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GEOLOGY 12 CHAPTER 7 WORKSHEET METAMORPHIC ROCKS Name __________________ Use the following terms to complete the fill-in-the-blank questions. Terms may be used more than once. 700-800 atoms banding contact denser diagenesis directed stress equal fault zone foliation heat high hornfels hydrothermal index minerals isograds layering limestone low melting metamorphic facies metasomatism migmatite non-foliated plutonic pressure regional schist slate 1. The two most important causes of metamorphism are _________________ and _________________. 2. The low end of metamorphic temperatures represent temperatures in which __________________ occurs. 3. The high end of metamorphic temperatures is limited by the _______________ temperature of rocks, above which the rocks are molten. 4. The typical range of metamorphic temperatures would be from 100-200°C to about _______________ °C, although dry mafic rocks could be heated to even higher temperatures without melting. 5. ___________________ activity can locally increase the temperatures caused by the normal geothermal gradient. 6. Confining pressure is ________________ in all directions surrounding a rock. 7. Pressure that is not uniform in all directions is called ____________________________. 8. Mountain building generally places ____________________________ on rocks, which can result in deformation of the rocks. 9. The role of hot fluids in metamorphism is described as ____________________ activity. 10. During metamorphism, _______________ can rearrange themselves more readily in the presence of fluids. 11. As temperatures are increased during metamorphism, minerals that are stable at ________________ temperatures react or break down to form new high-temperature minerals. 12. Increased confining pressures favor the formation of ________________ minerals, whose atoms are packed more closely together. 13. Increasing the directed stress on rocks during metamorphism usually produces some sort of textural or compositional ___________________ or ___________________. 14. Schistosity and gneissic texture are two examples of _____________________ in metamorphic rocks, the product of directed stress. 15. The introduction of ions in fluids during metamorphism is called ________________________. 16. A fine-grained metamorphic rock exhibiting slaty cleavage would be called a __________. 17. A foliated metamorphic rock in which mica minerals are aligned in parallel layers would be called a ____________________. 18. Rocks which consist of only one type of mineral are likely to be _____________________ when they are metamorphosed. 19. Marble is a metamorphosed ________________________. 20. ____________________ metamorphism is commonly associated with mountain building, on a large scale. 21. ____________________ metamorphism happens adjacent to plutons, and generally lacks directed stresses. 22. Fault-zone metamorphism is characterized by increased pressures, but ___________ temperatures. 23. A fault breccia is formed by ________________________ metamorphism. 24. Rocks of a particular _____________________ ____________ will contain one or more minerals typical of a particular restricted range of pressures and temperatures. 25. Contact metamorphic facies (and minerals) are the product of ____________ pressure and a wide range of temperatures. 26. The contact metamorphic facies likely to be found closest to a pluton would be the ______________________ facies. 27. If partial melting begins during metamorphism, the resulting "mixed rock" would be termed a ______________________. 28. Differences of metamorphic grade are recognized on the basis of the presence of certain _____________ _______________, each of which is stable over a restricted temperature/pressure range. 29. _____________________.is an example of an index mineral. Chapter 7 WS page 2 30. Lines of equal metamorphic grade are called _____________________. 31. Describe the following rocks in terms of composition, texture and/or formation: a) stretched pebble conglomerate b) anthracite coal c) graphite 32. List the three main factors that affect metamorphism. • • • 33. 34. Classify the following rocks as foliated (F) or non-foliated (NF): _____ phyllite _____ quartzite _____ anthracite _____ marble _____ gneiss _____ metaconglomerate _____ schist _____ slate Arrange the foliated rocks from the lowest degree to the highest degree of metamorphism. _______________ → _______________ → _______________ → _______________ Chapter 7 WS page 3