ES Chap 5 & 6: Rocks

Objectives

  1. Identify and explain characteristics of igneous rocks. This means that if I am given an igneous rock I:
  2. Can use grain size to identify a rock as intrusive, extrusive, or porphyry. In addition, I can discuss how the rate of cooling is related to grain size.
  3. Can use color to identify a rock as felsic, intermediate or mafic.
  4. Combining grain size and color (as described in a & b), I can use Table 5-2 on page 107 to name the rock.
  5. Use Table 5-2 page 107 to identify a rock if I am given the percent composition of a rock.
  6. Understand which minerals and rocks in Table 5-2 are high in silica, iron and magnesium.
  7. Discuss the factors that affect how rocks melt & crystallize
  8. Describe uses of igneous rocks.
  9. Rocks that may be samples to identify on the exam: obsidian, pumice, rhyolite, granite, basalt, gabbro.
  1. Identify and explain characteristics of sedimentary rocks. This means that I:
  2. Can describe and list in order the steps that form clastic sedimentary rocks: Weathering (both physical and chemical), erosion, deposition, burial, lithification, cementation
  3. Can use information about ripple marks and fossils to infer what the past environment is like.
  4. Can identify a rock into one of the following subgroups; clastic, organic, chemical
  5. Can use the Law of Superposition to determine which rock layers are older or younger.
  6. Describe uses of sedimentary rocks.
  7. Explain miscellaneous terms such as porosity
  8. Rocks that may be samples to identify on the exam: conglomerate, breccias, sandstone, limestone, coal
  1. Identify and explain characteristics of metamorphic. This means that I
  2. Can identify a rock into a metamorphic subgroup; foliated vs. non-foliated
  3. Explain the formation of metamorphic rocks.
  4. You will be asked to identify a rock as metamorphic and then as foliated or non-foliated, but you will not be asked to give it a specific name.
  1. Understand how rocks continuously change from 1 type to another in the rock cycle.

5.  I can identify a given rock sample into:

  1. One of the 3 main types of rock described above: igneous, sedimentary or metamorphic.
  2. Into the appropriate subgroup as described above.

Sec 5.1 Classifying Igneous Rock

3 types of Rock:

  1. Igneous: Formed from ______of ______
  1. Lava is magma that reaches & flows onto Earth’s ______
  1. Sedimentary: Formed from sediments ______together
  1. Sediments: Small pieces of ______
  1. Metamorphic: Formed when a rock changes into a ______due to extreme ______

Igneous Rocks:

  1. Extrusive rocks: Fine (______) grained rocks due to ______cooling on Earth’s ______
  1. Examples: ______
  1. Intrusive rocks: Coarse (______) grained rocks due to ______cooling ______the surface
  1. Examples: The most common intrusive rock is ______

Magma:

1.  Composition:

  1. Mix of ______rock, gases, and mineral crystals
  1. Elements common in magma are the major elements found in Earth’s crust: ______
  1. Most common compound: ______
  1. Types of Magma: Based on the amount of______

Magma Type / Amount SiO2 / Relative color of rocks when cools / Special Characteristics (due to the amount of SiO2 Silica)
1.  Rhyolitic (Granitic)
2.  Andesitic
3.  Basaltic
  1. Origin of Magma:
  2. Must heat rocks to temperatures of 800 – 1200oC (1500-2200oF) to ______
  1. These temperatures are found in the ______and ______

What heats the upper mantle & lower crust?

  1. Minerals have ______points
  1. Because of this not all parts of the rock melt at the same time
  1. This explains why magma is often a slushy mix of ______rock & ______crystals
  1. Partial Melting: When some minerals melt at low temps and others remain solid

Section 5.2 Classifying Igneous Rocks

3 Classifications of Igneous Rock: based on the ______of the rock

  1. Felsic
  2. Intermediate
  3. Mafic

Igneous rock type / Felsic / Intermediate / Mafic
Type of Magma
Silica (SiO2 ) content
Relative color
High in: / Texture
Rock Examples / Extrusive
Intrusive

Main observations for igneous rock identification:

  1. Color: ______vs. ______
  1. Grain size: ______vs. ______

Special IG rocks:

  1. Porphyritic texture: Mixture of ______grains
  1. Complex cooling history:
  1. 1st ______cooling deep in Earth-forming the ______crystals.
  1. 2nd ______cooling of remaining magma due to sudden ______or

______close to the surface

  1. Obsidian: “Black glass”
  1. Cooled ______that ______crystals are formed: ______
  1. Pumice: 50% holes due to escape of trapped ______
  1. Formed from ______magma
  2. Used for abrasive polishing mixtures and cleansers

Igneous Rocks as Resources

  1. Building materials: They are ______& ______to weathering, especially the ____ rocks
  1. Ore deposits: ______of ______substances within the rock
  1. ______lead, & copper are not in compounds that form minerals, but they are found

as elements mixed with quartz

  1. ______
  1. Found in ______or ______
  1. Formed when liquid magma fills ______in other rocks & cools

