Earth Systems 3209

1. Earth Systems 3209 Reference: Chapters 2, 3, 6, 7; Appendix A & B Unit: 3Earth’s Materials

2. Unit 3: Topic 2.1 Rocks and the Rock Cycle Focus on . . . • defining rock and recognizing the connection between minerals and rocks. • the rock cycle diagram and explaining the origin of the three rock types. • explaining the different processes that link each rock type to the others (represented by arrows).

3. Orthoclase Feldspar Amphibole Quartz Rocks and the Rock Cycle What is a Rock? • A rock is a consolidated mixture of one or more minerals. • Rocks are generally composed of more than one mineral. For example, Granite consist of; Quartz, Feldspar, Hornblende and Mica.

4. Rocks and the Rock Cycle • Three Rock Types • Igneous Rocks • Sedimentary Rocks • Metamorphic Rocks • All rock types are interrelated through the rock cycle. Text Reference: pages 15-17

5. Rocks and the Rock Cycle Some common rocks include; Igneous:Granite, Gabbro, Diorite, Rhyolite, Basalt, Andesite, Obsidian, Pumice, and Scoria. Sedimentary:Conglomerate, Breccia, Sandstone, Siltstone, Shale, and Limestone. Metamorphic:Slate, Phyllite, Schist, Gneiss, Marble and Quartzite.

6. Igneous Rocks • Formed by the cooling and hardening of hot molten rock. • If the molten rock is located within Earth it is called Magma. • If the molten rock reaches the surface and exits through volcanoes, it is then referred to as Lava. • Two classifications of Igneous rock; • 1) Plutonic (intrusive) – forms from magma. • 2) Volcanic (extrusive) – forms from lava.

7. Sedimentary Rocks • Rock formed when the weathered products of pre-existing rocks have been transported, deposited, and compacted or cemented into solid rock. • Usually formed in marine (water) environments where sediment is deposited by streams and rivers. • Most of Earth’s crust (95%) is igneous rock but the surface is covered by sedimentary rocks. • Three classifications of Sedimentary Rocks: • Clastic (Detrital) – rock fragments • Chemical - precipitation and evaporation • Biochemical – organic remains

8. Metamorphic Rocks • Rock formed below Earth’s surface when pre-existing rock is altered by heat, pressure, and chemically active fluids. • Metamorphism changes rocks in size, shape, texture, and the minerals they contain. • Metamorphism varies in degree from: • High Grade. Ex. Granite changes to Gneiss. • Low Grade. Ex. Shale changes to Slate.

9. Melting Cool & Crystallize Heat & Pressure Weathering & Erosion Compaction & Cementing Rock Cycle Magma Metamorphic Igneous (Volcanic) (Plutonic) Sedimentary (Clastic) (Chemical) (Organic) Sediment Sand, Silt, & Clay

10. Cool & Crystallize Melting Melting Heat & Pressure Heat & Pressure Weathering & Erosion Weathering & Erosion Compaction & Cementing Weathering & Erosion Rock Cycle Magma Metamorphic Igneous (Volcanic) (Plutonic) Sedimentary(Clastic) (Chemical) (Organic) Sediment Sand, Silt, & Clay

11. Example 1: Which statement is true about the rock cycle? (A) magma cools and crystallizes to form metamorphic rocks (B) metamorphic rocks lithify to form sediments (C) sedimentary rocks may contain igneous and metamorphic rocks (D) weathering affects only igneous rocks What rock forms when a pre-existing rock is altered as a result of heat and pressure? (A) Igneous (B) Metamorphic (C) Sandstone (D) Sedimentary

12. Example 2: Which is a consolidated mixture of minerals? compounds (B) elements (C) fossils (D) rocks Which processes are responsible for the lithification of sediments? (A) cementation and compaction (B) faulting and folding (C) photosynthesis and respiration (D) weathering and erosion

13. Your Turn . . . Take the time and complete the following questions . . . In the diagram below, rocktypes/materials are indicated by numbers and processes are indicated by letters. Indicate the rock types/materials and processes for the rock cycle diagram by completing the table below. A E 1. Magma 2. 5. B D Weathering & Erosion C 3. 4.

14. Solutions . . . In the diagram below, rocktypes/materials are indicated by numbers and processes are indicated by letters. Indicate the rock types/materials and processes for the rock cycle diagram by completing the table below. A Answer: E 1. Magma 2. 5. B D Weathering & Erosion C 3. 4.

15. Your Turn . . . Take the time and complete the following questions . . .(Solutions to follow) Question: In relation to the rock cycle, explain two processes responsible for the formation of sedimentary rocks.

16. Solutions . . . Question: In relation to the rock cycle, explain two processes responsible for the formation of sedimentary rocks. Lithification is the process that turns sediment into solid rock. This is done through compaction and cementation.Compaction occurs as the weight of the overlying material increases. Compaction forces the grains closer together, reducing pore space and eliminating some of the contained water.Cementation occurs when water moving through pore spaces in sediment may contain chemicals (silica/calcite) dissolved in solution. These chemicals may precipitate as new minerals in the pore spaces. This causes cementation, which will then start to stick the individual particles together.

17. Summary . . . Overview of Points covered: • 3 Rock Types: • Rock Cycle Includes: