1 / 18

Chapter 4

Chapter 4. Rocks. Section 1: The Rock Cycle. What Is A Rock?. A rock is a mixture of one or more minerals, rock fragments, volcanic glass, organic matter, or other natural materials. Rock can be igneous, metamorphic, or sedimentary. Section 1: The Rock Cycle. The Rock Cycle.

yamka
Download Presentation

Chapter 4

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Chapter 4 Rocks

  2. Section 1: The Rock Cycle What Is A Rock? • A rock is a mixture of one or more minerals, rock fragments, volcanic glass, organic matter, or other natural materials. • Rock can be igneous, metamorphic, or sedimentary.

  3. Section 1: The Rock Cycle The Rock Cycle • Scientists created a model that describes how rocks slowly change from one form to another through time called the rock cycle. • James Hutton, a Scottish physician and naturalist, first recognized in 1788 that rocks undergo profound changes

  4. Section 2: Igneous Rock Formation of Igneous Rock • Molten rock material, called magma, flows when it is hot and becomes solid when it cools. • When hot magma cools and hardens, it forms igneous rock.

  5. Section 2: Igneous Rock Formation of Igneous Rock • When magma reaches Earth’s surface and flows from volcanoes, it is called lava. • As magma cools, atoms and compounds in the liquid rearrange themselves into new crystals called mineral grains.

  6. Section 2: Igneous Rock Formation of Igneous Rock • Rocks that form from magma below the surface are called intrusive igneous rocks. • Intrusive rocks are found at the surface only after the layers of rock and soil that once covered them have been removed by erosion. • Extrusive igneous rocks are formed as lava cools on the surface of Earth.

  7. Section 2: Igneous Rock Classifying Igneous Rocks • Igneous rock can form from basaltic, granitic, or andesitic magma. • Basaltic: • Igneous rocks are dense, dark-colored rocks. • They form from magma that is rich in iron and magnesium.

  8. Section 2: Igneous Rock Classifying Igneous Rocks • Granitic: • Igneous rocks are light-colored rocks of low density. • This magma is thick and stiff and contains a lot of silica but less amounts of iron and magnesium.

  9. Section 2: Igneous Rock Classifying Igneous Rocks • Andesitic: • Igneous rocks that have mineral compositions between those of basaltic and granitic rocks

  10. Section 3: Metamorphic Rocks Formation of Metamorphic Rocks • Rocks that have changed because of changes in temperature and pressure or the presence of hot, watery fluids is called metamorphic rock.

  11. Section 3: Metamorphic Rocks Formation of Metamorphic Rocks • Metamorphic rock can be formed by heat, pressure, and/or fluids. • In some places, the heat and pressure are just right to cause rocks to melt and magma to form. • In others, mineral grains can dissolve and recrystallizing occurs.

  12. Section 3: Metamorphic Rocks Classifying Metamorphic Rocks • When mineral grains line up in parallel layers, the metamorphic rock is said to have a foliated texture. • One example: • Slate

  13. Section 3: Metamorphic Rocks Classifying Metamorphic Rocks • Non-foliated texture is produced when mineral grains grow and rearrange but do not form layers. • Examples: • Sandstone • Marble

  14. Section 4: Sedimentary Rocks Formation of Sedimentary Rocks • 75% of the rocks exposed at the surface are sedimentary rocks. • Sediments are loose materials such as rock fragments, mineral grains, and bits of shell that have been moved by wind, water, ice, or gravity.

  15. Section 4: Sedimentary Rocks Formation of Sedimentary Rocks • Sedimentary rock forms when sediments are pressed and cemented together, or when minerals form from solutions. • Sedimentary rocks often form as layers.

  16. Section 4: Sedimentary Rocks Classifying Sedimentary Rocks • Sedimentary rocks can be made of just about any material found in nature. • Weathered and eroded rocks • Remains of organisms • Erosion moves sediments to a new location which causes it to build up layer upon layer.

  17. Section 4: Sedimentary Rocks Classifying Sedimentary Rocks • Pressure from the upper layers pushes down on the lower layers and they can stick together to form solid rock. • This process is called compaction.

  18. Section 4: Sedimentary Rocks Classifying Sedimentary Rocks • Cementation occurs when minerals such as quartz, calcite, and hematite are deposited between the pieces of sediment. • These minerals, acting as natural cements, hold the sediment together like glue.

More Related