary rock
Transformation
occurs in two ways:
Compaction
Cementation
Calcite, silica, and iron oxide are
the most common cements.
Clastic sediments
bits and pieces of old rock/plants/animals
Clastic sedimentary rocks are classified
by their sediment size and shape



Most common is shale--very fine particles
Sandstone—sand sized particles
Siltstone—silt size
Conglomeraterounded seds
Breccia—angular seds
Chemical Sediments
Chemical sediments precipitate
from water
Two types
 Carbonates
 Evaporites
Carbonates
Made of mostly calcite CaCO3or
CaMgCO3
Limestone CaCO3
Dolomite CaMgCO3
Evaporites
Evaporites evaporate from
water when a basin dries up
Gypsum Ca SO4. H2O
Halite (Rock Salt) NaCl
We find halite in Hutch
Metamorphism
Change occurs by
Recrystallization
 Often lose H2O or CO2
Mechanical deformation

No minerals are melted
Two Types
Foliated
Non foliated
Foliated rocks
Increasing grades of
metamorphism with increasing heat
and pressure
Slate-Phyllite-Schist-Gneiss
Slate-Phyllite-Schist-Gneiss
????????????????????????????
What would rock would come before slate?

shale
What kind of rock is it?

sedimentary
What happens after gneiss? (more heat and
pressure)
 melting
What kind of rock is it?

After cooling it is igneous
Slate
Very flat--fissile
Used for
 pool tables
 Roofing
they can break along planes
of weakness (cleavage)
where soft, platy minerals like
mica and chlorite grow during
metamorphism
Schist
Flakes of mica
visible on
surface
Often has
larger mineral,
like garnet
schist
Gneiss—
alternating layers
of dark and light
minerals
Minerals align
perpendicular to
direction of force
Non-foliated—not layered looking
formed around
igneous intrusions
where the
temperatures are
high but the
pressures are
relatively low and
equal in all directions
(confining pressure).
Marble
Marble forms
from
metamorphosed
limestone
CaCO3 so it fizzes
Cooling and
crystallization
magma
Melting
Heat and
pressure
igneous
Weathering, erosion and
deposition
Sediment
Metamorphic
rock
Weathering, erosion and
deposition
WED
Cementation & compaction
Heat
and
pressure
Sedimentary rock
Study bold words
in Sedimentary and Metamorphic
Sections
Honors Content
Bowen’s Reaction Series
Ternary Diagrams
Igneous Rock Composition
Non-silicate Minerals
Location
Felsic
Intermediate
Mafic
Texture
Intrusive
Granite
Diorite
Gabbro
Phaneritic
Extrusive
Rhyolite
Andesite
Basalt
Aphanitic