Presentation on theme: "Table of Contents Classifying Rocks Igneous Rocks Sedimentary Rocks"— Presentation transcript:
1Table of Contents Classifying Rocks Igneous Rocks Sedimentary Rocks Rocks from ReefsMetamorphic RocksThe Rock Cycle
2How Rocks Form - Classifying Rocks Geologists classify rocks into three major groups: igneous rock, sedimentary rock, and metamorphic rock.
3Asking Questions - Classifying Rocks Before you read, preview the red headings. In a graphic organizer like the one below, ask a what or how question for each heading. As you read, write answers to your questions.QuestionAnswerWhat does a rock’s color tell you?It can provide clues about the rock’s mineral and chemical composition.How do geologists describe a rock’s texture?Geologists use terms based on the size, shape, and patterns of the grains.
5Classifying Igneous Rocks Igneous rocks are classified according to their origin, texture, and mineral composition.
6Mineral Mixture - Igneous Rocks Granite is a mixture of light-colored minerals, such as feldspar and quartz, and dark-colored minerals, including hornblende and different types of mica. But granite can vary in mineral composition. This affects its color and texture.Study the circle graph and then answer the questions.
7Mineral Mixture - Igneous Rocks Reading Graphs: What mineral is most abundant in granite?Feldspar
8Mineral Mixture - Igneous Rocks Reading Graphs: About what percentage of granite is made up of dark minerals?10%
9Mineral Mixture - Igneous Rocks 100% - (35% + 10%) = 55% Calculating: If the amount of quartz increases to 35 percent and the amount of dark-colored minerals stays the same, what percentage of the granite will be made up of feldspar?100% - (35% + 10%) = 55%
10Mineral Mixture - Igneous Rocks Predicting: How would the color of the granite change if it contained less feldspar and more mica and hornblende?The overall color would be darker.
11Identifying Main Ideas - Igneous RocksIdentifying Main IdeasAs you read the section “Classifying Igneous Rocks,” write the main idea in a graphic organizer like the one below. Then write three supporting details. The supporting details further explain the main idea.Main IdeaIgneous rocks are classified by origin, texture, and composition.DetailDetailDetailExtrusive rock forms from lava on the surface; intrusive rock forms from magma from beneath the surface.Intrusive rocks have larger crystals than extrusive rocks because they cool more slowly.High-silica rocks are light colored; low-silica rocks are dark colored.
12Click the SciLinks button for links on igneous rocks.
14From Sediment to Rock - Sedimentary Rocks Most sedimentary rocks are formed through a series of processes: erosion, deposition, compaction, and cementation.
15Outlining - Sedimentary Rocks As you read, make an outline about sedimentary rocks. Use the red headings for the main topics and the blue headings for the subtopics.From Sediment to RockErosionDepositionCompactionCementationTypes of Sedimentary RockClastic RocksOrganic RocksChemical RocksUses of Sedimentary RocksBuilding MaterialsTools
16Links on Sedimentary Rocks Click the SciLinks button for links on sedimentary rocks.
18Using Prior Knowledge - Rocks From Reefs Before you read, look at the section headings and visuals to see what this section is about. Then write what you know about coral reefs in a graphic organizer like the one below. As you read, write what you learn.What You KnowCoral reefs grow in the oceans.Florida has coral reefs.Oceans used to be where there is dry land now.What You LearnedCoral animals cannot live below 40 meters.In the United States, only the coasts of Florida and Hawaii have coral reefs.Some limestone deposits on land formed from ancient reefs.
19More on Coral Landforms - Rocks From ReefsMore on Coral LandformsClick the PHSchool.com button for an activity about coral landforms.
21Previewing Visuals - Metamorphic Rocks Before you read, preview Figure 17. Then write two questions that you have about metamorphic rocks in a graphic organizer like the one below. As you read, answer your questions.PreviewingQ. Why do the crystals in gneiss line up in bands?A. Gneiss is a type of metamorphic rock that is foliated—the crystals are flattened to form parallel lines.Q. How does quartzite form from sandstone?A. High temperature and pressure on the minerals in sandstone cause them to be changed into minerals that make up quartzite.
22Links on Metamorphic Rocks Click the SciLinks button for links on metamorphic rocks.
24A Cycle of Many Pathways - The Rock CycleA Cycle of Many PathwaysForces deep inside Earth and at the surface produce a slow cycle that builds, destroys, and changes the rocks in the crust.
25Rock Cycle Activity - The Rock Cycle Click the Active Art button to open a browser window and access Active Art about the rock cycle.
26Sequencing - The Rock Cycle As you read, make a cycle diagram that shows stages in the rock cycle. Write each stage of the rock cycle in a separate circle in your diagram.MetamorphicIgneousSedimentary