Sec 6.1 Formation of Sedimentary Rocks

Sedimentary Rock Overview:

1.  Sediments = Pieces of ______(pieces of ______, ______, that have been deposited on Earth’s surface by wind, water, ice, gravity, or chemical precipitation

2.  Two of the processes involved in creating & moving sediments:

A.  Weathering

B.  Erosion

3.  As the sediments get “cemented” together, they form sedimentary rocks

Steps to Form Sedimentary Rocks:

  1. Weathering: Breaking down & ______of rocks into smaller pieces (called ______sediments which vary in size)
  1. Physical or mechanical causes that break rock into pieces include: ______

______

  1. Chemical causes include ______(chemical changing) of rocks by ______rain or chemicals
  1. Erosion: ______of sediments to a new locations
  1. Possible means: ______
  1. How can you tell how far a rock piece has traveled?
  1. It it is moved a SHORT distance, the rock pieces still have ______edges (Example rock: Conglomerate)
  1. The FARTHER it travels, the rock edges will become more ______as it bounces along (Example rock: Breccia)
  1. Deposition: ______or ______of sediments on the ground or bottom of bodies of water
  1. Burial: Becomes ______beneath more & more sediments
  1. Lithification: means “making of ______” and has 2 parts
  1. Compaction: Bottom layers of sediment are ______together by______of upper sediment layers
  1. Cementation: Sediments are ______or ______together by minerals in the water that ______
  1. Example “cements” that precipitate out of solution:

Ø  Halides like ______

Ø  Carbonates like ______

  1. Summary: Lithification turns ______into ______

Features of Sedimentary Rocks:

  1. Layers (AKA beds)
  2. Law of ______: ______rocks on the ______if layers are undisturbed
  1. Exception occurs when layers are overturned by ______forces
  1. The following always form on the top of a layer. If they are found on the bottom instead, it

indicates that layers have been overturned: ______

  1. Sedimentary rocks usually form in ______
  1. Sedimentary rock is ______rock on the ______(not in crust) of Earth
  1. Igneous rock is the most common rock in the CRUST, but it is buried. Most igneous rock is formed underground, not through lava on surface.

Evidence of Past Life

  1. Fossils: Preserved ______of once-living organisms
  1. Only found in ______rocks. WHY?
  1. During lithification, parts of organisms are replaced by ______& turned into rocks

Sec 6.2 Types of Sedimentary Rocks

3 main groups of sedimentary rocks:

  1. Clastic
  1. Organic
  1. Chemical

Sedimentary Rock Group / Made from / Subgroups & examples
Clastic
NOTE:
Clastic means “pieces of rock” / sedimentary rock / 3 clastic subgroups based on grain size:
1.  Coarse-grained: ______grains or larger
a.  Due to high water flows & speeds which can carry large pieces: ______
______
2.  Medium-grained: ______-sized grains
a.  Form ______which has high porosity (incomplete cementation leaves ______between grains)
b.  Valuable reservoirs of ______
3.  Fine-grained: ______
a.  Low porosity (barrier)
Organic / Examples:
1.  ORGANIC Limestone: ______
2.  ______: rock from buried swamp plants
Chemical / Example: ______
Example locations:
1.  Coast of ______or the ______

Importance of Sedimentary Rocks:

  1. Fossils tell about ______
  1. Type of area and types of organisms: ______
  1. ______tell the direction of ______in the past:
  1. Symmetrical ripple marks:
  1. Both sides of ripple have same shape
  1. Indicates ______wave action
  1. Asymmetrical ripple marks:
  1. 1 side is gently sloped & other side is steep
  1. Indicates ______wind or wave motion
  1. Examples: ______
  2. Energy
  3. ______
  1. Reservoir for ______when ______(open space) present
  1. Limestone to make ______

Metamorphic Rocks

1.  Definition of Metamorphic Rocks: Rocks that change form while ______

2.  Cause or Metamorphic Rock:

  1. ______and ______increase with depth
  1. Temperature and pressure combine to alter texture, mineralogy, or chemical composition of a

rock ______(If it melts, ______rock is formed)

  1. Heat comes from Earth’s internal heat or nearness to a magma chamber
  1. Pressure comes from overlying rocks or tectonic plate movement

3.  Metamorphic Rock Classification

  1. ______(alternate light & dark bands) due to ______with ______
  1. Lines may be straight or wavy
  2. Example: Gneiss is formed from the igneous rock ______
  1. ______
  1. Example: Marble is formed from the sedimentary rock ______


The Rock Cycle:

  1. Is the ______of rock
  1. Based on how new rock type is formed.
  1. Following is an example of the possible changes the igneous rock granite could undergo. When it is:
  1. Weathered into ______Þ new ______rock is formed
  1. Buried (but not melted) where ______affect it Þ new ______rock is formed


Comparison of the Characteristics of the 3 rock types:

ES Ch 5 & 6 Rocks Outline.doc - 9 - 2/13/2014