Warm-up
11/28/07
Test Question p.144 & 131
1. List two examples of non-foliated rocks.
2. Give one example of porphyritic textured
igneous rock.
Warm-up
11/14/07
1. How many minerals have scientists
identified?
2. What is the most common silicate
mineral?
ROCKS
Chapter 6
Starter
11/09/07
List the names of five rocks that you are
familiar with. Describe the characteristics
of the rock and identify how each type is
used.
Objectives
Identify the three major types of rock, and
explain how each type forms.
Summarize the steps in the rock cycle.
Explain Bowen’s Reaction series.
Major Types of Rock
Igneous Rock
Latin for “ from fire”
Form when magma cools and hardens
Sedimentary Rock
Fragments of rocks,
Minerals, crystals and
organic matter
Sediment carried by weather
Major Rock Types
Metamorphic (changed) Rock
Forms when existing rock is altered
Pressure, extreme heat, chemical forces
Rock Cycle
Types of Rocks and How they are Formed
R
O
C
K
C
Y
C
L
E
N.L. Bowen
Canadian Geologist 1900s
Different minerals
form at different times
Bowens Reaction Series
Bowen’s Reaction Series
Explains the order in which minerals form
as magma solid.
Objective
Summarize the factors that affect the
stability of rocks.
Sec 2 Objectives
 Summarize three factors that affect whether
rocks melt.
 Describe how the cooling rate of magma and
lava affect the texture of igneous rocks.
 Classify igneous rocks according to their
composition and texture
 Describe intrusive and extrusive igneous rock
structures
Igneous Rocks
 Magma cools and hardens
 Identified as crystalline
 Identity = Chemical composition and texture
Formation of Magma
Three factors that affect rock melt
1. Temperature
2. Pressure
3. Presence of fluids
Partial Melting
Different minerals in rock melt at different
temperatures
Fractional Crystallization
Crystallization and removal of different
minerals from the cooling magma
Igneous (Magma) Rocks
Volcanic (extrusive) formed at earth’s surface
Igneous (Magma) Rocks
Dike
Plutonic (intrusive) formed below earth’s surface
Texture
Coarse-Grained= large mineral grains
Ex. Granite
Fine-Grained= composed of small crystals
Ex. Rhyolite
Porphyritic= large and small
Ex. Granite
Glassy= cools quickly, small % of crystals
Ex. Obsidian
Vesicular= rapid cooling, vesicles
Ex. Pumice
Composition
Felsic- rich in feldspars & silica, light color
Mafic- rich in Mg & Fe, dark color
Intermediate- low portion of silica
What is the difference between stocks and
batholiths?
Intrusive Igneous
Rock Structures
Batholiths
Deep rock, cover 100 km²
Stocks
Cover less 100 km²
Laccoliths
Laccoliths
“lake of rock”
Occur in groups, dome-shaped mountains
What is the difference between a dike and a
sill?
Extrusive Igneous
Rock Structures
Igneous rock masses
that form on Earth’s
Surface.
Warm-up
11/16/07
True or False
1. Fine-grained igneous rock result from
rapid cooling.
2. Mafic magmas generally produce lightcolored rocks.
3. During partial melting, minerals that have
lower melting points melt first.
Igneous Characteristic Chart
CoarseGrained
Mafic
Felsic
Intrusive
Extrusive
Fine-Grained
Sedimentary Rock
 Fragments of rock,
minerals, organic
material
 Characteristics
determined- source,
travel/move, and
deposited
Sedimentary Rocks
Sandstone
Conglomerate
Limestone
Shale
• Eroded rock pieces
carried by water,
deposited in layers,
pressed down by other
layers until they form
rock
CH 6 Sec 3
Objective 1
Explain the process of compaction and
cementation.
Two main processes that convert sediment
to sedimentary rock- compaction and
cementation.
Compaction
Sediment is squeezed,
pore space reduced from
pressure of layers
Cementation
Sediment are glued together by minerals
that are deposited by water.
Objective 2
Describe how chemical and organic
sedimentary rocks form.
There are three main classes of sedimentary
rocksChemical, Organic, and Clastic
Chemical Sedimentary Rock
Forms from minerals that were once
dissolved in water
Some form when dissolved minerals
precipitate out of water because of
changing concentrations
Organic Sedimentary Rock
Forms from remains of living things
Objective 3
Describe how clastic sedimentary rock
forms.
Over time, individual fragments may be
compacted and cemented in solid rock.
The rock formed from these deposits is
Clastic Sedimentary Rock
Clastic Sedimentary Rock
Classified by size of sediment
1. Large fragments- conglomerate, breccia
2. Sand-sized grains- sandstone
3. Clay-sized particles- shale
Characteristics
Sorting
Currents of air or water
separate sediment
according to size
Angularity
Particles break from source
rock, tend to angular
and uneven
Objective 4
Identify seven sedimentary rock features.
Stratification, Cross-Beds, Graded Bedding, Ripple
Marks, Mud Cracks, Fossils, Concretions
Read p. 138-140- two bullets per feature
Warm-up
11/20/07
1. Describe how clastic sedimentary rock differs from
chemical and organic sedimentary rock. P.136
Clastic rock forms from rock fragments that were
transported away from their source by weather,
rather than chemical processes.
Chemical
Limestone
Sandstone
Breccia
Evaporites
Shale
Clastic
Organic
Metamorphism
 Heat, pressure, or
chemical
 Rock changes from
one type into another
 Forms from igneous,
sedimentary, or
metamorphic
Formation of Metamorphic Rocks
Heat, pressure, and
hot fluids = minerals change to
other minerals
Type of rock indicates
conditions from original rock
Two Types
Contact with magma
Plate tectonics
Contact Metamorphism
Magma comes in contact with existing
rock
Only small area of rock that surrounds the
magma is changed
Chemical fluids
through fractures
Regional Metamorphism
Occurs over a large area
Movement of tectonic plate
cause heat and pressure
against another
Chemical change in minerals
Volcanism
Both contact/regional
Classification of Metamorphic
Rocks
Chemical composition/texture
Minerals from original rock help determine
type
Either foliated or nonfoliated
Foliated Rocks
Minerals are arranged in planes or bands
Ex. Slate, Schist, Gneiss
Nonfoliated Rocks
Do not have bands or aligned minerals
Share 1 or 2 main characteristics
Ex. Quartzite, Marble
Metamorphic Rocks
Schist
From Basalt, Shale
or Slate
From Limestone or
Dolomite
Gneiss
From Granite
• Pressure and Heat
morphs igneous or
sedimentary rocks into
metamorphic rocks