ESC 1000L Space Science Video Notes Name:
____________
Earth Revealed #14: Intrusive Igneous Rocks (1992)
Please watch the video in
class. Take notes on the Earth Revealed Disc #14 disk: Intrusive Igneous Rocks.
Please circle each of the Chapter 3 vocabulary words discussed in the video.
When the film is finished and after
reading Chapter 3:Rocks Materials of the Solid Earth finished, write questions with
answers that a student should be able to answer if she/he viewed this video.
You should have at least two or more questions for each chapter. List the most
significant discovery you made about Minerals which you did not know before
watch the film.
Play Video: http://www.learner.org/resources/series78.html
Chapter 3: Rocks:
Materials of the Solid Earth:
Key Concepts
After reading and studying
Concept 1: Diagram the rock cycle and discuss the geologic processes and energy
sources that contribute to each rock group.
Concept 2: List some of the most common igneous rocks and use them to explain how
igneous rocks form and are classified.
Concept 3: Briefly explain the origin, compositional variations, and crystallization
of magma and the distribution of igneous rocks.
Concept 4: Provide examples to compare and contrast the most common detrital and chemical sedimentary rocks and their
environments of formation.
Concept 5: Classify the most common metamorphic rocks according to how the rocks form
and their textures.
Concept 6: Understand the importance of rocks and how their characteristics provide
clues to geologic events and as indicators for exploration of metallic and
nonmetallic mineral resources.
Chapter Summary
The following statements summarize and describe many of the key terms and
concepts presented in the chapter.
· Igneous rock forms from magma that cools and solidifies in a process called crystallization. Sedimentary rock forms from the lithification of sediment. Metamorphic rock forms from rock that has been subjected to great pressure and heat in a process called metamorphism.
·
The rate of cooling of magma greatly
influences the size of mineral crystals in igneous rock. The four basic igneous
rock textures are (1) fine-grained, (2) coarse-grained,
(3) porphyritic, and (4) glassy.
·
Igneous rocks are classified by their
texture and mineral composition. Igneous rocks are
divided into broad compositional groups based on the percentage of dark and
light silicate minerals they contain. Felsic rocks (e.g., granite
and rhyolite) are composed mostly of the
light-colored silicate minerals potassium feldspar and quartz. Rocks of intermediate
composition (e.g., andesite) contain plagioclase
feldspar and amphibole. Mafic rocks (e.g., basalt) contain
abundant olivine, pyroxene, and calcium feldspar.
·
The mineral makeup of an igneous rock
is ultimately determined by the chemical composition of the magma from which it
crystallized. N. L. Bowen showed that as magma cools, minerals crystallize in
an orderly fashion. Magmatic differentiation changes the
composition of magma and causes more than one rock type to form from a common parent magma.
·
Detrital sediments are materials that originate and are transported as solid particles
derived from weathering. Chemical sediments are soluble materials
produced largely by chemical weathering that are precipitated by either
inorganic or organic processes. Detrital sedimentary rocks, which
are classified by particle size, contain a variety of mineral and rock
fragments, with clay minerals and quartz the chief constituents. Chemical
sedimentary rocks often contain the products of biological processes
such as shells or mineral crystals that form as water evaporates and minerals
precipitate. Lithification refers to the processes by which
sediments are transformed into solid sedimentary rocks.
·
Common detrital
sedimentary rocks include shale (the most common sedimentary
rock), sandstone, and conglomerate. The most
abundant chemical sedimentary rock is limestone, composed chiefly
of the mineral calcite. Rock gypsum and rock salt are chemical
rocks that form as water evaporates and triggers the deposition of chemical
precipitates.
·
Some of the features of sedimentary
rocks that are often used in the interpretation of Earth history and past
environments include strata, or beds (the single
most characteristic feature), fossils, ripple marks, and mud
cracks.
·
Two types of metamorphism are (1) regional
metamorphism and (2) contact or thermal metamorphism. The
agents of metamorphism include heat, pressure (stress), and chemically
active fluids. Heat is perhaps the most important because it provides
the energy to drive the reactions that result in the recrystallization
of minerals. Metamorphic processes cause many changes in rocks, including
increased density, growth of larger mineral crystals,
reorientation of the mineral grains into a layered or banded appearance
known as foliation, and the formation of new minerals.
·
Some common metamorphic rocks with a foliated
texture include slate, schist, and gneiss.
Metamorphic rocks with a nonfoliated
texture include marble and quartzite.
·
Some of the most important
accumulations of metallic mineral resources are produced by
igneous and metamorphic processes. Vein deposits (deposits in
fractures or bedding planes) and disseminated deposits (deposits
distributed throughout the entire rock mass) are produced from hydrothermal
solutions—hot metal-rich fluids associated with cooling magma bodies.
·
Nonmetallic mineral resources are mined for the nonmetallic elements they contain or for the physical
and chemical properties they possess. The two groups of nonmetallic mineral
resources are (1) building materials (e.g., limestone and gypsum)
and (2) industrial minerals (e.g., fluorite and corundum).
Earth Revealed #14: Intrusive Igneous Rocks (1992)
Intrusive Igneous Rocks unveils the rock-forming processes
of magmas that do not reach Earth's surface but solidify underground.
Most magma does not extrude onto Earth’s surface but cools slowly deep inside
Earth. This magma seeps into crevices in existing rock to form intrusive
igneous rocks. Experts provide a graphic illustration of this process and
explain the types and textures of rocks such as granite, obsidian, and quartz. Once
again, plate tectonics is shown to be involved in the process.
Play Video:
http://www.learner.org/resources/series78.html
Video Notes:
Chapter 3 Rocks: Materials of the Solid Earth Word List
|
Andesitic composition |
Fossils |
Metamorphism |
|
Basaltic composition |
Foliated texture |
Nonfoliated texture |
|
Bowen’s reaction series |
Glassy texture |
Pegmatite |
|
Chemical sedimentary rock |
Granitic composition |
Porphyritic texture |
|
Coarse-grained texture |
Hydrothermal solution |
Regional metamorphism |
|
Contact metamorphism |
Igneous rock |
Rock cycle |
|
Crystallization |
Intermediate composition |
Sediment |
|
|
Intrusive rock |
Sedimentary rock |
|
Detrital sedimentary rock |
Lava |
Strata |
|
Disseminated deposit |
Lithification |
Texture |
|
Evaporate |
Mafic |
Thermal metamorphism |
|
Extrusive |
Magma |
Ultramafic composition |
|
Felsic |
Magmatic differentiation |
Vein deposit |
|
Fine-grained texture |
Metamorphic rock |
|
Video Notes continued:
Student Questions (with Answers):
1.
2.
Most Significant Discovery (discoveries):
Video Study Guide: Earth Revealed
Episode 14: Intrusive Igneous Rocks
What factors contribute to the formation of magmas?
Discuss in detail the differences between mafic, intermediate, and felsic magmas.
How does cooling history relate to the texture of the resulting rock?
How do textural variations within the dike illustrate the effect of cooling history?
Discuss cooling and the formation of phaneritic, aphanitic, and glassy textures.
What is Bowen's Reaction Series and how does it describe magma crystallization?
How does differentiation relate to the evolution of magmas?
How does magma composition relate to plate boundaries?
Describe the formation of intermediate (andesitic) magmas in subduction zones.
Describe granitic (felsic) rocks.
What are xenoliths and what do they represent?
Describe the formation of a batholith.
How does the study of igneous rocks help in our interpretation of earth history?
Compare and contrast igneous rocks found on the continents and ocean floor.