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:


Chapter 3: Rocks: Materials of the Solid Earth:

Key Concepts

ObsidianCh. 3: Rocks: Materials of the Solid Earth

After reading and studying Ch. 3, you should be able to:

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:

Video Notes:










Chapter 3 Rocks: Materials of the Solid Earth Word  List


Andesitic composition



Basaltic composition

Foliated texture

Nonfoliated texture

Bowen’s reaction series

Glassy texture


Chemical sedimentary rock

Granitic composition

Porphyritic texture

Coarse-grained texture

Hydrothermal solution

Regional metamorphism

Contact metamorphism

Igneous rock

Rock cycle


Intermediate composition


Crystal settling

Intrusive rock

Sedimentary rock

Detrital sedimentary rock



Disseminated deposit





Thermal metamorphism



Ultramafic composition


Magmatic differentiation

Vein deposit

Fine-grained texture

Metamorphic rock



Video Notes continued:





















Student Questions (with Answers):








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.