Igneous, Sedimentary, Metamorphic Rocks and The Rock Cycle

Transcription

1 Igneous, Sedimentary, Metamorphic Rocks and The Rock Cycle The earth is an ever-changing dynamic planet. As one investigates the various rock types making up the earth, it is clear that rocks vary in both textural and compositional characteristics. Earth processes continually produce new rock through volcanic activity, the breakdown, transportation, as well as deposition of pre-existing rock, and the subjection of pre-existing rock to varying pressures and temperatures caused by tectonic forces. These processes define the rock cycle. Wherever one goes on the earth s surface, the rock cycle can be observed in continual action. If the earth s internal processes had ceased to continue, the external processes, exacerbated by gravity, would have long ago leveled the continents, and the resulting sediments would have been deposited on the sea floor. In other words, the dynamics of earth would be at rest or in a state of equilibrium. Yet, this is not the case. The rock cycle clearly demonstrates that internal and external forces on the earth are alive and well, constantly battling each other. The result is a state of non-equilibrium which results in an ever-changing earth surface. Lab Objectives: Determine the meaning of the rock cycle and what conditions are necessary to form igneous, sedimentary, and metamorphic rocks. Identify the names of common rock forming processes and how textural/compositional characteristics are associated with the various geologic processes Determine that the rock cycle is an open system that interacts with various other open systems within the geosphere and how the rock cycle contributes to positive and negative feedback mechanisms Infer how specific hand samples representing all three rock groups have formed in relation to the rock cycle Rock Review: In your own words, briefly explain how each rock group forms. Igneous rocks: Sedimentary rocks: Metamorphic rocks:

2 Part A Learning the Rock Cycle Below is a diagram depicting the rock cycle. Complete the following: Use the terms provided at the bottom of the page and fill in the various blanks to make the rock cycle complete. On a separate piece of paper, define each term as it relates to the rock cycle. Describe the geologic environment that results in igneous, sedimentary, and metamorphic rock types. Choose three different colors (use colored pencils), and shade in the regions that represent igneous, sedimentary, and metamorphic rock environments on the rock cycle below. weathering sediment consolidation magma metamorphic rocks transportation igneous rocks (extrusive) melting deposition sedimentary rocks igneous rocks (intrusive) lithification crystallization metamorphism sedimentary rock cycle

3 Part B- The Rock Cycle in Action The diagram below demonstrates an ocean to continent plate convergent boundary where the oceanic plate (A) is subducting beneath the continental plate (B). Complete the table below using the rock specimens in the rock ID box, and describe each geologic environment associated with the rock cycle in Part A A 1 2 B Circle number Geologic Environment Rock Texture Rock s Chemical Composition Rock Name

4 Part C The Rock Cycle Critical Thinking Questions 1. Why is the rock cycle considered an open system? 2. Describe other earth open systems that are related to processes within the rock cycle. 3. Where would you identify positive and negative feedback mechanisms within the rock cycle? Does the rock cycle ever achieve equilibrium or maintain balance? Why or why not? 4. Do you consider the rock cycle important to the existence of the human species? Why or why not? 5. Describe three observations you have had regarding some aspect of the rock cycle. 6. Without looking at a picture of the rock cycle, draw your own rock cycle, and include at least two rock types for each rock group.

5 Part D Rock Cycle Crossword Puzzle Across 5. compaction and cementation 6. molten rock 10. volcanic rock 12. loose, unconsolidated particles 13. evaporated or precipitated sedimentary rock 14. plutonic rock 15. light-colored igneous composition 17. a foliated metamorphic rock consisting of alternating bands of dark and light minerals 18. your instructor's name 20. the laying down of sediment 21. sedimentary rock composed of inorganic particles 23. factors that promote change in a process Down 1. rocks produced by weathering processes 2. geologic processes that form new rock, modify rock, transport rock, and break rock down 3. phaneritic rock high in SiO2 4. rocks formed as the result of pressure and temperature 5. a sedimentary rock consisting of calcite 7. the wearing away and transport of loosened particles 8. factors that resist change within a process 9. the physical and chemical breakdown of rock 11. aphanitic rock high in Fe and Mg 16. dark-colored igneous composition 19. sedimentary rock composed of organic material 22. rocks produced by solidifying magma