Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Rocks Table of Contents Classifying Rocks Igneous Rocks Sedimentary Rocks Rocks from Reefs Metamorphic Rocks The Rock Cycle Rocks Rocks - Classifying Rocks How Rocks Form Geologists classify rocks into three major groups: igneous rock, sedimentary rock, and metamorphic rock. Rocks - Classifying Rocks Asking Questions 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. Question Answer What does a rock’s color tell you? It can provide clues about the rock’s mineral and chemical composition. How do geologists describe Geologists use terms based a rock’s texture? on the size, shape, and patterns of the grains. Rocks End of Section: Classifying Rocks Rocks Rocks - Igneous Rocks Mineral Mixture Granite is a mixture of lightcolored minerals, such as feldspar and quartz, and darkcolored 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. Rocks - Igneous Rocks Mineral Mixture Reading Graphs: What mineral is most abundant in granite? Feldspar Rocks Rocks - Igneous Rocks Classifying Igneous Rocks Igneous rocks can be made from either lava and cool quickly (Extrusive) or magma (Intrusive) and cool slowly. They are then classified according to their origin, texture, and mineral composition. Label each as intrusive or extrusive Rocks - Igneous Rocks Mineral Mixture Reading Graphs: About what percentage of granite is made up of dark minerals? 10% Rocks - Igneous Rocks Mineral Mixture 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% Rocks - Igneous Rocks Mineral Mixture 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. Rocks - Igneous Rocks Identifying Main Ideas As 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 Idea Igneous rocks are classified by origin, texture, and composition. Detail Extrusive rock forms from lava on the surface; intrusive rock forms from magma from beneath the surface. Detail Intrusive rocks have larger crystals than extrusive rocks because they cool more slowly. Detail High-silica rocks are light colored; lowsilica rocks are dark colored. Rocks End of Section: Igneous Rocks Rocks Rocks - Sedimentary Rocks From Sediment to Rock Most sedimentary rocks are formed through a series of processes: Weathering, erosion, deposition, compaction, and cementation. (Cementation is also known as Lithification ) Weathering – breaking down of rocks to make sediment. Often times this happens due to weather Rocks Rocks Rocks Rocks Rocks Rocks Metamorphic Rocks Metamorphic rocks come from the transformation of any existing rock types, The original rock (protolith) is subjected to heat (temperatures greater than 150 to 200 °C) and pressure (1500 bars),[1] causing physical and/or chemical changes. The beginning rock may be sedimentary rock, igneous rock or another older metamorphic rock (but it does not melt completely). Rocks - Sedimentary Rocks Outlining Lithification - Another word for Cementation (the gluing together of clastic pieces with deposited minerals) in sedimentary rocks. Sedimentary Rocks I. From Sediment to Rock A. Erosion B. Deposition C. Compaction D. Cementation II. Types of Sedimentary Rock A. Clastic Rocks B. Organic Rocks C. Chemical Rocks III. Uses of Sedimentary Rocks A. Building Materials B. Tools Rocks Rocks - Rocks From Reefs Using Prior Knowledge 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 Know 1. 2. 3. Coral reefs grow in the oceans. Florida has coral reefs. Oceans used to be where there is dry land now. What You Learned 1. 2. 3. Coral 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. Rocks - Metamorphic Rocks Previewing Visuals 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. Previewing Q. 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. Rocks - The Rock Cycle A Cycle of Many Pathways Forces deep inside Earth and at the surface produce a slow cycle that builds, destroys, and changes the rocks in the crust. Rocks Rocks - The Rock Cycle Sequencing 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. Rock Cycle Magma Metamorphic Sedimentary Igneous Rocks End of Section: The Rock Cycle Rocks Graphic Organizer Rocks can be Igneous Sedimentary Metamorphic include include include Intrusive Extrusive Clastic Organic Chemical Foliated Nonfoliated Rocks End of Section: Graphic Organizer